[Energy balance and evapotranspiration in broad-leaved Korean pine forest in Changbai Mountains].

Based on the continuous measurements of an open-path eddy covariance system, this paper analyzed the characteristics of energy balance components and evapotranspiration in a broad-leaved Korean pine forest in Changbai Mountains in 2008, as well as the differences of energy balance components and evapotranspiration between growth season and dormant season. For the test forest, the year-round energy balance closure was 72%, being at a medium level, compared to the other studies in the Fluxnet community. The energy balance components had significant differences in their diurnal and seasonal variations. In growth season, turbulent energy exchange was dominated by upward latent heat flux, accounting for 66% of available energy; while in dormant season, the turbulent energy exchange was dominated by upward sensible heat flux, accounting for 63% of available energy. The accumulated annual evapotranspiration in the study site in 2008 was 484.7 mm, occupying 87% of the precipitation at the same time period (558.9 mm), which demonstrated that evapotranspiration was the main water loss item in temperate forests of northern China.

[Effects of snow cover on soil temperature in broad-leaved Korean pine forest in Changbai Mountains].

A snow-shading experiment was conducted in a broad-leaved Korean pine forest in Changbai Mountains from 2004 to 2007 to observe the soil temperature with and without snow cover. Snow cover played an important buffering role in the change of soil temperature, namely, slowed down the change process of soil temperature. The effect of snow cover on preserving soil heat was quite obvious in shallow soil layer (0-20 cm), and enhanced with increasing snow depth. When the snow depth increased from 10 to 20 cm, the effect enhanced significantly. However, when the snow depth exceeded 30 cm, the increasing trend turned to indistinctive. In the period of snow-melting, soil temperature kept around 0 degrees C for some time, and after then, increased gradually. The length of the period keeping soil temperature around 0 degrees C was determined by snow depth and the duration of snow cover.