特呈岛退化红树林林窗特征

调查了广东省特呈岛整片退化红树林的林窗大小结构、形成方式、形成木林窗特征及边界木特征等。结果表明:该地区林窗主要以小型面积林窗为主,形状大多数近似于椭圆形,林窗平均高度较矮; 形成方式主要是枯立、折枝和枯立+干折等。分析认为,林内海水水文作用为退化红树林林窗所特有的新形成方式以及林窗形成后有盐地鼠尾栗入侵。形成木数量多,基径偏小,以白骨壤和红海榄为主; 林窗边界木以中小径级为主,健康程度较差的边界木接近一半,主要分布在低潮带和中潮带,有恶化的趋势。因此,退化红树林林窗特征与健康红树林林窗特征有很大不同,海边风浪过度侵蚀是红树林退化的主要诱因。

Forest gap character of degradation mangrove in Techeng Island

The survey of forest gap character of degradation mangrove has important ecological significance, which could provide reference for the development and protection of Techeng Island mangrove. This paper investigated the whole piece of degraded mangrove forest of gap size structure, mode formation, character of forest gap maker and gap border trees in Techeng Island, Guangdong province.The results showed that: mangrove forest gap was main of small area of forest gaps, shapes was most similar to ellipse,the average height of forest gap was low. Most gaps were created by a combination of natural death, breakage on branch,stem breakage+natural death,which first reported forest gap forming new way of hydrological effect of seawater unique belong to degraded mangrove forest and after the formation of gaps, Sporobolus virginicus invade. The numbers of gap maker were more significant than health mangrove forest gap, diameter incline to small, with mian for Avicennia marina and Rhizophora stylosa.Gap border trees were mainly small and medium diameter, with poor health mostly distributed in low tide and middle tide, had the trend of deterioration. We concluded that degraded mangrove forest gap presented the different character of the healthy forest gap, the excessive erosion of sea wind, and wave was the main inducement.