Plant community attributes 12 to 14 years following precommercial thinning in a young lodgepole pine forest

2006 ◽  
Vol 36 (1) ◽  
pp. 48-61 ◽  
Author(s):  
P M.F Lindgren ◽  
D B Ransome ◽  
D S Sullivan ◽  
T P Sullivan

We investigated plant community responses (abundance, species diversity, and structural diversity) to a range of precommercial thinning densities in young lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands 12 to 14 years after thinning, with both unthinned and old-growth stands for comparison. Abundance of understory plants, especially herbs, appeared to increase dramatically in the thinned stands. The moss layer was significantly more abundant in old-growth stands than in the young pine stands. Of a total of 108 species sampled, only three were introduced species, all of which occurred more frequently in the low-density stands than in any of the other stands. Thinning treatments appeared to increase the abundance of late-seral species. Our results suggest that by disrupting canopy closure, thinning decreased the dominance of tall trees and increased the abundance of herbs, shrubs, and trees in the understory height classes. As a result, thinning to low densities significantly increased the structural richness of the tree layer and caused an increase in total structural diversity, which, although only marginally significant (p = 0.06), was likely biologically important. Our results suggest that thinning will enhance the abundance, species diversity, and structural diversity of the plant community 12 to 14 years postthinning.

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.


2000 ◽  
Vol 78 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Thomas P Sullivan ◽  
Walt Klenner

This study was designed to test the hypothesis that large-scale habitat alteration by stand thinning over a range of densities would increase the abundance and related population dynamics of northwestern chipmunks (Tamias amoenus) in young lodgepole pine (Pinus contorta) forest. Replicate study areas were located near Penticton, Kamloops, and Prince George in south-central British Columbia, Canada. Each study area had three stands thinned to densities of approximately 500 (low), 1000 (medium), and 2000 (high) stems/ha, with an unthinned young pine stand and an old-growth pine stand for comparison. Chipmunk populations were sampled intensively in thinned stands from 1989 to 1991 and in the unthinned and old-growth stands from 1990 to 1991. Habitat structure was sampled in all stands in 1990. For herbs and shrubs, the crown volume index values were similar among stands; for trees, this index was lowest for the low-density stands, with the index for all three thinned stands being lower than that for the unthinned stands. Species diversity and the structural diversity of vegetation were similar among stands. The abundance of chipmunks was significantly higher in low-density than in high-density thinned stands at Penticton (1.3-1.9 times higher) and Prince George (2.4-3.8 times higher) but not at Kamloops. Chipmunks were less abundant in old-growth stands than in the other four treatment stands. Breeding performance and recruitment followed the same pattern as abundance. Chipmunk survival was generally similar among stands. There were heavier chipmunks in the low-density stands in some years at Penticton. Northwestern chipmunks appear to prefer "open" habitats generated by heavy thinning of young lodgepole pine stands. This result was achieved in three different forest ecological zones and may enhance the overall forest ecosystem.


2004 ◽  
Vol 19 (4) ◽  
pp. 277-287 ◽  
Author(s):  
Suzanne W. Simard ◽  
Jean L. Heineman ◽  
Shannon M. Hagerman ◽  
W. Jean Mather ◽  
Donald L. Sachs

Abstract Five-year growth and survival responses of lodgepole pine and hybrid spruce to manual cutting of Sitka alder were studied in two montane vegetation complexes in interior British Columbia. The effects of brushing on plant community diversity and structure also were examined. Alder cover and height were reduced throughout the 5-year posttreatment measurement period, but this had no effect on growth or survival of either 5- to 7-year-old lodgepole pine growing in the Dry Alder complex or 4- to 7-year-old hybrid spruce in the Wet Alder complex. Moderate alder cover, which was characteristic at these sites, did not appear to inhibit diameter growth of lodgepole pine or spruce. This was supported by competition thresholds for conifer diameter of 30 and 37% alder cover in the Dry Alder and Wet Alder complexes, respectively. In neither complex did manual cutting result in any changes in species richness, species diversity, or structural diversity of the vascular plant community. The results of this study suggest that brushing of Sitka alder is unnecessary for release of healthy lodgepole pine growing on mesic sites in the Dry Alder complex and is ineffective at alleviating growth limiting factors to spruce on Wet Alder sites. West. J. Appl. For. 19(4):277–287.


2006 ◽  
Vol 36 (9) ◽  
pp. 2080-2089 ◽  
Author(s):  
Thomas P Sullivan ◽  
Druscilla S Sullivan ◽  
Pontus MF Lindgren ◽  
Douglas B Ransome

This study was designed to test the hypothesis that large-scale precommercial thinning (PCT) and repeated fertilization of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) would enhance relative habitat use by snowshoe hares (Lepus americanus Erxleben) in managed stands. Study areas were located near Summerland, Kelowna, and Williams Lake in south-central British Columbia, Canada. Each study area had nine treatments: four pairs of stands thinned to densities of 250, 500, 1000, and 2000 stems/ha, with one stand of each pair fertilized five times at 2-year intervals, and an unthinned stand. Understory vegetation and relative habitat use by snowshoe hares were measured annually from 1999 to 2003, 6–10 years after the onset of treatments. Mean crown volume index of herbs was significantly higher in fertilized than unfertilized stands, but density had no effect. Shrub volume was not affected by either treatment. Mean crown volume index of trees was significantly greater in the fertilized and high-density stands. Mean total richness of vascular plants was significantly reduced by fertilization. Mean total structural diversity of vegetation was highest in the low-density stands but was not affected by fertilization. Relative habitat use by hares, based on fecal pellet counts, was highest in the 2000 stems/ha and unthinned stands in summer. This pattern also occurred in winter when hare use was higher in fertilized than unfertilized stands. Overall, fertilized 2000 stems/ha stands provided habitat for hares to a degree comparable with unthinned stands of lodgepole pine.


2006 ◽  
Vol 36 (4) ◽  
pp. 878-885 ◽  
Author(s):  
J M Wolken ◽  
P V Blenis ◽  
I Duncan

The probability of lodgepole pine (Pinus contorta Dougl. ex Loud.) having main-stem galls caused by western gall rust, Endocronartium harknessii (J.P. Moore) Y. Hiratsuka, surviving to rotation is unknown. To evaluate survival, 400 galled trees with at least one stem gall and 400 trees without stem galls were measured in 1992 in two precommercially thinned stands approximately 20 years old. The survival of trees was assessed in 2003. Nonlinear regression using iteratively reweighted least squares was employed to estimate the survival of galled trees as a function of the proportion of the main stem encircled by galls. Galls encircling >79% and >91% of the stem in the two stands increased the risk of mortality relative to non-galled trees, with the risk increasing steeply with percent gall encirclement; smaller stem galls did not cause tree mortality. The 11-year pattern of survival of galled trees was similar for infections that occurred on the main stem and those that had reached the stem from a nearby branch infection. Based on an earlier model of gall expansion, 38%–43% of stem-galled trees would be expected to survive until age 80. Scribing of stem galls to prevent their expansion does not appear to be a feasible management strategy.


2005 ◽  
Vol 119 (2) ◽  
pp. 186 ◽  
Author(s):  
Gilbert Proulx ◽  
Rhonda M. Kariz

In central British Columbia, recent epidemics of Mountain Pine Beetle (Dendroctonus ponderosae) have resulted in the use of expansive clearcut areas to remove infested mature and old Lodgepole Pine (Pinus contorta) stands. This study aimed to determine if Moose (Alces alces) use late-successional Lodgepole Pine stands in mid- to late-winter. Moose activity and habitat use was determined during February-March track surveys in 2000 (60 km) and 2001 (55.7 km). In 2000 (69 tracks) and 2001 (313 tracks), Moose track distribution differed significantly (P < 0.05) from random. They were significantly more abundant than predicted in young stands (dominated by Picea spp.), or early seral stages; they were less abundant than predicted in mature and old Lodgepole Pine stands. It is unlikely that harvesting late-successional Lodgepole Pine stands would affect Moose winter habitat supply.


2020 ◽  
Vol 3 (1) ◽  
pp. 75
Author(s):  
Oladele Fisayo Falade ◽  
Janet Ugochukwu Iheke

Tree size diversity is an indicator of biodiversity values of a forest. Microsite conditions of a forest determine the survival and growth of trees. However, the contribution of variable habitats to tree size hierarchy and segregation is poorly understood. Tree size variation in a population is caused by different competition mechanisms. Therefore, the size distribution and spatial pattern of trees can identify the process governing resource utilisation in the forest. The objective of the study was to investigate the tree stem structural diversity in the Elephant Camp natural forest in the Omo Forest Reserve. Three and four 0.09 ha sample plots were established in Riparian (RF) and Old-growth forests (OF) in the Elephant Camp natural forest, respectively. The tree stems (Dbh ≥ 5cm) were identified to the species level and enumerated within each plot, and the stem density was computed. The diameter at breast height (Dbh) was measured with diameter tape. Species diversity was assessed using Shannon–Weiner (H’) and Simpson indices (1-D’), while size inequality was assessed using the Gini coefficient (GC), coefficient of variation (CV), H’ and I-D’. The performance of single two- and three-parameter Weibull models was evaluated using Kolmogorov–Smirnov (K-S) chi-square (χ2), root-mean-square error (RMSE), bias and the coefficient of determination (R2). Data were analysed using descriptive statistics. A total of 27 and 24 tree species were identified in RF and OF, respectively. The stem density of RF was significantly higher than that of OF. The values of species diversity (H’, 1-D’) and evenness (E’) were higher in OF than in RF, while richness (Margalef and number of species) was higher in RF than in OF. The Dbh was 38.30 ± 21.4 and 42.87 ± 19.2 cm in Riparian and Old-growth forests, respectively. Size-density distributions of both forests were positively skewed and expressed exponential pattern. The forest types of the Elephant Camp natural forest comprise the same size-density frequency shape but a different proportion of tree sizes and structural diversities.


ISRN Ecology ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Druscilla S. Sullivan ◽  
Pontus M. F. Lindgren ◽  
Douglas B. Ransome

We tested the hypotheses H1 that relative habitat use by snowshoe hares (Lepus americanus) would have a bimodal distribution with the highest abundance in young lodgepole pine (Pinus contorta) stands (both managed and unmanaged), minimal numbers in mature forests, and moderate abundance in old-growth forests and H2 that habitat use would increase in response to enhanced stand attributes from PCT (precommercial thinning) and fertilization treatments. Habitat use was measured by counts of fecal pellets of hares from 1999 to 2003 in forest stands in south-central British Columbia, Canada. Our results did not support the bimodal distribution of hares among coniferous stands, such that old-growth stands, at least in our region, do not provide sufficient habitat for hare populations. High-density (5000 to 13000 stems/ha) unthinned young lodgepole pine stands provide optimum habitat for hares in terms of overstory and stand structure. Thinned and fertilized stands may also provide habitat, particularly at densities ≤1000 stems/ha, and over time as understory conifers develop. Managed stands provided habitat for hares at the same level as mature stands, at 6–10 years after PCT. Maintenance of a range of managed and unmanaged stands in a landscape mosaic would be ideal for integration of silvicultural and wildlife management goals.


2006 ◽  
Vol 36 (6) ◽  
pp. 1395-1406 ◽  
Author(s):  
Thomas P Sullivan ◽  
Druscilla S Sullivan ◽  
Pontus M.F Lindgren ◽  
Douglas B Ransome

This study was designed to test the hypothesis that large-scale precommercial thinning (PCT) and repeated fertilization of young lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands would enhance relative habitat use by mule deer (Odocoileus hemionus Rafinesque) and moose (Alces alces L.) in summer and winter periods, compared to that in mature and old-growth stands. Replicate study areas were located near Summerland, Kelowna, and Williams Lake in south central British Columbia, Canada. Each study area had a range of PCT densities, with and without fertilization, and mature and old-growth stands. Habitat use in summer and winter was measured by pellet-group counts of deer and moose from 1999 to 2003, 6–10 years after the onset of treatments. During summer months, habitat use by deer was enhanced by PCT with fertilization, and the 1000 stems/ha fertilized stands experienced greater use than the unthinned or mature stands. Winter habitat use by deer was similar in the 1000 stems/ha fertilized stands and old-growth stands. In both summer and winter, moose preferred fertilized to unfertilized stands and low-density to high-density stands. Intensive management of young lodgepole pine forests has considerable potential to develop summer and winter ranges for these ungulates.


2003 ◽  
Vol 33 (6) ◽  
pp. 997-1009 ◽  
Author(s):  
R C Godfree ◽  
R O Tinnin ◽  
R B Forbes

The relationships between abundance of dwarf mistletoe (Arceuthobium americanum Nutt.) and the canopy structure of stands of lodgepole pine (Pinus contorta var. murrayana (Grev. & Balf.) Engelm.) were investigated in the central Oregon pumice zone. Foliage height profiles were generated for stands containing light, moderate, and heavy infestations of A. americanum, and the vertical distribution of P. contorta foliage was modeled using the Weibull distribution. Stand-level changes in the Weibull parameters σ (scale parameter) and c (shape parameter) as well as other canopy indices were related to the abundance of A. americanum, the density of competing tree species, and stand-level abiotic factors. Foliage intercept diagrams showed that heavily infested stands had more foliage in the lower canopy and less in the upper canopy than lightly infested stands, but that total canopy height and canopy volume were similar regardless of infestation level. We also found that dwarf mistletoe abundance was strongly related to σ (r = –0.74, p < 0.001) and c (r = –0.54, p < 0.0001). Since heavily infested stands contained fewer large but many more small P. contorta than lightly infested stands, we conclude that A. americanum causes the canopy of infested stands to change, in part, by inducing demographic changes in populations of the host tree. These results illustrate the significant effects that dwarf mistletoes can have on the structural diversity of conifer forest communities and have important consequences for the conservation and management of these systems.


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