We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight ...We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight plots in stands that were lightly thinned, eight plots in heavily thinned stands and eight plots in unthinned stands as a control. Height and diameter distributions of the stands were measured to assess stand structure. We quantified individual tree stability and collective stability. Heavy thinning during the first thinning operation damaged the storied structure of the stand in thicket stage and affected collective structuring ability. While most control plots had multi-storied stands, after light and heavy thinning two-storied structure became more common.Large gaps occurred in the canopy after heavy thinning. On average, nine tree collectives were formed per sampling plot in the untreated stand, seven collectives after thinning in 2008 and four collectives after thinning in 2009. Stable trees accounted for 17 % of trees in control plots, 24 % in lightly thinned plots, and 15 % in heavily thinned plots. Collective stability values were 83 % in control plots, 82 % in lightly thinned plots and 36 % in heavily thinned plots. We conclude that it is necessary to retain collective structuring capacity during thinning operations for sustaining stand stability.展开更多
This study is devoted to the global existence,blow-up and orbital stability of standing waves for the Schröinger equation with mixed nonlinearities.Firstly,we derive some criteria for global existence and blow-up...This study is devoted to the global existence,blow-up and orbital stability of standing waves for the Schröinger equation with mixed nonlinearities.Firstly,we derive some criteria for global existence and blow-up of the solutions by making use of the ground state and scaling techniques.Secondly,by taking advantage of the refined compactness argument,scaling techniques and the variational characterization of ground state solutions,we explore the L^(2)-concentration phenomenon and limiting behavior of blow-up solutions in the L^(2)-critical case withμ=±1 and 1<q<p=1+4/N.Finally,we research the orbital stability of standing waves in the cases withμ=−1,1<q<p≤1+4/Norμ=1,1+4/N=p<q<N+2/N-2,by combining the variational methods,profile decomposition and the arguments of concentration compactness.Our study complements the conclusions of some known works.展开更多
基金supported by Karadeniz Technical University Research Fund,Project number 2010.113.001.11
文摘We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight plots in stands that were lightly thinned, eight plots in heavily thinned stands and eight plots in unthinned stands as a control. Height and diameter distributions of the stands were measured to assess stand structure. We quantified individual tree stability and collective stability. Heavy thinning during the first thinning operation damaged the storied structure of the stand in thicket stage and affected collective structuring ability. While most control plots had multi-storied stands, after light and heavy thinning two-storied structure became more common.Large gaps occurred in the canopy after heavy thinning. On average, nine tree collectives were formed per sampling plot in the untreated stand, seven collectives after thinning in 2008 and four collectives after thinning in 2009. Stable trees accounted for 17 % of trees in control plots, 24 % in lightly thinned plots, and 15 % in heavily thinned plots. Collective stability values were 83 % in control plots, 82 % in lightly thinned plots and 36 % in heavily thinned plots. We conclude that it is necessary to retain collective structuring capacity during thinning operations for sustaining stand stability.
文摘This study is devoted to the global existence,blow-up and orbital stability of standing waves for the Schröinger equation with mixed nonlinearities.Firstly,we derive some criteria for global existence and blow-up of the solutions by making use of the ground state and scaling techniques.Secondly,by taking advantage of the refined compactness argument,scaling techniques and the variational characterization of ground state solutions,we explore the L^(2)-concentration phenomenon and limiting behavior of blow-up solutions in the L^(2)-critical case withμ=±1 and 1<q<p=1+4/N.Finally,we research the orbital stability of standing waves in the cases withμ=−1,1<q<p≤1+4/Norμ=1,1+4/N=p<q<N+2/N-2,by combining the variational methods,profile decomposition and the arguments of concentration compactness.Our study complements the conclusions of some known works.
