Q. How is the El Niño weather pattern going to affect my trees? I have several fruit trees, a large evergreen ash and a very large native oak in my yard. Also, why does rainwater seem to make my plants grow better?

A. I’ll start with the last question first because it’s pretty interesting. The first thought that comes to mind regarding why rainwater seems to be better for plants than water that comes out of your faucet is that there must be something added to or removed from the tap water that diminishes its beneficial effects on plants.

According to water officials, however, the chemicals that are added to the drinking water to ensure its purity quickly dissipate, and nothing is being done to the water that makes it less beneficial to plants, grass or trees.

This issue could go back and forth either way depending upon whom you talk to, so the answer is probably somewhere in the middle. I think it’s possible that the combination of fewer “unnatural” chemicals in rainwater as well as natural nutrients that are available in rainwater just makes it a little more effective for plant growth.

Don’t forget, though, when it rains for several days, your yard may be getting more inches of rain in those few hours than you normally give it in an entire month with your sprinkler system. I like the idea of natural rain watering my trees, plants and grass not only because I like the effect it has on them but also because it’s free.

Along with the heavy rains that accompany the El Niño weather pattern, strong winds are associated with the storms as well. Most trees that are well-established and healthy can withstand pretty strong winds under normal circumstances when the soil is relatively dry.

As we get further into the rainy season, things could change. Soil that is heavily saturated by rain becomes weaker, thereby providing tree roots less to hold on to.

Many of the thousands of downed trees I’ve seen during heavy storms are a result of saturated soils followed by strong, steady winds mixed with even stronger wind gusts. Additionally, many of the fallen trees were growing on hillsides.

Though trees of all species can blow over, the ones that seem to end up on the ground the most are pines and eucalyptus. When large oak trees come down in a storm, it’s almost always related to decay in the root system or heartwood of the tree.

The end result is that, if we get a lot of rain during an El Niño or any other rainy season, it’s good for the health of the trees. The high winds, however, could blow down some species of trees more readily if the soil is saturated, especially if the tree is very large or has some health or structural problems.

If in doubt about the health or stability of your trees, have a certified arborist give you an opinion on their condition.

David D. Mortimer is a certi fied arborist with more than 30 years’ experience in the tree-care industry. E-mail questions to dmortimer@theacorn.com.