SURFACE POLLEN ASSEMBLAGES OF SOME MAJOR FOREST TYPES IN NORTHERN CHINA
中国北方几种主要森林群落表土花粉组合特征研究

Studies on surface pollen of 68 different forest communities in Northern China show that arboreal pollen percentages are more than 30WTB3]%WTBZ] and herbs pollen percentages are less than 50% in the eastern broadleaves forest areas, while arboreal pollen percentages are less than 30WTB3]%WTBZ] and herbs pollen percentages are more than 50WTB3]%WTBZ] in the forest communities in the western steppe and desert areas. In Pinus, Picea and Betula forests, the pollen taxa with the highest percentages are dominated plants. In Larix forest, Artemisia has the highest percentages, then followed by Pinus and Larix. In Populus forest, Pinus and Betula are the two abundant components in the pollen assemblages. In Quercus, Juglans, Carpinus and Pteroceltis forests, except for their dominated plants, Pinus is the most important arboreal pollen type with certain fern spores. Pinus, Betula and Selaginella percentages are advantageous in mixed broadleaves forests and Pinus mixed broadleaves forests. The result of DCA, PCA and CLA analyses of samples show that the trees which mostly prefer to live in wet and cold areas are Picea, Larix and Betula, and the species which mostly prefer to live in arid areas are Elaeagnus, Ulmus and artificial Populus forest. Populus prefer to warmer and drier condition than Betula. Quercus, Carpinus and Pteroceltis prefer to warmer and drier condition than Populus. Juglans more prefer to warm conditions than all above the forest types. All those results are consistent with their ecological conditions. The pollen percentages ratios of Pinus/Artemisia (P/A) are more than 0.1 in the eastern broadleaves forests, and less than 0.1 in the western forest communities of steppe and desert. Pinus forests, Pinus mixed broadleaves forests and mixed broadleaves forests have high P/A ratios and F/H ratios (fern/herbs) with relative low A/C ratio (Artemisia/Chenopodiaceae). Picea, Abies, Larix and Betula forests have low P/A and F/H ratios with high A/C ratios. The high P/A and A/C ratios with low F/H ratios in Quercus, Juglans, Carpinus, Populus, Peroceltis forests distinguished from mixed broadleaves forests, Pinus mixed broadleaves forests, Pinus forests, Betula forests and needle forests. However, whether these results can be used widely still need further verification.