In order to assess water conservational function of different forests types in Laotudingzi natural reserve

six forest soils were selected to test soil storage capacity and infiltration characteristics.The results indicate that soil bulk density(0-40cm)under these forests ranged from 0.76to 1.71g/cm3

non-capillary porosity ranged from 8.15%to 22.07%

capillary porosity ranged from 27.060%to 53.28%

soil porosity conditions of natural secondary forests

such as shrub

Betula ermanii

Spinney

were better thanLarix pricepis-ruprechtii andPinus koraiensis

soil water storage(0-40cm)ranged from 1 429.8 to 2834.3t/hm2

effective capacity ranged from 325.9to 882.7t/hm2

capillary water holding capacity ranged from 1103.8to 2131.0t/hm2

soil wate-holding capability of natural secondary forest was relatively stronger than plantation

initial infiltration rates(0-20cm)ranged from 0.28to 21.1mm/min

and initial infil-tration rates(20-40cm)ranged from 0.07to 6.7mm/min

steady infiltration rates(0-20cm)ranged from 0.14to 8.3mm/min

steady infiltration rates (20-40cm)ranged from 0.05to 2.0mm/min

initial infiltration rates and steady infiltration rates of natural secondary forests were relatively stronger than plantation.A power function can be used to describe the relationship between soil infiltration rate and time.