by Washington Agricultural Experiment Station, College of Agriculture, Washington State University in [Pullman] .
Written in English
|Series||Circular / Washington Agricultural Experiment Station -- 535, Circular (Washington Agricultural Experiment Station) -- 535|
|The Physical Object|
|Pagination||23 p. :|
|Number of Pages||23|
The effects of fertilization and density on Douglas-fir forests have been studied in the past few decades across the Pacific Northwest. General re-sults from previous research are summarized below (for a complete literature review, see Li, ): Density: Douglas-fir diameter growth is very sensitive to stand density with diameter growth. The objectives of this experiment were to: (1) assess soil and foliar Ca in Douglas-fir plantations in Southwestern Washington where sinuosity occurs; (2) determine Ca partitioning in Douglas-fir foliage; (3) determine incidence and severity of sinuosity following Ca fertilization with gypsum or lime. 2. Materials and methods SiteCited by: 9. To examine the effects of density control and fertilization on stand growth and yield of young Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations, seven treatment regimes were applied in sixty-three 9-year-old plots from nine installations across western Washington and by: 4. These findings suggest that N fertilization could potentially increase site productivity of young Douglas-fir stands found on low quality sites in the Pacific Northwest 15–22 years after application by a carryover effect.
Large acreages of mature Douglas-fir (Pseu dotsugamenziessi [Mirb.] Franco) exist in Westen Washington and Oregon. Recognizing the potential for accelerating growth in such stands, several organizations have tested the effects of N fer tilization in to . a year-old, Site V, Douglas-fir plantation on the Wind River Experimental Forest in southwestern Washington. n the initial report, Reukema () reported sub stantial increases in height, diameter, and basal area growth per acre during the first 4 years after fertilizing. This present report describes the continuing effects. RESPONSE TO FERTILIZATION IN THINNED AND UNTHINNED DOUGLAS'FIR STANDS Richard E. Miller, Donald L. Reukema, and Richard L. Williamson ABSTRACT Growth data from thinning and fertilizing trials in 27 Douglas-ir stands in western Oregon, Washington, and British Columbia are summarized. These stands ranged rom 15 to 68 years and from sites I to V. Beneficial effects of fertilizing Douglas-fir forests include temporary improvements in vegetative color and growth of trees and associated vege- tation and faster rates of nutrient cycling between the soil and the Douglas-fir stand (Miller et al. ). Negative environmental impacts are also probable.
Brix and Mitchell () measured soil and tree water-potentials in a year period in thinned and fertilized Douglas-fir stands on Vancouver island, and concluded that thinning initially increased soil water-potential during the dry July-September period, while fertilization had little effect on soil water-potential despite up to 60% increases in growth. Impacts Douglas-fir responses to nitrogen fertilization have been well documented, but these trials are the first in the region to test application of calcium and phophorus, as well as blends based on soil or foliar analysis. Fertilization with urea N, lime, and phosphorus produced a significant volume growth response, and application of calcium chloride a marginally significant volume growth response. Scotch broom (Cytisus scoparius (L.) Link) is a highly competitive, nonnative, leguminous shrub species of major concern in coast Douglas-fir (Pseudot. To examine the effects of density control and fertilization on stand growth and yield of young Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations, seven treatment regimes were applied.