The answer to 'tree trimming yellowing' is that yellowing leaves on a recently trimmed tree can be a common symptom of stress from the pruning process. Trimming removes a significant portion of the tree's branches and leaves, which disrupts the tree's natural processes and can cause the remaining leaves to yellow and wilt as the tree adjusts.
This yellowing is usually temporary and the tree should recover within a few weeks as it adapts to the reduced leaf area. However, if the yellowing persists or spreads, it may indicate a more serious underlying issue like disease, pests, or improper pruning techniques. In those cases, it's best to consult a professional arborist to diagnose and treat the problem.