Remove or thin chaparral growth, but leave native trees and large shrubs to hold the hillside. Occassional summer irrigations will help to prevent the leaves from drying out. Please, please, clear your land, and get your neighbors to clear theirs. While it won't stop a firestorm in its full fury, clearing dry, dead brush and grass goes a long way in preventing fires from starting and spreading. The Oakland Hills Firestorm Protecting Your Home from Brush Fire Trees and Shrubs Plant palms and tropical plants.
Conditions are dry enough to discourage root rot.
Trim hedges, topiaries, and espaliers. Maple leaves get burnt from heat and from wind. Strip off the damaged leaves and feed. The maple will leaf out again in 3 to 4 weeks. Remove dead flowers from hydrangeas, crape myrtles, and other summer blooming shrubs.