With strong El Nino storms still on the horizon, local arborists recommend Pleasanton residents inspect their trees to protect them from tumbling down.

The yearslong drought has been tough on East Bay trees, especially non-native but beautiful species like Redwoods, said Joe Berg, assistant district manager of Davey Tree's East Bay office.

"We're definitely seeing a lot of impact from the four-plus years of drought," he said. "Most of the trees that are getting hit really hard are the ones that aren't exactly native to the area, like Monterey pines and Redwoods."

The lack of water can weaken or kill a tree, leaving it susceptible to falling or losing limbs that snap off in strong gusts. Now is the best time to check out one's trees, arborists said, because a big El Nino storm could topple a stressed tree onto a home or car.

Even using recycled water -- such as from Dublin San Ramon Services District's residential recycled water program -- can only help for a time, and certain trees start to feel the effects of the alkaline water faster.

"The basic water tends to limit the tree's ability to take up certain nutrients," Berg said. "Redwoods get really, really bad. You tend to see a purplish color in the canopy."

Pleasanton arborist Michael Santos said some trees handle the saltiness better than other plants.

"The principal thing of concern there is salt, especially salt like sodium, chloride and boron," he said. "Just like people, trees have different tolerance level to those salts."

Santos said residents should have an arborist regularly inspect and trim their trees. Residents can also mulch around their trees, install a low-water drip irrigation system and remove struggling trees.

Signs to look for include dead limbs, thinning of the canopy, discoloration of the canopy and unusual cracks in the trunk.

"People need to be paying ongoing attention, not just when the tree is in stress," said Santos, owner of Michael Santos Consulting Arborist LLC.