甘肃黄土高原气候植被类型初探

A PRELIMINARY STUDY OF CLIMATE AND VEGETATION TYPES IN LOESS PLATEAU, GANSU PROVINCE

甘肃黄土高原位于我国黄土高原的西部,它西起乌鞘岭,东抵子午岭,南至太子山、西秦岭和甘陕省界,北止甘宁省界,包括临夏州、平凉和庆阳两地区、兰州和白银两市的全部,以及定西和天水两地市的绝大部分,面积约11万km^2,占甘肃面积的24％左右。陇山以西部分称之为陇西黄土高原,呈丘陵、沟壑地貌,大部分海拔高度在1200—2500m;陇山以东部分叫做陇东黄土高原,塬面较完整,多呈塬、沟地貌,大部分海拔为1200—1800m。 多年以来,在对甘肃黄土高原历史时期的自然植被和治理等问题上,存在着很大的意见分歧。一种观点认为,这里历史时期曾是森林广布、水草丰美的地方。

According to geological sediment, paleontological evidence, historical and locol records preserved from ancient times, recent meteorological observations and vegetation survey materials, the author studied the evolution and distribution characteristics of the climate and vegetation types in the loess plateau, Gansu Province. The results show that during the Quaternary Ice Age, the sandy loess zone in the Gansu Loess Plateau was arid desert and semi-desert, and the typical loess zone was arid steppe. During imerglacial period the former changed into subarid steppe and the latter into humid forest and subhumid forest steppe. Before hundreds of years, the vegetation in the Gansu Loess Plateau was much better then that at present. Forest could be seen in the southeastern part and higher rocky mountains of this area. Afterwards, because of unreasonable economical activities of mankind it leaded to deterioration in ecological environment and desertification in climate. Nowadays the northern and central parts of the sandy loess zone and the typical loess zone have already been arid and subarid desert, subdesert and steppe. Only in the southern and southeastern parts of the typical loess zone, the subhumid forest and steppe and humid forest still continue to exist.