Global Distribution of Wood-Decay Fungi: Patterns Without Predictability

Abstract

There are three principal types of wood-degrading fungi: white-rot, brown-rot, and soft-rot. A basic role of wood-degrading fungi in forest ecosystems is to recycle the carbon stored by autotrophic organisms. Differences in the pathway through which each type of fungi degrades wood determines whether the carbon is released to the atmosphere as CO2, a greenhouse gas, or is recycled to the soil. Understanding the distribution and dominance of the different wood-decay fungi is pertinent to predicting their effect on the carbon cycle and a prerequisite for any type of mitigation strategy. Early theories attributed distribution to latitudinal geography based on correlative analysis. Attention then turned to the effects of climate, specifically moisture content and temperature, on this distribution. The prevailing theory is the connection between the wood substrate – either hardwood or softwood – and the fungal rot type, though recent evidence has called the absoluteness of this relationship into question. Current research is turning its focus to chemical growth factors of fungi such as nitrogen and phosphorous to see if these factors can explain rot type distribution. At present, many patterns between variables and distribution have been identified, but consistent counterexamples limit their predictability.