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Title: Douglas-fir in northern California: effects of shade on germination, survival, and growth
Author: Strothmann, Rudolph O.
Source: Res. Paper PSW-RP-84. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station; 10 p
Station ID: RP-PSW-084
Description: Effects of four light intensities on germination, survival, and early growth of Douglas-fir (Pseudotsuga menziesii) were studied on south-facing cutblocks in northwestern California. Tested were four shade intensities: 0, 25, 50, and 75 percent. On seeded spots, 50 percent shade resulted in greatest germination and survival, being significantly better than either no shade or 25 percent shade, but not better than 75 percent-shade. Shade did not significantly improve the survival of planted trees (either 1-0 or 2-0 age class), but growth was generally best on plots with least shade. Good survival on all treatments was probably due to careful planting, excellent stock, periodic weeding, and deep loam soil. An implication of these findings is that for direct-seeding, early shading is desirable, though difficult to achieve. A possible solution is to use a nurse crop converted to dead shade the spring after seeding.
Key Words: Pseudotsuga menziesii, California (northwestern), artificial regeneration, light relations, protective shading, germination, survival, early growth, height increment
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Strothmann, Rudolph O. 1972. Douglas-fir in northern California: effects of shade on germination, survival, and growth Res. Paper PSW-RP-84. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station; 10 p.