Abstract: The measurement of soil hydro-physical properties under broadleaved Korean pine and dark coniferous forests on the northern slope of Changbai Mountains showed that under these two for-est types, soil bulk density and porosity had the same variation trend with increasing soil depth, i . e ., bulk density and capillary porosity increased, while total porosity and non-capillary porosity decreased. The average bulk density, total porosity, capillary porosity and non-capillary porosity in 0—100 cm soil layer were 1.41 g·cm^-3, 52.31%, 46.11% and 6.20% under broadleaved Korean pine forest, and 0.98 g·cm^-3, 50.65%, 40.32% , 10.33% under dark coniferous forest, respectively. Owing to the differences in soil hydro-physical properties, the water storage capacity in 0—100 cm soil layer was 619.89 t·hm^-2 under broadleaved Korean pine forest, but 1 033.05 t·hm^-2 under dark coniferous forest. For these two forests, their soil water characteristic curves were consistent with the general one.

Key words: Plutella xylostella, Low temperature, Development time, Survival, Fecundity