Treesearch

The widespread nature of ozone air pollution in California and the suspected potential for ozone damage to forests near cities in other Western States led to field surveys and establishment of monitoring plots beginning in the mid–1960’s. The surveys and plot results were divided into three categories depending on the evidence of injury that was documented, including (1) surveys that failed to reveal any evidence of injury even though ozone air pollution was suspected; (2) visible foliar injury that was detected although no structural or functional changes were evident in the forest...

Elevated N deposition has occurred in the Los Angeles Basin in southern California for at least the last 40 years. Elevated streamwater NO; fluxes and high nitric oxide (NO) fluxes from soil, indicators of N saturation, have recently been reported for chaparral watersheds exposed to chronic N deposition in the San Gabriel Mountains north/northeast of Los Angeles. A number of nutritional and edaphic parameters across a deposition gradient in the San Bernardino Mountains (SBM) support the hypothesis that the mixed conifer forest in the western end of the range is also N saturated. Concentrati...

Uniform, or standard, measurement methods of data are critical to projects monitoring change to forest systems. Standardized methods, with known or estimable errors, contribute greatly to the confidence associated with decisions on the basis of field data collections (Zedaker and Nicholas 1990). Quality assurance (QA) for the measurement process includes operations and procedures so that the data are of the specified quality within a stated level of uncertainty. Quality is acceptable when data are consistent, lack uncertainty, and meet users’ needs. Some of the elements of a QA plan for...

For most of this century the goal of fire management in the Sierra was to control fire. The policy was aggressively and successfully ap-plied, substantially reducing annual acres burned. This goal was based on a fire policy that emphasized keeping wildland fires as small and inexpensive as possible. As the role of fire in maintaining Sierran ecosystems has been recognized, fire has been reintroduced through the application of planned prescribed fire and prescribed natural fire. Despite changes in fire-management policy that have allowed ex-panded use of fire, relatively few acres have been...