Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia.

Master of Science / Apparel, Textiles, and Interior Design / Sherry J. Haar / This study compared the colorfastness of potassium aluminum sulfate (PAS) mordanted and nonmordanted 30/2 wool yarn, dyed with black walnut (Juglans Nigra), Osage orange (Maclura pomifera), and eastern redcedar (Juniperus virginiana) sawdust. Information from this study is intended to inform natural dye artisans and to increase the profitability of sawdust for farmers, ranchers, and mill owners who would otherwise find little use for this byproduct of timber manufacturing. Pre-testing ensured dyeings of visually comparable color depth and dye concentrations were pre-tested to find a standard depth of shade between the same dye on PAS mordanted and nonmordanted wool yarns. Tests for colorfastness to light, laundering and staining were performed in accordance to AATCC test methods. Resulting colors for exposed and unexposed specimens were rated using CIE L* a* b* values and AATCC gray scale for color change. GLM Anovas and two-sample t-tests were used to statistically analyze CIE L* a* b* values. As expected, findings indicated that dye absorption was improved with the use of a PAS mordant, especially for black walnut and eastern redcedar. For yarns premordanted with PAS the dyewoods became yellower. A PAS mordant slightly improved colorfastness to light for black walnut and eastern redcedar, but did not influence Osage orange which had an unexpected color change from bright yellow to warm brown after exposure to light. Colorfastness to laundering was slightly improved with PAS for Osage orange, while black walnut and eastern red cedar had slightly less color change without the mordant. This research was supported by the Agricultural Research Experiment Station and Kansas State University.

Growth release of trees following canopy disturbances is of interest to ecological scientists and forest managers. Using dendroecological techniques, I examined growth release of canopy and subcanopy trees following the formation of natural, fine-scale canopy gaps in old-growth, western red cedar-western hemlock forests of coastal British Columbia. I aimed to quantify detailed information on release of the three shade-tolerant tree species that constitute these stands: western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis). As a first step, I calibrated the radial-growth averaging method to account for regional-scale variability and capture a more complete range of growth releases that may occur following the formation of fine-scale gaps in the study stands. A 25% threshold, 5-year moving average, and 10-year window emerged as appropriate parameters for detecting releases using radial-growth averaging. Basal area increment was also the most appropriate growth index for detecting releases. Establishing these empirically-based criteria was important for quantifying the magnitude and duration of releases. Tree diameter and growth rate prior to release were the most important predictors of the magnitude and duration of releases, but identity of the tree species and distance from the gap center were also important predictors. Western hemlock and Pacific silver fir were often growing slowly both in the canopy and subcanopy, giving them tremendous potential to release. For these species, releases were generally intensive and persistent. In contrast, western red cedar were often growing quickly both in the canopy and subcanopy, giving them less potential to release. Compared to western hemlock and Pacific silver fir, western red cedar releases were less intensive and persistent. Patterns related to distance from the gap center emerged for trees growing along the north-south axis of gaps. Regardless of species, increasing distance from the gap center resulted in decreasing magnitude and duration of releases. However, patterns for duration were complex, as the distance effect was greater for trees north of the gap center. Information on growth release of trees is useful for reconstructing the history of past canopy disturbances, elucidating mechanisms of tree species coexistence, and assessing and predicting stand changes due to forest management in coastal British Columbia. / Arts, Faculty of / Geography, Department of / Graduate

Western redcedar (Thuja plicata Donn ex D. Don; redcedar), an indeterminate conifer in the Cupressaceae family, is vulnerable to maladaptation in the face of climate change. Assisted gene flow is one mitigation strategy and involves human-mediated migration of populations, where the projected climate of the area of deployment matches the source climate of the population. Despite the overall projections of warmer temperatures globally, in British Columbia (B.C.), the risk of seasonal frost events will remain and therefore the potential for cold damage and mortality of redcedar exists if the newly migrated populations cannot withstand these freezing events. Knowledge of redcedar's ability to withstand freezing temperatures (cold hardiness) is therefore crucial. Redcedar, like many Cupressaceae species, produces and accumulates the purple-coloured carotenoid rhodoxanthin during the winter. This was hypothesized to be correlated with cold hardiness. Assessment of variation in overall, fall and spring cold hardiness and associated rhodoxanthin concentrations were done through repeated, seasonal freeze testing of clonal grafts originating from across the range of redcedar, and seedling progeny from a subset of these clones. Cold damage was quantified using electrolyte leakage and rhodoxanthin concentrations were quantified using high performance liquid chromatography. Cold hardiness and rhodoxanthin were individually modelled using univariate and bivariate mixed effect models with clone/family as a random effect. Model outputs were compared to climatic variables associated with clonal origin to test for climatic relationships. This study found genetic variation in cold hardiness of redcedar with weak climatic clines. This indicates that assisted gene flow of redcedar should be done on a case-by-case basis, with no need for a climatic threshold. Overall heritability of cold hardiness was 0.17 ± 0.03. Novel findings included the positive genetic correlation between fall and spring cold hardiness (0.55 ± 0.33); lack of reciprocal or parental effect for overall cold hardiness; and weak climatic relationships between cold hardiness and predominantly temperature, with the strongest correlation between number of frost-free days in January (0.38, p < 0.01) in the location of origin and cold hardiness. All findings related to rhodoxanthin were novel. Rhodoxanthin varied with family/provenance and season with heritabilities of 0.30 ± 0.09 in fall, 0.42 ± 0.09 in winter and 0.28 ± 0.09 in spring. Winter and spring rhodoxanthin concentrations were phenotypically correlated (0.50, p < 0.01) and genetically correlated (0.76 ± 0.14). Surprisingly, rhodoxanthin was not detected in clonal grafts of redcedar in any season. Results also indicate that rhodoxanthin cannot be used to estimate cold hardiness. The absence of rhodoxanthin in the clonal grafts compared to the seedlings suggests that plant age impacts rhodoxanthin accumulation. / Graduate / 2021-12-14

No description available.

Master of Arts / Department of Geography / Kevin P. Price / Due primarily to changes in land management practices, eastern redcedar (Juniperus virginiana L.), a native Kansas conifer, is rapidly invading onto valuable rangelands. The suppression of fire and increase of intensive grazing, combined with the rapid growth rate, high reproductive output, and dispersal ability of the species have allowed it to dramatically expand beyond its original range. There is a growing interest in harvesting this species for use as a biofuel. For economic planning purposes, density and biomass quantities for the trees are needed. Three methods are explored for mapping eastern redcedar and quantifying its biomass in Riley County, Kansas. First, a land cover classification of redcedar cover is performed using a method that utilizes a support vector machine classifier applied to a multi-temporal stack of Landsat TM satellite images. Second, a Small Unmanned Aircraft System (sUAS) is used to measure individual redcedar trees in an area where they are encroaching into a pasture. Finally, a hybrid approach is used to estimate redcedar biomass using high resolution multispectral and light detection and ranging (LiDAR) imagery. These methods showed promise in the forestry, range management, and bioenergy industries for better understanding of an invasive species that shows great potential for use as a biofuel resource.

Cedar, represented by Western redcedar (Thuja plicata) and Yellow Cedar (Chamaecyparis nootkatensis) was known as the “Tree of Life” to the Nuu-chah-nulth on Vancouver Island’s west coast, and most other groups of the Pacific Northwest. This thesis investigates the Culturally Modified Trees (CMTs), or more specifically Tapered Bark Strips (TBS), created through the extraction of cedar bark removed for all manner of material goods. CMTs are now the most common archaeological site type within British Columbia. Current regional chronologies have inherent biases that make interpretations difficult. The chronologies created through Archaeological Impact Assessments (AIAs) are weighted heavily to the contact period and the highest frequency of use corresponds with indigenous population collapse rather than peak. Investigations are made into the true distribution of existing CMT features. This thesis details the survey of 16 recent old growth cedar clearcuts which found extensive unrecorded CMT features that have recently been logged throughout the southern Nuu-chah-nulth study region. Half of all TBS scars in exposed stumps were found embedded within healed trees, otherwise invisible to archaeologists. Comparing all AIA report dates (surveyed prior to logging activity) with all post-impact assessments surveys it was found the latter contain a greater and older distribution of scarring events corresponding to high First Nations populations before the contact period. The study also compares CMT chronologies with local histories, investigates the antiquity of Northwest Coast CMTs and the indigenous management of cedar trees to maximize bark harvests. The findings of this research hint at the expanded extent of anthropogenic forests in the Northwest Coast, the inadequate recording and heritage protections of CMTs, and what it all means for Aboriginal Land Rights in British Columbia. / Graduate / 0324 0740 0329 / kinze.earnshaw@gmail.com

In the wetter climates associated with the coastal forests of northwestern North America, coarse woody debris (CWD) accumulations in the form of snags, downed boles, and large branches can be large in natural forest ecosystems. Seedlings often regenerate on stumps and downed logs in the understory of old-growth coastal forests. The question remains though, whether CWD is a necessary component for seedling survival and growth in forests managed for commodity production. This study addresses one concern of forest managers: is there an immediate nutritional or moisture supply advantage conferred by CWD for the survival and growth of seedlings in the coastal climate of British Columbia? We compared survival and growth of seedlings planted in decaying wood compared to non-woody humus forms and mineral soil under heavy shade and full light conditions. Low light environments are of particular interest since reports of the strong association between CWD and regeneration has primarily referred to understory seedlings and saplings in old-growth forests.

In BC, it is required that harvested areas be regenerated with a mixture of tree species whenever appropriate to the site. This policy is based upon the assumption that increases in stand productivity, reliability, and/or biodiversity can be achieved in mixed-species stands. However, the knowledge justifying this policy is at best incomplete. Differences in forest productivity of mixed-species stands have been attributed mostly to competition. However, an increasing number of studies are providing evidence to support alternate theories, in which positive plant interactions play a major role. Positive plant interactions are divided into two components: (i) competitive reduction through structural and physiological differences in above and below ground structures, and (ii) facilitation through any positive effect on the growing environment of one plant species by another. These theories have yet to be tested in forest ecosystems. The objectives of this study, with respect to naturally established, unmanaged, second-growth stands of western hemlock (Hw) (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Cw) (Thuja plicata Donn ex D. Don in Lamb.), and their mixtures, were: (1) to review the mechanisms of positive plant interactions and their potential to occur in these mixtures, and (2) to compare the productivity of these three stand types, using relative and absolute yield.

While wildfire is globally most common in the savanna-grassland ecotone, the flammability of coastal temperate rainforests is considered low and little is known regarding historic fire activity. Reconstructing historical fire activity typically requires dendrochronological records from fire-scarred trees and post-fire cohorts, but this type of information is rare in perhumid temperate rainforests, which are dominated by dense fuels with high year-round moisture content. I reconstructed historic fire activity using fire scars, tree rings, soil charcoal, and remote sensing techniques in a 2000 km2 island group located within the Hakai Lúxvbálís Conservancy on the coastal margin of central British Columbia. I broadly assessed 13,000 years of fire activity with charcoal deposited in soils, and reconstructed late Holocene fire events with a 700-year chronology built from living fire-scarred trees and stand establishment data. I used a weight of evidence approach to hypothesize the origins of fires and whether First Nations intentionally utilized fire for resource management. Low-severity fires occurred most frequently in forests surrounding former First Nations habitation sites, and lightning strikes do not occur often enough to explain the observed temporal or spatial patterns of fire activity in the study area. Low-severity fires occurred approximately every 39 years, and were 25 times more likely to occur than previously estimated. Fires influenced the composition and structure of vegetation by creating a mosaic of vegetation types in different stages of succession, and thus increased the abundance of culturally important food plants. Fire events have not occurred in the study area since 1893, which also coincides with the reduction of First Nations activities in their traditional territories. My data are consistent with the hypothesis that humans intentionally used fire to manage resources, though further research and ethnographic data collected elsewhere in the region is required to corroborate these findings. Ecological legacies of historic fires remain visible on the present day landscape, and by reconstructing the historic range of fire cycle variability we gain a better understanding of human-driven fire activity and the abrupt changes that occurred in the 20th century. / Graduate