Research On The Frozen Rain And Snow Interference’s Influence On Jiang Xi Da Gang Shan Evergreen Broad-leaved

Freezing rain and snow, as one of the most important natural interference factor, have received people’s attention for a long time because it’s vital ecological significance and serious destructiveness to the forest. In 2008, the south china suffered a rare disaster of severe freezing rain and snow for a long time, and Dagang Mountain is one of them.The freezing rain and snow in 2008 provided a quite rare opportunity to study the forest ecosystems, especially the ecosystem of natural evergreen broad-leaved forests that suffered natural interference. In this paper, take the seriously damaged evergreen broad-leaf forest in Dagang Mountain as studying object,15 different sample area were selected to investigate and detect the community structure, undergrowth vegetation and soil nutrient at November 2007 (before the disaster) and December 2008 (disaster year), and recheck the sample area in 2011 and 2012 year, analyze the freezing rain and snow interference characters, under canopy update, plant diversity dynamics and soil nutrient dynamics of subtropical evergreen forest, and to further expose the freezing disaster responding mechanism of evergreen broad-leaf forest. The results shows that:1.Different broad-leaf species shows different degree of extent of damage of freezing rain and snow that sloanea sinensis and rhododendron latoucheae of minor damage and sapium discolor of greatest damage.2.After the freezing rain and snow disaster, the under canopy update of evergreen broad-leaf is the number of shade arbor species and light-loving fast growing species increase, and shrub-grass increase significantly. Evergreen broad-leaf forest biodiversity significantly increase. The damage class is three which is the biodiversity of severely damaged community increased greatly.3.In the process of community recovery after the disaster, Undergrowth increased markedly, vegetation biodiversity also has different change, Simpson diversity index were 0.8827(before the disaster),0.8845 (the disaster year),0.9441 (the fourth year after the disaster), revealing that in the process of community restoration,biodiversity has a rising trend.4.Before and after the snow disaster interference, the soil nutrient content of Dagangshan evergreen broad-leaved forest appeared obviously differences, the content of soil organic ncreased by 29.12%; N, P, K content were substantialy increased, the average rate of increase were 18.92%,19.05%,18.61%.