How to protect your trees during a major rainstorm

By Canopy Team on January 5, 2024

A large fallen tree in a park

Mitchell Park, Palo Alto - this Italian stone pine tree fell due to heavy rainstorms in January 2023.

When it rains, it pours! After 2023 winter rainstorms and heavy wind devasted the Bay Area’s trees, Canopy is encouraging Midpeninsula residents to brush up on emergency preparedness while maintaining the health of their trees. Extreme weather, such as these recent storms, may only increase in the future due to climate change, and it’s important to protect our valuable urban trees.

Jump ahead in this blog:

Before a storm: look for warning signs.

This article from Davey and this guide from New York’s Department of Environmental Conservation are good primers on what to look for. Cracks in the soil or a leaning trunk with upraised soil near the base can be signs that a tree’s roots are unstable.

According to arborist Kurt Stegen, conifers like Redwoods, Pine, and Cypress can be especially vulnerable since their needles can hold extra water, making their evergreen canopies extra top-heavy.

Multi-trunk trees with weak attachments (see examples in the New York guide) are also at risk of failure.

If needed, get an expert (and objective) assessment.

If there’s a tree on your property that concerns you, it’s a good idea to have a consulting arborist take a look and assess the risk. Consulting arborists have no financial incentive to recommend pruning or removing your tree, so you can feel confident they’re giving you their best advice.

You can never be 100 percent sure a tree won’t cause damage in a storm, but hiring a professional to inspect the tree should give you peace of mind.

Consult Canopy’s arborist list for a searchable list of local certified professionals.

During a storm: know who to call for tree emergencies.

During a big storm, it’s inevitable that some weakened trees will not survive. For downed trees on your private property, check Canopy’s arborist list, and search for companies that provide “Emergency Tree Services” (under “Other Services”).

Here are local resources to help you weather the storm. Remember, in case of a serious emergency, like a tree falling on your house or a downed power line, call 911.

In Palo Alto:

  • For downed street trees (or any public tree): call Public Works at 650-496-6974 on weekdays from 7:00 a.m. – 4:00 p.m. or 650-329-2413 after hours and on weekends.
  • For power outages and electrical problems: call Palo Alto Utilities Electric Operations at 650-496-6914. Find other useful numbers on Palo Alto Utility’s outages page
  • For news on current conditions, visit the city’s Storm Updates or Storm FAQs webpages.

In East Palo Alto:

In Mountain View:

  • To report locations of flooding or downed trees and limbs, please call and leave a message with the City of Mountain View’s Public Works Department at 650-903-6329.
  • For other storm preparedness tips, visit

In Menlo Park:

  • For blocked storm drains, sinkholes, landslides, and fallen trees, call 650-330-6780 from 7:30 a.m.–4:30 p.m on weekdays and 650-330-6300 on weekends and after hours.
  • For Storm Preparedness resources, visit

Emergency preparedness resources are also available through the County of San Mateo and County of Santa Clara.

After a storm: check your trees for damage.

This article from Arbor Day Foundation provides good tips for providing “first aid” to your tree after a storm. But be safe! If your tree has sustained significant damage, it’s probably time to call an arborist who can assess whether the tree will recover, or if it’s time to remove it before it becomes a hazard.

Looking ahead: maintain your tree’s health

Preventative tree care is the most effective way to maintain the health of your trees, and healthy trees are unlikely to fall during storms and wind. Canopy’s website contains extensive resources to help tree stewards better understand and care for the trees they own. Below are some DIY steps you can take year-round to prepare for extreme weather.

  • Apply Mulch: applying mulch to the base of your tree protects the roots from compaction and aids in stronger root attachment to the ground. Additional benefits of mulch include temperature regulation, weed suppression, fertilizer, and increased water conservation. Apply 2” thick from just next to the trunk out to the dripline (farthest reaching branches) in an even layer anytime during the year to provide these benefits for your tree of any age.
  • Water Your Trees: When trees are stressed, they cannot perform their functions properly which can lead them to fail in our urban environment. Making sure we water trees appropriately will ensure they can better root themselves in the ground and survive storms. Read Canopy’s Tree Watering Guidelines to see if you are adequately watering the trees on your property.
  • Don’t Top Trees: avoid over-pruning or topping your trees. Over-pruning can cause additional stress to an already damaged tree, and topping your tree can cause new stubs or branches to be weakly attached and more likely to break in future storms. Topping a tree also puts a significant amount of stress on an already damaged tree and will likely lead to a decline in health, poor recovery, or failure of the tree itself over time or in a significant storm. (from the Arbor Day Foundation’s Tree First Aid After a Storm.)
  • Care for Young Trees Properly: early tree maintenance ensures greater longevity for the life of your tree, providing lasting benefits to your community; however, it’s never too late to start your tree care journey! Canopy offers resources tailored for young trees vs. mature trees, and if your tree was planted by Canopy, we offer free tree care for the first few years. Visit to request care.

Stay informed with Canopy

Once the immediate danger of a tree emergency passes, look to Canopy as a hub of urban forestry education and resources for residents of the Midpeninsula.

You can learn more from the below resources:

  • Canopy’s Tree Library: use our tree selection tool to ensure you’re planting the right trees for your yard, including native and climate-appropriate species.
  • Canopy’s online Arborist list: consult this list of consulting arborists and tree care companies for preventative, diagnostic, and corrective tree care services to maintain the health of your trees.
  • Subscribe to Canopy’s mailing list to stay updated on the latest news on the Midpeninsula’s urban forest.

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