Key Points:
- El Niño is expected to bring above-average rainfall to California this winter, with experts predicting higher humidity and potential flooding.
- Proactive tree care, such as improving soil drainage and pruning strategically, helps trees survive dangerous winter weather.
- During tree risk assessments, arborists will look for signs of compromised tree health, including tree leaning, bark peeling, and canopy dieback.
El Niño—the warm phase of the El Niño Southern Oscillation, during which temperatures in the equatorial Pacific are above average for several months—was confirmed in June 2026 by NOAA’s National Weather Service. While every El Niño event is unique, this one is expected to reach Super El Niño strength—and experts are predicting increased rainfall and a potentially dangerous storm season in California.
What does this mean for Marin County homeowners and their landscapes? Below, we’ll get into how to prepare your trees for a harsher, wetter winter with proactive maintenance and expert guidance from the ISA-Certified Arborists at Treemasters.
Why This El Niño Season Matters for Your Trees
During an El Niño event, warmer-than-usual sea surface temperatures cause the Pacific jet stream to shift, altering temperatures and weather patterns across the Northern Hemisphere. As of late August 2026, NOAA is predicting above-normal precipitation across California from December through February, according to The San Francisco Chronicle.
In an interview published by the University of California Agriculture and Natural Resources, climate scientist Daniel Swain described some of the impacts to expect this winter, including high coastal humidity, disruption to marine ecosystems, and potential inland flood risk from heavier precipitation.
Severe-enough storm winds can compromise tree stability, especially for newly planted trees or those with lopsided canopies. Likewise, intense rainfall can damage root systems and deteriorate tree health literally from the ground up.
How to Prepare Your Landscape Before the Storms Hit
Investing in proactive tree care now can help you avoid tree damage and emergency removals this winter. Consider these steps before El Niño’s effects reach your area.
Get a Tree Risk Assessment
One of the most effective first steps in preventing tree damage is to get a professional tree risk assessment from an ISA-Certified Arborist. During a tree risk assessment, your arborist will inspect your trees and landscape, determine their needs, identify any weaknesses, and provide you with expert service recommendations.
Treemasters offers three levels of tree risk assessments:
- Level 1: Visual Tree Risk Assessment. This limited inspection is conducted when there’s no reason for concern about a tree’s health.
- Level 2: Moderate Tree Risk Assessment. This more thorough assessment focuses primarily on the tree’s roots, trunk, and crown.
- Level 3: Comprehensive Tree Risk Assessment. The most detailed inspection, this assessment may include tissue testing and resistance drilling along with a review of the tree’s root system, trunk, and crown.
The assessment gives arborists the information they need to make informed decisions about your tree care.
Improve Drainage Around Root Zones
Because most tree species in Marin County are drought-resistant, the predicted increase in precipitation will likely lead to waterlogged soil and secondary problems, such as fungal development or increased pest activity in the spring. Improving drainage can help you avoid this.
For dry, compacted soil, loosen it with a gardening tool and add a layer of mulch or other organic matter. Do not walk on or work with waterlogged soil, as this can increase compaction and damage roots. If water tends to pool at the trunk of a tree, consider grading and vertical drainage options to prevent it.
Prune Strategically
After a tree inspection, your arborist will determine whether your trees could benefit from pruning before El Niño weather begins. Removing dead, damaged, or diseased branches keeps your property safe from potential harm. While a tree may appear safe and intact to the untrained eye, arborists are expertly attuned to recognizing issues your tree may be experiencing.
Regular pruning also prevents overgrowth and ensures your trees get adequate sunlight and shade, keeping them healthy for longer.
Support Young or Newly Planted Trees
Recently planted trees may not have yet established their root systems, making them more vulnerable to extreme winds and stormy weather. One solution is tree guying, the process of using stakes or wires to keep young trees supported during storms. Guying differs from tree cabling and bracing, which are methods of reinforcing more established trees that are weak or unstable.
Watch for Pests and Root Disease
Many tree pests and pathogens thrive in moist conditions and will be more attracted to waterlogged trees come spring. Armillaria root rot, for example, is a common threat in California; this fungal disease can destroy a tree’s root system, preventing the uptake of water and nutrients.
Keep an eye out for pest activity or signs of tree health decline—not only after storms but throughout the year. Catching infestations and diseases early increases the chance of effective treatment and recovery.
Warning Signs Your Tree May Not Survive El Niño
An arborist’s tree risk assessment may determine that your trees are already compromised and need more than the El Niño-prep steps. Here are some of the warning signs of tree problems to address sooner rather than later:
- Tree Leaning: A sudden, new lean is a strong indicator of instability and should be addressed as soon as possible, especially before a storm. Other signs of instability to look for are soil heaving and visible roots.
- Fungal Conks: While not all mushrooms indicate tree health issues—some species are actually beneficial—those growing near the trunk base can indicate advanced decay in root tissues or lower trunk wood.
- Bark Symptoms: Severe bark cracks, peeling, or a sudden spongy texture are signs of tree health decline. When inspecting tree bark, look out for small holes or other signs of pest activity.
- Canopy Dieback: Losing leaves outside the tree’s normal seasonal cycle signals a problem. Canopy dieback can occur on one part of the tree or across the whole canopy. Similar symptoms include premature leaf yellowing, a change in leaf shape or size, and branch dieback.
Let Treemasters Storm-Proof Your Landscape Before El Niño Hits
While the threat of a damaging El Niño is stressful, proactively protecting your trees now can help them weather any storms to come. Serving Marin County and surrounding Bay Area regions for more than 35 years, Treemasters is committed to providing homeowners with high-quality, full-service tree care.
From tree removal to pest and disease control, fertilization, and other tree healthcare services, our team provides personalized care and tailored solutions that cater to the unique needs of your property.
Prepare your landscape for winter today. To schedule a consultation, call Treemasters at 415-532-1290 or contact us online today!
FAQs
How far in advance should I schedule a tree risk assessment before El Niño storms arrive?
Arborists recommend scheduling risk assessments in the fall, so they can provide preventative tree care before El Niño storms arrive. Generally, tree care companies see demand spike once storms hit, so booking ahead ensures you receive proactive (rather than reactive) tree care.
Can I prepare my trees for El Niño myself, or do I need to hire an arborist?
Adding mulch around root zones and monitoring for visible warning signs, such as leaning or bark damage, are safe for homeowners to do on their own. That said, pruning, tree guying, and diagnosing root or trunk health require the training and equipment of an ISA-Certified Arborist. When in doubt, consult an arborist, who can assess your property and determine what needs professional attention.
Who is liable if a tree on my property falls during an El Niño storm?
In California, liability generally turns on whether the tree owner knew or should have known the tree was hazardous. A tree that showed visible warning signs—such as leaning, cracks, or deadwood—before it fell can create liability for the owner, even in a major storm. Documented risk assessments are among the best ways homeowners can protect themselves, since they create a record that reasonable care was taken.
Will California homeowners insurance cover tree damage from El Niño storms?
According to the California Department of Insurance, most standard homeowners policies cover storm-related tree damage to structures. Coverage for removing a fallen tree that missed your house, or for trees that damage a neighbor’s property, varies by insurer and policy. Insurers may also deny claims if a tree was already visibly diseased or hazardous before the storm, which is another reason documented professional inspections matter. Homeowners should review their policy’s specific tree-related language before storm season, not after a claim is needed.