A study on the influencing factors of Larix gmelinii post-fire seed germination

Fire disturbance exerts great influences on the structure and function of Larix gmelinii forest ecosystem. Post-fire regeneration of Larix gmelinii is affected by multiple factors, and determines the community succession trajectory. By setting in-situ experiment at burned area of the Huzhong natural reserve in Great Xing′an Mountains, we used BRT(Boosted Regression Tree Analysis) to quantify relative influence of driving factors(temperature, depth of organic layer, coverage, et al.) that influenced Larix gmelinii seed germination of post-fire tree recruitment. The results showed that three main factors of Larix gmelinii post-fire seed germination were temperature, seeds number, and coverage, which explained 28.51%, 22.40% and 20.66% of the seedling quantity variation, respectively. Significantly differences in relative influence of these driving factors on seedling quantity were found among different topographic positions: temperature had important influence at the top of slope and the bottom of sunny slope; seeds quantity was the most influential factor of seedling quantity at the mid of slope; and soil water content played the most important role at the bottom of shady slope. Moreover, removing the organic layer and weeding significantly increased quantity of seedlings. In summary, the germination of Larix gmelinii seeds were influenced by different factors under different topographic positions(environment conditions). Therefore, local conditions should be an importance concern when artificial regeneration was implemented to promote post-fire Larix gmelinii restoration.