A gap in regional agriculture research and extension has restricted farmers' ability to cultivate long-term sustainable, profitable operations in the Omineca Region, BC. An interdisciplinary project was designed to re-initiate regionally focused research. First, an autoethnography was conducted (2012-2014) to explore cultural practices of northern farmers and to identify needs and opportunities within the region. It was found that diversity of environment, economic and cultural contexts of farmers will impact management decisions, and there is an immediate need for contextual, regional research that addresses the realities of farmers working outside the industrial agriculture system. Second, a greenhouse study was designed to examine the implications of breeding strategies on water stress tolerance of modern and heritage barley (Hordeum vulgare) cultivars. Significant differences were found in phenology and resource allocation traits of modern and heritage cultivars, suggesting breeding strategy has impacted adaptive tolerance of modern cultivars and may impact future management practices within the region. --Leaf ii.
How climate change will affect tree growth across species' ranges remains a critical knowledge gap. Tree-ring data were analyzed from 33 Douglas-fir stands spanning a wide climatic and geographic range in the interior of British Columbia to identify regional and ecological patterns between climate and growth. Populations growing in warm and dry climates had growth patterns correlated mostly to local annual precipitation, whereas populations growing in high-elevation wet and cold climates were more correlated to annual/winter snowfall/winter temperatures and quasi-periodic ocean-atmosphere climate systems. Populations growing near the climatic margins of the species' range had the strongest responses to climate variability. Examining these relationships over different temporal scales revealed that some climate-growth relationships have varied substantially over time. Our results indicate that in the interior of British Columbia, Douglas-fir growth responses to climate change will not be uniform over time and space.
The latitudinal forest-tundra ecotone is an area that is experiencing substantial changes with respect to tree growth and climate change. We examined the response of radial tree growth to climate in adjacent regions of northern Yukon and Northwest Territories, Canada, across environmental and spatial gradients using dendrochronological methods. Principal components analysis was used to derive the primary modes of variation in the tree-ring records, which were subsequently attributed to environmental and climatic features. We found that slope gradient (small spatial scales) and ecoregional classification (larger spatial scales) played substantial roles in determining the response of tree growth to climate. Climate correlations were found for current and previous years to growth, many of which challenge currently held assumptions regarding the dominant climatic determinants of tree growth at high latitudes. These findings indicate that Arctic forest environments are highly complex, and that expected changes in the biosphere will occur at various rates, times and places. --P. ii.
The one-year growth of lodgepole pine seedlings on two contrasting sites in interior British Columbia, a ploughed sandy nursery bed of low available moisture and a clayey wet forest soil, were investigated to evaluate the performance of seedlings subjected to chemical and mechanical root pruning techniques. Two sizes of chemically pruned seedlings were treated with a copper based paint (PCT 5-12 and PCT 4-10). The other treatments were containerized Styroblock (PSB) 4-15 seedling that were knife pruned in four ways (i.e. bottom plug removal = RPB, bottom plug removal and two lateral cuts = RPB+2, and lateral cutting with three cuts = RP3 and six cuts = RP6). Growths of pruned seedlings were compared to the un-pruned PSB 4-15 control group. While site soil conditions proved to be a stronger contributing factor to growth, pruning treatments induced different effects on seedlings particularly in root development. Root counts, root symmetry and proportion of direct large roots, showed greatest improvements. Root pruned seedlings also had better distribution of root growth throughout the plug. Among knife pruning treatments, lateral cutting methods were more favourable to early root growth with greater root counts after a twenty-one day period than bottom plug removal. The most extreme knife pruning treatment, consisting of six laterial cuts (RP6), had a mean of 60% removal of roots within the plug and showed no differences in height growth regardless of site. Also the RP6 seedlings had 100% survival. It shows that the PSB 4-15 seedling is to a great extent resilient to knife pruning, which should be encouraged where chemical root pruning is less useful as it improves rooting development in the early establishment of confer seedlings. Improved rooting establishment of planted seedlings may result to better adaptation to environmental conditions and competitive stresses, as well as improve stem morphology and long-term growth.--P.ii.
Tree ring analyses and an interpolated climate model (ClimateBC) were used to compare radial growth responses to climate variables among three coexisting, ecologically distinct conifer species, including interior spruce (Picea glauca x Picea Engelmannii), lodgepole pine (Pinus contorta var. latifolia) and subalpine fir (Abies lasiocarpa) across a range of climate conditions in western Canada, and altitudinal treelines in the Engelmann Spruce-Subalpine Fir forests in central British Columbia (BC). Ring-width chronologies were developed and correlated with site-specific climate data in the past 50 years from 1953-2002. June-July temperature appeared to be the dominant climate factor influencing radial growth of spruce across the sample sites, and the relationships changed from positive to negative as summer site temperature increased. Growth-climate relationships of lodgepole pine and subalpine fir varied within species. October-March temperatures appeared to be important for growth of lodgepole pine and subalpine fir at colder sites in BC. The Pacific Decadal Oscillation during October and March was also important for pine and fir at altitudinal treelines. Given the species- and site-specific growth responses to climate, future climate change will likely alter interactions among coexisting species, potentially leading to changes in species dominance, compositions and distribution of forest communities.--P.ii.
