Physical Property of Soil in the Plantation and Natural Forest in Jiulong Mountains of Beijing

The physical property of soil in the plantation of Larix principis-rupprechtii,Pinus tabulaeformis,Fraxinus chinensis and second natural forest of Tilia mixed with Quercus and Populus had been studied in Jiulong Mountains of Beijing,China.Result of the study shows that the physical property of soil in the second natural forest is better than that in the plantation.For plantation species,physical property of the soil under Larix principis-rupprechtii is better than those under Pinus tabulaeformis and Fraxinus chinensis.This is because there is higher organic matter in the soil under the second natural forest of the Tilia mixed with Quercus and Populus and under the plantation of Larix principis-rupprechtii mixed with plants.The organic matter comes from discomposed leaves and branches fallen down from the species.