Abstract
We measured the annual pollen production rates of Salix pseudoyoshinoi in 2003 in a young (tree age, 8 to 11years) and pure stand of S. pseudoyoshinoi. No female trees were identified within a 20×40m plot set, and no female inflorescences or infructescences were caught with litter traps. Pollen production rates were determined on an area basis from the number of male inflorescences in the studied stand, and the mean number and dry weight of pollen grains contained in male inflorescences before pollen release. The mean number of pollen grains per stamen was 3,883. The mean dry weight of pollen per stamen was 0.02228mg, giving a mean single pollen grain dry weight of 5.8×10^<-6>mg. The mean number and dry weight of pollen grains for the two stamens borne by each flower were 7,766 grains and 0.04456mg respectively, and, per inflorescence, were 0.967×10^6 grains and 5.54mg. These figures were obtained by multiplying the quantity of pollen grains per flower by the mean number of flowers per inflorescence. The yield of open male inflorescences per hectare of the study stand, measured with litter traps, was 8.2067×10^6/ha/yr. Therefore, the production rates of pollen grains from this S. pseudoyosinoi stand, in terms of grain number and weight, were estimated to be 7.93×10^<12>/ha/yr and 45.4kg/ha/yr, respectively.
