**2.Changes in chemical components**

The chemical compositions of diverse wood species at different periods by brown rot and white rot fungi are summarized in **Table 2**.

**Figure 1.** *Mass loss of different wood species decayed by white and brown rot fungi.*


#### **Table 2.**

*Relative chemical compositions of control and degraded wood.*

For *P. yunnanensis* wood, *Trametes versicolor* (white rot fungi) caused simultaneous rot, resulting in a rather uniform depletion of glucan, xylan and lignin. Conversely, in brown rot groups, fungi preferentially decomposed carbohydrates, which led lignin retained selectively. However, they decomposed cellulose and hemicellulose in their own selective approach. The xylan decreased from 9.73 to 2.97%, which decayed by *G. trabeum*, while the glucan decreased from 33.67 to 19.50% after *Rhodonia placenta* biodegradation, revealing that *G. trabeum* could degrade hemicellulose selectively, while *Rhodonia placenta* could preferentially attack cellulose. It is interesting that different fungi exhibited obviously different degradation in softwood species, e.g. the *Picea jezoensis* decayed by *Porodaedalea pini*, both cellulose and lignin were depolymerized due to the respective decreased contents, whereas, the increased content of hemicellulose showed the slight degradation of hemicellulose probably due to the weak influence on hemicellulose from this fungus. This also reveals that wood rot fungi depolymerize the chemical compositions of wood substrate through their own degradation pathway.
