In forest ecology we try to understand the factors that influence the health and development of a forest ecosystem. This project explores several of these factors (spatial distribution, water uptake, elevation, and edge effect) and their relation to large (90 cm DBH or greater) canopy trees in Seward Park, a 270-acre old growth forest in Seattle, WA. Transects were performed as East-West ten meter swaths across the park, focusing on five major species of canopy trees in the park: Western red cedar (Thuja plicata), Douglas fir (Pseudotsuga menzesii), Western hemlock (Tsuga heterophylla), Big leaf maple (Acer macrophyllum), and Pacific madrone (Arbutus menzesii). Each tree was measured for DBH, height, canopy spread, and canopy density. The GPS coordinates of each tree were marked for later use in analyses of distribution and spatial orientation of canopy trees in the park. Standard tree measuresments (DBH, height, etc.) combined with the presence or absence of invasive English ivy (Hedera helix) were used to assess the health of individual trees and therefore the forest as a whole.
Results/Conclusions
Data collected on 44 trees have revealed several patterns in the composition and distribution of canopy trees in the park. T. plicata and P. menzesii were the most abundant (N=18 for both species) and predominantly in good health, whereas individuals of the A. menzesii, A. macrophyllum, and T. heterophylla were in lower abundance and poorer health. The ultimate goal of this ongoing research is to create a comprehensive map of Seward Park’s large tree population, a valuable tool for the Seattle Parks Department in their management of the park. Future research will continue tree surveys and include measurements of water uptake in a small population of trees.
