Pacific Southwest Research Station

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Title: Growth and yield of southwest pinyon-juniper woodlands: Modeling growth and drought effects

Authors: Shaw, John D.

Date: 2008

Publication In: Gottfried, Gerald J.; Shaw, John D.; Ford, Paulette L., compilers. 2008. Ecology, management, and restoration of pinon-juniper and ponderosa pine ecosystems: combined proceedings of the 2005 St. George, Utah and 2006 Albuquerque, New Mexico workshops. Proceedings RMRS-P-51. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 20-27

Abstract: A complex of drought, insects, and disease caused widespread mortality in the pinyon-juniper forest types of the American Southwest in recent years. Most public and scientific attention has been given to the extent of drought-related mortality and causal factors. At the same time, there has been relatively little attention given to non-lethal drought effects. As part of standard data collection protocol, the Interior West Forest Inventory and Analysis program measures radial increment on a portion of tally tree species. Between 1981 and 2005, data were collected on 14,929 plots with pinyon or juniper species present. These data included 10-year increment measurements on 23,080 pinyon and juniper trees. These data were used to characterize the "typical" growth patterns of pinyon and juniper species, and to analyze the effects of drought on radial increment. In addition, these measured increments were compared to those projected by the Forest Vegetation Simulator (FVS). Most species showed a reduction in diameter increment when data from pre-drought years were compared to post-drought years. FVS produced diameter increments that were within the range found in the data, but height growth may be over-predicted in some cases.

Keywords: diameter increment, height growth, Forest Inventory and Analysis (FIA), mortality, Forest Vegetation Simulator

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Citation

Shaw, John D. 2008. Growth and yield of southwest pinyon-juniper woodlands: Modeling growth and drought effects. In: Gottfried, Gerald J.; Shaw, John D.; Ford, Paulette L., compilers. 2008. Ecology, management, and restoration of pinon-juniper and ponderosa pine ecosystems: combined proceedings of the 2005 St. George, Utah and 2006 Albuquerque, New Mexico workshops. Proceedings RMRS-P-51. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 20-27