Grant: CCI Applied Research and Development Grants

Timber demand globally is expected to quadruple by 2050, however current growth and harvesting of timber does not meet this expected need. Regulating timber forest density, through pre-commercial (PCT) and commercial thinning (CT), by optimizing tree growth and merchantability is a key tool to influence tree production and quality. With this practice, approximately 70% of timber can be made into sawlogs – a log large enough make into lumber – and a major driver of timber supply and pricing for the forest industry. Density management practices also have the potential to increase tree and forest resilience, an important consideration in a changing climate. As thinning opens the overstory canopy, increases in understory vegetation abundance and composition may be observed though the length of this effect varies. An additional, but largely unexplored benefit of density management can be the acceleration of carbon sequestration as the choice of tree species, intensity of the thinning regime, and length of the rotation cycle are decisions that influence biomass and soil carbon stock. The Northern Alberta Institute of Technology and University of Alberta have partnered with the Forest Growth Organization of Western Canada (FGRoW; an association of fRI Research), to initiate a multi-year study investigating the impacts of PCT and CT on understory plant communities, above- and below-ground stand carbon pools, and tree resiliency in northern Alberta. The present proposal encompasses a 3-year timeframe that provides an opportunity to assess near-term impacts while providing essential foundational data for future, long-term evaluations. Without the collection of this foundational data, the long-term objectives will not be possible. This project aims to quantify the potential tradeoffs/benefits in multiple forest values (timber productivity, biodiversity, tree resilience and stand carbon) that density management may bring. This project is expanding the knowledge base on density management effects from those associated with volume and tree attributes to a more holistic accounting; this is particularly interesting as we hypothesize that stand thinning may stimulate some non-timber values. Lastly, while the study is in Alberta, this work will provide information that will be of interest to a broader national audience interested in using PCT and CT to meet timber objectives and potentially enhance forest values.