Using tree canopy to analyze and evaluate the state of ecological land and its potential for rural residential

Tree canopy cover is the most efficient and scientific indicator for evaluating ecological construction in the world. Compared with conventional indicators (such as woody plant cover rate and percent green coverage), tree canopy cover have many outstanding advantages in ecosystem services assessment as it does not distinguish land ownership or emphasize green space quality. Under new rural construction conditions, evaluating the state and potential of village forest using tree canopy cover can more efficiently guide environmental protection and reconstruction in the countryside. Instead of urban tree canopy cover (which has been the focus of most domestic and international research), this paper investigated tree canopy cover at town level. Based on true color aerial image of Linghe Town (in a grid cell size of 25 cm × 25 cm) Shadong Province, for July and August 2009, we analyzed ecological lands in Linghe Township using existing and possible tree canopy covers as indicators. The tree canopy cover was quantitatively analyzed at the town and smaller scale such as administrative village, tree species. Statistical analysis in GIS environment showed that the investigated area was 17.12% under tree canopy cover, of which 99% was arbor tree canopy cover. Based on the area proportions of tree canopy cover of different tree species, Populus accounted for 69.92% (the highest) of the total tree canopy cover with 11.97% of canopy cover. The other dominant tree species included protecting trees of Paulownia spp., and Robinia pseudoacacia, economic trees of Malus spp., Diospyros kaki, etc. Based on the distribution of patch size of tree canopy cover, middle and small patches were dominant in terms of quantity, while large patches dominated in terms of area. The evaluation on tree canopy cover of different administrative villages indicated that among 66 villages, 24 villages’ tree canopy cover was higher than the average level of the study area (17.12%), 36.36% villages was in middle level for tree canopy cover. The proportions of villages with very low and low coverages were 21.21% and 18.18%, respectively, and that with high coverage was only 7.58%. From the standpoint of greenable land in the future, theoretically possible tree canopy cover area was 190.51 hm2, accounting for 2.91% of the study area. This included shallow land, bare land, wild grassland and other unused lands. The theoretically maximum tree canopy cover of the study area was 20.12%. However, reserving 10% of the landscape for protected diversity, the actual maximum of possible tree canopy cover was 2.7%, in which shallow land occupied the most area, 59.64 hm2. Given the distribution relationship between hydrographic network and tree canopy cover network, the river network of forest need more attention in future ecological reconstruction of countryside.