| In the intensive cultivation and management practices on moso bamboo (Phyllostachys heterocycla var. pubescens Ohwi) forests in China in the past decades, a series of specific cultivation practices have been implemented in a large scale for achieving high productivity of the stands. The major management practices include shifting mixed bamboo forests into pure bamboo forests in a large area, shortening harvesting rotation, intensively harvesting edible shoots and culms, top-cutting and whole bamboo harvesting and utilization, herbicide application for cleaning undergrowth, loosening soil and fertilizer application, etc. The implementation of these management practices have being brought a high economic outputs from the managed bamboo stands in a relevant short term. On the other hand, however, the natural bamboo forest ecosystems have been heavily disturbed by the frequently strong management practices. As a fact, the physical, chemical and biological properties of the soil have been negatively impacted by the management activities. As a result, the capacity of load and rehabilitation of site productivity in the disturbed bamboo forests obviously declined and the long-term site productivity has been threaten. To address the issues of the negative impacts of the management practices on long-term site productivity in the intensive management of bamboo forests, this research has be conducted in the following aspects: the impacts of long-term pure bamboo management after shifted from natural mixed bamboo forests on long-term site productivity, the differences of phy-chemical and biological (micro-organic) properties of soils in pure moso stands and mixed bamboo forests, the impacts of practices such as loosing soil and chemical fertilizer application on the output of run-off, soil and nutrients, the impacts of five major practices on the stand and site productivity, the herbicide applications and management practices on the status of micro-organism and enzyme in soil, as well as the impacts of stand component and practices on undergrowth and the function of undergrowth in the biodiversity of the managed ecosystems. The impacts of the disturbance of management practices on long-term site productivity of the managed bamboo forest have been focused in this research.1. The impacts of pure bamboo forest management after shifted from natural mixed bamboo forest on long-term site productivityThe annual number of culms, diameter and annual yields of culms in 2 pairs of 40 fixed experimental plots have been recorded from 1983 to 1997, combining with the chronosequence study and retrospective studies. Among the 40 plots, each 20 of them were set up in two pure bamboo stands shifted from mixed bamboo forests in 1974 and 1985. Meanwhile, the physi-chemical properties of soils in the two pure stands and neighboring sites have sampled and analyzed to study the impacts of long-term pure bamboo forest management on site productivity of bamboo stands. To study the impacts on the biodiversity and micro-organism properties in soil, the comparison researches on soil micro-organisms have been done between long-term managed pure bamboo stands and mixed bamboo stands.1.1 The Stand ProductivityThe research shows that the pure bamboo stands grows in a single-population after shifted from the mixed from mixed forests. In terms of the annual culm, average diameter and annual yield, the growing period can be divided into three stages as followings:1) 1st-4th year: increase of the number of annual culms and decline of the diameter.2) 5th -11th year: increase of the diameter and annual yield.3) 11th -21st year: decline of diameter and yield of annual culms, in which the average diameter of annual culms decreased by 0.95 cm from 1985 to 1996 and annual yield decreased by 17% during same period.The result shows that the stand productivity starts to decline around at 10 years since the stand shifted from mixed forests.1.2 Site ProductivityThe sampling and analyses of soils in the two plots and the neighboring...
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