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Managing air pollution impacted forests of California

Informally Refereed

Abstract

Fuel treatments (prescribed fire and mechanical removal) on public lands in California are critical for reducing fuel accumulation and wildfire frequency and severity and protecting private property located in the wildland–urban interface. Treatments are especially needed in forests impacted by air pollution and subject to climate change. High ambient ozone (O3) concentration and elevated nitrogen (N) deposition weakens and predisposes trees to bark beetle attacks, increases foliar senescence and fuel build-up, and increases water stress during drought periods. Climate variability  is expected to increase beyond historic ranges of variation, resulting in more severe droughts. Combinations of future climate variability and air pollution are likely to increase risk of episodic tree mortality, long-term ecosystem changes, and frequency and severity of wildland fires. Fuel treatments, however, are difficult to implement in these forests. Smoke from prescribed fires can adversely affect local and regional air quality leading to conflicts with local and regional air regulatory agencies. Over the past several years federal land air quality and fire managers have responded to these conflicting needs by expanding beyond the boundaries of their historical job responsibilities. For example, they are now actively forging cooperative relationships with local, state, and federal air regulators. The result has been fewer conflicts about smoke in populated or protected areas, with managers achieving an adequate level of prescribed fire treatments. Smoke monitoring by air managers has played a key role in this success. Social and regulatory acceptance of fire as a management tool in air polluted forests will depend on land managers developing a better understanding of air pollution and smoke interactions and interactions between air pollution, drought, and insects. Acceptance of fire as a management tool also requires better large-scale monitoring efforts (field collected and remotely sensed), development of models for predicting spatial and temporal distribution of air pollution and smoke resulting from forest fires, and incorporation of air pollution and climate effects into forest mensuration models used to predict stand development.

Parent Publication

Citation

Arbaugh, Michael J.; Proctor, Trent; Esperanza, Annie. 2009. Managing air pollution impacted forests of California. In: Bytnerowicz, Andrzej; Arbaugh, Michael; Andersen, Christian; Riebau, Allen. Wildland Fires and Air Pollution. Developments in Environmental Science. Amsterdam, The Netherlands: Elsevier: 567-582. Chapter 25.
https://www.fs.usda.gov/research/treesearch/34285