— Except for your home, trees are the most valuable thing on your property.

And now is the time to act if they are to be saved, experts say.

Central Texas is enduring day after day of 100 or near-100 degree temperature days with no real relief in sight. Moreover, the past nine months or so are the driest in the region’s history.

“This is nearly a record drought. Trees are dying and the ones that aren’t dying are suffering,” Robert Hager, board-certified master arborist at Bartlett Tree Experts, said. “There’s going to be trouble for years from what we’ve been experiencing.”

Although there was a period of relatively good rainfall in late 2009 through early 2010, trees really hadn’t recovered, Hager said. “We’ve relapsed back into a situation that’s in my opinion worse than two years ago.”

The stress trees are now feeling, he said, is cumulative because trees have not recovered from prior shocks in recent years. “The weakest ones go first, now even some of the strong ones are going.”

Hager said to the west of San Marcos there are 200 to 300 year old oaks dying. “Lots of roots are dying. Just in general it’s pretty bad.”

Hager said even native species are succumbing, particularly if they have been installed in an area that’s not optimal. “It depends on their particular location — how deep the soil is, how exposed the roots are.” For that reason, pecan trees do well in San Marcos historic neighborhoods and along the river corridor because their is deeper soil, while they “aren’t appropriate” for the limestone hills to the west.

Even though the region is under strict water conservation measures, Hager said homeowners should do what they can to keep their trees alive.

“You may have to sacrifice some shrubs and grass to save your trees,” he said. “Trees take years and years to grow big enough to provide the shade and the aesthetics they do. You can’t let 150, 200 year old trees die.”

Younger trees have value as well. “Landscape trees that are five or 10 years old, you’ve spent all that time growing those trees at considerable expense. You lose the value that you have, all the time you’ve put into it. The cost will be multiplied substantially when you let a tree die.”

Keeping trees alive in this drought should include both mulching and watering. For the latter, Hager said “gray water”  is a “great idea.” The city of San Marcos allows “gray water” from showers, bathtubs and hand washing lavatories to be used for watering plants or foundations so long as it is not from food preparation sinks or from laundry that contained diapers. (For the complete ordinance, visit www.sanmarcostexas.gov.)

Also, capturing the drip from air conditioning units. “That’s very good water too and you can even hook a hose up to it and run it out to your tree and move it around every once in a while.”

He recommends watering late in the evening and when there is no wind.

Mulch should be about three to four inches deep from near — but not touching — the tree’s trunk to the dripline.

How often the tree should be watered depends on its age. “If you water a 50-year-old tree every two to three weeks that will go a long way to keeping it going. A younger tree, in the ground three or four years, will require more frequent watering. A tree installed last year probably needs to be watered twice a week.

Hager said now is not the time to fertilize or promote growth. “Water with mulch is the best thing you can do.”

He suggested the website treesaregood.org as a good source of further information.