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Abstract
We developed methods to assess the impacts of diseases and arthropods on sapling and mature rangeland oaks, and applied these methods at 18 sample plot locations in northern California. The impact of arthropod damage was generally rated as minor. Leafy mistletoe (
Phoradendron villosum) was found on 5 percent of the rated trees. There was a slight correlation between mistletoe infestation levels and dieback ratings. Characteristic canker rot symptoms were seen in 9 percent of the trees surveyed, and 16 percent of the trees had at least 20 percent of the bole volume decayed by fungi. In
Quercus douglasii, the percentage of trees showing more than 20 percent wood decay in the bole differed significantly between locations, ranging from 0 to almost 43 percent. Canker rot fungi and other wood decay fungi were the most significant agents affecting health and survival of rangeland oaks.
Parent Publication
Citation
Swiecki, Tedmund J.; Bernhardt, Elizabeth A.; Arnold Richard A. 1991. Monitoring Insect and Disease Impacts on Rangeland Oaks in California. In: Standiford, Richard B., tech. coord. 1991. Proceedings of the symposium on oak woodlands and hardwood rangeland management; October 31 - November 2, 1990; Davis, California. Gen. Tech. Rep. PSW-GTR-126. Berkeley, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; p. 208-213
