A Study of Man-made Shelter Forest Decline in Sichuan Province

Shelter forest is one of the main forest categories in Sichuan Province,occupying an area of more than half of all forests.Its dominant tree species is cypress and its area accounts for 17.33% of the total shelter forest area.Based on the features of man-made shelter forest and the definition of the shelter forest decline,in the paper studies were made of an assessment index system and the degree system of man-made shelter forest decline in Sichuan province.Through analysis,man-made shelter forest decline area was 448.5 thousand hectares and its volume was 45 million 268 thousand and 600 cubic metres in Sichuan province.Finally,analysis was made of the causes of man-made shelter forest decline from natural factors,social factors and management technology.