The Response Of Regeneration Process And Litter Water Storage Function Of Larix Principis-rupprechtii On Management Measures

The Larix pricipis-rupprechtii forest is one of the major forest management types in north China. In the mountain area of north Hebei, the productivity of Larix pricipis-rupprechtii forest is universality low, existting the issue of age class and tree species are unitary and also having serious disease and pest as well as low landscape heterogeneity which urgently need to change the thought of management in order to improve the forest quality. Therefore, in this paper take the Larix 38 years old principis-rupprechtii artifical pure forest as the research objection the original gaps characteristic were analysised by using the methord of tipical transactions, distribution and variation discipline of the regeneration situation litter storage and holding water capability in understory and gaps of different origins and areas were reaserched by employing sample investigation quadrat sampling. The shoret-term response of capability of forest regeneration and litter water storage function on planting stratified uneven-aged mixed stratified forest and gradually replacing treess on the bace of blockade was probed.The primary results are as follows:1 The characteristic of original gaps and their effort on natural and artificial regeneration The main area of EG and CG are 30m²and 60m² repectively, the distribution of gaps is wide; Most of the gap's S_CG/S_EG are 0.4～0.6, shap index are 1.0～1.2, D_EG/H is 0.6～2.0, DCG/H is 0.3～1.0. The state of regeneration in gaps is suoerior to regeneration in underatory, the highest density of seedling and sapling are found in gaps of 150¹80m²and 60⁹0m²respectively, the capability of natural regeneration of Larix principis-rupprechtii is weakened. With the extension of time, the introduced pinus tabulaeformi and Pinus sylvestrisvar.mongolicaL show the trend of the annual height growth under gaps are greater than under canopy, under gaps the annual height growth in transition region greater than in centre and edge, the annual height growth of pinus tabulaeformi and area of gaps are positively correlated, the annual height growth of Pinus sylvestrisvar.mongolicaL is heightest under gaps of 60-90m². The results above preliminary certify at the same time of executing blockade artificial planting seedling of pinus tabulaeformi and Pinus sylvestrisvar.mongolicaL under gaps are effective way to improve forest structure.2 The effect of hole type and banding tree replacement on natural and artificial regenerationNatural regeneration: in general the density of seedlings in selection cutting holes and clear cutting stripes are higher than in only blockade area, the density of the 30m stripes is the highest, the sapling density under crown comparatively high. The highest density of Larix pricipis-rupprechtii seedling is found in selective cutting holes of 500-700 m², the seedlings density of Populus davidiana continually increase with the cutting area. The saplings density of Larix pricipis-rupprechtii decreases with the increase of gaps area, the saplings density of Populus davidiana increases with the increase of gaps area. The effort of different management measure on artificial regeneration: the highest height of Larix pricipis-rupprechtii sapling is found under the sparse canopy, which is positively correlated with the area of holes, in the cutting stripes the upper and lower edges clear cut strip 30m>leave strip , the enhancement of maximum water holding capability was : leave strip> clear cut strip 15m>clear strip 30m, the enhancement of effective water retention was : leave strip >clear cut strip 30m>clear strip 15m. The litter mass, maximum water holding capability and effective water retention of afforestation land of Betula platyphylla Suk were larger than that of afforestation land of Larix principis-rupprechtii and Quercus mongolica Fischer ex Ledebour 2 years after artificial regeneration promotion. It is shown that, by the result, banding tree replacement significantly enhanced the water conservation function of forest land in short-term.Hole type tree replacement: the order of litter storage is blockading only>not blockading>selective cutting holes, in the position of the four edge of and centrol 300-500m² is the highest. the order of natural water holding rate is only>not blockading>selective cutting holes,which decrease progressively follow the increase of area. Both the maximum water holding rate and effective dammed-up rate are similar in small selective cutting holes and blocking area but decrease in the selective cutting holes follow the increase of area; the index of all position in blocking area are higher than not blocking area. Selective cutting holes of large area may bring about serious impairment of water conservation fouction of litter, therefore proposing the area of selective cutting shouldn't be surpass 500m².