United States 

Department of 

Agriculture 

Forest Service 

Intermountain 

Research Station 

Research Paper 

INT-364 

June 1986 

Site Treatments 

Influence 

Development of a 

Young MixedSpecies Western 

Larch Stand 

Dennis M. Cole 

Wyman C. Schmidt 

LP WL OF SAF ES 

This file was created by scanning the printed publication.

Errors identified by the software have been corrected;

however, some errors may remain.
THE AUTHORS 

DENNIS M. COLE is a research silviculturist with the 

Silviculture of Conifers in Montane and Subalpine 

Forest Ecosystems of the Intermountain and Northern 

Rocky Mountain West research work unit at the Forestry 

Sciences Laboratory, Bozeman, MT. His studies have 

focused on lodgepole pine silviculture, particularly 

growth and yield relationships, culture of immature 

stands, and management of the species in the face of 

major insect and disease problems. 

WYMAN C. SCHMIDT is a research silviculturist and 

Project Leader of the Silviculture of Conifers in 

Montane and Subalpine Ecosystems of the lntermoun· 

tain and Northern Rocky Mountain West research work 

unit at the Forestry Sciences Laboratory, Bozeman, 

MT. Dr. Schmidt's research has focused on the ecology, regeneration processes, stand development, and 

related cultural practices in coniferous forests of the 

Intermountain West. Much of his research has centered on the interrelationships of timber, water, and 

other resources as well as the interaction of cultural 

practices with insect pests such as western spruce 

bud worm. 

ACKNOWLEDGMENTS 

We gratefully acknowledge previous researchers 

involved in the initial planning, installation, and subsequent remeasurements of this study, including 

Kenneth N. Boe, Steven A. Haglund, Ward W. 

McCaughey, Arthur L. Roe, Jack A. Schmidt, Raymond 

C. Shearer, and Anthony E. Squillace. 

July 1986 

Intermountain Research Station 

324 25th Street 

Ogden, UT 84401 

Site Treatments Influence 

Development of a young MixedSpecies Western Larch Stand 

INTRODUCTION 

Dennis M. Cole 

Wyman C. Schmidt 

More intensive management could be applied to many 

young stands in conifer forests of the Northern Rockies. 

Vast areas are stocked with stands that contain a mixture of conifer species. An important mixed species 

cover type in this region is the western larch type 

(formerly called the larch-Douglas-fir type)(Society of 

American Foresters 1980). It is usually dominated by 

western larch (Larix occidentalis Nutt.) and Douglas-fir 

(Pseudotsuga menziesii var. glauca [Beissn.] Franco); but 

also has appreciable amounts of Engelmann spruce 

(Picea engelmanii Parry) and subalpine fir (Abies 

lasiocarpa [Hook.] Nutt.). Species sometimes occurring in 

the cover type are lodgepole pine (Pinus contorta var. 

latifolia Engelm.), western white pine (Pinus monticola 

Dougl.), western hemlock (Tsuga heterophylla [Raf.] 

Sarg.), and western redcedar (Thuja plicata Donn ex D. 

Don). The exact species composition in the western larch 

type is determined largely by the successional stage of 

the stand and the physical environment in which the 

stand occurs. Usually the above-mentioned mixture of 

conifer species occurs in habitat types of the Pseudotsuga 

menziesii and Abies lasiocarpa successional series 

(Daubenmire and Daubenmire 1968; Pfister and others 

1977). 

Mature and overmature forests of the western larch 

type, containing appreciable amounts of larch, Douglasfir, spruce, and white pine in the overstory, have long 

been sought for timber harvest. Many of the accessible 

mature stands have been harvested and regenerated to 

young mixed-species stands that show the influence of 

the particular cutting system and site preparation 

methods that were used. Knowledge of the effects on 

future stands of cutting systems and various site preparation and vegetation-manipulation treatments is an 

important consideration for proper management of 

stands still to be harvested. 

Because of its rapid growth, excellent wood, desirable 

esthetic qualities, and low incidence of insect attacks, 

disease, and defects, western larch is usually featured in 

management of the western larch type. But because 

most managers seek to maintain a mixture of species, 

Douglas-fir, Engelmann spruce, and lodgepole pine are 

also encouraged in the regeneration process. These objectives usually result in even-age management of stands of 

the western larch type, including either clearcutting, 

shelterwood, or seed-tree methods of regeneration 

(Schmidt and others 1976). Each of these cutting 

methods can provide favorable conditions for natural 

regeneration of the favored species-but depending on 

seedbed and understory vegetation conditions following 

cutting, the composition, density, and growth of the 

future stand can vary widely (Polk and Boe 1951; Roe 

1955; Schmidt 1969). 

Polk and Boe (1951) and Roe (1955) concluded that 

desired composition of the future stand can neither be 

attained nor maintained through cutting method alone; 

seedbed preparation and later stand improvement practices are necessary. Specifically, practices are required 

that obtain establishment of desired tree species before 

shrubs and other vegetation overwhelm the site. Roe 

(1955) studied the relative need for sunlight and mineralsoil seedbeds of larch and its common associates in the 

western larch type at Terrace Hill on the Coram 

Experimental Forest in northwestern Montana. He 

described the relationships among method of cutting, 

proportion of ground surface in favorable seedbed, and 

resultant stocking percentages of each species. 

Schmidt (1969) later reported on seedling and early 

sapling development and concluded that site 

preparation-in the form of mechanical scarification, 

prescribed burning, and slashing of competing shrubsinfluenced not only regeneration establishment, but subsequent seedling development. He found, after 12 to 

15 years, that larch regenerated abundantly, grew 

rapidly, and became dominant where prescribed burning 

or mechanical scarification provided a sufficient area of 

ash or mineral soil seedbeds and reduced the amount of 

competing vegetation. Spruce seedlings also required 

mineral soil for successful establishment but grew slowly 

on the exposed seedbeds favored by larch. In contrast, 

Douglas-fir was insensitive to seedbed condition in the 

regeneration phase, but tended to dominate the stands 

where seedbeds had little or no preparation and larch 

competition was light. 

From the above observations, Schmidt (1969) predicted 

that the direct effects of seedbed and understory would 

continue to diminish and the effects from differences in 

stand density and shade tolerance would increase as the 

stand grew past the early" sapling stage. This report 

tests this hypothesis by comparing subsequent growth 

patterns against site treatments in the 25-year-old stand. 
STUDY DESCRIPTION AND 

PROCEDURES 

This study was established at Terrace Hill on Coram 

Experimental Forest in northwestern Montana within a 

large, recently logged stand of western larch and 

Douglas-fir. The stand was located on a lower northeast 

slope and had a larch site index of 58 ft at 50 years-a 

medium site. The original stand consisted primarily of 

western larch (WL) and Douglas-fir (DF), but contained 

small numbers of spruce (ES), western white pine 

(WWP), lodgepole pine (LP), subalpine fir (SAF), and 

western hemlock (WH). The stand was logged in 1943, 

leaving about five healthy, well-distributed dominant 

larch seed trees per acre and a heavy residual understory 

of trees (chiefly subalpine fir and tall shrubs such as yew 

[Taxus brevifolia Nutt.]). Slash was piled and burned in 

1944. In 1945, the residual understory of trees and tall 

shrubs was slashed on an area of 8 acres and an equalsize area left unslashed. The ground surface after logging and burning included undisturbed forest floor and 

mineral soil exposed by tractor skidding, road construction, and slash burning. These operations left four generalized combinations of seedbed-vegetative competition 

conditions for study: (1) unslashed-unscarified, (2) unslashedscarified (scarified only), (3) slashed-unscarified (slashed 

only), and (4) slashed-scarified. It is important to understand that unslashed and unscarified treatments still 

received some soil disturbance in the course of the logging process. 

Fifteen milacre (0.0004-ha) plots were randomly established for each of the four seedbed/competing vegetation 

conditions, making a total of 60 sample plots. In 1949, 

after several years had been allowed for adequate seedfall, reproduction was tallied by species. Following the 

reproduction tallies, the study was converted to a stand 

development study and the initial seedling establishment 

and early seedling development results were reported 

(Roe 1955). Upon conversion to a stand development 

study, all tree seedlings on the milacre study plots were 

recorded by species and measured for height to the 

nearest 0.1 ft (3 em) and their vigor subjectively classified as good, fair, or poor, on the basis of crown length 

and density, needle color and length, and prior growth. 

As the trees grew into and beyond the sapling stage at 

the third and fourth measurements, crown class of trees 

on the milacre plots was also recorded. At the fourth 

measurement at 25 years, diameter at breast height 

(d.b.h.) was also measured on all trees exceeding 4.5 ft 

(1.37 m) in height. 

Data from this completely randomized study were subjected to analysis of covariance to determine the statistical significance of treatments on growth of the different 

species. Trees-per-acre stocking at establishment in 1949 

was used as the covariate in these analyses. Trends in 

stocking, composition, vigor, and dominance were also 

analyzed. 

2 

RESULTS 

A brief review of the 15-year results shows that the 

seed trees, adjacent timber, and small understory trees 

left after logging produced enough seed to adequately 

stock, and in most cases overstock, the study area. The 

mineral soil seedbeds were especially overstocked, 

primarily with larch and spruce (Schmidt 1969). Nonscarified forest floor seedbeds had only about one-third 

the stocking of the mineral soil seedbeds and had higher 

proportions of Douglas-fir and subalpine fit in comparison to larch and spruce. These treatment-related differences in stocking density and composition provided the 

basis for earlier forecasts of significant differences 

among the species in future survival, growth, vigor, and 

relative expression of dominance in the stand (Schmidt 

1969). 

The earlier report (Schmidt 1969) of growth differences 

among species featured dominant trees, but after 25 years 

many dominant sample trees were dead. Therefore, 

growth results presented here are in terms of all trees 

surviving on the quadrats at the last measurement. 

Height growth from 15 to 25 years of age and breast 

height diameter at 25 years of age were analyzed for the 

major species regenerated in the study area: western 

larch, lodgepole pine, Douglas-fir, Engelmann spruce, 

and subalpine fir. With the additional 10 years of stand 

development, growth effects have become more evident, 

earlier conclusions can be tested, and still stronger inferences for future stand development can be made. 

Diameter Growth 

Several treatments had produced no Engelmann 

spruce or subalpine fir of breast height at the time of 

the last measurement; therefore only western larch and 

Douglas-fir were analyzed for diameter growth differences among species and treatments. Treatment effects 

differed significantly (p=0.05) between western larch and 

Douglas-fir. Scarification resulted in greater diameters 

among western larch than Douglas-fir (fig. 1). Slashing 

promoted growth of larch more than Douglas-fir, but 

only on unscarified plots (fig. 1). The largest diameters 

were registered for larch on unscarified, slashed plots; 

the smallest diameters were also larch, but where no 

slashing or scarification had occurred. The slow diameter 

growth of larch in unscarified areas likely results from 

the intolerance of larch to competition from overtopping 

residual vegetation in the unslashed plots. The rapid 

diameter growth of larch is likely a consequence of limiting competition by slashing but not scarifying seedbeds. 

In contrast to larch, slashing on unscarified plots 

reduced diameter growth of Douglas-fir. This effect 

seems to be related to the strong growth performance of 

the larch; the higher densities and faster growth of larch 

apparently suppress diameter growth of Douglas-fir 

established at the same time. Slashing had virtually no 

effect on either larch or Douglas-fir on scarified plots. 
] 

] 

3.0 WESTERN LARCH DOUGLAS-FIR 

~ f<'~Q ~'\ 

en 2.0 (j~ 

a: ~C:J 

> ~ 

II) 

N 

J: 

Ill 

c 1.0 

0 ---·------------·- • • 

• • • • UNSLASHED SLASHED UNSLASHED SLASHED 

Figure 1.-Effect of scarification and slashing on diameter 

growth to 25 years of age. 

Height Growth 

Height growth differences among western larch, 

Douglas-fir, Engelmann spruce, and subalpine fir were 

not significant when adjusted for stand density, but 

treatments did significantly affect (p=0.05) height 

growth of all species (fig. 2). Slashing of understory 

shrubs and trees left after the seed tree harvest resulted 

in significantly greater height growth of regeneration 

than when left unslashed, while scarification significantly reduced height. growth only in plots where slashing had occurred. The best height growth occurred where 

no scarification occurred but where residual trees and 

shrubs were slashed. In contrast, the poorest height 

growth occurred where scarification had occurred, but 

where no slashing was done. 

Seedling vigor-classified on the basis of early growth, 

foliage density, and needle color and length-was a good 

indicator of subsequent height growth in earlier measurements of this study (Schmidt 1969). For example, from 

age 10 to 15, good-vigor larch, lodgepole pine, Douglasfir, and subalpine fir grew about two and six times 

faster than their fair-vigor and poor-vigor counterparts. 

Good-vigor spruce grew only about twice as fast as their 

poor-vigor counterparts. Each vigor class of western 

larch and lodgepole pine grew about twice as fast as 

other species of corresponding vigor classes during that 

period. 

Tree vigor at the last measurement was again considered as a means of evaluating height growth. A discriminant analysis was made to determine whether vigor 

could be classified using species and treatment variables; 

however, no effective discriminator involving treatments 

was found. Therefore, vigor was evaluated as before as 

an influence on growth, irrespective of treatments. 

3 

1-

u. 

u; 

a: 

> 

5 

4 

~ 3 I 

It) 

-::Z:: ........................ UNSLASHED 1- ........................ .. ~ ............................... . 0 2 

a: 

.... " 

::z:: 

" w 

::z:: 1 

0~--·-------------------------------·-- • UNSCARIFIED 

Figure 2.-Effect of scarification and slash· 

ing on height growth of major species from 

age 15 to 25 years. 

• SCARIFIED 
The same general height growth relationships apparent 

in the 10- to 15-year age period among and between species and vigor classes were also apparent in the 15- to 

25-year age period (fig. 3). On the basis of average periodic annual increment (P AI), however, growth rate 

differences of the good-vigor class lessened for most species, as did differences between species within the same 

vigor class. Douglas-fir was the exception; trees in the 

good-vigor class at 15 years of age increased in height 

PAl from 15 to 25 years of age, suggesting that favorably located Douglas-fir seedlings of good vigor can be 

expected to gradually increase their growth rate and 

maintain their vigor in the first 25 years of stand 

development. The two seral species, larch and lodgepole 

pine, continued to exceed other species in rate of height 

growth, but trees originally noted for good vigor grew 

substantially slower from age 15 to 25 than they had 

from age 10 to 15. Differences in PAl between the two 

growth periods were less apparent and less consistent 

for the fair and poor vigor trees. Major seral species, in 

particular, were influenced in the regeneration stage by 

seedbed conditions and competing vegetation; with time 

this becomes less important than intertree competition. 

A composite of the total 25-year period shows the two 

sera! species-lodgepole pine and western larch-making 

the greatest total height growth (fig. 4). Even the fairvigor lodgepole pine and western larch had greater 

... 

u.. 

..: 

z 

w 

::E 

w 

a: 

0 

! 

... 

::r: 

CJ 

iij 

::r: 

1.5 

1.0 

~ 0.5 

0 

a: 

w 

0. 

0 

Figure 3.-Periodic annual height increment 

for the age periods 10 to 15 and 15 to 25 of 

five conifers in three different vigor classes. 

VIGOR 

GOOD 

4 

height growth than the good-vigor trees of all other species, but the good-vigor Douglas-fir were accelerating. 

The shade-tolerant subalpine fir and spruce lagged 

behind in keeping with their normal understory positions 

in this forest type. How differential species performance 

influenced the character of the stand at age 25 is discussed in the following section. 

30 

25 

... 

u.. 

u) 20 a: 

> 

II) 

N 

... 15 ::r: 

CJ 

iij 

::r: 

..... 

o( 10 ... 

0 

... 

Figure 4.-Total height at age 25 of five 

different conifers in three different vigor 

classes. 

Stand Character 

VIGOR 

Western larch and spruce comprised two-thirds or 

more of the large number of trees per acre established 

on seedbeds that had been scarified; Douglas-fir and 

subalpine fir comprised about two-thirds of the lessdense regeneration in tlie treatments where the forest 

floor was unscarified (Schmidt 1969). But total stand 

density, species stocking frequency, and stocking frequency of dominant trees have changed markedly during 

the 25 years of study (table 1). Where the forest floor 

was not scarified, initially modest stand densities 

increased by about 1,000 trees per acre. Where scarified, 

stand densities increased substantially where understory 

had not been slashed-apparently due to continued 

regeneration of the more tolerant species from the 

residual seed source. Where scarified and slashed, stand 

density peaked at age 15 but by age 25 declined below 

the density at age 10, due mainly to mortality of western larch from interspecies competition. At age 15, larch 
Table 1.-Stand density and stocking frequency of all trees and dominants by 

age and treatment 

Density Stocking frequency 

of 

Treatment Age regeneration WL1 DF ES SAF Other2 

Trees/acre ---------------Percent---------------

Unslashed, 10 3,140 333(33) 67(53) 7(0) 20(7) (7) 

unscarified 15 4,210 40(40) 73(40) 13(0) 20(7) (13) 

25 4,267 40(40) 73(36) 7(0) 33(7) (17) 

Unslashed, 10 13,390 100(93) 80(0) 80(0) 60(0) (7) 

scarified 15 17,330 100(93) 80(0) 100(0) 87(0) (7) 

25 16,733 87(67) 73(13) 93(0) 80(0) (20) 

Slashed, 10 3,270 67(47) 73(53) 20(0) 33(0) (0) 

unscarified 15 4,410 73(47) 67(46) 40(0) 33(0) (7) 

25 4,067 53(33) 67(40) 47(0) 33(0) (7) 

Slashed, 10 10,470 93(73) 80(13) 73(0) 7(0) (14) 

scarified 15 12,800 87(66) 80(7) 80(0) 20(0) (27) 

25 9,467 87(59) 67(7) 80(0) 20(0) (34) 

1Relative shade tolerance ranking of species is from left to right, least (WL) to most 

(SAF). 20thar species were primarily lodgepole pine and a few western white pine. 3Frequencies in parentheses are the percentages of milacre quadrats in which dominant trees of the species occur. 

occurred uniformly on scarified areas and dominated up 

to 90 percent of such areas, but by age 25 their stocking 

distribution had declined and they dominated only about 

two-thirds of scarified area. Most of the decline in larch 

dominance on scarified seedbeds occurred where competitive shrubs and understory trees were not removed. 

Larch only stocked 40 to 50 percent of the unscarified 

areas, but where they were able to establish, they 

usually became dominant. 

Like larch, spruce was well-distributed, stocking at 

least 50 percent of the area where slashing had occurred 

and over 80 percent of the area where scarification had 

occurred. Because of its slow juvenile growth, spruce 

was overtopped by other species and exhibited no dominance in any treatment. 

Douglas-fir was well-distributed at age 25, indicating 

little establishment preference for any treatment. In 

unscarified treatments, Douglas-fir was able to express 

dominance about equally with larch, apparently because 

of significantly lower larch stocking densities there; but 

it expressed little dominance in scarified areas where 

larch and lodgepole pine dominated. 

Tree Vigor 

Considering the treatment-related differences in stocking and dominance, changes in the relative vigor status 

of the species were expected. Initially larch, Douglas-fir, 

spruce, and subalpine fir each had about 60 percent of 

seedlings classified as good vigor, but by age 25 each 

except subalpine fir had declined to about 30 percent 

high-vigor trees. Overstocking was taking its toll on 

vigor. 

The vigor of subalpine fir increased slightly to about 

65 percent classified as good vigor. This slight increase 

occurred on the scarified-only treatment, but was offset 

by a similar decrease on the treatments where slashing 

5 

had occurred. These effects are consistent with the relative shade tolerance ranking of subalpine fir. 

At 25 years of age, more than three-fourths of the 

good-vigor larch occurred on the treatments receiving 

scarification. Conversely, the percentage of poor-vigor 

larch there increased from 5 to over 25 percent. More 

than three-fourths of poor-vigor larch occurred on scarified plots-an apparent consequence of the high stand 

densities on scarified treatments. 

The reduction in numbers of good-vigor spruce at age 

25 occurred almost exclusively on scarified treatments, 

even though such sites supported nearly all of the 

remaining good-vigor spruce. Like larch, these reductions 

in vigor indicate that the heavy stand densities in the 

scarified treatment areas reduce spruce vigor, despite 

the encouragement of spruce establishment by scarification. 

Initially, good-vigor Douglas-fir occurred at about the 

same frequency on all treatments, but by age 25, twothirds of the good-vigor Douglas-fir were found on 

unscarified treatments. Poor-vigor Douglas-fir increased 

from 10 percent to more than 35 percent of trees at age 

25. The highest proportion of good-vigor trees and the 

lowest proportion of poor-vigor trees occurred on the 

slashed-only treatment. 

DISCUSSION AND CONCLUSIONS 

The Terrace Hill study demonstrates that seed-tree 

cutting in the western larch type allows considerable 

flexibility in guiding the composition and development of 

the new stand, depending on seedbed and understory 

vegetation treatment in the establishment phase. It also 

demonstrates the consequences of failing to control density through the late sapling-early pole stage-in terms 

of height and diameter growth, dominance, and vigor. 
As pointed out earlier (Schmidt 1969), precise regulation of stocking is difficult in natural regeneration systems because of yearly variations in seed production, 

germination, and seedling survival among species; therefore, cleaning or thinning in the sapling stage assumes 

critical importance for guiding the composition and 

growth of the future stand. Because this study was neither thinned nor cleaned, the known benefits of these 

practices for furthering stand development and management objectives could not be quantified. On the other 

hand, at age 15 longer term consequences of the overstocking on the different species could only be speculated upon by extrapolating trends in the first 15 years 

of stand development. The additional 10 years of natural 

stand development to age 25 provided a better basis for 

testing of earlier conclusions on the apparent course of 

mixed species stand development in overstocked natural 

regeneration in the western larch type. 

Results of this study to age 15 suggested that where 

there had been little or no scarification or removal of 

understory vegetation, intolerant species-especially 

larch-were disadvantaged and expected to decline further in vigor and generally be poor prospects for future 

management. At age 25, this expectation is less clear. 

Western larch and lodgepole pine, both very shadeintolerant species, have maintained their relative positions of dominance and growth in the stand even where 

no scarification or removal of competing understory 

vegetation occurred. Apparently, once established with 

other species in the western larch type, larch are able to 

express dominance as well or better than other species. 

This is not to suggest that choice and timing of seedbed 

and competing vegetation treatments is not important. 

Composition and relative growth of the different species 

are strongly affected by seedbed and competing vegetation conditions and their resultant stand density effects. 

From a management perspective, considerable flexibility is provided managers by seed-tree cutting in this forest type, when seedbed and vegetation conditions are 

manipulated in the regeneration process. If the objective 

is to maximize timber production on a short rotation, 

scarification and removal of competing vegetation will 

ensure prompt and predominant larch regeneration with 

significant representation of spruce and Douglas-fir. But 

growth rates will not meet short rotation objectives 

unless stand density is controlled at an early age. 

Because larch and lodgepole pine have regeneration and 

growth advantages on disturbed sites, they have strong 

timber production advantages; but the beginning of 

growth decline due to overstocking during the 15- to 

25-year age period demonstrates the need for early cleaning and spacing to enhance vigor and growth. On the 

other hand, a delay in cleaning and thinning does not 

appear as critical for the more shade-tolerant Douglasfir, subalpine fir, and spruce. Even though the treatment 

areas that had not been scarified but had competing 

vegetation removed had the best overall vigor and 

growth after 25 years, it is possible that, had stand density been reduced, the early height growth advantage of 

larch on scarified areas might have been maintained. 

*U.S. GOVERNMENT PRINTING OFFICE: 1986-0-676-039/41,000 

6 

Several conclusions are drawn from the study: 

1. Seed-tree cutting in the western larch type generally leaves interspersed areas of scarified soil and 

undisturbed forest floor, on which regeneration of mixed 

species generally ranges from adequate to overstocked. 

2. For all species in general, slashing of residual 

understory trees and shrubs results in greater height 

growth. The greatest height growth occurs in the 

slashed-unscarified areas where both effects of stand 

density and understory vegetation are minimized. 

3. Larch is dominant or codominant in early stand 

development, particularly on scarified areas. Douglas-fir 

is codominant with larch in early stand development 

where no scarification occurs. 

4. After 25 years, good-vigor larch and lodgepole pine 

were able to maintain significantly faster height growth 

on all treatments than the other major species; all vigor 

classes of larch grew significantly faster in diameter 

than Douglas-fir, except on the unslashed-unscarified 

treatment. 

5. Although considerable flexibility is possible in the 

seed-tree system in guiding initial species composition, 

density of regeneration, and early growth through 

scarification and understory vegetation control, the best 

opportunity for long-lasting influence on composition 

and growth of the stand is through early cleaning and 

thinning operations. 

6. The first 25 years is a dynamic period in, the life of 

a stand in this forest type, and it is then that managers 

have the greatest opportunity to shape the character of 

the future forest in terms of density, composition, structure, and timber yield. 

REFERENCES 

Daubenmire, R.; Daubenmire, Jean B. Forest vegetation 

of eastern Washington and northern Idaho. Technical 

Bulletin 60. Pullman, W A: Washington Agricultural 

Experiment Station; 1968. 104 p. 

Pfister, R. D.; Kovalchik, D. B.; Arno, S. F.; Presby, R. C. 

Forest habitat types of Montana. General Technical 

Report INT-34. Ogden, UT: U.S. Department of 

Agriculture, Forest Service, Intermountain Forest and 

Range Experiment Station; 1977. 174 p. 

Polk, R. Brooks; Boe, Kenneth N. Succession of trees in 

cutover larch-Douglas-fir stands in western Montana. 

Montana Academy of Science Proceedings. 10: 31-37; 

1951. 

Roe, Arthur L. Cutting practices in Montana larchDouglas-fir. Northwest Science. 29: 23-34; 1955. 

Schmidt, Wyman C. Seedbed treatments influence seedling development in western larch forests. Research 

Note INT-93. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range 

Experiment Station; 1969. 7 p. 

Schmidt, Wyman C.; Shearer, Raymond C.; Roe, Arthur L. 

Ecology and silviculture of western larch forests. Technical Bulletin 1520. Washington, DC: U.S. Department 

of Agriculture, Forest Service; 1976. 96 p. 

Society of American Foresters. Forest cover types of the 

United States and Canada. Eyre, F. H., ed. Washington, 

DC; 1980. 148 p. 
Cole, Dennis M.; Schmidt, Wyman C. Site treatments influence development of a 

young mixed-species western larch stand. Research Paper INT-364. Ogden, 

UT: U.S. Department of Agriculture, Forest Service, Intermountain Research 

Station; 1986. 6 p. 

Four treatments, all combinations of leaving or removing residual trees and 

shrubs or scarifying or not scarifying seedbeds, were evaluated for species 

differences in growth, vigor, and expression of dominance. Western larch was 

the dominant species in regeneration and growth but had begun to lose some 

of its advantage by age 25, particularly on scarified areas where overstocking 

commonly occurred. Douglas-fir was less sensitive to the treatments and, 

although significantly slower in absolute growth than larch, began to accelerate 

after 15 years of age. This study confirms that early cleaning and thinning will 

be necessary to achieve composition, density, and performance goals. 

KEYWORDS: western larch, mixed species, stand development, regeneration 

treatments, site preparation, vegetation control 
INTERMOUNTAIN RESEARCH STATION 

The Intermountain Research Station provides scientific knowledge and technology to improve management, protection, and use 

of the forests and rangelands of the Intermountain West. Research 

is designed to meet the needs of National Forest managers, 

Federal and State agencies, industry, academic institutions, public 

and private organizations, and individuals. Results of research are 

made available through publications, symposia, workshops, training 

sessions, and personal contacts. 

The Intermountain Research Station territory includes Montana, 

Idaho, Utah, Nevada, and western Wyoming. Eighty-five percent of 

the lands in the Station area, about 231 million acres, are classified 

as forest or rangeland. They include grasslands, deserts, shrublands, alpine areas, and forests. They provide fiber for forest industries, minerals and fossil fuels for energy and industrial development, water for domestic and industrial consumption, forage for 

livestock and wildlife, and recreation opportunities for millions of 

visitors. 

Several Station units conduct research in additional western 

States, or have missions that are national or international in scope. 

Station laboratories are located in: 

Boise, Idaho 

Bozeman, Montana (in cooperation with Montana State 

University) 

Logan, Utah (in cooperation with Utah State University) 

Missoula, Montana (in cooperation with the University of 

Montana) 

Moscow, Idaho (in cooperation with the University of Idaho) 

Ogden, Utah 

Provo, Utah (in cooperation with Brigham Young University) 

Reno, Nevada (in cooperation with the University of Nevada)