2026-03-15T05:39:10Z https://u-ryukyu.repo.nii.ac.jp/oai

oai:u-ryukyu.repo.nii.ac.jp:02004811 2022-10-31T02:23:20Z 1642837622505:1642837957109:1642837975146 1642838403551:1642838406414

Time-trajectory of Mean Phytomass and Density in Self-thinning Plant Populations Hagihara, Akio 萩原, 秋男 Reconciling the competition-density (C-D) effect observed at a particular moment\nin time with the 3/2 power law of self-thinning observed over time, a model for\ndescribing the time-trajectory of mean phytomass w and density p (briefly, the w-p\ntrajectory) during the course of self-thinning is theoretically derived. The model gives\na consistent, full explanation of the w-p trajectories of populations starting with any\ninitial density. The larger value of the relative mortality rate with respect to biological\ntime of a population, which is governed by the 3/2 power law of self-thinning, plays an\nimportant role in relieving the C-D effect, so that the w-p trajectories asymptotically\napproach the self-thinning line on logarithmic coordinates at the earlier stage of\ngrowth. The survivorship curve is divided into three types owing to initial density:\nlogistic, exponential and cologistic types of decrease. All populations tend to decrease\nexponentially in number at the same rate of relative mortality after a sufficient lapse of\ntime, irrespective of their initial density. The populations decreasing exponentially in\nnumber follow the 3/2 power law of self-thinning. The carrying capacity of yield is\nexplicitly defined as a function of biological time, so that it is concluded that the\ncarrying capacity increases exponentially with increasing biological time. An\napproximated expression of the model for the w-p trajectory is proposed and is\nconfirmed to mimic well the time-trajectories of mean stem volume and density during\nthe development of eastern white pine (Pinus strobus L.) plantations. 紀要論文 http://purl.org/coar/resource_type/c_6501 琉球大学理学部 2000-09 VoR 70 112 99 http://hdl.handle.net/20.500.12000/11818 0286-9640 AN00250774 琉球大学理学部紀要 Bulletin of the College of Science. University of the Ryukyus http://hdl.handle.net/20.500.12000/11818 https://u-ryukyu.repo.nii.ac.jp/records/2004811 eng open access