We can call fungi that decompose hardwoods ‘ecosystem engineers’, as they greatly enhance the carbon availability that so many other forest organisms depend on. Perennial shelf fungus are the masters of breaking down dead trees. Without these fungi, the carbon in the dead woody material would remain locked up, unavailable to flora and fauna that make a living from the forest floor. Forests would not be forests. Not the diverse, regenerative places dwelling under dense canopy that we know and love.
Over evolutionary time, the fungi that most efficiently and rapidly decompose dead woody material were selected. Many species became super-efficient at chemically breaking down dead trees. This enhanced turnover of forest carbon makes the forest floor a dynamic ever-changing place that supports an impressive array of species. Not all fungi are created equal in the chemical breakdown of lignin rich wood. The insatiable appetite for one deciduous hardwood decomposer helps describe its abundance all over the continent.
Trichaptum biforme is found in every U.S. state, and Canadian province. Its spores don’t travel farther than other spore producing fungi, so why is it found everywhere? For one, it’s a generalist. It can decompose the debris from several deciduous trees all over the continent, so it has a bounty of available resources. Secondly, this fungus is voracious. It breaks down woody material so fast that if you happen to find a log completely infested with this polypore, chances are, you will be able to lift what was once a heavy log. In a few growing seasons Trichaptum biforme nearly hollows out the insides of whatever woody debris lays in its wake.
Its ability to rapidly decompose makes it an incredible competitor. T. biforme uses the available resources faster and more efficiently than other fungi. Its supreme competitiveness has led to its gargantuan distribution over the continent. One study out of Minnesota that sampled 120 plots in four aspen dominated forests found that out of 86 found polypore species, eight species made up nearly 70% of the occurrences. Out of these eight dominant decomposers, T. biforme was found the most.
There are rare species, there are common species, and then there are species that are found just about everywhere. What makes some fungi dominate? This kingdom isn’t dispersal limited, that’s for sure. Driven by competition, some species have achieved a chemical edge, and can break down and utilize woody debris faster. That’s the case for T. biforme. It’s hungry, and it can eat.