Seasonal Changes in Nutrient Concentration and Content of Aspen Suckers in Minnesota

Abstract

Abstract Aspen ( Populus tremuloides , Michx.) suckers on a site in North Central Minnesota were sampled 6 or 7 times per year for 3 years. Ovendry biomass and N, P, K, Ca, and Mg content were determined for foliage, branches, bolewood, and bolebark. All tissues had large seasonal variation for at least some nutrients. The foliage showed particularly large seasonal variation for N and P because these nutrients are translocated from perennial tissue (primarily bark) to foliage in the spring and then translocated back to the perennial tissues in the autumn. Seasonal nutrient concentration changes in the perennial tissues are often as large as for the foliage, but usually in the reverse direction. These changes are largest in the spring and autumn, but substantial changes also occur in midsummer. The most suitable time to sample perennial tissues for nutrient content is during the leafless period when seasonal fluctuations are minimum. Forest Sci. 31:785-794.