Stand treatment and sampling time of hardwood foliage

A 70-year-old thinned northeastern Fagus-Betula-Acer stand in the Adirondack Mountains of New York was fertilized with varying combinations of N, P, K and lime.Acer saccharum Marsh. andBetula alleghaniensis Brit. foliage was collected periodically during the frost-free season and analyzed for foliage areas and weights, and levels of ash, Mn, Na, Fe, Zn, Al, Cu and Co. Comparisons were made within species, and among treatments, expressed as concentration on dry weight and ash bases, and as contents on per leaf weight and area bases. Elemental composition trends over time were examined to determine treatment effects and optimum sampling period.