The Effects Of Release Cutting On Structure And Dynamic Of Artifical And Natural Mixed Forest Of Korean Pine In The Eastern Forestry Region Of Liaoning

The structure,productivity,plant diversity,succession and Korean Pine's growth of artificial and natural mixed forest of Pine Korean were studied by means of simple transect method and a,B diversity index methods in the eastern forestry region of Liaoning in past 40 years,furthermore,the effects of different restoration methods on their structure and dynamic were assessed quantitatively and the restoration techniques and optimal mode were probed.The results showed that:(1) The different release cutting measures(control,selective cutting in the upper layer and clear cutting in the upper layer) had great influence on community trees composition sturcture and diameter class distribution,the important value of Korean pine in the community gradually increased(49.3%,75.8%and 100.0%respectively) as the release cutting intensity increasing,but the broad-leaved trees showed the opposite trend;The medium-diameter lumber and small-diameter lumber were dominant in the control stand(94.8%),and the medium-diameter lumber was dominant in the selective cutting stand in the upper layer (88.9%),but the big-diameter lumber and medium-diameter level lumber were dominant in the clear cutting stand in the upper layer(100%).(2) The site(slope position) also had certain influence on community structure,the important value of Korean pine increased along from the lower slope position to the upper slope position environmental gradient(61.5%,74.5%and 75.8%respectively) and the broad-leaved trees showed regular replacement.Moreover,the proportion of big-diameter lumber decreased in the selective cutting stand in the upper layer;The medium-diameter lumber quality declined in the clear cutting stand in the upper layer.(3) The productivity of artificial and natural mixed forest of Pine Korean had a close correlation with different release cutting measures in the eastern forestry region of Liaoning.The stand productivity was biggest in the clear cutting stand in the upper layer,it increased by 24.14%compared with the control area,but the productivity in the selective stand in the upper layer reduced by 7.00%compared with the control area.Moreover,the productivity of Korean pine increased,but the productivity of broad-leaved trees decreased as the release cutting intensity increasing.(4) The constructive species(Korean pine) diameter annual increment,height annual increment and volume annual increment in the artificial and natural mixed forest of Pine Korean showed the obvious regularity as the release cutting intensity increasing in the eastern forestry region of Liaoning.After being processed by selective cutting and clear cutting in the upper layer,the annual increment of tree height,diameter breast height and volume of Korean pine was both higher than that of control,and the effect was most obvious throught selective cutting process.(5) The richness index was the largest in the selective cutting stand as release cutting intensity in the upper layer increasing,but the diversity index and evenness index were the largest in the clear cutting stand in the upper layer.The diversity index(1.7677,1.7354 and 1.4954 respectively) and evenness index(0.4617,0.4614 and 0.3976 respectively)were showing the same trend:upper slope＞middle slope＞lower slope in the selective cutting stand in different slope positions.But the situation was different in the clear cutting stand in different slope positions,the diversity index(2.0498,1.9739 and 1.8805 respectively)and evenness index(0.5862,0.5508 and 0.5170 respectively) were showing the same trend:lower slope＞upper slope＞middle slope.Meanwhile,the rate of species change were relatively high(12～14 and 10.5～15 respectively),and the community similarity coefficient(0.697～0.721 and 0.568～0.761 respectively) were very low in the selective cutting stand and in the clear cutting stand in different slope positions,which indicating the diversity of both communities high.(6) So far the succession trends of the stands would be developing to the stage of Korean pine hard broad-leaved mixed forest in the control stand,selective cutting stand and the clear cutting stand.Analyzed comprehensively with method of divided-stratum number,the selective cutting stand and clear cutting stand in the upper layer showed the same distribution pattern- the number of trees species in the regeneration layer and succession layer was much more than that of tree layer.