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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Spridning av contorta från bestånd i södra Sverige : En fältstudie i Östergötland och Småland / Self-dispersal of lodgepole pine from forest stands in southern Sweden : A field study in Östergötland and Småland

Agestam, Elin January 2020 (has links)
Contorta (Pinus contorta) är ett barrträdslag som naturligt finns i västra Nordamerika och är inplanterat främst i norra Sverige. Syftet med detta arbete är att utvärdera hur långt och i vilken omfattning contorta spridit sig från äldre bestånd i södra Sverige. Resultatet skulle kunna användas vid bedömning om det finns en spridningsrisk i södra Sverige. De tre bestånden som användes vid detta arbete ligger i södra Östergötland och norra Småland. Datainsamlingen utfördes i tre steg i respektive bestånd: 1. Bedömning om contorta kan spridas och etableras från bestånd i södra Sverige. 2. Inventering av contortaplantor i subjektivt valda ytor. 3. Kvantitativ inventering av contortaplantor i systematiskt utlagda linjer, 2 meter breda och 250 meter långa, i fyra riktningar utgående från beståndskant. I inventeringen av subjektivt utvalda ytor hittades contortaplantor 350 meter från contortabestånd och i den kvantitativa inventeringen 50 meter från contortabestånd. Totalt hittades 27 contortaplantor (motsvarande 450 st/ha) i subjektivt utlagda ytor och 18 contortaplantor (45 st/ha) hittades i den kvantitativa inventeringen. Alla funna contortaplantor hittades på störd mark och där trädkronans täckning var noll, dvs. där ljustillgången var högst. Det är däremot inte möjligt att, utifrån denna studie, säga vilken faktor som är primär för contortaplantornas etablering, markstörning eller ljustillgång. / Contorta (Pinus contorta) is a coniferous tree species from western North America that has been introduced mainly in northern Sweden. The purpose of this work was to evaluate how far and to what extent (number of self-dispersal seedlings/ha) Contorta has spread from older populations in southern Sweden. The result can be used in assessing the risk of spreading in southern Sweden. The three forest stands used for this work were located in southern Östergötland and northern Småland, Sweden. The data collection was done in three stages in each stand: 1. Assessment if contorta can be disseminated and established from stocks in southern Sweden. 2. Subjective inventory of Contorta plants in selected areas. 3. Quantitative inventory of contorta plants along defined corridors, 2 meters wide and 250 meters long, in four directions from the edge of the stock. In the inventory of subjectively selected areas, contorta plants were found 350 meters from a contorta stand and in the objective inventory 50 meters from a contorta stand. A total of 27 contorta plants (equivalent to 450 plants/ha) was found in subjectively inventory and 18 contorta plants (45 plants/ha) were found in the quantitative inventory. All Contorta seedlings were found on disturbed ground and where the canopy cover of trees was zero, i.e. where the access to light was highest. On the other hand, based on this study, it is not possible to say which factor is most important for the establishment, field disturbance or light supply.
62

Forage Preferences of Mule Deer in the Lodgepole Pine Ecosystem, Ashley National Forest, Utah

Deschamp, Joseph A. 01 May 1977 (has links)
During the summer of 1976, five tame, trained mule deer (Odocoileus hemionus hemionus) were used to determine botanical composition and relative preference of mule deer diets on five habitat segments in the lodgepole pine (Pinus contorta) ecosystem of northeastern Utah. Diets were statistically analyzed according to estimated we1ghL consumption per unit of time spent feeding on the different segments. Habitat segments sampled were: clearcut forest, dry and wet meadow, mature forest, and stagnated forest. Diets differed between segments mainly because of differences in plant species available and their abundance. The diets in the non-forested segments averaged over 90 percent forbs,while in the forested segments forbs were only 65 percent of the diet. Differences are attributed to the low availability of forbs in the forested segments which are composed of over 90 percent browse, mainly grouse whortleberry (Vaccinium scoparium). Grasses and sedges were an insignificant part of the diet on all segments. Dietary differences based on forage classes were unimportant within the three non-forested segments as were diet differences within the two forested segments. Dietary differences based on estimated weight consumed per unit of time spent feeding were significantly different between all segments except the dry and wet meadow. The segments were thus ranked according to their importance as feeding areas for mule deer: 1. clearcut forest, 2. dry and wet meadow, 3. mature forest, and 4. stagnated forest. There was no apparent difference between diet composition computed from weight estimates and that computed based on bite counts for the first part of the summer. However, when mushrooms began growing and were eaten during the last part of the summer, comparisons of percent composition of diet derived from bite counts with that from estimated weights showed major differences. Especially was this true for diets from forested segments which had a larger proportion of mushrooms available in the community.
63

Solar Radiation Under Thinned and Unthinned Lodgepole Pine Stands on the Utah State University School Forest

Durtschi, Belden B. 01 May 1968 (has links)
Shortwave solar radiation was measured in the late winter of 1967 by means of actinographs below the canopy of two lodgepole pine stands, one thinned and the other unthinned, in northern Utah. Observations were made at four randomly selected stations in each stand and at one station in a large clearing. Radiation available below the thinned and unthinned stands was compared, and radiation in the open was compared with radiation beneath each stand. Nearly a ll differences between stands were significant as were the differences between each stand and the open area. A close correlation was shown between total radiation in the open and total radiation beneath forest stands. It was concluded that the radiation beneath either the thinned or the unthinned stand was above the minimum (ca. 10 percent of full sunlight) required for adequate reproduction of Engelmann spruce and subalpine fir.
64

Physical and mechanical properties evaluations of a new engineered wood product

Linton, Jonathan Michael 10 December 2010 (has links)
Finding alternative uses for small diameter raw materials is a critical problem throughout the United States. Insufficient markets for small diameter, southern yellow pine (Pinus spp.) trees from first plantation thinnings are impacting silvicultural practices on millions of acres of land. In western states, the lack of markets for small diameter ponderosa pine (Pinus ponderosa) and lodgepole pine (Pinus contorta) creates multiple problems in terms of excess material in the forest. This excess material enhances fire potential and reduces land management practices. This research deals with a new structural composite from small diameter raw logs using a technology called steampressed scrim lumber (SPSL). Mechanical and physical properties were performed and evaluated for each species. This research was conducted to evaluate these properties and to determine the suitability for commercialization.
65

Tracing changes in uptake of precipitation and groundwater and associated consequences for physiology of Douglas-fir and lodgepole pine trees in montane forests of SW Alberta

Andrews, Shilo F., University of Lethbridge. Faculty of Arts and Science January 2009 (has links)
Douglas-fir (Pseudotsuga menziesii) and lodgepole pine (Pinus contorta) in southwestern Alberta were studied to determine the water sources used and the effect of changing soil moisture on tree ecophysiological function. The hydrogen stable isotope ratios of water from local groundwater and precipitation were compared to tree stem water to determine the amount of stem water coming from those two sources. There were no significant differences between species in the portion of summer precipitation taken up. However, Douglas-fir shifted towards using more groundwater as shallow soil moisture declined. In addition, Douglas-fir showed large changes in shoot water potential, but maintained relatively constant rates of oxygen evolution, whereas lodgepole pine exhibited smaller changes in shoot water potential and had severely reduced rates of oxygen evolution during mid-summer drought. Lower leaf-area to sap-wood area and higher leaf δ13C (carbon isotope composition) suggested a less efficient hydraulic system in Douglas-fir compared to lodgepole pine. / x, 91 leaves : ill. ; 29 cm
66

Relationships between site index of major tree species in the ESSF zone and ecological measures of site quality

Klinka, Karel, Krestov, Pavel, Chourmouzis, Christine January 1999 (has links)
Knowledge of ecological characteristics of sites and growth of trees on different sites is fundamental for silvicultural decision-making and planning. With the biogeoclimatic ecosystem classification in place in British Columbia, silvicultural management has been given an ecological foundation; however, relationships between growth and site quality have not yet been fully investigated, particularly for high-elevation tree species and sites. One of the contributing factors for this situation is limited knowledge of forest productivity in the high-elevation Mountain Hemlock (MH) and Engelmann Spruce - Subalpine Fir (ESSF) biogeoclimatic zones. Consequently, the management and planning in the high-elevation forest is fraught with difficulties and uncertainties. Current harvest rates of old-growth forest stands and the method and distribution of cuttings in these zones suggest that there needs to be more recognition of the uppermost elevation limit for harvesting. Subalpine fir (Bl), Engelmann spruce (Se), and lodgepole pine (Pl) are important timber crop species in the interior high-elevation forest which is represented predominantly by the subalpine boreal ESSF zone. This zone extends from 49° to approximately 57° N latitude and from approximately 900 to 1,700 m in the north, from 1,200 to 2,100 m in central BC, and from 1,500 to 2,300 m in the south. In view of this relatively wide climatic and edaphic amplitude, a large variability in productivity is expected. The objective of this study was to quantify relationships between site index (height @ 50 yrs @ bh) of Bl, Se, and Pl, and three ecological determinants of site quality: climate, soil moisture, and soil nutrients. Quantitative relationships between site index and these measures provide predictive models for estimating site index. Additionally, we compared the site indices of the three study species to each other to examine their early height growth performance on the same sites.
67

An assessment of Pinus contorta seed production in British Columbia: Geographic variation and dynamically-downscaled climate correlates from the Canadian Regional Climate Model

Lew, Alicia 28 April 2015 (has links)
Lodgepole pine (Pinus contorta Douglas ex Louden) is the most widespread pine in North America and the single most abundant tree species in British Columbia (BC). Its vast distribution, diversity and economic value make it an important species for timber harvest and subsequent reforestation. Climate change raises serious concerns over the adaptability and effective management of BC’s future forests. The majority of lodgepole pine seedlings requested for replanting are produced from seed obtained from wild stands, but the relationship between climate variation and the seed production of natural populations has yet to be assessed. The purpose of this study is to determine if variation in P. contorta seed yield is related to the climate of BC. Historical cone collection data were obtained from archived records of 1948 seedlots in 22 different natural stand seed planning zones (SPZs) of BC. Collections were made between 1963 and 2013 and seed yield (kg fresh seed/hL cone) was determined for each seedlot. First, natural variation in seed production of lodgepole pine was examined in 18 different SPZs. The Nass Skeena Transition (NST) represents a unique intersection between continental and maritime ecosystems and was found to have a significantly higher mean seed yield compared to all other zones, with the exception of Hudson Hope (HH). However, variance in seed yield for NST was found to be an order of magnitude higher than that of other SPZs, indicating that seed production in this region is exceptionally variable. These findings provide a valuable geographic baseline for the reproductive fitness of lodgepole pine, suggesting that climate adaptation and mitigation strategies for some areas of the province may need to be region-specific. In addition, the relationship between climate variation and the seed production of P. contorta in BC was evaluated. The climate of each region was described using dynamically-downscaled Global Circulation Model (GCM) and reanalysis climate output from the Canadian Regional Climate Model (CRCM). Annual, winter, and summer means were explored for each of the climate variables of interest: total precipitation (mm) and surface air temperature (°C). Temporal correlations between the mean annual seed yield anomaly and the anomaly of both climate variables were significant under a variety of climate schemes in a number of SPZs. Significant overall trends in climate variables were also captured using GCM-driven CRCM output. While these two analyses independently highlighted significant relationships between seed yield and climate, their joint implications were unclear. Shifts in the CRCM boundary conditions revealed that the results lacked robustness during the historical period, inhibiting the investigation of future projections. Ambiguous age ranges for each cone collection and temporal restrictions of the seed collection data may be partially responsible for these inconclusive results. Results from the first half of this thesis suggest that, with few exceptions, seed production is relatively stable across SPZs spanning a wide range of climate regimes. Thus, the investigation of the relationship between reproductive fitness and climate may be complicated by the extraordinary adaptability of lodgepole pine and the high genetic variation in natural populations. / Graduate
68

Climate - radial growth relationships in some major tree species of British Columbia

Klinka, Karel, Splechtna, Bernhard E., Dobry, Jaroslav, Chourmouzis, Christine January 1998 (has links)
This study examines the influence of climate on tree-ring properties of several major tree species: Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Forbes), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and lodgepole pine (Pinus contorta var. latifolia Dougl. ex Loud.). Our three objectives were to determine how (1) tree-ring properties change along an elevation gradient, (2) short-term climatic influences are correlated with tree-ring properties, and (3) long-term climatic influence on tree-ring properties.
69

Predicting site index of Lodgepole pine and interior spruce in the sub-boreal spruce zone

Klinka, Karel, Wang, Qingli, Wang, G. G., Coates, K. Dave, Chourmouzis, Christine January 2001 (has links)
Knowledge of ecological site characteristics and tree growth on different sites is fundamental for silvicultural decisionmaking and planning. With biogeoclimatic ecosystem classification in place in British Columbia, silvicultural management has been given an ecological foundation; however, relationships between growth and site quality have not yet been fully investigated. The purpose of this study was to determine how site conditions within the SBS zone affect the height growth of lodgepole pine (Pl) and interior spruce (Sx).
70

Height growth curves and site index tables for subalpine fir, Engelmann spruce, and lodgepole pine in the ESSF zone of BC

Klinka, Karel, Chen, Han Y. H., Wang, Qingli, Chourmouzis, Christine January 1998 (has links)
Height growth models of coastal low- and mid-elevation Pacific silver fir, low-elevation white spruce, and low- and midelevation lodgepole pine have been used for predicting productivity of subalpine fir, Engelmann spruce, and lodgepole pine, respectively. These models, however, are biased in predicting height growth of high-elevation subalpine fir, Engelmann spruce, and lodgepole pine. To improve this situation, 329 sample plots (165 for subalpine fir, 90 for Engelmann spruce, and 74 for lodgepole pine) were located throughout the Engelmann Spruce-Subalpine Fir (ESSF) zone. Stem analysis was carried out on three dominant trees in each 0.04 ha sample plot. For each study species, a height growth model was developed on the data from two-thirds of the sample plots using the conditioned Chapman-Richards’ function; the model was validated using the remaining one-third of the sample plots.

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