Effects of Drought on Forests and Rangelands in the United States

Effects of Drought on Forests and Rangelands in the United States

Author: James M. Vose

Publisher:

Published: 2016

Total Pages: 302

ISBN-13:

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This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed; however, even moderate drought can have long-lasting impacts on the structure and function of forests and rangelands without these obvious large-scale changes. Large, stand-level impacts of drought are already underway in the West, but all U.S. forests are vulnerable to drought. Drought-associated forest disturbances are expected to increase with climatic change. Management actions can either mitigate or exacerbate the effects of drought. A first principal for increasing resilience and adaptation is to avoid management actions that exacerbate the effects of current or future drought. Options to mitigate drought include altering structural or functional components of vegetation, minimizing drought-mediated disturbance such as wildfire or insect outbreaks, and managing for reliable flow of water.


Ground-truthing the Drought Code

Ground-truthing the Drought Code

Author: Bruce D. Lawson

Publisher:

Published: 1996

Total Pages: 32

ISBN-13:

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Users of the Canadian Forest Fire Weather Index System are required to precede computation of the drought code component each spring by first calculating a mathematical model of overwinter recharge of moisture in the forest floor. Limitations of the model, required for operational simplicity, have led to requests for a field sampling procedure that can be used to verify the model when and where desired. This report describes a standard procedure for destructively sampling the forest floor by depth class, oven-drying the material, and comparing the actual moisture contents against empirically derived regression equations of forest floor moisture versus drought code for representative mature coastal and interior British Columbia forests, and for white spruce forests in southern Yukon. The field verification procedures and calibration equations presented will be applicable to drought code start-up at any time during the fire season.