Before Qin and Han Dynasty the loess plateau was with dense forestand grass

dressed in picturesque scenery

and praised as "How beautiful place it is. There are large lake and clear water" in many ancient booksand inscriptions on tablet.But since the War Period of the Spring andAutumn (770476 B. C. ) the ecological enviroment of the area has beendamaged by human being frequently through war destroyment. denudationto build palace

firewood gathering and taking off forest to reclaime

etc. It is thought that the main trouble root is in extensive cultivationwith little harvest

farming with rotate wasteland

which result in loessto be naked. crisscross gullies

serious soil and water loss and poor economy. The controlling policy suggested includes "taking vegetation construction

halting soil and water loss

developing forestry and husbandryas the main tasks

in order to realizethe grain selfsuficient". It couldbe expected soon that the goal of green hill and clear water

dense forestand rich harvest and prosperous economy is achieved if the policy isupholded.