YU Shunli
China possesses various types of sparse forests. Except sparse forests in tropic regions of China, other two types of sparse forests are classified, namely, temperate zone spare forests and temperate zone mountain spare forests. In temperate zone of China, there are many types of sparse forests, such as Ulmus pumila sparse forest, Picea schrekiana sparse forest, Platycladus orientalis sparse forest, Juniperus rigida sparse forest, Pinus sylvestnis var. mongolica sparse forest, Larix tibetica sparse forest, Abies densa sparse forest, Cupressus gigantean sparse forest, Sabina tibetica sparse forest, Sabina wallichiana sparse forest, Sabina saltuaria sparse forest, Larix potaninii var. macrocarpa sparse forest, Cupressus torulosa sparse forest, Sabina convallium sparse forest, Pinus roxburghii sparse forest, Pinus yunnanensis sparse forest, Picea likiangensis var. balfouriana sparse forest, Ulmus macrocarpa sparse forest, and Ailanthus altissima sparse forest, etc. Sparse forest ecosystem is a transition between forest and grassland or shrub ecosystem. It belongs to a zonal vegetation type. Comprehensive ecological factors have determined its geographical distribution; however, the key factor is water (local rainfall amount). In the mainland of China from south to north, there are rain forests, season rain forests, evergreen broad leaf forests, summer green broad leaf forests, sparse forests, and grassland or shrubs along altitudinal gradient. From east to west, there are forests, sparse forest, shrubs, and grassland or meadow along longitudinal gradient. Compared with the distribution area of forests and grassland,the distribution of sparse forest occupies the smaller areas. Temperate zone sparse forests of China mainly distribute in the transition area between agriculture region and pasture region. Understanding the causes of sparse forest formation could give the help to select the best methods for ecological restoration.
