Diseases and damage caused by other agents

A variety of biotic (living) or abiotic (non-living) agents cause diseases and damage to trees. Biotic agents, including birds and mammals, along with abiotic agents such as nutrient imbalances, chemicals, pollutants, and detrimental weather contribute to tree diseases and damage.

Biotic

Various animals and birds damage trees, either by directly feeding on them or while searching for food sources, such as fungi and insects on or in the trees.

Abiotic

Abiotic agents can act directly by killing or damaging tree parts (e.g., buds, leaves, and roots). Examples of direct abiotic agents include excessive heat or cold, some pollutants, and some pesticides. Abiotic agents can also act indirectly by occurring at insufficient or excessive levels to meet the trees physiological needs (e.g., light, nutrients, oxygen, and water), or by altering soil in which the tree is growing (e.g., pollutants that change soil chemistry).