Growth Simulation of Young Chinese Fir Based on Virtual Plant

Abstract

Energy fixation and organic matter production of forest ecosystem were dominated by plants,which are impacted by their growth environment.The forest ecosystem has the characteristic of long life-span,which makes its research laborious and costly using field experiment.The virtual geographical environment can provide a new way for its research due to its character of trying to exceed the limit of time and space.In order to estimate the biomass and evaluate relationships among tree and environments,an L-systems based functional-structural model was developed for simulating the development of tree architecture,taking into account tree physiology and environment.The L-systems was used to represent the morphological development of tree.The basic growth unit was described in line with the development of young Chinese fir(Cunninghamia lanceolata).LSTree system integrated the photosynthesis,photosynthates allocation and morphogenesis models.The spatial distribution of solar radiation in tree canopy was simulated for calculating photosynthetically active radiation(PAR) of each leaf obtained.PAR is a key parameter for photosynthesis model to estimate biomass.The dynamic growth of an individual 3-to-4-year-old Chinese fir in Fuzhou was simulated in growing season.Based on the 2010 Fuzhou weather and Chinese fir photosynthetic characteristic,net photosynthesis rate and product were calculated for each stage.The amount of photosynthates allocated to the growth of new segments and leaves or branches and leave amplification are based on source-sink theory.The growth of tree is driven by available photosynthetic products after respiration losses were accounted for.The morphogenesis change in the young Chinese fir in response to environment was simulated dynamically in three dimensional representations.The result of net photosynthesis was compared to the previous field observation research,and it showed the simulation result was reasonable.The methodology has promising benefits to depicting the interaction of plant and environment,which will be valuable for estimation of organic matter production too.