In low-elevation forests of south coastal BC, complex, mixed-species stands often develop when early successional deciduous hardwoods regenerate in plantations intended to contain one or two species of conifers. Silvicultural interventions to remove these naturally regenerating hardwoods are expensive and may reduce both the ecological and economic value of the stand. These early successional hardwood species are characterized by prolific reproduction and rapid juvenile growth1, which makes them formidable competitors. However, most of the hardwood species found in coastal BC also have substantial commercial value. Ecologically appropriate management of such species in conifer plantations requires knowing how their regeneration varies with site and stand management and if benefits of retaining the species offset costs of removal.
We propose to examine the natural regeneration and growth of bitter cherry, Prunus emarginata, a species that has received little study. Bitter cherry can aggressively colonize lowland forest sites of south coastal B.C. following disturbance: after harvest of coniferous stands, bitter cherry can regenerate at a high density (>20,000 stems ha-1). Similar densities of pin cherry in the northeastern U.S. at age 3 reduced heights of deciduous associates by 25% through 15 years2. Densities of bitter cherry associated with growth reductions of planted conifer seedlings are unknown. However, in order to meet stocking standards and achieve free growing status for planted conifers, licensees effectively must remove all cherry from the plantation, typically and at much expense.
Although bitter cherry is a concern for conifer regeneration, the species is also a valuable resource. The wood of larger trees is desirable for woodworking-related value-added products345; regional hardwood mills readily process cherry logs when available, but limited availability constrains utilization of the resource. Cherry is often milled as an alternative when log supplies of red alder are limiting. Fruits and seedlings are also a preferred food source for wildlife.
Maintaining appropriate densities of cherry in young plantations depends on understanding its regeneration ecology. Hence, this proposal is closely linked to priority topic 1.1c Complex stands-natural regeneration. Bitter cherry regeneration occurs mainly from a soil seed bank7; germination and emergence of bitter cherry seedlings are probably promoted by canopy removal and soil disturbance by logging, as occurs with pin cherry in eastern North America. The seedbank strategy is favored when disturbance intervals are shorter than the lifespan of seed in the soil. Thus, cherry regeneration may increase if conifer stands are harvested at younger ages. Regeneration of cherry may also vary with degree of soil disturbance and canopy retention at harvest. Therefore, cherry regeneration should be related to both how often and the way in which conifer stands are harvested. Hence, the proposal is also consistent with priority topics 2.1a, Complex stands - Relationships between residual stand structure and understory recruitment and development and 2.1b, Complex stands - Development and monitoring of the impact of various stand treatment regimes on regeneration.
We will examine bitter cherry reproduction and early growth as they relate to cherry abundance in the CWHxm BEC unit of southern Vancouver Island. This information is a key to ecologically-based management of cherry-conifer complexes. Bitter cherry ecology is poorly documented, so we also address other topics critical to its management. Understanding competitive effects of high densities of cherry on planted conifers provides context for the regeneration studies and guidance in how to manage cherry in conifer plantations. Also, since cherry is potentially valuable, it is useful to document its potential growth and perceived value. Our study will address the following questions: a) What is the competitive e ...
Brown, Kevin R., Douglas, Mary-Jane; Negrave, Roderick W.; Antos, Joseph A.. 2010. Regeneration, Growth and Potential Value of Bitter Cherry as a component of young complex stands on Southern Vancouver Island. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2010MR316
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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