Visualization Research Of Vegetation Succession In Aquatic-terrestrial Ecotones Based On Virtools

In recent years, the phenomenon of the landscape degradation in the river basin has been more and more serious because of over ecotourism, and forestry visualization technology provides important reference for ecosystem restoration and landscape optimization decision. So it is necessary and practically significant to research the visual simulation of vegetation growth in the river basin. This paper presents the case of Pterocarya stenoptera in aquatic-terrestrial ecotones in Lijiang River, and found that total nitrogen content of soil plays a critical role in its growth after analyzing the correlation between soil sample and growth data. Based on this finding, we adopted modified Hegyi’s simple competition index model with added Nitrogen factors to the single tree growth model for Pterocarya stenoptera stands built in Lijiang River, then we applied diameter distribution model and random algorithm to whole stand model. In the process of simulation, we confirmed the information of location and diameter at breast height distribution of Pterocarya stenoptera in the plot by the Trees distribution model first; the next step, the height and the crown of each Pterocarya stenoptera was simulated according to the fitting relationship between tree height and diameter at breast height, crown with diameter at breast height and the diameter at breast height of each Pterocarya stenoptera we measured, and then, we could simulate the growth of Pterocarya stenoptera by iterative execution of the growth model using the data we got before; after that two-dimensional simulation with different soil nitrogen content was achieved by implementing C# programming language and GDI+ technology, and then the dot and the circle in two-dimensional simulation would be mapped into specific Pterocarya stenoptera model on 3Dmax; finally we achieved the three-dimensional visual simulation of the growth of Pterocarya stenoptera in Virtools platform. The result shows that a ignificantly positively relationship exists between diameter at breast height growth and soil total nitrogen content of Pterocarya stenoptera, and the correlation coefficient is 0.749; a significantly negative relationship exists between competition index and diameter at breast height growth, and the correlation coefficient improved from -0.621 to -0.657 with the competition index model improved; the error rate were 6.25% and 11.9% respectively when we fit the diameter distribution of Pterocarya stenoptera in the simulation and the decision coefficient of diameter at breast height growth model reaches 0.734. We found that adopting modified Hegyi’s simple competition index model and random algorithm had strong applicability and higher fidelity for Pterocarya stenoptera growth simulation in aquatic-terrestrial ecotone. The originality of this paper is to adopted modified Hegyi’s simple competition index model with added Nitrogen factors, with the help of Virtools platform, to lay the foundation for further development of human-computer interaction, real time walkthrough. In this article, we provide theoretical basis and reference for the vegetation restoration and succession simulation in Lijiang River watershed, and present a feasible research idea and implementation method for the forestry visualization research by visualization simulation of Pterocarya stenoptera growth in the Lijiang River watershed.