Etiology and evidence of systemic acidification in SOD-affected forests of California

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Title: Etiology and evidence of systemic acidification in SOD-affected forests of California

Author: Klinger, Lee; Zingaro, Ralph

Date: 2006

Source: In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 181-182

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Station ID: GTR-PSW-196

Description: Pathologists investigating the widespread death of oak trees in the forest ecosystems of northern California concluded, in 2000, that the problem was due to a new plant disease, dubbed sudden oak death (SOD), which is caused by the fungal pathogen Phytophthora ramorum. Since then this one organism has been the focal point of notable efforts to understand, monitor, and control SOD. While not disputing that P. ramorum is involved in the final demise of many oaks, there is a growing number of scientists and arborists who do not agree that this pathogen is the fundamental cause of the overall decline. These experts point out that most of the dying oaks in SOD-affected forests show no expression of P. ramorum. They further note that the etiology of SOD closely resembles that seen in other aging forests where the decline of the trees has been attributed to an increase in acidity and mineral deficiency of the water and soils. In these places, acidic conditions create mineral imbalances and deficiencies in trees, especially calcium, which greatly weaken the trees, raising their susceptibility to secondary pests and pathogens. Here we present evidence that suggests systemic acidification of forests can explain, quite well, the entire SOD phenomenon.

Key Words: acidification, soil, mosses

Publication Notes:

Citation

Klinger, Lee; Zingaro, Ralph 2006. Etiology and evidence of systemic acidification in SOD-affected forests of California In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 181-182.