Dynamic analysis of forest land conversion and forest ecological services value in Chaobai River Basin

Through building an evaluation index, the ecological services value of forests was quantified and evaluated dynamically in Chaobai River Basin with four periods’ land-use data and the spatio-temporal Markov chains model to realize green GDP accounting. The results showed that all types of land-use turned to forest land gradually in a whole trend, with the forest land transformation method changing from simple to complex, the frequency changing from small to large, while forest land and other land-use types showed the opposite process of transformation during the four periods from 1972 to 2008 in Chaobai River Basin. The total forest area in 1987, 2000, 2008 increased by 5.4%, 36.9%, 46.7%, and predicted area in 2020, 2030, 2040 would increase by 46.1%, 46.0%, 46.0% compared with that in 1972. The total value of forest ecosystem services increased by 6.2%, 55.5%, 71.2% and 72.1%, 72.9%, 73.6% than that in 1972. Among all the functions, water conservation accounted for the highest percentage of the total value of ecological services, as well as the broad-leaved forests among all the types of forests; the proportion of mixed forests increased remarkably. Coniferous, broadleaf and mixed forests play a dominant role in the changes of the forest ecological value in 1972–1987, 1988–2000 and 2001–2040, respectively. The forest ecosystem service value per unit area has increased by periods and forest structure has got optimized.