Category: Theses and Dissertations
Title: Fire Regimes and Forest Structure in Pine Ecosystems of Arizona, U.S.A., and Durango, Mexico
Author: * Fule, P.Z.
Subject: Fire behavior, Fire effects, Spatial Dynamics
Abstract: Frequent, low-intensity fire regimes are keystone ecological processes in long-needled pine forests of western North America. This study compared related ecosystems in the southwestern U.S., where extended fire exclusion has led to the development of unsustainably dense forests, and in northern Mexico, where forests have a complex mix of fire regimes. In Arizona, U.S.A., reference conditions of the historic fire disturbance regime and forest structure prior to Euro-American settlement (circa 1880 A.D.) of a Pinus ponderosa landscape were quantified. Presettlement fire return intervals averaged 4 years for all fires and 7 years for widespread fires. After excluding fire, forest density increased from an average of 148 trees/ha in 1883, an open forest dominated by relatively large pines, to 1,265 trees/ha in 1994/95, a dense forest of relatively small and young trees. Species composition has shifted toward greater dominance by Quercus and conifers less-adapted to frequent fires (Abies and Pseudotsuga)
Source: Ph.D. Dissertation
Publisher: NAU School of Forestry, http://www.for.nau.edu