If a contractor recommends thinning a dense crown to improve airflow, ask what problem the work is intended to address. More space between branches may change air movement, but “better airflow” is not a complete explanation of the benefit to your tree.
Connect the recommendation to an observed problem
Ask which parts of the canopy are crowded and how that crowding relates to the concern. A naturally dense species does not automatically need its crown opened simply because another tree looks more transparent.
If the concern is foliage that stays wet or recurring leaf symptoms, describe when it happens and provide existing photographs. Those details are more useful than requesting the most open canopy possible.
Do not confuse airflow with a disease cure
Opening selected areas may improve ventilation, but leaf spots, dieback, and other symptoms can have different causes. Thinning cannot be assumed to eliminate an infection or correct unsuitable watering.
Ask whether the suspected problem needs diagnosis before live branches are removed. If irrigation repeatedly wets foliage, changing that practice may be part of the discussion rather than relying on canopy work alone.
Question wind-safety promises
Air movement in ordinary conditions is not the same as how a tree behaves during strong winds. A proposal to make a tree “windproof” by thinning it should not be accepted as a guarantee.
Branch attachments, decay, roots, exposure, and other conditions influence failure potential. Creating visible gaps does not establish that those concerns have been resolved.
Agree on a realistic way to judge results
Have the contractor explain the intended improvement, the foliage to retain, and any separate issues that thinning will not address. If leaf symptoms are involved, ask how they should be monitored afterward rather than assuming an immediate cure.
San Diego owners considering selective thinning of crowded canopy growth should expect a tree-specific reason for the work. A modest, clearly explained objective is more useful than broad promises about airflow, disease prevention, or storm protection.