3:00 pm - 5:00 pm
85th Forest Industry Lecture Series
Future Research Leaders
March 4, 2021
3:00 – 5:00PM MST
Esteban Galeano (Barb Thomas Lab)
Implementing cutting-edge molecular technologies in Alberta’s tree breeding programs to increase genetic gain and meet provincial policy requirements.
Forest companies implement tree breeding programs to increase volume in less time while ensuring that enough genetic diversity is maintained in the production (seed) orchards. Seed orchards need to have a sufficient number of trees in the initial establishment so they can withstand roguing (removal of undesirable trees), maintain genetic diversity during the lifetime of the orchard and ensure low inbreeding levels. In the Tree Improvement Lab, we have been promoting the use of DNA genotyping techniques to reconstruct pedigrees, estimate effective population sizes and determine pollen contamination levels in seed orchards. This information will improve estimates of the genetic worth of seedlots, allow for implementation of genomic selection and finally provide more precise estimations of genetic gain. With the addition of DNA genotyping, we have been able to provide several recommendations for orchard managers, foresters, and the Government of Alberta, including: (1) avoid severe roguings to prevent the risk of genetic diversity losses; (2) consider mixing stored seedlots from different years to ensure desired genetic diversity and genetic gain levels are met; (3) before establishing seed orchards, use information about wind speed/direction, distance between orchards/forests, altitude and consider barriers, to reduce pollen contamination; and (4) applying molecular markers in Alberta’s tree breeding programs has become cost effective and will help meet provincial tree Improvement policy requirements. This presentation will provide an overview of these recommendations.
Kazi Hossain (Brad Pinno Lab)
Modelling intensive silviculture yield projection and sawlog profile for conifer plantations
Intensive silviculture, including commercial thinning, has the potential to increase growth of individual trees and stands by 2-3 times relative to natural forests thereby increasing annual allowable cut and allowing harvest at an earlier age. However, this practice is yet to be widely adopted in public forests of Canada, in part due to lack of understanding of tree, stand, and forest level yield implications. However, site productivity is expected to influence this trade off. In this study, we use the Mixedwood Growth Model (MGM) to investigate the effects of intensive silviculture, with and without commercial thinning, for pure pine and spruce plantations in the lower foothills region of Alberta on a range of site qualities. Initial results on pine reveal decrease in volume due to commercial thinning but gain in overall piece size on both good and medium sites. On good sites, at an early harvest age (e.g. 50-yr), volume reduction was 19 m3/ha with a gain in average piece size of 0.18 m3/tree than that of non-thinned scenario. Further investigation into MGM’s sawlog projection for pine strata demonstrates that stands on good sites at year 50 yield more commercial sawlogs of spruce and pine (about 548 stems/ha of ≥ 20 cm dbh) than stands of 80 years without commercial thinning (520 stems/ha). Older stands without thinning produced more stems of less commercial value (about 1,716 stems/ha as opposed to 187). Finally, we recommend that intensive silviculture forest management strategy and its impact of harvesting time should be evaluated broadly for other stand types (pure spruce and mixedwoods), at the landscape level.
Tanvir Ahmed Shovon (Charles Nock Lab)
Using imagery from unmanned aerial vehicles to analyze variation in snag frequency
Advances in unmanned aerial vehicle (UAV) technology have opened new opportunities for measuring canopy mortality processes through high-resolution aerial imagery. Unlike traditional plot-based sampling, UAVs can easily survey areas several hectares in size that encompass several hundred canopy trees. The resulting imagery provides extensive data on the number and locations of dead trees (snags), which can be related to neighbourhood conditions and environmental factors that vary among stands. Here, we used a UAV to measure the relative proportions of live and dead canopy trees in stands varying in soil moisture across a mixed forest landscape. Crowns of live trees and snags were first segmented and classified to species from high-resolution canopy imagery. We then modeled whether crowns of each species were alive or dead as a function of tree height, neighbourhood competition, soil moisture, and the relative abundance of conspecifics. Short lodgepole pine (Pinus contorta) trees were more likely to be dead when surrounded by a tall canopy on wetter sites, reflecting effects of competition on this shade-intolerant species. Trembling aspen (Populus tremuloides) was more likely to be alive when surrounded by tall neighbours, perhaps because this clonal species can benefit from facilitation through root connections with neighbouring aspen stems. There was a higher frequency of white spruce (Picea glauca) snags in sites where it had a high relative abundance, suggesting strong effects of intraspecific competition for this species. Soil moisture did not appear to have a direct effect on the snag frequency of any of these species, despite pronounced niche partitioning along an elevation-driven moisture gradient. Our models explained 36% and 42% of the variation in white spruce and lodgepole pine snag frequency, respectively, but did not have much predictive power for trembling aspen or total snag frequency. Our results reflect the important role of competition in determining tree mortality, but also indicate that stochastic or unexplained processes account for considerable variation in snag frequency among stands. As UAV technology becomes more widely used by ecologists, it may enable a better understanding of how biotic and abiotic processes produce local variation in canopy mortality.