Preliminary study on dynamics of evergreen broad-leaved forest in Eastern Ningbo using 3S methods

This paper classified land use and vegetation types of Ningbo with Landsat remote sensing data of 6 times(1974～2009) using 3S methods,extracted the regions of different vegetation types which turn into evergreen broad-leaved forest in each period and calculated transformation rate of every type for evergreen broad-leaved forest.Results showed that physical succession rules and economic benefits are the main causes of evergreen broad-leaved forest dynamic changes in the past 37 years.It is likely to conversed with coniferous and broad-leaved mixed forest and evergreen and deciduous broad-leaved mixed forest without considering human influence.On this basis,we measured the distance between vegetation types turned into evergreen broad-leaved forest in each period and the type remained evergreen broad-leaved forest in the same period,calculated total average value of five periods,and ordered them by vegetation types: coniferous and broad-leaved mixed forestevergreen and deciduous broad-leaved mixed forestbambooconiferous foresttea plantations and orchardsshrubfarmland,it is found that seed spread and land use history are key factors which affected direction of degraded evergreen broad-leaved forest community's secondary succession.