How do fungi decompose dead plant material in taiga soils?

In the taiga, fungi are the dominant organisms responsible for the decomposition of plant litter. Because the taiga biome generally lacks large soil invertebrates—such as earthworms and millipedes—that would otherwise shred and consume leaf litter, fungi play a critical role in breaking down complex organic matter.1

Fungi decompose this material through a process known as absorptive nutrition. They secrete specialized enzymes directly onto the dead plant material, which act as biological catalysts to digest complex polymers extracellularly. Specifically, fungi have evolved to break down cellulose and other complex carbohydrates that most other organisms cannot efficiently metabolize.23

Once these enzymes convert the detritus into simpler molecules, the fungi absorb the resulting nutrients directly through their mycelial surfaces. Despite this activity, the rate of decomposition in the taiga often fails to keep pace with the rate of plant production, leading to the characteristic accumulation of partially decomposed organic matter in the forest floor.2314