A Study of Factors Influencing Wood Decay and Fungal Activities Based on Mathematical Modelling Methods

Abstract

This paper establishes a series of mathematical models to describe the wood decay by fungi and important factors affecting fungi activities. First, it is assumed that the external environment will not change; by doing so, a simplified model was established. In continuous time intervals, the model took two situations into account – only single species involved and only multiple species involved. We then used the logistic model to describe the growth rate of fungi. In the situation of multiple species, we also considered competitions between different species. Given the initial area, combined with the relationship between fungal growth rate and decomposition rate, a simplified lignin decomposition model was established. On the basis of this model, a graph of the expansion rate and decomposition rate of different fungi over time was drawn, describing the decay effect of a single fungus and multiple fungi on wood in two different time ranges, short-term and long-term. When multiple species involved, competition between each fugal strain will also be considered. Secondly, considering the complexity of the environment in reality, we include two factors – temperature and moisture – into our model. These two would significantly affect fungi’s activities. Based on the research of Dianel S. Maynard and others, we establish a linear model-The Temperature and Moisture Change Model-to describe the impact of temperature and moisture. We also apply the model in five regions of different climatic characteristics and compare the growth rate and decomposition rate of different fungi to these five regions.