It's Ok to Water Trees

Trees are having a tough time right now because of the drought. Nobody knows better than residents of Bear Valley Springs and other forested areas. The drought has weakened the trees and left them more vulnerable to bark beetles, mistletoe, and other pests and diseases. When was the last time you took a good look at the trees in your yard or along your street?

How many of us have a tree in the middle of the lawn, and have stopped (or at least reduced) watering the lawn. That tree had an easy life up until now, and didn’t need to grow its roots deep or wide to get water. Suddenly, all that easy water is gone, and the tree doesn’t have enough roots grown to support itself. These may be the most important trees to water.

One of the differences between plants and animals is how they die. For us animals, death is abrupt, either you’re alive or dead, there is a clear line that is crossed quickly. Not so for plants. They die little by little. They can make a decision to let go of a whole limb to save resources for the rest of the plant, then another limb, and so on. There’s a shrub in my yard that looked thoroughly dead, but when I put some new plants beside it and watered them, the shrub sprouted again. Go figure.

Although we mostly don’t give them much thought, trees are so valuable in our urban and suburban lifestyles. Monetary value is just the start. A home with a nice big tree in the lot will sell for 10-20% more than the lot without. Trees shade our homes and reduce our air conditioning bill in the summer, and then block the wind and reduce our heating bill in the winter. Trees absorb carbon dioxide and incorporate it into their tissues, reducing greenhouse gases, and give off oxygen. They catch and slow raindrops so the water is better able to soak into the ground, incidentally reducing erosion and stormwater runoff. The list goes on and on, but don’t forget the spiritual aspect. When was the last time you sat under a tree and relaxed?

We got some good rain this winter/spring, and while it didn’t end the drought in Southern California, it did replenish the soil moisture bank that trees depend on. When you water a tree, you are giving it supplemental water to keep that deeper soil moisture from being depleted. Supplemental means once a month at the most, but you’re watering to soak a few feet into the soil. It takes some time to get that much water around the tree.

Be sure to consider the roots. Many of us have a mental image of tree roots going deep into the soil, but most of a tree’s roots are in the top two feet of soil. The shape of the tree is more like a wine glass, with the roots spreading shallowly like the base of the wine glass. Around the trunk, the roots are thick and mostly function to transport what the roots have collected. It is the tiniest of roots where the water is absorbed. Don’t water the tree near the trunk, water underneath the furthest reach of the small twigs and leaves. That is where the tiny water absorbing roots are the thickest.

Remember to abide by your community’s watering rules!