One-year-old container-grown Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings were outplanted on north, east, south, and west aspects on steep, skeletal Xerochrepts in southwest Oregon. After 2 years, survival rates were highest on north and south aspects, but biomass production (dry weight) was greatest on the west aspect. Shadecards, used to artificially shade half of the seedlings on each aspect, increased survival by 27 percent on the south aspect but had little effect elsewhere. Shadecards significantly increased height growth on the west aspect but affected height less on the south aspect. These results and those of other studies suggest that shadecards may increase Douglas-fir seedling survival under certain conditions.
This work has no parents.
Downloadable ContentDownload PDF