Intra-annual Radial Growth Dynamics of Larix principis-rupprechtii Plantations with Different Stand Densities and Its Response to Environmental Factors
[Objective]To investigate the seasonal variation characteristics of radial growth of Larix princip-is-rupprechtii plantations with different densities and its responses to environmental factors for providing a scientific basis for accurate assessment and prediction of the radial growth of L.principis-rupprechtii at re-gional scales,and achieving sustainable management and multi-functional maintenance.[Method]In the small watershed of Xiangshui River in the south of Liupanshan,four sample plots of L.principis-rupprechtii with different densities were set up,and the intra-annual radial growth process of L.principis-rupprechtii was monitored using a manual band dendrometer,and meteorological factors,soil temperature and humid-ity were monitored simultaneously.[Result]The results indicated that:(1)in the growing season,the radi-al growth of L.principis-rupprechtii showed a"S"curve.The rapid increasing stage mainly occurred from early June to late June,DOY152‒210.(2)The average cumulative radial growth of L.principis-rupprechtii decreased with the increase of stand density.In the plantations with densities of 544,742,999 and 1 020 N·hm-2,the average cumulative radial growth of L.principis-rupprechtii was 1 070±230,775±181,518±214 and 494±124 μm,respectively.With the increase of stand density,the cumulative radial growth of L.principis-rupprechtii showed a downward trend during the year,but its rapid increasing stage was shortened.(3)The results of mixed-effect model showed that the radial growth of L.principis-rupprechtii was mainly affected by soil moisture and average temperature,but stand density and growth period also had significant effects on radial growth during the year.The model including the variables of stand density,growth period,tree size and meteorological factors could explain 72.0%of the variance,but after exclud-ing the factors of stand density and growth period,model with tree size and meteorological factors could only explain 46.4%of the variance.[Conclusion]More than two-thirds of the radial growth of L.principis-rupprechtii occurrs the rapid growth period.The average cumulative radial growth of L.principis-rup-prechtii decreases with increasing density.Stand density,growth stage,tree size and meteorological factors jointly regulate the intra-annual radial growth of trees.
Larix principis-rupprechtiiIntra-annual growthradial growthstand densityenvironmental factormanual band dendrometer
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万方数据
