Describing condition-specific determinants of competition in boreal and sub-boreal mixedwood stands

Abstract

There is a growing economic and ecological incentive in developing best-management practices for broadleaf-conifer mixedwood stands in boreal and sub-boreal regions of Western Canada. Current free-growing guidelines employed in these areas appear to be poor predictors of interactions between primary growth determinants and environmental conditions in these complex stands. Density dependent relations between broadleaf and conifer components in mixedwood stands may vary across a range of conditions due to interactions discussed in this paper between primary growth determinants (i.e., light limitations, edaphic limitations and species specific traits) and local environment. Clarifying these interactions will promote the development of adaptable tools that can be used to develop context-specific mixedwood management strategies. Key words: mixedwood management, free-growing guidelines, boreal, sub-boreal, density-dependent competition

Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

“…Trembling aspen is more sensitive to cold soil conditions than lodgepole pine [25]. Aspen's ability for water uptake is limited at soil temperatures below 10…”

An analysis framework for linking regeneration standards to desired future forest conditions

“…Total volume will certainly change with site index, and patterns of succession will change if the relative site index between the species is altered by changes in environmental gradients (Green 2004, Green andHawkins 2005). The importance of the latter factor is primarily of concern for the species composition models.…”

Competitive interactions in sub-boreal birch–spruce forests differ on opposing slope aspects

“…higher latitudes/elevations or more northerly slope aspects) (Turner and Jarvis, 1975;Tryon and Chapin, 1983;Van Cleve et al, 1983;Day et al, 1990;Landhäusser et al, 1996Landhäusser et al, , 2001Landhäusser et al, , 2003Landhäusser and Lieffers, 1998;Green, 2004). For instance, lower soil and air temperatures are known to be key limiting factors in tree growth and reproduction in stands where cold conditions naturally occur (Tryon and Chapin, 1983;Van Cleve et al, 1983;DeLucia and Smith, 1987;Bonan, 1992;Landhäusser et al, 2001;Green, 2004).…”

“…free growing) guidelines in Alberta and British Columbia (which were developed to promote conifer establishment in a non-mixedwood environment) employ a description of the ''competition neighborhood'' around conifer crop trees, implicitly seeking to describe density-dependent competition based on a small sampling area around crop trees (MacIssac and Navratil, 1996;Lieffers et al, 2002). Yet, growing evidence suggests that such free-to-grow guidelines are too restricted to predict competitive interactions among mixedwood components (Lieffers et al, 2002;Green, 2004).…”

“…With a growing interest in managing widely occurring deciduous-coniferous species forests (mixedwoods) in western Canada has come the realization that these stands are inherently more complex than single-or mixed-species conifer forests (Simard, 1996;Green, 2004). Deciduous broadleaf and evergreen coniferous tree species have distinct growth patterns that manifest themselves following the initiation of mixedwood stands.…”