What is considered the most casual agent of tree rot?

Fungus is considered the most casual agent of tree rot due to its ability to penetrate and decompose wood. Many fungal species thrive in moist environments and can invade trees through natural openings, wounds, or damaged areas in the bark. Once inside, they break down cellulose and lignin, which are key structural components of wood, leading to the degradation of the tree's integrity. This process not only weakens the tree but can also contribute to other secondary issues, such as insect infestations or further disease spread.

While bacteria, insects, and environmental factors can also contribute to tree health decline and decay, fungi are particularly adept at causing rot by directly decomposing the wood material, making them the primary agents responsible for tree rot in many cases. They can also establish long-term infections, leading to progressive damage that is often not evident until significant decay has occurred. This unique capability distinguishes fungi as the most significant contributors to the issue of tree rot.