PARENT SESSION
Oral Session #48: Spatial patterns, spatial processes. Presiding: D. Deutschman.
Wednesday, August 8, 2001. 1:00 PM to 5:00 PM. Madison Ballroom C.
Coherent spatial relationships of species distribution and production in an old-growth Pseudotsuga-Tsuga forest.
Song, Bo1, Chen, Jiquan2, Moeur, Melinda3, Rudnicki, Mark4, Bible, Ken5, Shaw, Dave5, North, Malcolm6, Braun, Dave5, 1 2 3 4 5 6
ABSTRACT- A 12-ha plot (300 m x 400 m) was established in an old-growth Douglas-fir forest between 1994 and 1997. We mapped and recorded live/dead condition, species, and diameter at breast height (DBH). Ripley's K statistic and semivariance analysis were used to examine the spatial distribution of trees and patterns of biomass patches across scales. All species were found clustered across the scales examined. Several potential mechanical controls of the spatial patterns of species and biomass were discussed. We found that there is no single process driving the distribution of these species. Our data indicates that P. menziesii distribution is largely influenced by a lack of large canopy gaps; Thuja plicata is moisture limited; T. brevifolia is restricted by both moisture and the distribution of other trees affecting shade and competition; T. heterophylla is restricted by P. menziesii distribution and the amount of coarse woody debris in the stand; Abies sp.are likely controlled by the availability of shading and mineral soils; and Pinus monticola had been eliminated by past disturbance and lack of seed sources, large canopy gaps, and exposed mineral soils. All of these patch patterns and their cohesive spatial relationships are scale dependent. Clear patch patterns were also detected for basal area, above-ground biomass, and foliage distribution.
KEY WORDS: spatial pattern analysis, old-growth, biomass, Ripley's K statistic