| Rare species that were in four forest types(mixed broadleaved-Pinus koraiensis forest,Juglans mandshurica trees,Fraxinus mandshurica trees,mixed broad-leaved forest)as the object of study,each forest type were selective cut with different intensity in the 1970s,(the control)?15%intensity?30%intensity,respectively.a total of 12 plots.Using the method of spatial point pattern to study the effects of harvesting with different intensity on the spatial patterns and spatial correlation of rare species.Also succession trends of trees were studied in each sample plot.The main results of this study are summarized as follows:(1)Under different selective cutting intensity,succession trend of each forest type was difference.The changes of succession and community structure of Mixed broad-leaved Pinus koraiensis forest and Juglans mandshurica forest were small relatively,A significant change of Fraxinus mandshurica forest and mixed broad-leaved forest with different selective cutting intensity.The change of importance value of dominant species depends not only on the selective cuting intensity also on the type of forest.The number of tree species in mixed broad-leaved Pinus koraiensis forest and Juglans mandshurica forest decreased with increasing of selective cutting intensities.Importance value of Pinus koraiensis in broad-leaved Pinus koraiensis forest and Juglans mandshurica in Juglans mandshurica forest improved with the increase of selective cutting intensity,as follows:Pinus koraiensis not interfering with 24.97%,light interference 25.99%,heavy interference 33.48%.Juglans mandshurica no interferencel3.56%light interference 23.53%,heavy interference 33.80%.The dominant species in Juglans mandshurica forest was different with intensity increased.performance:no interference,Juglans mandshurica,Fraxinus mandshurica,Quercus Mongolia;mild disturbance,Juglans mandshurica,Ulmus pumila,Fraxinus mandshurica;severe interference,Juglans mandshurica,populus.But the dominant tree species in mixed Pinus koraiensis broad-leaved forest did not change with the cutting intensity changes as follows:Pinus koraiensis and Acer mono.the advance position of Pinus koraiensi and Juglans mandshurica did not changed in the forest with the selective cutting intensity changes.The dominant tree was differnt in Fraxinus mandshurica forest and mixed broad-leaved forest with the increasing of selective cutting intensity,severe cutting made the dominant tree species of Fraxinus mandshurica lost status in Fraxinus mandshurica forest,dominant tree species were Populus davidiana and Acer mono,cutting made the number of tree species reduced to 8 in mixed broad-leaved forest,the dominant tree species was different with different cutting intensity(2)The change of spatial pattern of different tree species was different to selective cutting intensity,the same species in the same forest type,selective cutting intensity was dominant factor for the pattern of trees.The same species in different forest types,because of different selective cutting objects,even the same selective cutting intensity,the pattern was different,both cutting objects and selective selective cutting intensity were the major factors for different degrees of change of spatial pattern.But the change of pattern of Fraxinus mandshurica were less influenced by forest type and cutting objects.Selective cutting intensity was important to the change of pattern.The change of pattern of Pinus koraiensis was not only associated with the selective cutting intensity,but the selective object.In mixed broad-leaved Pinus koraiensis forest,15%selective cutting intensity can lead to the change of pattern.but spatial pattern did not change significantly compared mild selective cutting to heavy selective cutting.Pinus koraiensis was the associated species in Fraxinus mandshurica forest,the dominant species were cut by 30%intensity can lead to changes in the pattern of Pinus koraiensis,mild thinning of dominant tree species to the change of the pattern is not obvious.In the mixed broad-leaved Pinus koraiensis forest and Juglans mandshurica forest,it was different for the effetion on the pattern of Pinus koraiensis and Juglans mandshurica to mild cutting intencity.Mild logging caused pine pattern changed significantly,but no significant changes of Juglans mandshurica.Light harvesting had little effect on the pattern of Juglans mandshurica but heavy selective cutting impact greatly,with the increase of cutting intensity,the aggregation degree of Juglans mandshurica decreased;Fraxinus mandshurica both in broad-leaved Pinus koraiensis forest and Fraxinus mandshurica forest,mild thinning,has little influence on the pattern of its,severe thinning has great impact on the patternTilia amurensis in mixed broad-leaved Pinus koraiensis forest and mixed broad-leaved forest,pattern change obviously to the changing of selective cutting intensity,Light harvesting made the pattern change significantly.Tilia amurensis in Juglans mandshurica forest and Fraxinus mandshurica forest mild cutting had less of an impact on the pattern,heavy selective cutting impact greatly.when selective cutting intensity is the same,the pattern of Tilia amurensis is different according to the cutting object and forest typeThe distribution pattern of Quercus Mongolia in Juglans mandshurica forest were less affected by the change of cutting intensity.Aggregated distribution under different cutting intensity at 0-50m scale.their distribution patterns changed little in mixed broad-leaved Pinus koraiensis forest under Mild harvesting intensity.randomly distributed at 0-50m the scale.But change significantly in the Fraxinus mandshurica forest and mixed broad-leaved forest.Quercus Mongolia was aggregated at 0-50m scale in Fraxinus mandshurica forest without interference,aggregated at 0-30m scales under mild interference,randomly distributed more than 30m scale.Quercus Mongolia was randomly distributed at 0-50m scale in mixed broad-leaved forest.was aggregated at 7-25 m scale under mild interference,randomly distributed at 0-8m and 25-50m scaleLight harvesting interference caused Phellodendron amurense distribution pattern changed in varying degrees in Juglans mandshurica forest,Fraxinus mandshurica forest,mixed broad-leaved forest.In the three forest types.mild harvesting made pattern form a random distribution,Severe cutting resulted in aggregated distribution pattern to form on the whole.(3)The correlation between the same species and different rare species was different.the reaction of correlation between different tree species to change of selective cutting intensity was different.The correlation between the two species showed differences in different forest types.Light harvesting made some species correlation changed,severe disturbance caused all species correlation to change.Selective cutting intensity on the correlation between Pinus koraiensis and Quercus Mongoli and Fraxinus mandshurica with smaller effects.The correlation between the Pinus koraiensis and Tilia amurensis significantly affected by changes in selective cutting intensity.In Fraxinus mandshurica forest,15%selective cutting intensity was not enough to change the correlation between Fraxinus mandshurica and Tilia amurensis,Pinus koraiensis,but the impact on the correlation between Fraxinus mandshurica and Quercus Mongolia,Phellodendron amurensewas significant.30%of selective cutting intensity cause the correlation between Fraxinus mandshurica and all rare species to change significantlyJuglans mandshurica forest,15%selective cutting intensity significantly on the correlation between Juglans mandshurica and Phellodendron amurense,Quercus Mongolia,Populus davidiana Tilia amurensis,.Except for the correlation between Juglans mandshurica and Phellodendron amurense,severe and mild selective cutting on the correlation similarity.In summary,30%selective cutting intensity conducive to enhancing the dominance of the dominant species in mixed broad-leaved Pinus koraiensis forest and Juglans mandshurica forest,such selective cutting intensity can be used for this type forest cutting.In mixed broad-leaved Pinus koraiensis forest,30%selective cutting intensity was more conducive to Pinus koraiensis and Quercus mongolica,Fraxinus mandshurica,Tilia amurensis form good correlation.In Juglans mandshurica forest,15%selective cutting intensity was not conducive to form positive association between Juglans mandshurica and Tilia amurensis,Quercus mongolica,but was conducive to the relationship between Juglans mandshurica and Phellodendron amurense.30%selective cutting intensity can made dominant species changed in Fraxinus mandshurica forest,it was too high intensity for Fraxinus mandshurica forest,There was positive association bentween Fraxinus mandshurica and Tilia amurensis,Quercus mongolica,negative associationg between Fraxinus mandshurica and Pinus koraiensis,Phellodendron amurense under 30%selective cutting intensity.15%selective cutting intensity can be used for this forest type harvesting.Severe selective cutting intensity led to the number of species declined in mixed broad-leaved forest,this intensity was not suitable for mixed broad-leaved forest harvesting. |
PDF Full Text Request