PARENT SESSION
Poster Session 37: Forest Ecology.
Thursday, August 5 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Radial-growth release of gap-boundary trees in coastal old-growth forests, British Columbia, Canada.
Stan, Amanda*,1, DANIELS, L1, 1 University of British Columbia, Vancouver, British Columbia, Canada
ABSTRACT- Death of one to a few trees that results in fine-scale canopy openings is the principal disturbance in forests where stand-destroying events are infrequent. In old-growth forests of northwestern North America, gap-forming disturbances dominate, allowing release and recruitment of subcanopy trees to the upper canopy. We conducted a dendroecological study in old-growth stands north of Vancouver, British Columbia, Canada to quantify the positive radial growth responses (i.e. releases) of subcanopy and canopy western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), and Pacific silver fir (Abies amabilis) gap-boundary trees following gap creation. We used tree-ring methods to identify an approximate year of creation of natural canopy gaps formed by uprooted individuals. For those openings determined to be at least 20 years of age, we cored all gap-boundary trees and quantified radial growth prior to and after gap formation. Cores from approximately 170 gap-boundary trees from a total of 10 gaps indicate differences in release response of the three species in different canopy positions. In general, subcanopy western hemlock trees showed the greatest magnitude of release following gap formation, while western redcedar trees were the least responsive to canopy openings. Understanding short-term growth responses of individual trees to canopy openings is crucial for evaluating past and predicting future stand dynamics.
Key words: canopy gaps, old-growth forest, dendroecology, radial-growth release