Growth Characteristics Of Main Tree Species And Their Environmental Interpretation In Broad-leaved Korean Pine Forest Under Different Thinning Intensity

In this study,the broad-leaved Korean pine forest treated with different thinning intensity in Northeast China was studied.The main species Pinus koraiensis,Fraxinus mandshurica,Quercus mongolica,Acer mono,Tilia amurensis were selected.Based on tree-ring width data,growth pattern and their response mechanism to thinning intensity were analyzed.The relationship between tree species growth and climate and competition was constructed to reveal the environmental interpretations of main tree species in broad-leaved Korean pine forest before and after thinning.The main conclusions were as followed:(1)Thinning promoted the growth of main tree species in broad-leaved Korean pine forests,but different tree species responded differently to thinning intensity.Pinus koraiensis,Fraxinus mandshurica and Tilia amurensis were more sensitive to the interspecific thinning intensity.The net increase of basal area in the 5 years after deforestation decreased with the increase of tree species thinning intensity,but Pinus koraiensis and Fraxinus mandshurica increased with the interspecific thinning intensity,radial growth is on the rise in the fourth year after harvest.Quercus mongolica and Acer mono were mainly affected by the intensity of thinning of the stand,and the net increase of basal area after harvesting reached the maximum under mild thinning intensity,and the radial growth increased continuously after the thinning intensity.(2)The extent and nature of competition change is an important factor affecting the growth of single wood.The radial growth of single wood is significantly negatively correlated with the competition intensity(P<0.05).As the competition weakens,the radial growth of Pinus koraiensis increases rapidly,the radial growth of single wood of Fraxinus mandshurica,Quercus mongolica and Tilia amurensis showed a significant increase in the plots with less competition,but the radial growth of Acer mono showed an upward trend in the plots with a large degree of competition change.(3)The relationship between radial growth and climatic factors of Pinus koraiensis,Acer mono and Tilia amurensis was consistent under mild and moderate thinning intensity.With the increase of thinning intensity,the sensitivity of Pinus koraiensis and Acer mono to climate decreased,while Tilia amurensis is more sensitive to the climate in the winter of last year.The relationship between radial growth and climatic factors of Quercus mongolica and Fraxinus mandshurica was consistent under moderate and severe thinning intensity,as the thinning intensity decreased,the climate sensitivity of Quercus mongolica decreased,while the climate sensitivity of Fraxinus mandshurica increased,and there was a significant correlation between the temperature of the growing season in the previous year and the winter temperature and precipitation in the previous year(P<0.05).