The Regional Forest Nutrition Research Project

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Forest nutrition studies initiated by a UW researcher some 50 years ago have produced one of the largest databases in the world on the growth characteristics of Douglas fir and western hemlock, and spawned a highly successful research cooperative comprising over 35 organizations that continues today. Over three million acres of forest have been fertilized in western Washington and Oregon, largely based on the results of the program.

Nutrition studies in coastal forests were initiated at the University of Washington by the now late forestry professor Stan Gessel shortly after he arrived at the UW in 1948. The work resulted from observations that although Douglas fir grew well over a broad range of climate and soil conditions, on a considerable number of soils the trees were chlorotic (yellowish) and had poor growth rates and poor vigor, probably due to mineral deficiencies. Gessel's early work suggested that nitrogen fertilization would increase the growth of Douglas fir trees and stands of these trees. These promising results led to the formation at the UW of the Regional Forest Nutrition Research Project (RFNRP) in 1969.

The goal of the program was to provide forest managers with information on the growth of Douglas fir and western hemlock and the response of these trees to fertilization. Gessel and colleagues compared the responses of thinned versus unthinned stands; they investigated alternative sources of nitrogen and other critical nutrients; they studied the influence of fertilization practices on forest ecosystems, the economic aspects of forest fertilization, and the effects of fertilization on wood quality.

The program developed an extensive base of field installations. Over the years, researchers have maintained and monitored over 280 sites in western Washington and western Oregon. The oldest plots are located in unthinned and thinned stands spanning a range of age, stock, and productivity. More recently, a series of research plots were established in young stands and plantations. This segment of RFNRP represents the largest research program in the country focused on the evaluation of fertilizer response in young, spaced Pacific Northwest Douglas fir stands.

In 1991, the RFNRP was integrated into the Stand Management Cooperative (SMC), a long-term effort that integrates research in forest nutrition, silviculture, wood quality, and modeling. Over 35 organizations from the regional forest products industries, state and federal agencies, and forest fertilizer manufacturers currently participate in the Cooperative. The long-standing work in forest nutrition and fertilizer response continues as a part of SMC, now integrated with other silvicultural research and increasingly focused on issues of sustainability in managed forests.

"The RFNRP was one of the earliest applied forestry research cooperatives in the country, and had a long and successful record," says UW forestry professor Nick Chappell, who is SMC director and the Cooperative's nutrition project leader. Chappell stresses the pioneering work of Stan Gessel not only in research, but also in the training of many students, and in transferring the program's advances into industrial practice.

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