The comparative study was conducted on the biomass of understory vegetation with the three typical for-est stands at Pangjiapu Forest Farm in northwest Hebei Province as the research objects.The results showed as the following four aspects.(1)Among the three typical forest stands,the highest biomass of the arbor layer was in the pure Betula platyphylla forest,and the lowest was in the mixed forest of Pinus tabulaeformis and poplar birch.The order of size was:pure Betula platyphylla forest＞pure Pinus tabulaeformis forest＞mixed forest of Pinus tabulaeformis and poplar birch.(2)The overall biomass and each tree species biomass of the three typical forest stands exhibited the same pattern,with underground biomass being lower than aboveground biomass.The biomass patterns of various organs in the three tree species of white birch,black birch and Quercus mongolica were the same in the three forest stands,all showing as follows:trunk＞branch＞root＞bark＞leaf.(4)The proportion of trunk and bark biomass of Pinus tabulaeformis and Betula platyphylla in the mixed forest of Pinus tabulaeformis and poplar birch was higher than that in the two pure forests.
维普
万方数据