Interaction of Trembling Aspen and Lodgepole Pine in a Young Sub-Boreal Mixedwood Stand in Central British Columbia

Abstract

Strategies for managing mixed broadleaf-conifer stands in British Columbia (BC) have been under review in recent years as the benefits of mixedwood management have been recognized. More has been learned about the role of broadleaves in forest ecosystems however ecosystem-specific knowledge about the competitive interactions between mixed broadleaf-conifer stands is still scarce. Therefore a competitive interactions study was conducted to facilitate ecosystem-specific management for lodgepole pine (Pinus contorta Dougl. Ex Loud. Var. latifolia Engelm.) and trembling aspen (Populus tremuloides Michx.) in the sub-boreal spruce (SBS) zone of central BC. The experiment was a completely randomized block design with six different aspen densities replicated three times. Each replicate was sampled three times between ages 14 to 19 years. Pine diameter and height growth were influenced by aspen density. Our current quantitative findings suggest that lodgepole pine growth was not impacted when growing with aspen densities up to 2500 stems ha −1. Considering free growing (FTG) and not free growing (NFTG) pine at the time of trial establishment, an insignificant difference was found for DBH, height and crown volume responses. Leaf area index (LAI) and diffuse non-interceptance (DIFN) radiation were also not significantly different between FTG or NFTG trees suggesting our results exceed the current BC's free growing standard. Further work is recommended to determine whether or not the current free growing standards are appropriate for producing the desired crop outcome.

Lodgepole pine and trembling aspen mixedwoods: Growth and yield within 22 to 39 year old pine plantations of northern interior British Columbia

“…Other studies of young pine within mixed aspen and pine stands have been used to suggest threshold aspen densities where tree-level pine growth appears unimpeded (Newsome 1999, Newsome et al 2008, Dhar et al 2015. The stand-level results presented here from older stands are not suggestive of an aspen threshold where pine growth is unimpeded.…”

Silviculture as a tool to support stability and diversity of forests under climate change: study from Krkonoše Mountains

“…In this respect, mixed forests have been more frequently established in Europe over the last two decades (Bravo-Oviedo et al 2014;Forrester & Pretzsch 2015;del Río et al 2016;Metz et al 2016;Pretzsch & Biber 2016) and it is neces-& Biber 2016) and it is neces-Biber 2016) and it is necessary to obtain exact knowledge about their management (Fahlvik et al 2005;Agestam et al 2006;Hynynen et al 2011;Novák et al 2017). Knowledge of thinning in various stand mixtures is not yet sufficient (Štefančík & Kamenský 2006;Štefančík 2010;Prévost & Gauthier 2012;Dhar et al 2015;Drössler et al 2015), especially in terms of stand growth, stability and vitality. Based on the described changes, the forest management practices should be significantly changed in following decades.…”

Lodgepole pine and trembling aspen competition: Neighbourhood studies within 22 to 39 year-old pine plantations of northern British Columbia

“…Some studies are without an aspen-free treatment from which to quantify a zero competition environment, which may confound attempts to define growth threshold impacts (Wagner et al 1989). Many of the published aspen competition studies were established in response to the government's need for evidence to support regeneration standards and free-growing guidelines (Lieffers et al 2008, Dhar et al 2015. In British Columbia, the Forest and Range Practices Act (FRPA; BC MFLNRO 2015) requires a licence holder to establish a free-growing stand defined as a stand of healthy trees of commercial value, "the growth of which is not impeded by competition from plants, shrubs or other trees".…”