中国海岸的灾害及防护林体系的规划

The coastal disasters and the plan of protected forest system in China

中国海岸每年都有台风、暴潮、风沙和水土流失等严重的灾害,必须遵照“因地制宜,因害设防”的原则,对防护林体系做好综合规划。我国的海岸类型,按地面物质构成不同,可概括为基岩海岸、砂砾质海岸、淤泥质海岸和生物海岸;按海岸地貌时差异,可划分为13个海岸地貌区。这些地区的海岸森林的自然地理特点:一是森林气候类型复杂多样,可分为12种森林气候类型;二是平原海岸形成以耐盐树种为主的森林;三是南方海湾和沿岸有红树林广泛分布;四是海岸森林以防护林为主。现有海岸森林资源的特点:一是森林覆被率低,仅有16.6％;二是林木蓄积量极低,约3,000万立方米,平均每公顷19.07立方米;三是以强阳性先锋树种占绝对优势;四是宜林面积大,约占林业用地的1/3,但造林难度大。因此,防护林体系的规划,要适应抗御灾害和“对外开放,对内搞活”的要求。

There are serious disasters such as typhoon, stormwave, shifting sand, soil and water loss, etc. every year in the coast of China, for this it is thought that the principle of 'suiting measures to local conditions and putting protection according to harm' shouid be obeyed, and that protected forest system be envisaged comprehensively. The coastal types of China,according to the composing matter of ground,could be generalized into the coasts of rock estuary, sand, mud-deposition and biogenic coast. The geomorphic diAision of coast in China, could be divided into thirteen district. The natural characters of the forests along the coasts of the region are the points as follows: one is the multiplicity of forest climate types, including twelve types; the second is that the forests are mainly composed of salt-tolerated species on the plain coast; the third is mangroves scattering in estuaries of south China;and the fourth is that the coastal forests are mainly for protection. The resource of the coastal forests are characterized with lower percentage of forest cover, being only 16.6%; lower timber storation,totaling for 30 million cubic meters, being equal to 19.07m^3; that pioneer tree species are predominated, and that the current area available to afforest is great,being one third of the land area for forest,but with difficulties to afforest. The main purpose of the envisaging projects of the protected forest system is to befend disasters and ameliorate ecological environment, but it also should adapt to the demand to develop economy completely of the coastal region in accordence with the policy of 'opening to the outside world and stimulating economy'.