Tree health troubleshooting guidelines (adapted from Johnson et al., 2008).
Link to this table

If you see: Potential cause: You should:
TRUNK
A flat-sided trunk at the base of the tree Encircling root restriciting the flow of water and nutrients between the roots and rest of the tree Excavate to check for encircling root
Bark damage near the bottom of the tree Rodent or string trimmer Apply mulch/trunk guard to protect from further damage
An elm tree with liquid oozing from the trunk Slime flux or wetwood Not worry about health
BRANCHES
An elm tree with bright yellow leaves on one or two branches Dutch elm disease Immediately call the university* or an arborist
Webs in the branches or webs covering the tips of branches Fall webworm or Eastern tent caterpillar Not worry about health>
Many branch tips snipped off and laying on the ground Squirrel damage Not worry about health
Black clumps on branches of a cherry tree Black knot Call for advice*
Very little growth Many Call for advice*
Hole in trunk or branches Many</td Call for advice*