On baseline vegetation in Northern China

A few of concepts related to a baseline vegetation have been defined. Among them, potential vegetation is defined as the vegetation that would occur under the current climate condition without any disturbance from human activity, and original vegetation is defined as the vegetation that actually occurred prior to the significant interference from human activity. Both potential vegetation and original vegetation are classified into baseline vegetation. Potential vegetation distribution could be obtained by investigating the current botanic relics or by means of calculation based on the relationship between climate and vegetation, and original vegetation status could be reconstructed by using paleo-ecological data. In China north of the Yangtze River, potential temperate and sub-tropical forests with high closure could occur only in the southeastern most parts; temperate woodlands or forest-steppe could developed in central west Northeast, most parts of the North China Plain, southeastern Loess Plateau and eastern rim of the Qinghai-Tibet Plateau, where rain fed agriculture can be practiced and eco-reconstruction of the degraded landscapes should be emphasized; potential temperate steppe could grow in western Northeast, southeastern Inner Mongolia, northwestern Loess Plateau and central east Qinghai Province, where only animal husbandry could be developed and the previously cultivated lands should be returned back to the pastures. At about 6000 a BP, the original vegetation in northeastern Northeast was temperate deciduous forest, which is rather different from the current mixed needle and deciduous forest; Southern Northeast, eastern North China Plain and the Huaihe Basin saw a warm temperate deciduous forest which bears little similarity to the current forest with pines as one of dominant trees; Significantly larger extent of original forests occurred in southeastern Loess Plateau, western North China Plain and eastern rim of the Qinghai-Tibet Plateau, with pines/deciduous trees and fir/spruce as the dominant components respectively. Although human activities have been thought to bear a main responsibility for the shrinkage of the forests, climate variation might also contribute to the change in vegetation in some extent. It thus is inspirable to mention that the expansion of the forests in mid-Holocene provides a maximum possibility for afforestation in the regions. The reconstruction of the original vegetation does not encourage the effort to afforest in such areas as northwestern Loess Plateau and central Inner Mongolia. The saying of turning cultivated fields back to forestlands is also improper.