[Time lag effects of throughfall in natural Larix gmelinii forest in the north of Great Xing'an Mountains, China].

Based on a natural Larix gmelinii forest from Mohe Ecological Station, located in north of Great Xing' an Mountains, time lag effects of throughfall inside the Larix gmelinii forest were analyzed by measuring rainfall, throughfall and stemflow with the method of location observation. The result showed that forest throughfall, stemflow and canopy interception accounted for 76.5%, 2.6% and 20.9% of total rainfall, respectively. Time lag of rainfall inside L. gmelinii forest was found both in beginning and termination of rainfall compared to outside, and the higher the rainfall level, the shorter the time lag of throughfall. For throughfall and stemflow, variations of time lag were (67.8 ± 7.8)--(17.2 ± 3.9) min and (112.0 ± 38.8)--(48.3 ± 10.6) min, respectively. The time lag of throughfall decreased with the increasing rainfall intensity under the same rainfall level. When the rainfall intensity was greater than 2 mm · h(-1), the time lag of throughfall was shortened significantly, but it increased with prolonging the antecedent dry period before rainfall. Rainfall would be the critical factor to affect the time lag of throughfall when the antecedent dry period was longer than 48 h. Termination of throughfall also lagged when rainfall termination happened with a rainfall greater than 5.0 mm. The time lag of throughfall termination increased with increasing the rainfall intensity, but it had no significant relationship with the antecedent dry period before rainfall. However, the termination of stemflow occurred prior to rainfall, which was relevant to the rainfall level, and the smaller the rainfall level, the sooner the stemflow terminated.