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I assessed the relationship between natural disturbances and climate in Douglas-fir forests in western North America. I quantified synchrony within disturbance types, explored the potential for synergism between disturbance types, and analyzed changes in disturbance dynamics that have occurred following Euro-American settlement of western North America. I used new and previously published dendrochronological reconstructions of disturbance histories and climatic variability to explore these complex interactions at multiple spatial scales over the last three centuries. I used dendroentomological methods to reconstruct western spruce budworm outbreaks at thirteen sites along a transect running from central Oregon to western Montana. These forests experienced repeated, often decadal-length western spruce budworm outbreaks over the last three centuries. I compared my records with previously published outbreak reconstructions and found widespread synchrony of outbreaks at stand-level, regional, and sub-continental scales. At ten of my sites, I also reconstructed or obtained previously published reconstructions of fire dates. I compared these disturbance histories with dendroclimatological drought records to quantify the influence of moisture availability on disturbances. I found that fires were more likely to occur during drought years, while western spruce budworm outbreaks were most likely to begin near the end of droughts. After approximately 1890, fires were largely absent from these sites and western spruce budworm outbreaks became longer-lasting, more frequent, and more synchronous, likely due to land-use induced changes in the structure and composition of forests. My results show no discernible impact of defoliation events on subsequent fire risk. Any effect from the addition of fine and coarse fuels during defoliation events was too small to detect given the overriding influence of climatic variability. If there is any relationship between the two disturbances, it is a subtle synergistic relationship wherein each disturbance type dampens the severity but does not alter the probability of occurrence of the other disturbance type over long time scales. This dissertation includes unpublished co-authored material. / 10000-01-01

The aim of the study was to determine the effect of spruce swamp forest drainage and water regime restoration on soil organic matter (SOM) quality. Six localities of spruce swamp forests in Šumava Mountains were studied (2 drained, 2 restored and 2 pristine). SOM quality was affected by long-term drainage. Spruce swamp forest restoration (3-7 years) did not have significant effect on SOM quality although other parameters (pH, bulk density, water level, plant coverage) changed.

Competition from non-crop vegetation decreases the productivity of conifer plantations across Canada. The objectives of this research were: (1) to develop reliable indices of perennial, interspecific competition; (2) to compare the responses of black spruce and jack pine seedlings to tree and brush competition in northern Ontario; and (3) to identify the silvicultural implications of the responses. An examination of potential components of a competition index considered measures based on hemispherical photographs, fractal geometry, stand maps, and mensurational data from 360 seedling-centred plots for each of the two crop species. Reliable competition indices should be simple formulations which include horizontal and vertical dimensions and which express the amount of competition relative to the size of the seedling. The optimum index was found to be the area of competing canopy on hemispherical photographs, relative to the seedling leaf area. An alternate index, requiring no elaborate equipment, was the sum of the competing stem volumes (relative to the seedling stem volume) of the largest competitor in each quadrant surrounding the seedling. Comparisons of crop tree responses were made using functional growth analysis, replacing the conventional time axis with a competition axis. The relationship between growth and competition was adequately modelled with a power exponential composite function. Jack pine and bare root stock of both species maintained superior growth despite greater sensitivities to competition, compared to black spruce and container stock, respectively. Thus, jack pine or bare root stock of black spruce would outperform the alternatives if tending were delayed, but competition should be removed in all cases to capture the maximum growth potential. The rate of growth decline in response to competition was consistently greatest at the lowest competition levels, indicating that no beneficial effect on growth was provided by a light cover of non-crop vegetation. Allometric analyses indicated that black spruce had a greater morphological plasticity than jack pine. At high competition levels black spruce allocated more biomass to branches and foliage, at the expense of stem and roots. Jack pine demonstrated no such adjustment in allocation pattern, but followed a strategy of stress avoidance through sustained high growth rates. / Forestry, Faculty of / Graduate

The study was concerned with lodgepole pine, Pinus contorta Douglas and Engelmann spruce, Picea engelmannii Parry, particularly in the southern interior of British Columbia. Classifications of the forests of the Province as well as distribution, silvics, effects of fire upon succession, forest associations, and productivity classes of the two species were described. Sample plots were located in the Interior Douglas-fir and Engelmann Spruce - Alpine Fir Biogeoclimatic Zones. Hohenadl's form factor was used to compute volume growth by individual decades from stem analyses. On 124 plots, 137 trees were collected for stem analyses, 108 saplings were used for height - age studies, 100 point samples were made for determining basal area and stand volume and several hundred heights as well as diameters and borings at breast height, were taken. Thirty-four stand variables were subjected to multiple correlation analyses, particularly in regard to forest associations and growth of height, diameter at breast height and volume of the two species. Simple regressions were used to estimate height growth of several species on similar sites, and to compare several methods of volume calculation. Trees of the same diameter at breast height grown in different competitive positions (open, moderate to dense, and suppressed), contained different volumes. The largest volume of individual trees was found with trees grown in moderate to dense competitive position. Individual young lodgepole pines had a faster increment of height, diameter at breast height, and volume, than Engelmann spruces. This trend remained the same in yield tables based on individual tree studies and constructed for stands of good (average site index 100 ft. at 100 years), medium (average site index 70 ft. at 100 years), and poor (average site index 50 ft. at 100 years) productivity classes. The mean annual increment of volume of stands culminated earlier in lodgepole pine than in Engelmann spruce. The periods required were (in brackets are shown attained average diameters at breast height, total heights and volumes per acre). In the good productivity class in lodgepole pine 40 years (8.3 in., 58 ft., 6,700 cu.ft.) and in Engelmann spruce 75 years (10.0 in., 80 ft., 6,000 cu.ft.); in the medium productivity class in lodgepole pine 60 years (6.5 in., 50 ft., 4,600 cu.ft.) and in Engelmann spruce 130 years (9.0 in., 84 ft., 5,100 cu.ft.); in the poor productivity class in lodgepole pine 85 years (5.3 in., 45 ft., 3,100 cu.ft.) and in Engelmann spruce 150 years (6.3 in., 66 ft., 3,400 cu.ft.). Yield table volumes per acre in lodgepole pine were larger than those of Engelmann spruce, in the good productivity class, to the age of 120 years, in the medium productivity class to 150 years, and in the poor productivity class for an undetermined period. Present and suggested future trends of utilization and management of stands of the two species were reviewed. Generally, forest management in British Columbia shows a trend toward more intensive forest utilization, due to the increasing demand for wood. Smaller diameter trees and "smallwood" stands will be more and more frequently utilized. Utilization of whole trees, highly mechanized "harvesting" and transportation as well as intensified management of forest stands will compensate for increasing costs due to utilization of smaller diameters. Under intensive management, lodgepole pine deserves special consideration. It is as well-suited for artificial establishment of stands by planting as Engelmann spruce, but should cost less. Its value for the woodworking industry is similar to that of Engelmann spruce. However, on a rotation of maximal mean annual increment, its volume yield per acre unit will be higher than that of Engelmann spruce, and it should yield a higher rate of return on invested capital. / Forestry, Faculty of / Graduate

The thesis deals with lignin and soluble phenolic determination in Norway spruce foliace using hyperspectral data. A literature overview is focused on the analysis of lignin and soluble phenolics. The practical part focuses on the determination of wavelenghts intervals which are suitable for the detection of lignin and soluble phenolics. There is applied regression analysis for the determination of relationship between the foliage spectra and the content of biochemical substances for the chosen spektrum intervals. Indexes NDLI, mNDLI and RLI were than calculated. HyMap hyperspectral airborne images from 2009 and 2010 for the area of Sokolov, spectral curves of dry matter and fresh branches of Norway spruce and laboratory determination of lignin and soluble phenolics content were the inputs for the analyses. Maps of lignin content in Norway spruce are the final output of the work. Keywords: Norway spruce (Picea Abies), lignin, soluble phenolics, PLS (partial least square) method, multiple Stepwise regression, NDLI

Engelmann spruce (Picea engelmannii Parry ex Engelm.) exhibits cone crop periodicity, producing seed in a cyclic pattern. Variation in seed production has been noted between individuals of a population, but synchronization on a large scale is common. The theory that ultimately these periodic large cone crops have resulted from the selective pressures of seed and cone predators, referred to as the predator satiation hypothesis, is considered. Assuming predator pressures have operated over evolutionary time to select for periodic synchrony, associations between seed and cone predators and cone crop production levels were anticipated. These potential consequences of predator satiation were examined. Long-term data from 1948 to 1970 of Engelmann spruce cone production levels and small mammal populations, estimated from trappings, were analyzed for positive associations. Three small mammal categories, mice (Peromyscus spp.), chipmunks (Eutamias spp.) and red squirrels (Tamiasciurus hudsonicus) were examined. Only the correlation coefficient between population indices for mice and cone crop production was found to be significant. Engelmann spruce cones were collected throughout the summer of a year of low cone production. The impacts and timing of insect infestation were determined in developing cones. The major insects found were western spruce budworm (Choristoneura occidentalis (Freeman) (Lepidoptera: Torticidae)), fir coneworm (Dioryctria abietvorella (Grote) (Lepidoptera: Pyralidae)), and spruce seed moth (Laspeyresia youngana (Kearfott) (Lepidoptera: Olethreutidae)). Insects reduced the survival of cones to 11.48 cones out of 100. The high percentage of seeds and cones lost to insect predation supported previous studies of a similar nature. Both studies examined the potential consequences of the predator satiation hypothesis which has been suggested as an adaptive mechanism for trees to avoid seed and cone predation.

This paper is the result of research started on the Campus of the Utah State Agricultural College in the Spring of 1928. It is the intention of the writer to give the economic importance of the insect in the state, kind and extent of damage life history and control as far as it has been found.

Four general post-fire successional pathways leading to a climax Engelmann spruce (Picea engelmannii Parry)/subalpine fir (Abies lasiocarpa [Hook] Nutt.) forest were identified operating on the T.W. Daniel Experimental Forest in northern Utah. These included initial colonization by seral quaking aspen (Populus tremuloides Michx.), seral lodgepole pine (Pinus contorta Dougl. ex Loud.), colonization by lodgepole pine followed by a low intensity surface fire, and immediate colonization by late successional Engelmann spruce and subalpine fir. Post-fire establishment of the late successional species occurred earliest in the Engelmann spruce/subalpine fir pathway followed by the lodgepole pine and lodgepole pine ground fire pathways, and the quaking aspen pathway . The late successional species 11 grew fastest in the Engelmann spruce/subalpine fir pathway followed by the quaking aspen, lodgepole pine, and lodgepole pine ground-fire pathways. Conceptual models were presented showing how perturbations by fire, insect epidemics, and disease could interact to influence succession and shape the subalpine landscape. The subalpine forest changes through time to facilitate different types of disturbance that have varying effects on succession. In the continued suppression of fire, species and age class diversity will be reduced and disturbances may occur that are larger and more intense than those that have occurred historically.