An arborist is a professional who specializes in the care and maintenance of TREES. Their concern includes both the health of the TREES and the pests that can affect them. The solutions to the crossword for the term 'Arborist's Concern' are TREES (5 letters), PEST (4 letters), and Tree (4 letters). TREES are the primary focus of an arborist, and they must be aware of any pests that could harm them. Pests can range from insects to fungi, and can cause serious damage to TREES if left unchecked. Tree care is an important part of an arborist's job, as it helps ensure the health and longevity of the TREES they are responsible for.