What is one way cavities can start in trees?

Cavities in trees can begin to form due to the activity of insects, which is a significant factor in tree health. Insects such as wood-boring beetles and certain types of beetles can penetrate the tree's bark, introducing pathogens and causing damage to the internal tissues. This injury creates an entry point for decay fungi, leading to the breakdown of wood and the eventual formation of a cavity.

While healthy growth patterns, increased sunlight exposure, and better soil conditions can have positive effects on tree health, they are not factors that initiate the formation of cavities. Healthy growth patterns do not typically lead to injury, increased sunlight does not inherently harm trees, and improved soil conditions usually support overall tree vitality rather than contributing to the creation of cavities. Thus, insect activity stands out as a direct contributor to cavity formation by damaging the tree's protective barriers and allowing decay to start within.