Ayres Abstracts

Wilkens, R. T., M. P. Ayres, P. L. Lorio, Jr. and J. D. Hodges. 1997. Environmental effects on pine tree carbon budgets and resistance to bark beetles. Pages 591-616 in R. A. Mickler and S. Fox, editors. The productivity and sustainability of southern forest ecosystems in a changing environment. Springer-Verlag, New York. pdf
Our results indicate that increased nutrient availability leads to an increase in growth and a reduction in resin-based defenses. Because of this, we recommend that foresters and planners consider the effect of fertilization and site fertility on both tree growth and SPB risk. Unfortunately, increased tree growth may frequently be associated with increased SPB risk. The mechanism for the usefulness of thinning as a silvicultural technique to limit SPB infestations remain unclear. If, as expected, global change alters precipitation patterns and soil-nutrient availability in the southern United States, patterns of growth and secondary metabilism in southern pines will also change, and this will probably produce changes in the spatial and temporal pattern of SPB infestations. Because SPB have such a large impact on southern forests, even modest changes in SPB activity can have significant economic and ecological repercussions. Our theoretical and empirical understanding of environmental effects on the physiology of southern pine remains imperfect but is growing. With this study, we now have some basis for predicting the direction and magnitude of changes in risk of SPB attack, anticipating how these patterns will vary from region-to-region or site-to-site, and suggesting appropriate changes in land-use strategies. Further testing and parameterization of physiologically explicit models should increase our ability to manage southern forests in a changing world.

 

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