Relation of initial spacing and relative stand density indices to stand characteristics in a Douglas-fir plantation spacing trial

Robert Curtis; Sheel Bansal; Connie Harrington

doi:10.2737/PNW-RP-607

Treesearch

Relation of initial spacing and relative stand density indices to stand characteristics in a Douglas-fir plantation spacing trial

Informally Refereed

Authors:

Robert Curtis, Sheel Bansal, Connie Harrington

Year:

2016

Type:

Research Paper

Station:

Pacific Northwest Research Station

DOI:

https://doi.org/10.2737/PNW-RP-607

Source:

Res. Pap. PNW-RP-607. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 27 p.

Download (PDF 3.27 MB)

Download (PDF 3.27 MB): https://research.fs.usda.gov/download/treesearch/50790.pdf

Abstract

This report presents updated information on a 1981 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii ) plantation spacing trial at 33 years from planting. Stand statistics at the most recent measurement were compared for initial spacing of 1 through 6 meters and associated relative densities. There was no clear relationship of spacing to top height. Diameter, live crown ratio, and percent survival increased with spacing; basal area and relative density decreased with increase in spacing. Volume in trees ≥ 4 cm diameter was greatest at 2 m spacing, while utilizable volume (trees ≥20 cm dbh) was greatest at 4 m spacing. Live crown ratio decreased and total crown projectional area increased with increasing relative density indices. Total crown projectional area was more closely related to relative density than to basal area.

Keywords

plantation spacing, stand density, crown dimensions, yield, SDI, RD, Pseudotsuga menziesii

Citation

Curtis, Robert O.; Bansal, Sheel; Harrington, Constance A. 2016. Relation of initial spacing and relative stand density indices to stand characteristics in a Douglas-fir plantation spacing trial. Res. Pap. PNW-RP-607. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 27 p.