This study analyzes the structure and biophysical correlates of density of two whitebark pine (Pinus albicaulis) populations in the northern Rocky Mountains. Whitebark pine is a keystone species and an important component of treeline ecosystem dynamics; however, subalpine populations have declined nearly rangewide in recent decades. Though declines in subalpine forests have been well documented in the literature, few studies have assessed population structure and habitat requirements at treeline. Various disturbances have combined to impact whitebark pine populations across its range, but the primary threat at treeline sites in the northern Rocky Mountains is white pine blister rust, caused by the exotic fungal pathogen Cronartium ribicola. In this study, I aim to: 1) assess population structure and regeneration within two geographically different treelines experiencing contrasting levels of infection, and 2) examine associations among several biophysical variables and whitebark pine density to better understand treeline habitat variability and regeneration patterns. I used density-diameter curves and non-parametric Kruskal-Wallis tests to compare population structure between sites, and developed generalized linear mixed models to assess correlations between whitebark pine density and biophysical site variables. The results demonstrate that despite very different ecosystems and blister rust infection rates, our two study sites have similar population structure. Our model results highlight marked differences between populations in terms of biophysical correlates of density. While correlations are similar within site, seedlings and saplings have stronger correlations with biophysical variables than established trees. / Master of Science

Coal has been and will continue to be an important energy source in the U.S. for the foreseeable future. Surface mining for coal is one of the methods employed to extract this resource from below the ground. The process of surface mining removes native topsoils and any native vegetation that was support by these native soils. In the Appalachian coal-producing region of the United States, the pre-mining landscape is predominantly forested. Prior to the Surface Mining and Reclamation Act of 1977 (SMCRA), surface mined lands were commonly reclaimed to forests. Subsequent to the passage of SMCRA, reforestation of surface mined lands has decreased. As a result, thousands of hectares of land that were forested prior to mining are being reclaimed using grasses and legumes. This is done in spite of the fact that the SMCRA requires that land be reclaimed to an "equal or higher land use." The decline of reforestation stems from two main issues, namely: (1) reclaiming land to pasture is an easy and low-risk way for mining companies to obtain bond release; and (2) SMCRA reclamation requirements have led to unfavorable conditions for tree establishment and growth. Recent interest has been shown in reverting these surface mined lands that have been reclaimed to pasture back to forests for reasons related to the environmental, economic, and carbon sequestration benefits that forests are believed to have when compared to pasture land. It is believed that forests can be established on existing reclaimed pasture land through the use of silvicultural treatments, that mature stands of trees growing on surface mines will respond to treatment similarly to stands growing on native soils, and that mature stands growing on relcaimed surface mines have different soil properties controlling their growth than those that have been found for younger stands. The purpose of this investigation was to understand the biological feasibility of restoring forests on post-SMCRA surface mined lands in the Appalachian coalfields reclaimed to pasture and to understand the productive potential and factors governing the productive potential of pre-SMCRA surface mines supporting mature forests in an attempt to show the benefits of reclaiming these lands with forests. A 3x3x3 factor random complete block design was used to assess first-year survival and growth of three species assemblages under three levels of silvicultural treatment intensity at each of three study sites having different site characteristics. The native hardwood species assemblage was found to have the best survival across all three sites, with 80 and 85% survival for sites with spoils derived from shale and oxidized sandstone, respectively. White pine generally had the lowest survival of all species and ranged from 27% across treatments on siltstone spoils to 58% across treatments on oxidized sandstone spoils. Hardwood and white pine grew little over the first year, ranging from -3.7 to 8.9cm in height compared to hybrid poplar, whose height growth ranged from 22.4cm to 126.6cm. Response to silvicultural treatment was variable by site and species, but weed control in combination with tillage generally resulted in the highest survival. Greatest height growth (126.6cm) occurred on the oxidized sandstone spoil, where hybrid poplar was treated with weed control plus tillage in combination with fertilization. Hybrid poplar was found to have the greatest growth after one year compared with the hardwood and white pine and also had the greatest height growth at each level of silvicultural intensity for all sites. This superior growth should give hybrid poplar an advantage over the others used to revert these grass lands back to forests, as the amount of height growth observed (>50cm over one year in the weed control plus tillage treatment at all sites) may be enough to ensure that these trees will not succumb to aggressive competing vegetation without further weed control. The results of this study show that based on first-year data, reforestation of these lands does appear to be biologically feasible, given the species and treaments used. In an attempt to quantify the productivity of a 26-year-old white pine stand established pre-SMCRA, a random complete block experiment was used to compare the response to a thinning that occurred in this stand at age 17. Site index of the stand was found to be 32.3m at base age 50, indicating that this is a very productive stand. Neither stand volume nor stand value was statistically different at age 26 between treatments with volumes and values ranging from 290m3ha-1 and $5639 ha-1 to 313 m3ha-1 and $5478 ha-1 for the thinned and unthinned treatments, respectively. The difference in mean breast-height diameter, however, was significant at age 26, and this was confirmed by a significant difference in a repeated measures analysis of annual diameter data for these treatments (P < 0.0001). Projection to age 30 revealed that both stand volume and value would be significantly higher in the thinned treatment by margins of 8.7 m3 ha-1 and $2457 ha-1. Regression analysis of soil data within the observed rooting depth of the trees from this stand indicated that nitrogen mineralization index, bulk density, sand percentage of the fine soil fraction, and percentage of oxidized sandstone in the soil profile were the most important variables in determining the stand's productive capacity (R2 = 0.7174). It was also found that of the five different spoil types encountered in the stand, the oxidized sandstone spoil had the most favorable physical and chemical properties for tree growth. Common root-restricting layers were found to have high soil density or increased levels of soluble salts. It has been shown that reclaimed surface mines can grow productive forests if the appropriate spoil materials are returned to the surface in sufficient depth. It has also been shown that surface mined lands reclaimed to pasture can be successfully reforested using silvicultural treatments to ameliorate unfavorable conditions for tree establishment and growth, though these treaments may not be cost-effective, and the success of these treatments was variable based on the soil characteristics of each site. / Master of Science

Whitebark pine (Pinus albicaulis) is a foundation and keystone species at alpine treelines of the northern Rocky Mountains and is threatened by the fungus white pine blister rust (Cronartium ribicola). This disease affects all five-needled white pines, but has caused particularly widespread mortality in whitebark pine. Objectives of this research were: 1) to characterize the landscape structure of the treeline study sites at Divide Mountain in Glacier National Park and at Wyoming Creek in the Beartooth Mountains of Montana using landscape metrics and fieldwork; 2) to determine the frequency of blister rust infection of whitebark pine trees and determine if landscape pattern is correlated with higher infection rates; and 3) to characterize the climate at alpine treeline. I used both field surveys and subsequent statistical analysis to meet these objectives. Field data collection included detailed surveys of blister rust infection of treeline whitebark pine and characterization of landscape cover type in a combined total of 60 quadrats, positioned at the study sites using a random sampling scheme stratified by aspect. Landscape analysis of metrics such as patch area, proximity and contagion were generated in FRAGSTATS software and ArcGIS. Spearman's rank correlation analysis found significant correlations between tree island patch size, patch perimeter, and percent of landscape and blister rust infection intensity at both study sites. These findings support previous research involving the relationship between patch area and blister rust infection rates and contribute to the field of landscape ecology by understanding what other landscape metrics are significant in invasive disease infection patterns. / Master of Science

Grafts were made using 2-0 rootstock and scion from 12 ortets of eastern white pine (Pinus strobus L.) growing at the Radford Army Ammunition Plant (RAAP). The 12 ortets represented 4 symptom severity classes (3 ortets/class) ranging from trees with > 25% of their crowns exhibiting necrotic tipburn (Class I) to those with healthy crowns (Class IV). Grafts were made in spring 1976 and ramets were grown in a greenhouse drawing charcoal filtered air. Each treatment was performed twice, on separate days for a total of 10 ramets/clone/ treatment. Five ramets/clone were used in each 6 hour treatment. The current years growth was 7-10 weeks old when treated. The treatments were as follows: 1) 0₃-10 pphm, 2) 0₃-30 pphm, 3) NO₂-10 pphm, 4) NO₂-30 pphm, 5) 0₃-10+NO₂ -10 pphm, 6) 0₃-10+NO₂ -30 pphm, 7) no pollutant. The fumigation chamber was a modified open-top field chamber located indoors. Environmental conditions during the 14 treatments averaged: 26 C, 64% RH, and 16 Klux. The ramets were evaluated prior to fumigation and then 2, 7, and 14 days thereafter for visible symptoms. The overall injury was generally light with only 11% of the clone treatment combinations exhibiting injury on > 25% of the needle fascicles. Clones I-1 and I-2 were the most sensitive clones while clones III-1, IV-2 and to a lesser degree clones III-3 and IV-1 were tolerant. These results agree with field ratings of eastern white pine sensitivity at the RAAP and provide the first step in the development of an air pollution bioindicator system at the installation. / Master of Science

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Habitat selection by, ecological energetics of, and the effects of changes in white pine (Pinus strobus L.) forests on Red Crossbills (Loxia curvirostra) were studied in Algonquin Provincial Park, Ontario. Birds were surveyed in several forest habitats and daily activities were observed during the breeding season in the autumn of 1998, a good year for white pine seed production. During the autumn of 1997 and summer of 1998, surveys of white pine stumps from trees harvested in the mid-late 1800s were conducted. Breeding birds foraged in stands with a minimum of 40% white pine, and appeared to prefer stands, both mixed deciduous-coniferous (40--70% white pine) and pine (>70% white pine) along roads. Possible reasons for this were: (1) seeds from trees along the road were more available to birds; (2) open-grown trees along the road had larger crowns with more seeds; and (3) the road provided grit and was adjacent to a favorite foraging area. (Abstract shortened by UMI.)

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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