Title: Restoring the Health of Fire-Adapted Ecosystem in the Southwest: Some Effects on Soil and Water
Abstract: The Sky Islands of southeastern Arizona have a variety of ecosystems ranging from desert scrub to spruce forests (Lefevre 1998). Between these extremes are desert grasslands, oak woodlands, and mixed conifer forests. These are adapted to frequent fires and other disturbances. However, changes in stand structure and species composition within these systems have made many of them unsustainable (Harrington and Sackett 1992; Quinn and Wu 2004). Stand -replacing wildfire and insect attacks have resulted in upland and downstream changes within the sky islands. Recent dramatic changes in the number and size of disturbances are best illustrated with the following statistics. From 1977 through 2000, 17 fires greater than 300 acres required a Burned Area Emergency Response (BAER) action on the Coronado National Forest. The total acreage involved in those fires was about 82,000 acres, an average of 3444 acres per year. Since 2000, 17 additional fires totaling 250,000 acres have required BAER action. Insect activity was at endemic levels during that same period, with an average of 41,106 acres per year. In addition, approximately 12,000 acres of tree mortality due to insect attack were observed from 1975 through 2000. Since 2000, tree mortality due to insect attack in the sky islands has totaled more than 36,000 acres. Actions being taken in response to these changes in size and number of disturbances are part of the Southwestern Region of the Forest Service Central Priority: Restore Fire Adapted Ecosystems. The details include larger programs to thin stands through mechanical means and broadcast burning, fuel reduction by piling and burning and increased sales of forest products, and mechanized removal of woody material to off -site locations. These activities have long been recognized as having impacts on water-
Publication Year: 2006
Publication Date: 2006-04-08
Language: en
Type: article
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