Forest regions of Montana - USDA Forest Service

29 downloads 4526 Views 2MB Size Report
(8) Northeastern Montana is a Great Plains area having no forest, except for ..... The average elevation of alpine tree line is about 8,800 feet. Principal forest .... associated with prominent mountain ranges and the Missouri River Breaks. Forest ...

FOREST REGIONS OF MONTANA STEPHEN F. ARNO This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain.

USDA Forest Service Research Paper INT-218 INTERMOUNTAIN FOREST AND RANGE EXPERIMENT STATION Forest Service U.S. Department of Agriculture Ogden, Utah 84401

USDA Forest Service Research Paper INT-218 April 1979

FOREST REGIONS OF MONTANA STEPHEN F. ARNO

INTERMOUNTAIN FOREST AND RANGE EXPERIMENT STATION Forest Service U. S. Department of Agriculture Ogden, Utah 84401

THE AUTHOR STEPHEN F. ARNO i s a Plant Ecologist on the F o r e s t Ecosystems r e s e a r c h work unit at Missoula. He earned a B. S. in f o r e s t r y at Washington State University and a m a s t e r ' s d e g r e e and a Ph. D. in f o r e s t r y and plant science at the University of Montana before joining the F o r e s t Service in 1970.

ACKNOWLEDGMENTS Robert Pfister (USDA F o r e s t Service Project Leader) gave encouragement and advice throughout this study. The following fore s t e r s f r o m USDA F o r e s t Service, Northern Region, shared t h e i r information on the distributions of indicator plants: Robert Bigler, H e r b e r t Holdorf (Soil Scientist), John Joy, Bernard Kovalchik, Tom Lawrence, Gary Learn, B. John Losensky, and J a m e s Schaeffer. Similar information w a s provided by Joseph Antos, J a m e s Habeck, and Pete Zager f r o m the Botany Department of the University of Montana and by Tad Weaver, John Rumley, and Frank Forcella f r o m Montana State University. In addition, I would like to thank the many people who provided review comments during the development of t h i s manuscript.

Page INTRODUCTION

..........................

.......... FOREST REGION DESCRIPTIONS . . . . . . . . . . . . . . . . Northwestern Montana F o r e s t Region . . . . . . . . . . . . West- Central Montana F o r e s t Region . . . . . . . . . . . . North- Central Montana F o r e s t Region . . . . . . . . . . . Central Montana F o r e s t Region . . . . . . . . . . . . . . . Southwestern Montana F o r e s t Region . . . . . . . . . . . . South- Central Montana F o r e s t Region . . . . . . . . . . . . Southeastern Montana F o r e s t Region . . . . . . . . . . . . Northeastern Montana F o r e s t Region . . . . . . . . . . . . RESEARCH AND MANAGEMENT APPLICATIONS . . . . . . . PUBLICATIONS CITED . . . . . . . . . . . . . . . . . . . . . . DELINEATING MONTANA FOREST REGIONS

APPENDIX A.

DISTRIBUTION OF KEY TREE AND UNDERGROWTH SPECIES IN MONTANA

APPENDIX B.

NUMBER OF SAMPLE PLOTS (PFISTER AND OTHERS 1977) BY HABITAT TYPE. PHASE. AND FOREST REGION IN MONTANA

....

......

APPENDIX C.

NATIONAL FORESTS. INDIAN RESERVATIONS. AND NATIONAL PARKS WITHIN EACH FOREST REGION IN MONTANA

..............

The author categorizes forest vegetation across Montana into eight geographic subdivisions called "forest regions. " The regions correlate the influence of climate and general topography to forest vegetation--including the distributions of tree and undergrowth species and forest habitat types. The vertical zonation of forest s e r i e s (based on the potential climax tree species) also differs from one region to the next. Regional boundaries were fitted to distributions of certain t r e e and undergrowth species, habitat types, and natural climatic b a r r i e r s such a s the Continential Divide and broad grassland valleys that separate forest environments. (1)The northwestern Montana forest region has major representation by Pacific Coast species such a s Thujaplicata and Clintoniauniflora; its climate is strongly influenced by moist maritime airmasses. (2) The west-central region has a generally drier Pacific-influenced climate and only small amounts of Pacific Coast species; however, i t has major representation of intermountain plants like Larix occidentalis and Xerophyllum tenax. (3) North-central Montana lies in the severe climate of the "chinook wind belt" along the east slope of the Continental Divide. It is distinguished by being too cold for Pinus ponderosa, but having extensive Populus tremuloides groves and Pinus flexilis woodlands. (4) The central Montana forest region has a l e s s severe continental climate and it supports the east-side forin of Pinus ponderosa at lower elevations. However, both coastal and intermountain species a r e essentially absent from its mountain forests.

-

Both the ( 5 ) southwestern and (6) south-central forest regions have high base elevations and a r e without Pinus ponderosa. The former region's forests a r e generally d r i e r than the latter's and often have sparse undergrowth. (7) Southeastern Montana differs from previously mentioned regions in not having prominent mountains. It has extensive Great Plains Pinus ponderosa forests. (8) Northeastern Montana i s a Great Plains area having no forest, except for Populus deltoides groves along major streams. The regions may be usefulas a biologically based stratification for forest research and forest management studies.

INTRODUCTION T h i s r e p o r t d e s c r i b e s 'Montana's f o r e s t s by geographic s u b d i v i s i o n s c a l l e d " f o r e s t r e g i o n s . I ' I t emphasizes p a t t e r n s i n s p e c i e s composition ( t r e e s and undergrowth) and t h e r e l a t i o n s h i p o f t h e s e p a t t e r n s t o c l i m a t e and topography. The i n t e r p r e t a t i o n s a r e based on f i e l d e x p e r i e n c e and d a t a c o l l e c t e d d u r i n g a r e c e n t f o r e s t h a b i t a t t y p e c l a s s i f i c a t i o n ( P f i s t e r and o t h e r s 1977). There a r e two primary r e a s o n s f o r d e l i n e a t i n g t h e f o r e s t r e g i o n s of Montana. F i r s t , t h e r e g i o n s s e r v e a s a geographic r e f e r e n c e f o r d e s c r i b i n g p a t t e r n s of f o r e s t v e g e t a t i o n a c r o s s t h e S t a t e . Second, d e l i n e a t i n g t h e r e g i o n s c o n t r i b u t e s t o r e g i o n a l c l a s s i f i c a t i o n s t h a t a r e b e i n g developed from a n a t i o n a l p e r s p e c t i v e ( B a i l e y 1976, 1978). The geographic s u b d i v i s i o n s d i s c u s s e d i n t h i s paper a r e based on t h e d i s t r i b u t i o n of f o r e s t v e g e t a t i o n i n r e l a t i o n t o c l i m a t e ( a s i n f l u e n c e d by topography). Thus, t h e s e s u b d i v i s i o n s a r e proposed f o r u s e o n l y f o r i n t e r p r e t a t i o n s r e l a t e d t o f o r e s t v e g e t a t i o n . A f t e r reviewing d e f i n i t i o n s provided i n Kuchler (1973) and B a i l e y (1976), t h e term " f o r e s t region" seemed most a p p r o p r i a t e f o r u s e h e r e . "Region" i s a g e n e r a l term t h a t does n o t n e c e s s a r i l y s p e c i f y a l e v e l i n t h e land c l a s s i f i c a t i o n h i e r a r c h y , and t h e term " f o r e s t region" h a s been a p p l i e d i n Canada (Rowe 1 9 7 2 ) . ("Province" was a l s o c o n s i d e r e d , b u t i t h a s a more p r e c i s e h i e r a r c h i c a l d e f i n i t i o n r e l a t e d t o t h e dominant v e g e t a t i v e t y p e s i n an a r e a , o r t o physiography; t h u s , some o f Montana's f o r e s t r e g i o n s o c c u r within grassland provinces. j Other r e g i o n a l d i v i s i o n s o f Montana have been developed from d i f f e r e n t t y p e s of i n f o r m a t i o n t o meet d i f f e r e n t o b j e c t i v e s . Schmidt and Dufour (1975) emphasized geomorphology i n d e s i g n a t i n g s i x r e g i o n s w i t h i n Montana. Those r e g i o n s were used i n a s s e s s i n g r e s e a r c h n a t u r a l a r e a needs from t h e f o l l o w i n g v i e w p o i n t s : f o r e s t v e g e t a t i o n , g r a s s and shrubland v e g e t a t i o n , geology, zoology, and a q u a t i c s . Crowley (1972) d e p i c t e d seven major environmental r e g i o n s w i t h i n Montana based on c h a r a c t e r i s t i c s of human e n v i r o n ments, i n c l u d i n g landforms, c l i m a t e , and e l e v a t i o n a l z o n a t i o n s o f v e g e t a t i o n . S t i l l o t h e r s (Kuchler 1964; Payne 1973; Ross and Hunter 1976) have provided maps o f Montana's n a t u r a l v e g e t a t i v e t y p e s ; but t h e maps a r e n o t focused on r e g i o n a l v a r i a t i o n i n f o r e s t v e g e t a t i o n . In c o n t r a s t t o t h e s e r e f e r e n c e s , t h e Montana " f o r e s t r e g i o n s " proposed h e r e d e l i n e a t e r a t h e r broad a r e a s having s i m i l a r z o n a t i o n i n f o r e s t v e g e t a t i o n . These f o r e s t r e g i o n s have g e n e r a l s i m i l a r i t i e s t o t h e f o r e s t d i s t r i c t s d e s i g n a t e d by t h e e a r l y Montana b o t a n i s t , Kirkwood (1922), f o r d e s c r i b i n g f o r e s t d i s t r i b u t i o n i n t h e Northern Rocky Mountains. During t h e Montana f o r e s t h a b i t a t t y p e s t u d y ( P f i s t e r and o t h e r s 1 9 7 7 ) , 1,500 s t a n d s were sampled " s u b j e c t i v e l y without b i a s t ' (Mueller-Dombois and Ellenburg 1 9 7 4 ) . The s t a n d s r e p r e s e n t a spectrum o f mature f o r e s t communities and s i t e s i n each mountain r a n g e and f o r e s t e d a r e a of t h e S t a t e . A s t h e h a b i t a t t y p e c l a s s i f i c a t i o n was being developed from t h e s e d a t a , i t became obvious t h a t d i s t r i b u t i o n s o f many t r e e and undergrowth s p e c i e s (and t h u s t h e d i s t r i b u t i o n s o f t h e h a b i t a t t y p e s ) a r e s t r o n g l y c o r r e l a t e d

t o p a t t e r n s of geography and c l i m a t e w i t h i n Montana. I t became e v i d e n t t h a t t h e S t a t e could be subdivided i n t o s e v e r a l r e l a t i v e l y homogeneous f o r e s t r e g i o n s based on t h e d a t a , f i e l d o b s e r v a t i o n s , and i n f o r m a t i o n on p l a n t s p e c i e s d i s t r i b u t i o n s (Herbarium c o l l e c t i o n s a t t h e U n i v e r s i t y o f Montana, Missoula; Montana S t a t e U n i v e r s i t y , Bozeman; t h e USDA F o r e s t S e r v i c e F o r e s t r y S c i e n c e s L a b o r a t o r y , Missoula; p e r s o n a l i n t e r v i e w s with l o c a l f o r e s t e r s and b o t a n i s t s ( s e e acknowledgments) ; Booth and Wright 1966, Hitchcock and o t h e r s 1955-1969, L i t t l e 1971, 1 9 7 6 ) . A map o f f o r e s t r e g i o n s ( c a l l e d " geographic s ~ b d i v i s i o n s ~was ~ ) p r e s e n t e d by P f i s t e r and o t h e r s (1977), and a b r i e f account o f each h a b i t a t t y p e ' s d i s t r i b u t i o n was g i v e n by r e g i o n . However, t h e b a s i s f o r t h e s e r e g i o n s was n o t d i s c u s s e d ; a l s o , Montana's f o r e s t v e g e t a t i o n and environments were n o t d e s c r i b e d by r e g i o n . These t o p i c s a r e a d d r e s s e d here.

The Canadian F o r e s t S e r v i c e (Rowe 1959, 1972) mapped and d e s c r i b e d " F o r e s t Regions o f Canada," which p r o v i d e s a p r e c e d e n t . Rowe (1972) e x p l a i n e d t h a t t h e Canad i a n r e g i o n a l d e s i g n a t i o n s a r e g e n e r a l i z e d , w i t h t h e broad p e r s p e c t i v e o f Canada a s a whole, a l t h o u g h t h e s t a t e m e n t was made t h a t it would be p o s s i b l e t o d e s i g n a t e such r e g i o n s from a d e t a i l e d knowledge o f s p e c i f i c a r e a s i f d e t a i l e d d a t a e x i s t e d . The l a t t e r approach i s used h e r e with d e t a i l e d d a t a from t h e h a b i t a t t y p e s t u d y ( P f i s t e r and o t h e r s 1977) a s a b a s i s . Kuchler (1973) d i s c u s s e d t e c h n i q u e s f o r d e s i g n a t i n g e c o l o g i c a l l y based " r e g i o n s . " He s t a t e d t h a t c l a s s i f i c a t i o n s o f n a t u r a l v e g e t a t i o n t y p e s and d e t a i l e d mapping o f t h e i r d i s t r i b u t i o n s a r e fundamental f o r e s t a b l i s h i n g such r e g i o n s . ( I t appears t h a t t h e Montana f o r e s t h a b i t a t t y p e c l a s s i f i c a t i o n a l o n g w i t h t h e sample p l o t s and o t h e r d i s t r i b u t i o n a l d a t a can p r o v i d e t h i s b a s i c i n f o r m a t i o n . ) Kuchler ( 1 9 7 3 ) ~a l s o concluded t h a t v e g e t a t i o n r e g i o n s should f i r s t be d e s i g n a t e d w i t h i n a l i m i t e d s t u d y a r e a , such a s a S t a t e o r g e o g r a p h i c r e g i o n , and l a t e r expanded t o surrounding a r e a s .

Montana's f o r e s t s a r e b o t h e x t e n s i v e and d i v e r s e . F o r e s t c o v e r s n e a r l y o n e - f o u r t h of Montana--about 2 3 m i l l i o n a c r e s a c c o r d i n g t o Green and S e t z e r (1974)--and s u b s t a n t i a l amounts o f f o r e s t a r e found i n a l l but t h e n o r t h e a s t e r n p o r t i o n s o f t h e S t a t e ( f i g . 1 ) . A t lower e l e v a t i o n s t h e s e f o r e s t s range from l u x u r i a n t s t a n d s of Tsuga heterophylla, Thuja plicata, Pinus monticola, and o t h e r P a c i f i c Coast s p e c i e s i n n o r t h w e s t e r n Montana t o open Pinus ponderosa woodlands on t h e Great P l a i n s of s o u t h e a s t e r n Montana. The h i g h - e l e v a t i o n f o r e s t s a c r o s s t h e Montana Rockies a l s o show s u b s t a n t i a l v a r i a t i o n . D i f f e r e n c e s i n c l i m a t e a r e p r i m a r i l y r e s p o n s i b l e f o r geographic v a r i a t i o n s i n t h e p o t e n t i a l climax f o r e s t v e g e t a t i o n , expressed i n h a b i t a t t y p e s ( P f i s t e r and o t h e r s 1977). The c l i m a t i c d i f f e r e n c e s a c r o s s Montana r e f l e c t t h e g r e a t e r importance o f P a c i f i c maritime a i r m a s s e s west o f t h e C o n t i n e n t a l Divide v e r s u s c o n t i n e n t a l c l i m a t i c c o n d i t i o n s e a s t of t h e Divide. Locally, c l i m a t e (and t h u s f o r e s t v e g e t a t i o n ) a l s o i s s t r o n g l y i n f l u e n c e d by changes i n e l e v a t i o n , a s p e c t , and landform w i t h i n t h e Montana Rockies. S o i l s and u n d e r l y i n g geology a l s o a f f e c t f o r e s t v e g e t a t i o n , b u t except f o r c e r t a i n limes t o n e s u b s t r a t e s and extremely rocky s i t e s , t h e e f f e c t s do n o t g e n e r a l l y obscure t h e o v e r r i d i n g i n f l u e n c e o f c l i m a t e and topography. The f o r e s t r e g i o n s o u t l i n e d on f i g u r e 1 c o r r e l a t e t h e i n f l u e n c e of c l i m a t e and g e n e r a l topography t o f o r e s t v e g e t a t i o n - - i n c l u d i n g t h e d i s t r i b u t i o n s o f t r e e and undergrowth s p e c i e s and f o r e s t h a b i t a t t y p e s and t h e v e r t i c a l zonation of f o r e s t s e r i e s ( d i s c u s s e d l a t e r ) . Because t r e e s p e c i e s s e r v e a s i n d i c a t o r s o f c l i m a t e (Daubenmire and Daubenmire 1968; P f i s t e r and o t h e r s 1977), t h e i r geographic d i s t r i b u t i o n s s e r v e a s a primary d e t e r m i n a n t o f r e g i o n a l boundaries. (Appendixes A-1 through A-6 i l l u s t r a t e how t h e d i s t r i b u t i o n s o f t r e e s p e c i e s c o r r e l a t e w i t h Montana's f o r e s t r e g i o n s . ) D i s t r i b u t i o n s of undergrowth s p e c i e s t h a t have proved u s e f u l a s i n d i c a t o r p l a n t s i n major f o r e s t h a b i t a t t y p e c l a s s i f i c a t i o n s i n t h e Northern Rockies ( R . and J . Daubenmire 1968; P f i s t e r and o t h e r s 1977; and Robert S t e e l e and o t h e r s 1 ) , a l s o were used ( f o r examples, s e e appendixes A-7 through A-10) . I t became obvious t h a t many o f t h e t r e e , undergrowth p l a n t , and h a b i t a t t y p e d i s t r i b u t i o n s showed s i m i l a r p a t t e r n s , and r e l a t e t o known c l i m a t i c d i f f e r e n c e s (U.S. Department o f Commerce 1971; USDA S o i l Conservation S e r v i c e 1968). P r e l i m i n a r y r e g i o n a l boundaries were drawn t o f i t t h e s e v e g e t a t i o n a l d a t a . The boundaries t h e n were a d j u s t e d s l i g h t l y t o c o r r e l a t e w i t h n a t u r a l c l i m a t i c b a r r i e r s such a s t h e C o n t i n e n t a l Divide and broad g r a s s l a n d v a l l e y s t h a t s e p a r a t e f o r e s t environments. Although t h e s e r e g i o n a l boundaries were f i t t e d t o v e g e t a t i o n d a t a and t o t o p o g r a p h i c b a r r i e r s a s l o g 2 c a l l y a s p o s s i b l e , sometimes t h e g e n e r a l p a t t e r n s of f o r e s t v e g e t a t i o n change g r a d u a l l y over r a t h e r broad a r e a s . I n t h e s e c a s e s , where p o s s i b l e , major t o p o g r a p h i c f e a t u r e s were used f o r f i n a l placement o f boundaries. Dashed l i n e s were used t o d e s i g n a t e r e g i o n a l boundaries i n nonforested a r e a s . The o c c u r r e n c e of t h e approximately 1,500 sample p l o t s by h a b i t a t t y p e and f o r e s t r e g i o n i s summarized i n appendix B . P l a n t composition a t t h e s e f o r e s t s i t e s p r o v i d e s b a s i c d a t a f o r r e g i o n a l b o u n d a r i e s . A t a broad l e v e l o f g e n e r a l i z a t i o n from t h i s d a t a

' ~ e v i e w d r a f t s of " F o r e s t h a b i t a t t y p e s of c e n t r a l Idaho" (1975) and t h o s e of t h e Nezperce N a t i o n a l F o r e s t (1976). I n t e r m t . For. and Range Exp. S t n . , Ogden, IJtah.

FORESTED

-

WEATHERSTATIONS

1

Figure 1.--Montana f o r e s t regions and forested areas (from Hutchinson and Kemp 1952, Ross and Hunter 1976, composite s a t e l l i t e photo o f Montana, GE Space Systems, B e l t s v i l l e , Md. J, Circled nwnbers are weather s t a t i o n s l i s t e d i n table 4.

I a

[7 NONFOREST

T a b l e 1.--Extent (area covered) o f forest series (potential climax) i n each o f Montana's f o r e s t regions A!

=

major

m = minor

r

=

rare

. = absent :

Series Tsuga and Thuja Abies g r a n d i s Picea Pinus c o n t o r t a P i n u s ponderosa Pinus f l e x i l i s Pseudotsuga Abies l a s i o c a r p a

:

North- : western :

West: central :

North- : central :

Forest region : South- : Central : western :

Soirthcentral

:

:

Southeastern

:

:

Northeastern

M

M

m r m

il M

t h e e x t e n t ( a r e a covered) of each climax s e r i e s can be c o m p a r e d- - i d e n t i f i e d by t h e most s h a d e - t o l e r a n t ( p o t e n t i a l climax) t r e e s p e c i e s c a p a b l e o f growing on a given s i t e . Table 1 shows which s e r i e s o c c u r i n each o f t h e f o r e s t r e g i o n s . For i n s t a n c e , t h e P a c i f i c Northwest c o a s t a l f o r e s t t y p e s (Thuja, Tsuga, and Abies grandis s e r i e s ) a r e o f major importance o n l y i n n o r t h w e s t e r n Montana. Low-elevation f o r e s t t y p e s (Pinus ponderosa climax s e r i e s ) a s s o c i a t e d w i t h d r y , i n l a n d c l i m a t e s a r e abundant o n l y i n c e n t r a l and s o u t h e a s t e r n Montana, and a r e a b s e n t o r r a r e i n t h e n o r t h - c e n t r a l , s o u t h w e s t e r n , and s o u t h - c e n t r a l f o r e s t r e g i o n s . D e t a i l e d i n t e r p r e t a t i o n s (from appendix B d a t a ) a r e p r e s e n t e d i n t a b l e 2, which shows t h e major h a b i t a t t y p e s i n each o f Montana's f o r e s t r e g i o n s . A d d i t i o n a l i n t e r p r e t a t i o n s and a d j u s t m e n t s were made i n developing t a b l e 2 from t h e sample p l o t d a t a (appendix B). C e r t a i n s u b s t r a t e - o r i e n t e d h a b i t a t t y p e s (such a s PicealSenecio strept a n t h i f o z i u s and Abies Zasiocarpa/CZematis pseudoaZpina h . t . on l i m e s t o n e s u b s t r a t e s ) were h e a v i l y sampled by P f i s t e r and o t h e r s (1977), and a r e n o t a s e x t e n s i v e a s appendix B i m p l i e s . Also, c e r t a i n a r e a s n e a r t h e b o r d e r of a f o r e s t r e g i o n were h e a v i l y sampled; t h e r e b y more p l o t s were c o l l e c t e d from c e r t a i n h a b i t a t t y p e s t h a n a r e i n d i c a t i v e o f t h e r e g i o n i n g e n e r a l . For i n s t a n c e , s e v e r a l Abies Zasiocarpa/CZintonia and Abies Zasiocarpa/XerophyZZwn h . t . p l o t s were t a k e n i n unusual l o c a t i o n s immediately e a s t o f t h e C o n t i n e n t a l Divide i n n o r t h - c e n t r a l Montana. The d i s t r i b u t i o n o f v a r i o u s t r e e s p e c i e s and undergrowth p l a n t s s e r v i n g a s h a b i t a t t y p e o r c l i m a t i c i n d i c a t o r s i s p r e s e n t e d i n t a b l e 3 by f o r e s t r e g i o n a c r o s s Montana. This t a b l e i s based on t h e 1,500 h a b i t a t t y p e p l o t s , and t h e f i e l d o b s e r v a t i o n s and p u b l i s h e d i n f o r m a t i o n on p l a n t d i s t r i b u t i o n s c i t e d p r e v i o u s l y . The d i s t r i b u t i o n s of P a c i f i c Coast and i n t e r m o u n t a i n s p e c i e s a r e u s e f u l f o r d i f f e r e n t i a t i n g f o r e s t s o f n o r t h e r n Idaho, n o r t h w e s t e r n Montana, and w e s t - c e n t r a l Montana, but t h e o t h e r f o r e s t r e g i o n s a r e c h a r a c t e r i z e d l a r g e l y by a l a c k of t h e s e s p e c i e s . (" Intermountain s p e c i e s " a p p l i e s t o p l a n t s found most o f t e n between t h e c r e s t of t h e Cascade Mountains and t h e C o n t i n e n t a l Divide.) C e r t a i n widespread s p e c i e s ( l i k e Vacciniwn scopariwn, Juniperus conormnis, Arnica cordifo l i a , Aster conspicuus, and even Pyro Za secunda) g e n e r a l 1y a r e accompanied by P a c i f i c Coast o r i n t e r m o u n t a i n s p e c i e s west o f t h e C o n t i n e n t a l Divide; f a r t h e r e a s t t h e c o a s t a l and i n t e r m o u n t a i n c o m p e t i t o r s d r o p o u t . T h i s s i t u a t i o n i s documented by t h e changes i n h a b i t a t t y p e s d e p i c t e d i n t a b l e 2. For i n s t a n c e , Pseudotsuga/Junipems c o r n i s , Pseudotsuga/l?rnica cordifozia, and Abies Zasiocarpa/Amica cordifoZia appear o n l y e a s t of t h e Divide. F i g u r e 2 shows a summary o f t h e c h a r a c t e r i s t i c s of each f o r e s t r e g i o n . The r e l a t i o n s h i p o f f o r e s t r e g i o n and N a t i o n a l F o r e s t b o u n d a r i e s i s shown i n appendix C.

Table 2.--Major habitat types ( P f i s t e r and others 1977) i n each o f J4mtana's f o r e s t regions (See appendix B for more detailed information on a l l habitat t y p e s ) Habitat type

Forest region

Pinus flexilis/Festuca idahoensis P. ponderosa/Agropyron spicatum P. ponderosa/Festuca idahoensis P. ponderosa/Symphoricarpos albus P. ponderosa/Prunus virginiana Pseudotsuga/Festuca idahoensis Pseudotsuga/Festuca scabrella Pseudotsuga/Vaccinium caespitosum Pseudotsuga/Physocarpus malvaceus Pseudotsuga/Vaccinium globulare Pseudotsuga/Linnaea borealis

x

Pseudotsuga/Syn~phoricarpos albus Pseudotsuga/Calamagrostis, Cal. phase

x

Pseudotsuga/Cal., other phases

x

x

Pseudotsuga/Spiraea betulifolia Pseudotsuga/Arctostaphylos uva-ursi Pseudotsuga/Juniperus communis Pseudotsuga/Arnica cordifolia Picea/Clintonia uniflora Picea/Physocarpus malvaceus Picea/Galium triflorum Picea/Linnaea borealis All Abies grandis h.t.s Thuja plicata/Clintonia uniflora Tsuga heterophylla/Clintonia uniflora Abies Abies Abies Abies

lasiocarpa/Clintonia uniflora lasiocarpa/Galium triflorum lasiocarpa/Calamagrostis canadensis lasiocarpa/Linnaea borealis

Abies lasiocarpa/Menziesia ferruginea All Tsuga mertensiana h.t.s Abies lasiocarpa/Xerophyllum tenax Abies Abies Abies Abies

lasiocarpa/Vaccinium globulare lasiocarpa/Vaccinium scoparium lasiocarpa/Arnica cordifolia 1as.-Pinus albic./Vaccinium scop.

Abies Pinus Larix Pinus

lasiocarpa/Luzula hitchcockii albicaulis-Abies lasiocarpa lyallii-Abies lasiocarpa contorta community types

x

x x

x

. x

x x x

Table 3.--Distribution of selected t r e e s and undergrowth indicator plants by forest region across Montana. ?iorthern Idaho data from Daubewnire and Daubenmire (19 6 8 ) x = common r = rare or scarce = absent

.

Forest region Species

: :

Northern : Idaho : NW

:

WC

:

NC

:

C

:

SW

:

SC

:

SE

Coastal species Adiantum pedatum Asarum caudatum Tsuga heterophylla Tsuga mertsnsiana

x x

x

x

x

x

x

x

x

x

x x x

x

x

x

x

x

x

x

x

x x

Thuja plicata Pinus monticola Taxus brevifolia Abies grandis Clintonia uniflora Intermountain species Larix occidentalis Larix lyallii Pinus ponderosa var . -ponderosal Xerophyllum tenax Menziesia ferruginea Luzula hitchcockii

x

x

x x x

r r r

r r r

r r r

x

x

x

x

x

x

Widespread species Widespread Rocky Mt. trees2 Calamagrostis rubescens Carex geyeri

x x

x x

x x

x

x

x

x

x

x

x

Physocarpus malvaceus

x

x

x

r

x

r

x

r

x r r x

x

x x

x

x x

x x

Eastside species Pinus flexilis Senecio streptanthefolius Frasera speciosa Geranium richardsonii

.

x

x x

x

Pinus ponderosa var . scopulorum3 Juniperus horizontalis Fraxinus pennsylvanica

x

x

x

x

r

x

x

x r

(Little 19531, having three-needle fascicles only. Pseudotsuga, Abies lasiocarpa, Picea, Pinus contorta, and Pinus albicaulis. (Booth 1950 and Little 19531, having many two-needle fascicles. 7

a

var. ponderosa

70-110 b

80 Intermtn. Species

90

Pacificcoast Species aspen grovelands

rl

10

60-80

90-130

50

50-100

Continental

cold d r y forests

cold moist forests

@ @ 25

40-70

Eastside Species E. slope P. ponderosa

20

var. scopulorum

0

Mountainous

*-

@ @

4

-

70-110 days

Modified Maritime

TRACE

Non forested

P. ponderosa

nonforest

Great P l a i n s and Eastern Species

20

I

00

var. scopulorum

+-i

100-130

Great P l a i n s

P

Figure 2. --Sumnary of the major characteristics of Montana's forest regions. (Average frost- free season, for s i t e s with good a i r circuZation, as interpreted from Caprio 1 9 6 5 . )

DIAGNOSTIC FOREST VEGETATION

PERCENT OF LAND FORESTED

LOWER ELEVATIONS SUPPORT P i n u s ponderosa

FOREST TOPOGRAPHY Average frost- free season in lower elevation forests

DOMINANT CLIMATE

MONTANA FOREST REGION

Northwestern Montana ForestRegion

The n o r t h w e s t e r n f o r e s t r e g i o n o f Montana i n c l u d e s t h e Kootenai, F l a t h e a d , and lower C l a r k Fork River ( a s f a r upstream a s F i s h Creek and Ninemile Valley) d r a i n a g e s . T h i s r e g i o n i s bounded on t h e e a s t by t h e C o n t i n e n t a l Divide, on t h e n o r t h by B r i t i s h Columbia, and on t h e west and southwest by Idaho and t h e c r e s t o f t h e B i t t e r r o o t Mount a i n s . The s o u t h e a s t e r n b o r d e r of t h e r e g i o n i s marked by t h e R a t t l e s n a k e Creek and Blackfoot R i v e r divTdes.

Diagnostic forest vegetation The northwest f o r e s t r e g i o n h a s an abundance ( i n a l l b u t t h e d r i e r v a l l e y s ) o f P a c i f i c Coast f o r e s t s p e c i e s t h a t a r e l e s s common o r a b s e n t elsewhere. Tree s p e c i e s l a r g e l y r e s t r i c t e d t o t h i s r e g i o n i n c l u d e Tsuga heterophylla, T. mertensianu, Thuja plicata, Abies grandis, Tams b r e v i f o l i a , and Pinus monticola. Undergrowth l a r g e l y r e s t r i c t e d t o t h i s r e g i o n i n c l u d e s Clintonia uniflora, Aralia nudicaulis, Gymocarpiwn dryopteris (and o t h e r P a c i f i c Coast f e m s ) , Dispomm hookeri, Tiarella t r i f o l i a t a , Viola glabella, and O p l o p a m horridwn (nomenclature i s from Hitchcock and Cronquist 1976).

Forest d i s t r i b u t i o n AS i s t h e c a s e i n o t h e r mountainous s e c t i o n s o f Montana, t h e rugged t e r r a i n c r e a t e s an a r r a y o f h a b i t a t s and accompanying v e g e t a t i o n , from s e m i a r i d g r a s s l a n d s i n t h e r a i n shadow o f l a r g e mountain masses t o moist mountain v a l l e y s , s u b a l p i n e f o r e s t s , and a l p i n e t u n d r a . The g e n e r a l i z e d d i s t r i b u t i o n o f f o r e s t t r e e s and climax s e r i e s f o r an a r e a i n t h e Kootenai River d r a i n a g e i s d e p i c t e d i n f i g u r e 3. Major f o r e s t h a b i t a t t y p e s f o r n o r t h w e s t e r n Montana a r e l i s t e d i n t a b l e 2 . About 90 p e r c e n t of t h e l a n d i n t h i s r e g i o n i s p o t e n t i a l l y f o r e s t e d (Hutchison and Kemp 1952; Green and S e t z e r 1974). Throughout much o f t h e r e g i o n , f o r e s t c o v e r s even t h e lowest e l e v a t i o n v a l l e y s ( a s low a s 1,800 f e e t ) ; i n t h e d r i e s t v a l l e y s southwest o f F l a t h e a d Lake, g r a s s l a n d p r e v a i l s below about 3,500 f e e t e l e v a t i o n . F o r e s t e x t e n d s over a l l but t h e h i g h e s t peaks (and r o c k i e s t s i t e s ) . The average e l e v a t i o n o f a l p i n e t r e e l i n e i s about 8,000 f e e t .

Figure 3.- - Distribution o f f o r e s t t r e e s i n a n area o f t h e Kootenai drainage i n northwestern Montana. Arrows show t h e r e l a t i v e e l e v a t i o n a l range o f each species; s o l i d p o r t i o n o f t h e arrow i n d i c a t e s where s p e c i e s i s p o t e n t i a l climax, dashed portion shows where it i s s e r a l . (Modified from P f i s t e r and o t h e r s 1977. ) Climatic i n f l u e n c e s Northwestern Montana i s s t r o n g l y i n f l u e n c e d by moist maritime a i r m a s s e s t h a t t y p i c a l l y f u n n e l through t h i s a r e a on t h e i r way i n l a n d from t h e P a c i f i c Coast (U.S. Department of Commerce 1971; Daubenmire 1969). The a i r m a s s e s p r o v i d e abundant r a i n and s n o w f a l l s and g e n e r a l l y humid, cloudy c o n d i t i o n s except i n midsummer. The a i r m a s s e s a l s o b r i n g t h e r e l a t i v e l y mild w i n t e r t e m p e r a t u r e s (even a t h i g h e l e v a t i o n s ) t h a t a r e n e c e s s a r y f o r t h e s u r v i v a l o f many of t h e c o a s t a l f o r e s t s p e c i e s . The m i l d e s t c o n d i t i o n s a r e g e n e r a l l y a s s o c i a t e d w i t h t h e Kootenai d r a i n a g e i n t h e western p a r t o f t h e r e g i o n . I n t h e Kootenai d r a i n a g e , f o r e s t s most n e a r l y resemble t h o s e of a d j a c e n t n o r t h e r n Idaho, r e p r e s e n t i n g a s t i l l m o i s t e r and m i l d e r c o a s t a l c l i mate. Pinus monticola i s abundant and i s g e n e r a l l y t h e t a l l e s t and f a s t e s t growing t r e e i n n o r t h e r n Idaho. However, eastward through n o r t h w e s t e r n Montana, Larix o c c i d e n t a l i s assumes t h i s r o l e ( a t t a i n i n g h e i g h t s of 150 t o 170 f e e t on f a v o r a b l e s i t e s ) . F a r t h e r e a s t , i n t h e upper F l a t h e a d V a l l e y , o u t b r e a k s of a r c t i c a i r o c c u r more f r e q u e n t l y i n t h e w i n t e r (1J.S. Department o f Commerce 1971). A s a r e s u l t , Tsuga h e t e r ophylla and Thuja s u s t a i n f r o s t damage and become r e s t r i c t e d t o s p e c i a l s i t e s . These s i t e s e i t h e r have a c l i m a t e t h a t i s moderated by t h e p r e s e n c e of a l a r g e l a k e (Flathead Lake and Lake McDonald) o r r e p r e s e n t s h e l t e r e d "cove" f o r e s t s i n r a v i n e s above t h e v a l l e y bottom f r o s t zones. S t i l l , even i n t h e upper F l a t h e a d Valley, t r e e and undergrowth f l o r a r e f l e c t a P a c i f i c i n f l u e n c e extending a l l t h e way t o t h e C o n t i n e n t a l Divide i t s e l f . Weather r e c o r d s f o r Libby and Trout Creek ( t a b l e 4 ) r e p r e s e n t t h e m i l d e r , western p a r t o f t h i s r e g i o n ; whereas t h e P o l e b r i d g e s t a t i o n l i e s i n t h e c o l d e r , upper Flathead

T a b l e 4.--Weather s t a t i o n records from Zower e z e v a t i o n forested s i t e s i n each o f E'ontana's forest regions. Locations o f t h e s e s t a t i o n s are shotm b y nwnber f a t Zeftl on figure I Region and station

: Fstimated : : Mean ma. temp. : Ave. l e n g t h o f : Mean annu. : Mean May: climax : : frost- free : precipi: August : series : Elev. : J a n . J u l y : s e a s o n - 32'F : tation : precip.

Feet

O F

O F

Days

Northwestern 1. Libby (1NE) 2. T r o u t Creek (2W) 3. Polebridge

PSME ABGR PICEA

2,080 2,480 3,690

22 23 17

66 64 61

West - c e n t r a l 1. Darbv . f2NNWl . , 2. Greenough

PIP0 PSME

3,815 4,000

25 18

65 63

--45

North-central 1. Babb (6NE) 2. B l a c k l e a f ( n e a r )

POTREM PIFL

4,300 4,600

19 21

60 60

=60

Inches

Inches

: ~ e a n : annual : s n o w f a L

Inches

79 50 30

99

60

Central 1. H e l e n a 2. Lewistown

n e a r PIP0 PIP0

3,893 4,130

19 20

68 66

134 107

11 17

5.7 9.6

48 61

Southwestern 1. Lakeview

PSME

6,710

10

59

== 30

20

8.4

142

South-central d r y e d g e o f PSME Y e l l o w s t o n e N.P. PICO-ABLA 2. M y s t i c Lake PICO-ABLA 3 . W. Y e l l o w s t o n e

6,266

15

58

-90

16

7.7

El00

6,558 6,662

24 12

64 60

-- 95 -- 30

24 21

10.4 7.0

140 145

Southeastern 1 . Lame Deer 2. Roundup

3,331 3.227

22 24

70 72

=lo5 129

15 11

8.2 6.5

=36

2,277

11

72

124

13

7.8

36

1. Tower F a l l s

Northeastern 1. Glasgow

PIP0 PIP0 no f o r e s t

51

V a l l e y . Average annual p r e c i p i t a t i o n i n most of t h e s u b a l p i n e f o r e s t s of t h i s r e g i o n r a n g e s from about 4 0 t o 65 i n c h e ~ . ~

West-Central Montana Forest Region

The w e s t - c e n t r a l f o r e s t r e g i o n i n c l u d e s t h e Clark Fork River d r a i n a g e from t h e Missoula-Frenchtown Val 1ey upstream, except f o r t h e C o n t i n e n t a l Divide range from Nevada Peak (northwest o f Helena) t o C a l i f o r n i a Pass ( s o u t h o f Anaconda). This r e g i o n i s bounded on t h e west by t h e l o f t y B i t t e r r o o t Range. The B i t t e r r o o t Range forms t h e Montana- Idaho Divide and c o n s t i t u t e s a s i g n i f i c a n t b a r r i e r t o P a c i f i c Coast m o i s t u r e and thus t o coastal plants.

' ~ h e s e e s t i m a t e s were based on U.S. Dep. Comm. (1971), U.S. Dep. Comrn. weather s t a t i o n d a t a , USDA S o i l Conserv. S e r v . (1968), Arno (1970), and an i s o h y e t a l a n a l y s i s f o r t h e Columbia River d r a i n a g e p r e p a r e d by t h e U.S. Weather Bureau R i v e r F o r e c a s t Cent e r , P o r t l a n d , Oregon, i n 1968. 11

Diagnostic f o r e s t vegetation Although i t h a s a r e l a t i v e l y m i l d , P a c i f i c - i n f l u e n c e d c l i m a t e , t h i s r e g i o n ' s f o r e s t s a r e g e n e r a l l y d r i e r t h a n t h o s e o f e i t h e r n o r t h w e s t e r n Montana o r a d j a c e n t n o r t h e r n Idaho. Thus, t h e r e g i o n h a s o n l y small amounts o f P a c i f i c Coast f o r e s t s p e c i e s such a s

Thuja p l i c a t a , Pinus monticola, T m s b r e v i f o l i a , Clintonia u n i f l o r a , Adenocaulon b i color, Coptis spp. (of western North America), and T i a r e l l a t r i f o l i a t a . These s p e c i e s a r e r e s t r i c t e d t o moist canyon-bottom s i t e s o r seepage a r e a s and g e n e r a l l y r e a c h t h e i r s o u t h e a s t e r n l i m i t s w i t h i n t h i s r e g i o n ( t a b l e 3 ) . Abies grandis i s l o c a l l y common, b u t i s much l e s s abundant t h a n it i s i n n o r t h w e s t e r n Montana. W e s t - c e n t r a l Montana i s c h a r a c t e r i z e d by an abundance o f t h e i n t e r m o u n t a i n f o r e s t s p e c i e s - - L a r i x o c c i d e n t a l i s , Larix l y a l l i i , Pinus ponderosa v a r ponderosa, Xerophyllwn tenax, Menziesia fermginea, and Luzula h i t c h c o c k i i . These s p e c i e s become r a r e o r a b s e n t i n t h e remaining r e g i o n s t h a t l i e farther east (table 3 ) .

.

Forest d i s t r i b u t i o n As f i g u r e 4 shows, t h e t y p i c a l a r r a y o f f o r e s t s e r i e s h e r e i s n o t a s d i v e r s e a s t h a t i n n o r t h w e s t e r n Montana, because o f t h e s c a r c i t y o f P a c i f i c Coast s p e c i e s . About

Figure 4.- - Distribution o f f o r e s t t r e e s i n an area o f west- central Montana. Arrows show t h e r e l a t i v e elevational range o f each species; s o l i d portion o f the arrow i n d i c a t e s where a species i s the potential climax and dashed portion shows where it i s seral. (Modified from P f i s t e r and o t h e r s 1 9 7 7 ) .

80 p e r c e n t o f t h e l a n d i n t h i s r e g i o n i s p o t e n t i a l l y f o r e s t e d . Most o f t h e n o n f o r e s t land i s g r a s s l a n d (Agropyron spieatwn, Festuea idahoensis, and F . scabrella a s s o c i a t i o n s o f Mueggler and Hand1 ( I n p r e s s ) ) t h a t o c c u r i n t h e b r o a d e r l o w - e l e v a t i o n v a l l e y s . Annual p r e c i p i t a t i o n on t h e s e n o n f o r e s t v a l l e y s i t e s i s l e s s t h a n 15 inches and s o i l s a r e w e l l - d r a i n e d . However, t h i s g r a s s l a n d i s n o t e x t e n s i v e , and lower t i m b e r l i n e g e n e r a l l y o c c u r s w i t h i n 1,000 f e e t o f t h e v a l l e y b a s e e l e v a t i o n ; t h u s i t i s found between a b o u t 3,200 and 5,500 f e e t . F o r e s t extends o v e r a l l b u t t h e h i g h e s t peaks (and r o c k i e s t s i t e s ) . The average e l e v a t i o n of a l p i n e t r e e l i n e i s about 8,800 f e e t . P r i n c i p a l f o r e s t h a b i t a t t y p e s o f w e s t - c e n t r a l Montana a r e shown i n t a b l e 2.

Climatic influences The comparatively d r y , P a c i f i c - i n f l u e n c e d c l i m a t e o f t h i s r e g i o n i s i l l u s t r a t e d by d a t a from t h e l o c a t i o n s o f Darby and Greenough ( t a b l e 4 ) . Average annual p r e c i p i t a t i o n i n t h e s u b a l p i n e f o r e s t s i s g e n e r a l l y 35 t o 55 i n c h e s ( f o o t n o t e 2 ) . S e r a 1 Pinus ponderosa and Larix occidentalis form t h e l a r g e s t and most commercially important w e s t - c e n t r a l Montana f o r e s t t r e e s ; t h e y o f t e n a t t a i n h e i g h t s of 130 t o 140 f e e t a t m a t u r i t y . The exception i s t h e s o u t h e a s t e r n p a r t of t h i s r e g i o n where v a l l e y b a s e e l e v a t i o n s a r e h i g h and f o r e s t s a r e doninated by Pinus contorts. (However, t h e intermountain undergrowth s p e c i e s dominate.)

North-Central Montana Forest Region

The n o r t h - c e n t r a l Montana f o r e s t r e g i o n i n c l u d e s a l l t h e f o r e s t e d t e r r a i n a l o n g t h e e a s t s l o p e of t h e C o n t i n e n t a l Divide from t h e d r a i n a g e of t h e North Fork o f t h e Dearborn River n o r t h t o t h e Canadian b o r d e r and e a s t t o Havre. Adjacent s o u t h e r n A l b e r t a h a s s i m i l a r f o r e s t environments.

Diagnostic forest vegetation T h i s a r e a s u p p o r t s t h e most e x t e n s i v e Populus tremuloides groves i n t h e S t a t e (Lynch 1955) a s well a s l a r g e p a t c h e s o f Pinus flercilis woodland a l o n g t h e lower s k i r t s o f t h e mountains. Pinus ponderosa i s a b s e n t , a p p a r e n t l y because of t h e e x c e s s i v e l y c o l d and windy w i n t e r c o n d i t i o n s . A narrow band of Abies lasiocarpa ( s e r i e s ) f o r e s t a l o n g t h e Rocky Mountain f r o n t s u p p o r t s t h e easternmost o c c u r r e n c e s of i n t e r m o u n t a i n undergrowth s p e c i e s , Menziesia ferruginea, Xerophyllwn tenax, Luzula hitchcockii, and even "cove s i t e s " w i t h Clintonia unifZora b a r e l y extending a c r o s s t h e Divide from n o r t h w e s t e r n Montana (appendixes A- 7, -8, and - 10); however, t h e l i m i t e d t r e e f l o r a and i t s s t u n t e d growth a r e d e f i n i t e l y i n d i c a t i v e o f t h e s e v e r e e a s t s i d e c l i m a t i c c o n d i t i o n s .

ELEVATIONS (approx. 1

a.l L U

ru 111 U

alpine t u n d r a

6000

-

:.

l,I

LAS IOCARPA SERIES

PSEUDOTSUGA SERIES 5000

4000

-

Populus tremuloides grovelands Northern Great Plains grassland

Figure 5.--Distribution of forest t r e e s i n an area of north-central Montana. Arrows show the r e l a t i v e elevationul range of each species; solid portion of the arrow indicates where a species i s t h e potential climax and dashed portion shows where it i s seral.

Forest d i s t r i b u t i o n Only about 10 percent of t h e land i n t h i s region i s p o t e n t i a l l y f o r e s t e d , most of it occurring i n a 20 t o 30 mile band along t h e e a s t e r n s k i r t s of t h e Continental Divide o r Front Range of t h e Rockies. Figure 5 i l l u s t r a t e s a c h a r a c t e r i s t i c d i s t r i b u t i o n of t r e e species i n t h i s region. A small area of s i m i l a r f o r e s t (8 mi 2 ), lacking only Lap& Z y a l l i i , occurs on t h e Sweetgrass H i l l s (elev. 6,983 f e e t ) 90 miles e a s t of t h e n e a r e s t Front Range stands (Thompson and Kuijt 1976). Lower timberline generally occurs between 4,500 and 5,000 f e e t and f o r e s t extends up t o a l l but t h e highest ridges and peaks. Alpine t r e e l i n e averages about 8,000 f e e t . Most of t h e nonforest land i s p o t e n t i a l l y grassland dominated by Agropyron, Festuca, Bouteloua, and Stipa (Kuchler 1964; Mueggler and Handl, In p r e s s ) .

Climatic influences North-central Montana has a continental climate with severe chinook winds and dramatic f l u c t u a t i o n s of winter temperatures t h a t o f t e n i n j u r e f o r e s t t r e e s . On windexposed slopes, t r e e growth i s stunted by "red b e l t " conditions. Branches, groups of t r e e s , o r even s i z a b l e stands a r e r o u t i n e l y k i l l e d by desiccation of f o l i a g e caused when warm, dry chinook winds occur while t h e ground i s frozen and l i t t l e water i s a v a i l a b l e t o replace t r a n s p i r a t i o n l o s s e s . Pinus f l e x i l i s ( a t low and middle elevations) and P. albicaulis ( a t high elevations) a r e l e a s t susceptible t o red b e l t damage.

Growing s e a s o n s a r e s h o r t and c o o l i n t h e lower e l e v a t i o n f o r e s t s i t e s ( t a b l e 4 and f i g u r e 2 ) . Except i n p r o t e c t e d v a l l e y s , t r e e s seldom r e a c h 70 f e e t i n h e i g h t . Average annual p r e c i p i t a t i o n i n t h e s u b a l p i n e f o r e s t s i s g e n e r a l l y 30 t o 40 i n c h e s ( f o o t n o t e 2 ) , a l t h o u g h i t i s much g r e a t e r i n a few a r e a s a l o n g t h e C o n t i n e n t a l Divide, p a r t i c u l a r l y i n G l a c i e r National Park. The s e v e r i t y o f w i n t e r t e m p e r a t u r e f l u c t u a t i o n s i s i l l u s t r a t e d by t h e world- record t e m p e r a t u r e d r o p of 100" F i n 24 hours (from +44" t o -56°F) a t Browning, n e a r East G l a c i e r Park, i n J a n u a r y 1916 (McWhirter and McWhirter 1972).

Central Montana Forest Regioln

The c e n t r a l Montana f o r e s t r e g i o n i n c l u d e s a l l t h e f o r e s t e d t e r r a i n from t h e Helena Valley e a s t t o Harlowton, Lewistown, and F o r t Peck R e s e r v o i r , and n o r t h t o Havre. Spec i f i c a l l y , t h e w e s t e r n edge r u n s a l o n g t h e C o n t i n e n t a l Divide from t h e d r a i n a g e of t h e Middle Fork o f t h e Dearborn River s o u t h t o t h e Boulder River d i v i d e . F o r e s t s contiguous w i t h and west o f t h e d i v i d e a r e i n c l u d e d from t h e Avon V a l l e y s o u t h t o Deer Lodge (from Nevada Peak t o E l e c t r i c Peak a l o n g t h e C o n t i n e n t a l Divide). Eastward, t h e a r e a encomp a s s e s t h e Elkhorn Mountains (except f o r t h e southwestern p o r t i o n o f t h a t range t h a t d r a i n s i n t o t h e Boulder River) a s well a s t h e Big B e l t , L i t t l e B e l t , C a s t l e , Big Snowy, L i t t l e Snowy, J u d i t h , L i t t l e Rocky, Bearpaw, and Highwood Mountains. The range a l s o c o n t a i n s r a t h e r e x t e n s i v e lowland Pinus ponderosa (var. scopulorwn, Booth 1950, L i t t l e 1953) f o r e s t s i n t h e Helena and Lewistown v i c i n i t i e s and i n t h e Missouri River Breaks.

Diagnostic forest vegetation Most o f c e n t r a l Montana h a s a l o w - e l e v a t i o n f o r e s t b e l t o f Pinus ponderosa ( v a r . In c o n t r a s t t o w e s t s i d e P. ponderosa ( v a r . ponderosa), t h e s e have many two- needle f a s c i c l e s and a s h o r t growth form. A d d i t i o n a l l y , c e n t r a l Montana h a s mount a i n f o r e s t s made up o f o t h e r climax s e r i e s ( t a b l e 1 ) . The o t h e r e a s t s i d e r e g i o n c o n t a i n i n g P. ponderosa ( s o u t h e a s t e r n Montana) does n o t have a d d i t i o n a l f o r e s t s e r i e s .

scopulorwn).

C o a s t a l and i n t e r m o u n t a i n s p e c i e s a r e e s s e n t i a l l y a b s e n t , while e a s t s i d e s p e c i e s , i n c l u d i n g Pinus fZexiZis and Juniperus horizontalis, a r e prominent ( t a b l e 3 ) . Great P l a i n s g r a s s l a n d elements such a s BouteZoua g r a c i l i s and B. curtipendula, Yucca glauca, and Opuntia fragiZis, and 0. polyacantha a r e commonly found i n t h e d r i e s t Pinus ponderosa and P. f l e x i l i s s t a n d s .

Forest d i s t r i b u t i o n Approximately 20 p e r c e n t o f t h e l a n d i n t h i s r e g i o n i s p o t e n t i a l l y f o r e s t e d . Most o f t h e n o n f o r e s t l a n d i s p o t e n t i a l l y g r a s s l a n d dominated by Agropyron, Festuca, BouteZowz, and Stipa (Kuchler 1964; Mueggler and Handl, I n p r e s s ) . The f o r e s t s a r e a s s o c i a t e d w i t h prominent mountain r a n g e s and t h e Missouri River Breaks. F o r e s t extends from v a l l e y b a s e l e v e l s o r from lower t i m b e r l i n e s on t h e p r i n c i p a l mountain r a n g e s ( a t 4,000 t o 5,500 f e e t ) and c o v e r s a l l b u t t h e h i g h e s t peaks. Alpine t r e e l i n e a v e r a g e s about 8,500 f e e t . F i g u r e 6 shows a c h a r a c t e r i s t i c d i s t r i b u t i o n of t r e e s p e c i e s on nonl i m e s t o n e p a r e n t m a t e r i a l s i n c e n t r a l Montana.

Figme 6.--Distribution of forest t r e e s i n an area of central Montana. Arrows show the r e l a t i v e elevational range of each species; solid portion of the arrow indicates where a species i s the potential climax and dashed portion shows where it i s seral.

Extensive a r e a s having limestone s u b s t r a t e s occur i n t h e mountain r a n g e s o f c e n t r a l Montana. The limestone- derived s o i l s d r a i n r a p i d l y and a r e g e n e r a l l y dominated by d r i e r s i t e s p e c i e s t h a n t h e a d j a c e n t nonlimestone s i t e s ( f i g . 53, 54, i n P f i s t e r and o t h e r s 1977). For example, a t medium e l e v a t i o n s t h e limestone s i t e s o f t e n support Pseudotsuga with a g r a s s - f o r b undergrowth, while a d j a c e n t g r a n i t i c s i t e s have Pinus contorta and Vacciniwn spp. (Goldin and Nimlos 1977; Weaver and Parry 1978).

Climatic influences This r e g i o n h a s a c o n t i n e n t a l c l i m a t e , b u t has f o r e s t s extending t o lower e l e v a t i o n s and l e s s s e v e r e w i n t e r c o n d i t i o n s than n o r t h - c e n t r a l Montana. The warmer J u l y temperatures and l o n g e r growing s e a s o n s ( f i g . 2) i n t h e lower f o r e s t zone a r e i n d i c a t e d by weather s t a t i o n d a t a i n t a b l e 4 . However, except on s h e l t e r e d s i t e s , t r e e s seldom a t t a i n 80 f e e t i n h e i g h t . Average annual p r e c i p i t a t i o n i n t h e s u b a l p i n e f o r e s t s i s e s t i m a t e d t o be 25 t o 35 i n c h e s ( f o o t n o t e 2 ) . I n t h e h i g h e r v a l l e y s and a t high e l e v a t i o n s i n t h e mountains, extreme temperature changes accompanied by s t r o n g winds i n f l i c t r e d b e l t damage. For i n s t a n c e , i n midJanuary 1971 such weather c o n d i t i o n s (temperatures f l u c t u a t i n g between -30" and +58" F a t Great F a l l s , accompanied by s t r o n g winds) k i l l e d about 20,000 a c r e s o f Pinus contorta f o r e s t i n t h e L i t t l e B e l t Mountains.

I

b

Southwestern Montana Forest Region

Area included The s o u t h w e s t e r n Montana f o r e s t r e g i o n i n c l u d e s t h e J e f f e r s o n , Madison, and Boulder River d r a i n a g e s , e a s t o f t h e C o n t i n e n t a l Divide, a s w e l l a s t h e f o r e s t s on b o t h s l o p e s o f t h e C o n t i n e n t a l Divide r a n g e i n t h e v i c i n i t y o f B u t t e ( s p e c i f i c a l l y from E l e c t r i c Peak, e a s t o f Deer Lodge, t o C a l i f o r n i a P a s s , s o u t h o f Anaconda).

A s i n c e n t r a l Montana, P a c i f i c Coast f o r e s t e l e m e n t s a r e a b s e n t and i n t e r m o u n t a i n elements a r e s c a r c e ( t a b l e 3 ) . R a t h e r s h o r t , b u t s t o u t Pseudotsuga ( o r Pinus f l e x i l i s ) occupy t h e warmest f o r e s t s i t e s , and Pinus contorta a l o n g w i t h Vacciniwn scopariwn undergrowth dominate most h i g h - e l e v a t i o n f o r e s t s . Undergrowth i s n o t a b l y s p a r s e i n t h e d e n s e r f o r e s t s t a n d s , and i n Pseudotsuga f o r e s t s undergrowth o f t e n c o n s i s t s p r i m a r i l y o f s c a t t e r e d Festuca idahoensis and even Artemisia t r i d e n t a t a F i g u r e 7 shows a c h a r a c t e r i s t i c d i s t r i b u t i o n o f t r e e s p e c i e s i n s o u t h w e s t e r n Montana. P r i n c i p a l f o r e s t h a b i t a t t y p e s a r e shown i n t a b l e 2 .

.V)

TORTA SERIES

uncertain)

MENZIESII SERIES

-

6000

grassland

Figure 7.- - Distribution of forest t r e e s i n an area of southwestern Montana. Arrows show the r e l a t i v e elevationai! range of each species; solid portion of the arrow i n d i c a t e s where a species i s the potential climax and dashed portion shows where it i s seral.

Forest distribution D e s p i t e i t s mountainous t e r r a i n , o n l y a b o u t o n e - f o u r t h o f t h i s r e g i o n i s f o r e s t e d . Most o f t h e n o n f o r e s t l a n d i s s e m i a r i d s t e p p e ( A r t e h s i a ) and g r a s s l a n d (Agropyron, F e s t u c a , and S t i p a ) , a l o n g w i t h s m a l l a r e a s of a l p i n e v e g e t a t i o n (Kuchler 1964; Mueggler and Handl, I n p r e s s ) above 9,500 f e e t e l e v a t i o n . Lower t i m b e r l i n e g e n e r a l l y o c c u r s somewhere between 5,700 and 7,000 f e e t i n e l e v a t i o n . However, some o f t h e mountain r a n g e s s o u t h o f D i l l o n a r e s o d r y t h a t l i t t l e f o r e s t i s s u p p o r t e d even a t 8,000 f e e t . Thus, t h e e n t i r e f o r e s t b e l t (between lower and upper t i m b e r l i n e ) may span o n l y 1,000 t o 1,500 f e e t of e l e v a t i o n , and may b e l o c a l l y a b s e n t on exposed s o u t h - and w e s t - f a c i n g s l o p e s . S i m i l a r l y h i g h , s e m i a r i d mountain r a n g e s , p r o j e c t i n g above a n A r t e m i s i a t r i d e n t u t a s t e p p e (Kuchler 1964), o c c u r i n a d j a c e n t e a s t - c e n t r a l Idaho ( S t e e l e and others (footnote 1 ) ) . Climatic influences A s i l l u s t r a t e d by weather r e c o r d s from Lakeview ( t a b l e 4 ) , t h i s i s a c o l d , d r y f o r e s t r e g i o n h a v i n g h i g h v a l l e y - b a s e e l e v a t i o n s , and a c o n t i n e n t a l c l i m a t e . Average a n n u a l p r e c i p i t a t i o n i n t h e s u b a l p i n e f o r e s t r a n g e s from a b o u t 22 t o 35 i n c h e s ( f o o t n o t e 2 ) . T h i s f o r e s t r e g i o n e v i d e n t l y h a s growing s e a s o n s t o o s h o r t and c o l d f o r P i n u s p o n d e r o s a ( f i g . 2 ) . The c o l d , d r y c o n d i t i o n s a r e a l s o evidenced by t h e l a c k o f P s e u d o t s u g a / P h y s o c q u s h a b i t a t t y p e ( t a b l e s 2 and 3 ) . However, chinook winds and temp e r a t u r e f l u c t u a t i o n s a r e l e s s s e v e r e t h a n i n n o r t h - c e n t r a l and c e n t r a l Montana, and r e d b e l t damage i s l e s s common.

south-central Montana Forest Region

The s o u t h - c e n t r a l Montana f o r e s t r e g i o n i n c l u d e s t h e G a l l a t i n and upper Yellowstone R i v e r d r a i n a g e s ( a l o n g w i t h t h e B r i d g e r and Crazy Mountains) a s w e l l a s t h e P r y o r Mount a i n s and t h e n o r t h end o f t h e Bighorn Range. The r e g i o n encompasses t h e n o r t h e r n p a r t o f an e x t e n s i v e , h i g h - e l e v a t i o n f o r e s t e d upland s u r r o u n d i n g Yellowstone N a t i o n a l Park. T h i s upland i s capped by l a r g e a l p i n e p l a t e a u s i n Montana and Wyoming. Diagnostic f o r e s t vegetation Most of t h e f o r e s t i n s o u t h - c e n t r a l Montana i s dominated by Pseudotsuga, P i n u s c o n t o r t u , P i c e a , o r A b i e s l a s i o c q a . The abundance o f P i c e a l P h y s o c a r p u s , Picea/Galium t r i f l o r w n , A b i e s lasiocarpa/GaZiwn t r i f l o r w n , and A b i e s lasiocarpa/CaZwnagrostis canad e n s i s h a b i t a t t y p e s ( t a b l e 2) a t t e s t s t o t h e m o i s t n e s s o f many o f t h e f o r e s t s . Also, s c a t t e r e d p o p u l a t i o n s o f Xerophyllwn and M e n z i e s i a (appendixes A-9 and -10) a r e found h e r e , more t h a n 100 m i l e s e a s t o f t h e i r u s u a l d i s t r i b u t i o n a l l i m i t s n e a r t h e C o n t i n e n t a l D i v i d e . In c o n t r a s t t o southwest Montana, o n e seldom f i n d s e x t e n s i v e s t a n d s h a v i n g a g r a s s l a n d undergrowth ( e x c e p t on l i m e s t o n e s u b s t r a t e s ) , n o r d o e s one f i n d v e r y s p a r s e undergrowth r e l a t e d t o d r y c o n d i t i o n s . I

Forest distribution

I

Nearly h a l f o f t h e l a n d i n s o u t h - c e n t r a l Montana s u p p o r t s f o r e s t , and most of t h e r e m a i n i n g a r e a i s p o t e n t i a l l y grassland--(Agropyron, F e s t u c a , S t i p a ) a c c o r d i n g t o

ELEVATIONS (approx )

Figure 8.- - Distribution o f forest t r e e s i n an area of south- central Montana. Arrows show t h e r e l a t i v e elevational range o f each species; s o l i d portion o f t h e arrow i n d i c a t e s where a species i s t h e potential climax and dashed portion shows where it i s s e r a l . (Modified from P f i s t e r and others 1977.1

Kuchler (1964)- - occupying t h e d r i e r , lower e l e v a t i o n v a l l e y s . Lower t i m b e r l i n e a v e r a g e s about 5,500 f e e t and a l p i n e t r e e l i n e o c c u r s n e a r 9,500 f e e t . F i g u r e 8 shows a c h a r a c t e r i s t i c d i s t r i b u t i o n of t r e e s p e c i e s i n an a r e a o f s o u t h - c e n t r a l Montana. Table 2 lists principal f o r e s t h a b i t a t types. Limestone s u b s t r a t e s a r e abundant i n t h e Pryor Mountains and occur s p o r a d i c a l l y elsewhere i n s o u t h - c e n t r a l Montana. These s i t e s , below about an 8 , 0 0 0 - f o o t e l e v a t i o n , g e n e r a l l y have f o r e s t s dominated by Pinus f l e x i l i s and Pseudotsuga.

Climatic i n f l u e n c e s S o u t h - c e n t r a l Montana h a s a c o n t i n e n t a l c l i m a t e , and r e d b e l t i n j u r y i s o f t e n s e v e r e a t lower t i m b e r l i n e . The v a l l e y s have h i g h b a s e e l e v a t i o n s and a r e t o o c o l d ( s h o r t growing season, f i g u r e 2) f o r any s i g n i f i c a n t amounts o f Pinus ponderosa; howe v e r , f o r e s t s a r e g e n e r a l l y m o i s t e r t h a n t h o s e o f southwestern Montana. Weather r e c o r d s f o r t h r e e f o r e s t e d s i t e s i n t h i s r e g i o n a r e found i n t a b l e 4 . Average annual p r e c i p i t a t i o n i n t h e s u b a l p i n e f o r e s t s i s g e n e r a l l y 30 t o 45 i n c h e s ( f o o t n o t e 2 ) .

Southeastern Montana Forest Region

The s o u t h e a s t e r n Montana f o r e s t r e g i o n i n c l u d e s t h e e x t e n s i v e p u r e Pinus ponderosa f o r e s t s on lowlands and h i l l y t e r r a i n ( m o s t l y 2,800 t o 4,400 f e c t e l e v a t i o n ) i n t h e n o r t h e r n G r e a t P l a i n s . I t c o v e r s t h e lower Yellowstone R i v e r d r a i n a g e a s f a r upstream (west) a s Big Timber. The r e g i o n e x t e n d s up t h e M u s s e l s h e l l V a l l e y t o Harlowton and i t s n o r t h e r n boundary i n c l u d e s t h e n o r t h e r n m o s t p i n e g r o v e s i n t h e v i c i n i t i e s of Roundu p , M i l e s C i t y , and Baker.

Diagnostic forest vegetation Although Pinus ponderosa i s t h e o n l y f o r e s t t r e e , i t o c c u r s i n r a t h e r d i v e r s e h a b i t a t t y p e s ( t a b l e 2 ) . The d r i e s t o f t h e s e f o r e s t s i t e s have v e r y open s t a n d s o f s h o r t t r e e s (35-60 f e e t ) , w i t h g r a s s l a n d undergrowth ( e . g . , Andropogon gerardii and A. scoparius, Agropyron spicatwn, Bouteloua g r a c i l i s , Carex f i l i f o l i a ) Conversely, m o i s t n o r t h - f a c i n g s l o p e s have d e n s e s t a n d s o f P. ponderosa (70-95 f e e t t a l l ) , w i t h a l u x u r i a n t s h r u b and h e r b undergrowth i n c l u d i n g many s p e c i e s c h a r a c t e r i s t i c o f t h e mountain f o r e s t s t o t h e west ( e . g . , Shepherdia camdensis, Arctostaphylos uva-msi, Berberis repens, Linmea borealis, Arnica c o r d i f o l i a , Dispomon trachycarpwn, PyroZa secunda, and

.

Smilacina s t e l l a t a ) . The p r e s e n c e o f Linnaea and some o t h e r undergrowth s p e c i e s s t r o n g l y s u g g e s t s t h a t t h e more m o i s t h a b i t a t s would s u p p o r t Pseudotsuga; however, t h e n e a r e s t seed s o u r c e f o r t h i s s p e c i e s i s a t l e a s t 70 m i l e s away i n t h e Bighorn Range. T h i s c o n c l u s i o n i s r e i n f o r c e d by t h e f a c t t h a t Pinus ponderosa s t a n d s d e v e l o p i n g on t h e m o i s t e r s i t e s a r e more h e a v i l y s t o c k e d t h a n i s c h a r a c t e r i s t i c o f P. ponderosa h a b i t a t t y p e s e l s e w h e r e i n t h e State. I n a d d i t i o n t o h a v i n g a s h o r t e r growth form t h a n i t s c o u n t e r p a r t west o f t h e Cont i n e n t a l D i v i d e , t h e P. ponderosa ( v a r . scopulorwn, Booth 1950 and L i t t l e 1953) i n s o u t h e a s t e r n Montana h a s a m a j o r i t y o f two- needle f a s c i c l e s . These may be m a n i f e s t a t i o n s of s u b s t a n t i a l g e n e t i c d i f f e r e n c e s between t h e west s l o p e and Great P l a i n s P. ponderosa. Two e a s t e r n d e c i d u o u s - f o r e s t s p e c i e s (Fraxinus pennsy Zvanica and Prunus americana) o c c u r a l o n g s t r e a m s and m o i s t lower n o r t h s l o p e s i n s o u t h e a s t e r n Montana, and two o t h e r such s p e c i e s (Ulmus americana and Quercus macrocarpa) r e a c h t h e e a s t e r n edge of t h i s r e g i o n ( L i t t l e 1971, 1 9 7 6 ) . P f i s t e r and o t h e r s (1977) have d i s c u s s e d c o m p o s i t i o n a l s i m i l a r i t i e s between t h e P. ponderosa f o r e s t s o f s o u t h e a s t e r n Montana and t h o s e of t h e Black H i l l s o f w e s t e r n South Dakota a s sampled by T h i l e n i u s (1972).

Forest d i s t r i b u t i o n Approximately 20 p e r c e n t o f s o u t h e a s t e r n Montana s u p p o r t s f o r e s t . T h i s i s a r e g i o n w i t h o u t prominent mountains, o r mountain f o r e s t s ; t h u s , it d i f f e r s from a l l o t h e r f o r ested regions. ( N o r t h e a s t e r n Montana does n o t have mountains, b u t a l s o i s w i t h o u t G r e a t P l a i n s Pinus ponderosa f o r e s t . )

L

Most o f t h e remainder o f t h e r e g i o n i s Great P l a i n s g r a s s l a n d (BouteZoua-StipaAgropyron, a c c o r d i n g t o Kuchler 1964). Some o f t h i s g r a s s l a n d h a s widely s c a t t e r e d p i n e s , and t h u s can be termed a "savanna."

S o u t h e a s t e r n Montana h a s a c o n t i n e n t a l c l i m a t e . Summers a r e l o n g e r , h o t t e r , and more humid t h a n t h o s e i n t h e mountainous f o r e s t r e g i o n s ( t a b l e 4 and f i g u r e 2 ) . Most o f t h e annual p r e c i p i t a t i o n ( r a n g i n g up t o about 18 i n c h e s i n m o i s t f o r e s t a r e a s ) comes i n s p r i n g and summer r a i n s . Winters a r e g e n e r a l l y d r y and c o l d , b u t a r e n o t a s s e v e r e a s t h o s e i n t h e n o r t h e r n p a r t s of Montana e a s t o f t h e C o n t i n e n t a l Divide.

Northeastern Montana

i-1,

The n o r t h e a s t e r n p a r t o f Montana i n c l u d e s t h e a r e a n o r t h o f Miles C i t y and e a s t o f t h e Missouri River Breaks. P o t e n t i a l n a t u r a l v e g e t a t i o n i s Great P l a i n s g r a s s l a n d (BouteZoua-Stipa-Agropyron and Agropyron- Stipa, a c c o r d i n g t o Kuchl e r 1964) except f o r s t a n d s o f PopuZus d e Z t o i d e s l i n i n g t h e p r i n c i p a l r i v e r s . This r e g i o n h a s no upland f o r e s t , except f o r a few widely s c a t t e r e d p o p u l a t i o n s o f s t u n t e d P i n u s ponderosa. (The most n o t a b l e s t a n d i s a t t h e P i n e s R e c r e a t i o n Area s o u t h o f Glasgow on Fort Peck Reserv o i r . ) The extremely c o l d c o n t i n e n t a l w i n t e r s , coupled w i t h d e s i c c a t i n g winds, may be t h e f a c t o r s p r e v e n t i n g P i n u s ponderosa from growing h e r e . Average annual p r e c i p i t a t i o n i s between 11 and 1 5 i n c h e s i n t h i s r e g i o n (U.S. Dep. Comm. 1971). Table 4 p r e s e n t s c l i m a t i c d a t a from Glasgow.

RESEARCH AND MANAGEMENT APPLICATIONS The f o r e s t r e g i o n s p r e s e n t e d h e r e were developed t o d e s c r i b e d i s t r i b u t i o n s of f o r e s t h a b i t a t t y p e s ( P f i s t e r and o t h e r s 1 9 7 7 ) - - i . e . , f o r e s t s i t e s and v e g e t a t i o n i n mature s t a n d s . The r e g i o n s can a l s o b e used i n d e s c r i b i n g d i s t r i b u t i o n s of i n d i v i d u a l f o r e s t s p e c i e s o r s e r a 1 f o r e s t communities ( e . g . , Acer gzabrwn-SaZix b r u s h f i e l d s ) The Northern Region o f t h e USDA F o r e s t S e r v i c e r e c e n t l y adopted f o r e s t r e g i o n s a s "seed t r a n s f e r zones" t o h e l p i n s u r e t h a t n u r s e r y - r a i s e d s e e d l i n g s a r e s e n t t o a geographic a r e a s i m i l a r t o t h e one where t h e s e e d s were c o l l e c t e d .

.

These f o r e s t r e g i o n s may be u s e f u l a s a b i o l o g i c a l l y based r e g i o n a l s t r a t i f i c a t i o n f o r f o r e s t r e s e a r c h and f o r e s t management s t u d i e s . For example, i t might be u s e f u l t o s t r a t i f y p r o d u c t i v i t y e s t i m a t e s ( s i t e index and y i e l d c a p a b i l i t y ) of i n d i v i d u a l h a b i t a t t y p e s by f o r e s t r e g i o n . S i m i l a r l y , t h e s e f o r e s t r e g i o n s l o g i c a l l y could b e i n c o r p o r a t e d i n s t u d i e s o f g e n e t i c v a r i a t i o n i n t r e e s p e c i e s and i n t r e e improvement programs. Responses o f t r e e s and o t h e r v e g e t a t i o n t o management a r e o f t e n s t r a t i f i e d by h a b i t a t t y p e , b u t it may b e u s e f u l t o a n a l y z e them by f o r e s t r e g i o n a s w e l l . F o r e s t r e g i o n s o f f e r an a d d i t i o n a l dimension f o r i n t e r p r e t i n g v a r i a t i o n i n f o r e s t v e g e t a t i o n . F o r e s t managers may f i n d appendix C u s e f u l f o r d e t e r m i n i n g t h e l o c a t i o n of f o r e s t r e g i o n boundaries.

Arno, Stephen F. 1970. Ecology o f a l p i n e l a r c h ( L a r i x ZyaZZii P a r l , ) i n t h e P a c i f i c Northwest. Ph.D. Diss., Univ. Mont., Missoula, 264 p . B a i l e y , R. G . 1976. Ecoregions o f t h e United S t a t e s (map) , USDA For. Serv. , I n t e r m t . Reg. , Ogden, Utah. B a i l e y , R. G. 1978. Ecoregions o f t h e United S t a t e s (manual t o accompany map). USDA For. S e r v . , I n t e r m t . Reg., Ogden, Utah, 77 p. Booth, W. E . 1950. F l o r a o f Montana. P a r t I , C o n i f e r s and Monocots. 232 p. Mont. S t a t e Univ., Bo z eman. Booth, W. E . , and J . Wright. 1966. F l o r a o f Montana. P a r t 11. Dicotyledons. 305 p. Mont. S t a t e Univ., Bozeman. Caprio, J. M. 1965. Average l e n g t h o f f r e e z e - f r e e season. Mont. Agric. Ext. S t n . , Bozeman. F o l d e r 83 (map) Crowley, J. M. 1972. Environmental r e g i o n s of Montana. I n Montana Environmental Q u a l i t y Council, F i r s t Annu. Rep., Helena, Mont., p. 2-11. Daubenmire, R. 1969. S t r u c t u r e and ecology o f c o n i f e r o u s f o r e s t s o f t h e Northern Rocky Mountains. Proc. 1968 Symp. (Coniferous F o r e s t s o f t h e Northern Rocky Mountains), Univ. Mont., Missoula, p . 25-41. Daubenmire, R . , and J. B. Daubenmire. 1968. F o r e s t v e g e t a t i o n o f e a s t e r n Washington and n o r t h e r n Idaho. Wash. Agric. Exp. S t n . , Pullman. Tech. B u l l . 60, 104 p. Goldin, A . , and T. J. Nimlos. 1977. V e g e t a t i o n p a t t e r n s on l i m e s t o n e and a c i d p a r e n t m a t e r i a l s i n t h e Garnet Mount a i n s o f western Montana. Northwest S c i . 51(3):149-160. Green, A. W . , and T. S e t z e r . 1974. The Rocky Mountain t i m b e r s i t u a t i o n , 1970. USDA For. Serv. Resour. B u l l . INT-10, 78 p. I n t e r m t . For. and Range Exp. S t n . , Ogden, Utah. Hitchcock, C. L . , and A. C r o n q u i s t . 1976. F l o r a o f t h e P a c i f i c Northwest. 730 p. Univ. Wash. P r e s s . , S e a t t l e . Hitchcock, C. L . , A. Cronquist, M. Ownbey, and J . Thompson. 1955-1969. Vascular p l a n t s o f t h e P a c i f i c Northwest (5 v o l s . ) . Univ. Wash. P r e s s , Seattle. Hutchison, S. B . , and P. D . Kemp. 1952. F o r e s t r e s o u r c e s o f Montana. USDA For. S e r v . , For. Res. Rep. 5 , 76 p. North. Rocky M t . For. and Range Exp. S t n . , Missoula, Mont. Kirkwood, J . E . 1922. F o r e s t d i s t r i b u t i o n i n t h e Northern Rocky Mountains. Mont. S t a t e Univ., B u l l . 247 ( s e r . 2 ) , Missoula, 180 p. Kuchler, A. W. 1964. P o t e n t i a l n a t u r a l v e g e t a t i o n o f t h e conterminous United S t a t e s (map and manual) Am. Geog. Soc. Spec. Publ. 36, 116 p.

.

I

I

Kuchler, A. W. 1973, Problems i n c l a s s i f y i n g and mapping v e g e t a t i o n f o r e c o l o g i c a l r e g i o n a l i z a t i o n . Ecology 54:512-523. L i t t l e , E. L . , Jr. 1953. Check l i s t o f n a t i v e and n a t u r a l i z e d t r e e s o f t h e U.S. USDA For. S e r v . A g r i c . Handb. 41, 472 p. L i t t l e , E. L., Jr. 1971. A t l a s o f United S t a t e s t r e e s . Vol. 1. C o n i f e r s and i m p o r t a n t hardwoods. USDA For. S e r v . Misc. Publ. 1146. L i t t l e , E . L. J r . 1976. A t l a s o f United S t a t e s t r e e s . Vol. 3. Minor w e s t e r n hardwoods. USDA F o r . S e r v . Misc. Publ. 1314. Lynch, D. L. 1955. Ecology o f aspen groveland i n G l a c i e r County, Montana. E c o l . Monogr. 25:321-344. McWhirter, N . , and R. McWhirter. 1972. Guinness book o f world r e c o r d s . 704 p. S t e r l i n g P u b l . Co., N. Y . Mueggler, W. F., and W. P. Handl. [ I n p r o c e s s . ] Mountain g r a s s l a n d and s h r u b l a n d h a b i t a t t y p e s o f w e s t e r n Montana. USDA For. S e r v . , Gen. Tech. Rep., I n t e r m t . For. and Range Exp. S t n . , Ogden, Utah, and North. Reg., Missoula, Mont. Mueller-Dombois, D. , and H. E l l e n b u r g . 1974. Aims and methods o f v e g e t a t i o n ecology. 547 p. John Wiley and Sons, N . Y . Payne, G. F. 1973. V e g e t a t i v e r a n g e l a n d t y p e s i n Montana. Mont. A g r i c . Exp. S t n . , B u l l . 671. Bozeman, 1 5 p. and map. P f i s t e r , R. D . , B. Kovalchik, S. Arno, and R . Presby. 1977. F o r e s t h a b i t a t t y p e s o f Montana. USDA For. S e r v . Gen. Tech. Rep. INT-34. 174 p. I n t e r m t . For. and Range Exp. S t n . , Ogden Utah. Ross, R. L . , and H. E . Hunter. 1976. Climax v e g e t a t i o n o f Montana based on s o i l s and c l i m a t e . USDA S o i l Cons. S e r v ., Bozeman. 64 p. and map. Rowe, J . S. 1959 and 1972 e d i t i o n s . F o r e s t r e g i o n s o f Canada. Canadian F o r e s t r y S e r v . P u b l . 1300. 172 p. Ottawa. Schmidt, W. C . , and W . P. Dufour. 1975. B u i l d i n g a n a t u r a l a r e a system f o r Montana. Western Wildlands 2 ( 1 ) : 2 0 - 2 9 . Mont. For. and Cons. Exp. S t n . , Univ. Mont., Missoula. T h i l e n i u s , J . F. 1972. C l a s s i f i c a t i o n o f d e e r h a b i t a t i n t h e ponderosa p i n e f o r e s t o f t h e Black H i l l s , South Dakota. USDA For. S e r v . Res. Pap. RM-91, 23 p. Rocky M t . For. and Range Exp. S t n . , F o r t C o l l i n s , Colorado. Thompson, L. S . , and J. K u i j t . 1976. Montane and s u b a l p i n e p l a n t s of t h e Sweetgrass H i l l s , Montana, and t h e i r r e l a t i o n s h i p t o e a r l y p o s t g l a c i a l environments o f t h e Northern G r e a t P l a i n s . Canadian F i e l d - N a t u r a l i s t 90(4):432-448. USDA S o i l C o n s e r v a t i o n S e r v i c e . 1968. Average a n n u a l mountain p r e c i p i t a t i o n (map). S o i l Cons. S e r v . , Bozeman, Montana. U . S. Department o f Commerce. 1971. C l i m a t e s o f t h e S t a t e s : Montana. Climatography o f t h e United S t a t e s No. 60: 24. Environ. Data S e r v . , S i l v e r S p r i n g s , MD. Weaver, T., and D. A. P e r r y . 1978. R e l a t i o n s h i p o f c o v e r t y p e t o a l t i t u d e , a s p e c t , and s u b s t r a t e i n t h e B r i d g e r Range, Montana. Northwest S c i . 52(3):212-219.

APPENDIX A Distribution of key tree and undergrowth species in Montana

NORTHWESTERN

Figure A-].--Natural d i s t r i b u t i o n of Tsuga heterophylla i n Montana. (Species common i n suitable habitats within shaded area. X's indicate small outlying populations. )

WES

Figure A-2.--Natural d i s t r i b u t i o n of Pinus monticola i n Montana. (Species common i n suitable habitats wlthin shaded area. X's i n dicate small outlying populations. )

Figure A-3.--Natural distribution of Thuja p l i c a t a in Montana. (Species common in suitable habitats within shuded area. X's indicate smaZ l out lying popu Zations. )

NORTHWESTERN

WES

Figure A-4. --Natural distribution of Abies g r a n d i s in Montana. (Species common in suitable habitats within shaded area. X's indicate small outlying populations.)

NORTHWESTERN

-

Fiaure A-5. --Natural d i s t r i " b u t i o n o f Larix o c c i d e n t a l i s \ I I i n ~ m. t a & . - (Species -. common . -. i n s u i t a b l e h a b i t a t s wzthzn I shaded area. X's i n d i c a t e *H'/ smal Z o u t l y i n g populations. )

- - . -- . . CENTRAL

-

-

NORTH- ,CENTRAL

I

\

WES

WES

I

Figure A-6.--Natural d i s t r i b u t i o n of Pinus f l e x i l i s ( p l o t l o c a t i o n s and observations onZy) i n Montana. 28

-

Figure A-7. --Natural d i s t r i b u t i o n of C l i n t o n i a u n i f l o r a i n Montana. (Species comon i n suitable habitats within shaded area. X's i n dicate small outlying populations. )

WES

NORTHWESTERN

Figure A-8. --Natural d i s t r i b u t i o n of Luzula h i t c h c o c k i i i n Montana. (Species comon i n suitable habitats w i t h i n shaded area. X's i n dicate small outlying populations. l

NORTHWESTERN

Figure A-9.--Natural d i s t r i b u t i o n of Menziesia ferruginea i n Montana. (Species common i n s u i t a b l e habitats w i t h i n shaded area. X's indicate small outlying populations. )

NORTHWESTERN

WES

Figure A-1 0. --Natural dist r i b u t i o n of Xerophyllum tenax i n Montana. (Species common i n s u i t a b l e h a b i t a t s within shaded area. X's in.dicate small outlying populations. )

APPENDIX B Number of sample p l o t s ( P f i s t e r and o t h e r s 1977) by h a b i t a t type, phase, and f o r e s t region i n Montana

T a b l e B-1--Number o f s q l e p l o t s ( P f i s t e r and others 1 9 7 7 ) by habitat type,

phase, and f o r e s t region i n Montana. NW WC NC C

SW = southwestern Montana SC = south-central Montana SE = southeastern Montana

Northwestern Montana west-central Montana north-central Montarxz = central Montana

= = =

S e r i e s / h a b i t a t type/phase

( c . t . = cort~mmityt y p e )

: NW

: WC

Montana f o r e s t r e g i o n : NC : C : SW : SC

: SE

: Total

Forested scree Pinus f l e x i l i s s e r i e s /Agropyron spicatum h . t . /Festuca idahoensis h . t . - F e s t u c a i d a h o e n s i s phase - F e s t u c a s c a b r e l l a phase / J u n i p e r u s communis h; t

.

. .

1

2

2

1

6

1 1 1 4

2 3 1 -

2

2

7 4

1 -

4 -

7 -

1 14

2 3

13 19 13 27

1

6

45

8

5

24

7

P i n u s ponderosa s e r i e s

.

.

/Andropogon spp h . t /Agropyron spicatum h . t . /Festuca idahoensis h . t . - F e s t u c a i d a h o e n s i s phase - F e s t u c a s c a b r e l l a phase /Purshia t r i d e n t a t a h . t . -Agropyron spicatum phase - F e s t u c a i d a h o e n s i s phase /Symphoricarpos a l b u s h . t . -Symphoricarpos a l b u s phase - B e r b e r i s r e p e n s phase /Prunus v i r g i n i a n a h . t . -Prunus v i r g i n i a n a phase -Shepherdia c a n a d e n s i s phase Pseudotsuga m e n z i e s i i s e r i e s /Agropyron spicatum h . t . /Festuca idahoensis h . t . /Festuca s c a b r e l l a h . t . /Vaccinium caespitosum h . t . /Physocarpus malvaceus h . t . -Physocarpus malvaceus phase -Calamagrostis r u b e s c e n s phase

1 1 5 15

4 1 2 9

12

23

1

7

5

.

i

6 2

3

8

(con. )

Table B-1.--(con.) Series/habitat ty-pe/phase

:

NW

:

WC

Montana forest region : NC : C : SW : SC

:

SE

Pseudotsuga menziesii series /Vaccinium globulare h.t. -Vaccinium globulare phase -Arctostaphylos uva-ursi phase -Xerophyllum tenax phase /Linnaea borealis h.t. -Symphoricarpos albus phase -Calamagrostis rubescens phase -Vaccinium globulare phase /Symphoricarpos albus h.t. -Agropyron spicatum phase -Calamagrostis rubescens phase -Symphoricarpos albus phase /Calamagrostis rubescens h.t. -Agropyron spicatum phase -Arctostaphylos uva-ursi phase -Calamagrostis rubescens ~hase -Pinus ponderosa phase /Carex geyeri h.t. /Spiraea betulifolia h.t. /Arctostaphylos uva-ursi h.t. /Juniperus communis h.t. /Arnica cordifolia h.t. /Symphoricarpos oreophilus

Picea series /Equisetum arvense h.t. /Clintonia uniflora h.t. -Vaccinium caespitosum phase -Clintonia uniflora phase /Physocarpus malvaceus h.t. /Galium triflorum h.t. /Vaccinium caespitosum h.t. /Senecio streptanthifolius h.t. -Pseudotsuga menziesii phase -Picea phase /Linnaea borealis h.t. /Smilacina stellata h.t.

3

2

1

1

i

i

9

1

2 5 5

2

-

4 -

2

8

16

.

i

4

i

i

31

1 5

4

19

4 1 10

ti

11 4 31

(con. )

:

Total

Table B-1.--(con.) Series/habitat type/phase

Montana forest region : NC : C : SW : SC

: NW

: WC

: SE

: Total

5

1

6

4

2 1

6 6

Abies grandis series /Xerophyllum tenax h.t. /Clintonia uniflora h.t. -Clintonia uniflora phase -Aralia nudicaulis phase -Xerophyllum tenax phase /Linnaea borealis h.t. -Linnaea borealis phase -Xerophyllum tenax phase

5 4

4

3

2

5

3

-

3 30

2 1 1

15 9 7 11 42

24

6

Thuja plicata series /Clintonia uniflora h.t. -Clintonia uniflora phase 13 -Aralia nudicaulis phase 8 -Menziesia ferruginea phase 6 /Oplopanax horridum h.t. 38

-

4

Tsuga heterophylla series /Clintonia uniflora h.t. -Clintonia uniflora phase 27 -Aralia nudicaulis phase 11 38

27

Abies lasiocarpa series (Lower subalpine h . t . s ) /Oplopanax horridum h.t. 4 /Clintonia uniflora h.t. -Clintonia uniflora phase 18 -Aralia nudicaulis phase 12 -Vaccinium caespitosum phase 8 -Xerophyllum tenax phase 13 -Menziesia ferruginea phase 12 /Galium triflorum h.t. /Vaccinium caespitosum h.t. /Calamagrostis canadensis h.t. -Calamagrostis canadensis phase -Galium triflorum phase -Vaccinium caespitosum phase 3 /Linnaea borealis h.t. -Linnaea borealis phase 1 -Xerophyllum tenax phase 5 -Vaccinium scoparium phase 2 /Menziesia ferruginea h.t. 19

.

4

11 4

3 2

32 18

2 7

i

10 21

8 10 2

2 4

i 3

i

8 2

1 1

8 2

1

1

2

4

2

1

i

4

10 8 3 37

5

22 34 10 23 5

6

7 2

i

i

20 13 17

2

1

64

(con. )

Table R-1.--(con.) Serieslhabitat tvnelnhase

: NW

: WC

Montana forest region : NC : C : S1.l " SC

: SE

: 'Total

Abies lasiocarpa series (Lower subalpine h.t.s) Tsuga mertensiana/Menziesia h.t. 8 /Xerophyllum tenax h.t. -Vaccinium globulare phase 18 -Vaccinium scoparium phase 3 Tsuga mertensiana/Xerophyllum h.t. 9 /Vaccinium globulare h.t. /Vaccinium scoparium h.t. -Calamagrostis rubescens phase -Vaccinium scoparium phase 1 -Thalictrum occidentale phase /Alnus sinuata h.t. /Calamagrostis rubescens h.t. /Clematis pseudoalpina h.t. . /Arnica cordifolia h. t. /Carex geyeri h.t. -Carex geyeri phase -Pseudotsuga menziesii phase

.

2 18 14

10 3 3

1 1

40 21 9

i

5

3

11

21

;1

2 3

3 4

5 5

10 17

1

5 2 2 1 15

4 2 4 6

10 6

i

i 1 1 1

i 7 8

2

1 2

8

15 24 3

1

3

6

3

3

6

15

13

44

(Upper subalpine h.t. s ) /Ribes montigenum h.t. Abies 1as.-Pinus albic./ Vaccinium scop. h.t. /Luzula hitchcockii h.t. -Vaccinium scoparium phase 5 -Menziesia ferruginea phase 14 Tsuga mertensiana/Luzula h.t. -Vaccinium scoparium phase 2 -Menziesia ferruginea 2 phase

4

3

18

4

9

1

9

2

29 24 2 2

(Timberline h.t .s) Pinus albicaulis-Abies lasiocarpa h . t. s Larix lyallii-Abies lasiocarpa h.t.s Pinus albicaulis h.t.s

4

6

5

29

1 - 168

221

3

4

6

-

i -

4 -

43

63

2 94

7

30

i

9 -

-

93

36 682 -=->-

(con. ) 35

Table R-1.--(con.) Series/habitat type/phase

-. :

NW

: WC

Montana forest region : NC : C : SW : S C

: Total

: SE

Pinus contorta series /Purshia tridentata h.t. /Vaccinium caespitosum c.t. . /Linnaea borealis c.t. 1 /Vaccinium scoparium c.t. 1 /Calamagrostis rubescens c.t. 2 Unclassified stands Total number of plots

4

3

3

;1

12 17 20

i

il

4

2

6

5

2 1 10

i

-

-

1

14

1

10

6 6 4 21

11

8

3

12

3

6

399

459

66

217

188

178

6 -

58

43 24

1

1,531

This total includes 35 Pinus contorta community type plots also listed under Pseudotsugo, Picea, or Abies Zasiocarpa habitat types.

APPENDIX C National F o r e s t s , Indian Reservations, and National Parks w i t h i n each f o r e s t r e g i o n i n Montana

N a t i o n a l F o r e s t s ( f i g . C - l ) , I n d i a n R e s e r v a t i o n s , and National Parks w i t h i n each f o r e s t r e g i o n . (N.F. = N a t i o n a l F o r e s t ; R.D. = Ranger D i s t r i c t ) :

Forest region

Areas incZuded

Northwestern

F l a t h e a d N.F. Kootenai N.F. Lolo N . F . (Thompson F a l l s , P l a i n s , S u p e r i o r , and W . and N . p o r t i o n s o f Ninemile R . D . ' s ) Flathead Indian Reservation G l a c i e r National Park (W. s l o p e )

West - c e n t r a l

B i t t e r r o o t N.F. (Montana p o r t i o n ) Deerlodge N.F. ( P h i l i p s b u r g R . D . , W . p o r t i o n o f Deer Lodge R.D.) Helena N . F. (Blackfoot R i v e r d r a i n a g e p o r t ion) Lolo N.F. (Missoula, S e e l e y Lake, and S.E. p o r t i o n o f Ninemile R.D.)

North- central

Lewis and C l a r k N.F. (Rocky Mountain Front p o r t ion) Blackfeet Indian Reservation G l a c i e r National Park ( E . s l o p e )

Central

Helena N . F . ( e x c e p t Blackfoot R . d r a i n a g e ) Lewis and Clark N.F. (except Rocky M t . Front and Crazy Mts.) F o r t Belknap (S. p o r t i o n ) and Rocky Boy Indian Reservation Chas. M . R u s s e l l N a t i o n a l W i l d l i f e Refuge (W. p o r t i o n )

Southwest e r n

Beaverhead N.F. Deerlodge N.F. (except P h i l i p s b u r g and W. p o r t i o n o f Deer Lodge R.D.'s) C u s t e r N.F. (Red Lodge R.D.) G a l l a t i n N.F. Lewis and Clark N . F . (Crazy Mts. p o r t i o n ) Crow I n d i a n R e s e r v a t i o n (Pryor and Bighorn Mts. p o r t i o n ) Yellowstone National Park (Montana p o r t i o n )

Southeastern

C u s t e r N.F. (Montana p o r t i o n except Red Lodge R.D.) Crow (except Pryor and Bighorn Mts .) and Northern Cheyenne I n d i a n R e s e r v a t i o n

Northeastern

F o r t Belknap (N. p o r t i o n ) and F o r t Peck Indian Reservation Chas. M . R u s s e l l National W i l d l i f e Refuge (E. p o r t i o n )

39 *LI.S.

G O V E R N M E N T P R I N T I N G O F F I C E : 1979-0-677-019/71

ARNO, STEPHEN F. 1979. F o r e s t regions of Montana. USDA F o r . Serv. Res. Pap. INT-218, 39 p. Intermt. For. and Range Exp. Stn., Ogden, Utah 84401. In this paper, Montanais divided into eight geographic subdivisions called " forest regions, " based on distributions of t r e e and undergrowth s p e c i e s and the relationship of these patterns t o climate and topography. The regions s e r v e a s a geographic r e f e r e n c e f o r describing patterns of f o r e s t vegetation a c r o s s the State. Data on the distributions of plant s p e c i e s and habitat types and f o r e s t zonation a r e presented f o r e a c h region. KEYWORDS: f o r e s t ecology, f o r e s t classification, plant geography, Northern Rocky Mountains

ARNO, STEPHEN F. 1979. F o r e s t regions of Montana. USDA For. Serv. Res. Pap. INT-218, 39 p. Intermt. For. and Range Exp. Stn., Ogden, Utah 84401. In this paper, Montana i s divided into eight geographic subdivisions called " forest regions, " based on distributions of t r e e and undergrowth s p e c i e s and the relationship of these patterns t o c l i m a t e and topography. The regions s e r v e a s a geographic r e f e r e n c e f o r describing patterns of f o r e s t vegetation a c r o s s the State. Data on the distributions of plant s p e c i e s and habitat types and f o r e s t zonation a r e presented f o r each region. KEYWORDS: f o r e s t ecology, f o r e s t classification, plant geography, Northern Rocky Mountains