A preliminary study on hydrological effects of litter and soil layers in natural Pinus tabuliformis forest was carried out at four different altitudes(751

890

1 012 and 1 211 m) in the Songshan Mountains in Beijing City. Results showed that:(1) The total storage capacity

maximum water holding capacity and maximum water holding rate of litter increased firstly and then decreased with increasing altitude. (2) The total storage capacity of litter was about 9.03~27.75 t/hm2. The maximum water holding capacity of litter was about 26.66~90.54 t/hm2 and had a visible logarithmic correlation with immersion time(R>0.93). The maximum water holding rate of litter was about 287. 62%~296.73% and had a power relation with immersion time (R>0.99). (3) The soil bulk density decreased with increasing altitude in the range from 1.38 to 1.66 g/cm3. The total soil porosity decreased firstly and then increased with altitude. (4) The initial infiltration rates of soils were largely different and the steady infiltration rates varied from 1.95 to 7.06 mm/min. The infiltration rate had power function correlation with infiltration time(R>0.70). Generally

Pinus tabulaeformis forest at low altitude has a stronger water conservation function.