[Текст] / USDA Forest Service. - Maryland : USDA Forest Service , 1993. - 15 с. + tables. - (Summary report ; NE/NA/INF-115-R93). - Библиогр: В надзаг.:. - free of charge р.
Аннотация: Researchers with the Northeastern Forest Health Monitoring program visited 256 plots in 1992, collecting data from nearly 8,000 trees in Delaware, Maryland, New Jersy, Massachusetts, Rhode Island, Connecticut, Vermont, New Hampshire, and Maine. There continues to be no evidence of large, regional-scale declines in the health of forest ecosystems as determined by observations of visual crown indicators on trees, e.g., crown dieback, crown density, and foliage transparency. Several individual species (eastern hemlock, northern white-cedar, Americal beech) show slight evidence of decline in one or more visual crown indicators. Some of this decline is attributed to known cases of disease/pest incidence, e.g., outbreakes of beech bark disease and
defoliation by the hemlock looper. Evidence of ozone damage was noted on 28 percent of 39 plots where ozone-sensitive plants were surveyed. Soil sampling was implemented on 50 plots in New England, with plants to cover all plots brginning in 1994.Surveys of off-plot insects and pathogens also showed no evidence of regional-scale decline of the forest resource in the Northeastern United States.
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