Bark beetles moving between trees routinely carry two fungi that are responsible for the Dutch elm tree disease outbreak.

The list of diseases attacking trees in the Pacific Northwest grows every year. A pathogen new to Pierce County brings an added concern: It can injure people. A research project using citizen ...

The list of diseases attacking trees in the Pacific Northwest grows every year. A pathogen new to Western Washington brings an added concern: It can injure people. A research project using citizen ...

The list of diseases attacking trees in the Pacific Northwest grows every year. A pathogen now found in Bellingham brings an added concern: It can injure people. A research project using citizen ...

Spruce bark beetles don’t just tolerate their host tree’s chemical defenses—they actively reshape them into stronger antifungal protections. These stolen defenses help shield the beetles from ...

As Colorado experiences its signature whiplash weather, arborists are warning that stressed trees are more vulnerable to pests and diseases. Peel back the bark, and you may find a predator in your ...

Q: I recently purchased a home with several mature navel orange trees. One of the trees has about half the bark missing from the trunk and sort of circular looking lesions that ooze sap in the area ...

Dead limbs, exposed roots, and fungus are signs a tree is in trouble. Dead limbs, visible fungus, or storm damage can all point to deeper issues—an arborist can help decide if the tree can be saved or ...