| Regeneration and assessment of restoration in four different forest communitieswas studied in this research.These communities include:Form.Larixprincipis-rupprechtii,Form.Pinus tabulaeformis,Form.L.principis-rupprechtii+Quercus liaotungensis,and Form.Q.liaotungensis+Tiliapaucicostata+Populus davidiana.Furthermore,the effects of ecotone and harvest onforest regeneration were studied.Finally,this research also studied the effect factor onregeneration ofL.principis-rupprechtii.The main results are as follows:1.Seedling richness,diversity index and seedling density were higher inbroadleaved forest and conifer-broadleaved mixed forest than coniferous forests.Species number was higher in broadleaved forest and conifer-broadleaved mixedforest than in coniferous forests.The major species was shade-tolerant species in L.principis-rupprechtii forest,such as Acer tetramerum Pax var.betulifolium,Acermaximowiczii,and Acer ginnala.The number of animal-dispersed species increased inconifer-broadleaved mixed forest and broadleaved forest.Q.liaotungensis and P.tabulaeformis can re-establish in evey communities,andthere was large number of their seedlings.There was not L.principis-rupprechtiiseedling in four communities.This result suggests that the population of L.principis-rupprechtii will be replaced by other populations.With the increase ofproportion of L.principis-rupprechtii,seedling richness and seedling densitydecreased.Seedling richness and density was highest when proportion of conifer andbroadleaved species was equal.2.After assessing the success of three restoration projects:planting Larixprincipis-rupprechtii (LS) and Pinus tabulaeformis (PS) on shrubland,and planting L.principis-rupprechtii on open forest land (LO),the results show that all threerestoration plantings facilitated the re-establishment of native species,increased thespecies diversity and soil nutrient contents.The results Suggests that plantinglate-successional species bypassed the early successional stages of restoration andaccelerated the succession process.Thus,it shows the ecological feasibility ofrestoration efforts.However,the reestablishment of native species in LS and PS was poorer than LObecause of the excessive stand density.Species diversity,seedling number,and seedling diversity were significantly higher in LO than in LS and PS.Soil nutrientwas also significantly higher in the LO treatment.The vegetation composition,speciesdiversity,and soil nutrient in LO,however,were more similar to these in the reference.This result indicated that planting L.principis-ruppreehtii on open forest standappears to be successful,and has accelerated the succession process for approximately30 years.For long-term restoration,in LS and PS,species richness and diversity will notincrease significantly until the self-thinning stage or the occurrence of naturaldisturbance,because excessive stand density greatly impedes the regeneration ofnative species.Thus,selective thinning is necessary for future forest management,andL.principis-rupprechtii forest will be replaced by native species in the future.In LO,although few native species still disappear,they will reestablish with improve ofenvironmental condition.Furthermore,post-planting activities are required aftertimber harvesting or the natural mortality of the species to make up the failureregeneration ofL.principis-rupprechtii.3.Although seedling richness and seedling density were lower in ecotone thanbroadleaved forest,seedling diversity index and evenness index was higest amongthree communities.Seedling richness,diversity index,evenness index and seedlingdensity were lowest in coniferous forest.The proportion of seedling in larger size washigher in ecotone than in broadleaved forest and coniferous forest.This result showsthat ecotone improved the growth of seedling and suggests that it is required toreplace the large area pure forest by small patches.4.Seedling richness,seedling diversity index and seedling density were highest inheavy thinned stands (＜650 stems/ha) and medium gaps (mean:114.62 m2).Saplingrichness,diversity index,and density were highest in heavy thinned stands and largergaps.In heavy thinned stands,medium gaps and large gaps,tree seedling distributedat all size classes.With the enhancement of disturb intensity,the average height andDBH of sapling increased.There was the significant positive relationship betweenlight and seedling richness,diversity and density in thinned stands.However,litterdepth impeded the increase of seedling richness,diversity and density.Moreover,herbaceous cover was the important factor,which impeded the increase of seedlingrichness and seedling density in large gaps.Increasing vertical and horizontal structural heterogeneity within stands,density management and creating gaps support the suitable environmental condition forseedling survival and growth.However,canopy openness will be filled quickly byexpansion of neighboring trees in light thinned stands and small gaps.As a result,those stands can not support long-term structural and environmental heterogeneity.Thus,the better development of understory vegetation and regeneration require moreintensive density management and variable density thinning.Activities on severaldisturbances are favorable for age and structural heterogeneity of forest.Moreover,the high competition from herbaceous has impeded the survival and growth ofseedling in large gaps.It is necessary to cut herbaceous regularly.5.The results of experiment about sowing seed and planting seedling of L.principis-rupprechtii by different treatments shows seedling can't survival duringwinter,which is the major reason of L.principis-rupprechtii can't regenerate inLiupan Mountain Natural Reserve.At the same time,light level,soil water content,and depth of litter also impede the seed germination and seedling survival.Furthermore,there was significant difference in seedling survival rate of 2 years oldbetween different planting times.This result suggests that 2-year seedling can survivalsuccessfully during winter.
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