Trees in extreme heat
Fresno's summers are extremely hot; National Weather Service records show 69 days at or above 100°F in 2021. Shade trees make a big difference to how hot a house and yard get, and they also face real stress through long, dry summers. Leaf scorch, early leaf drop, thinning canopies and dieback at branch tips are common signs of heat and drought stress.
Watering established trees
Deep, infrequent watering is best for established trees. Water should soak the soil out toward the drip line, where most absorbing roots are, not just at the trunk. In the hottest months, many trees benefit from a deep soak every couple of weeks, adjusted for soil type and species. Mulch over the root zone, kept a few inches away from the trunk, reduces evaporation and keeps roots cooler. When you cut back lawn watering, remember that trees growing in lawns may lose most of their water supply.
Summer branch drop
On hot, still afternoons, some large trees drop branches that appear healthy, a phenomenon arborists sometimes call summer branch drop. It isn't fully predictable, but long, heavy horizontal limbs over patios, driveways and play areas are worth having assessed and, where appropriate, reduced.
Pests and stress
Heat-stressed trees are more vulnerable to borers and other pests. Watch for small holes in bark, sawdust-like material at the base, oozing sap and sudden dieback. Keeping trees well watered is the first line of defense. An arborist can identify specific pests and recommend treatment where it's warranted.
Winter storms and fog
Fresno's rain comes mostly in winter, and storms can bring wind on saturated soil. Winter tule fog keeps canopies damp for days. Removing deadwood and correcting weak structure before winter reduces storm risk, and pruning during dry weather limits the spread of some diseases.
Choosing trees for Fresno
Choosing heat- and drought-tolerant trees, and planting them where they'll have room to grow, reduces future maintenance. Shade trees on the west and south sides of a house cut afternoon heat most effectively. Keep large trees away from foundations, sewer lines and overhead power lines. A local arborist or nursery can recommend species that thrive in Fresno's climate.
Before you hire
Ask Fresno tree care contractors how they'll protect your yard, whether they follow recognized pruning standards and avoid topping, whether a permit is needed for protected or street trees, and for proof of insurance. Look up their California license with the CSLB.
Roots and paving
Large trees in Fresno's older neighborhoods often lift sidewalks and driveways. Before cutting big roots to repair paving, talk to an arborist, since cutting major roots can destabilize a tree or kill it. Root pruning done carefully, root barriers and paving designs that bridge roots are sometimes options. If you're planting, choose a spot with enough room for the tree's mature roots as well as its canopy.
Storm and emergency work
When a limb comes down on a roof or fence, keep everyone away from it, especially if wires are involved, and call the utility first if lines are down. A tree crew can remove the limb safely and assess the rest of the tree.