Measurements of pinecone compositions
For each type of pinecone, we analyzed the complex organic compounds at two different states: (i) newly fallen cones, and (ii) cones being decomposed by fungi in the genus Auriscalpium . The contents of cellulose, hemicellulose and lignin were quantified using the automatic fiber analyzer according to the ANKOM 2000i instructions (https://www.ankom.com/technical-support/fiber-analyzer-a2000). We used the TAPPI standards in cones of P . armandii ,P . yunnanensis and P . sylvestris at KIB (Kunming Institute of Botany, CAS) as references. The pectin contents in these samples were quantified by using the method of sulfuric acid-carbazole colorimetry (Zhu, Huang, Wu, Chen, & He, 2017). Analyses for all samples were carried in decuplicate.