Summers in the South Bay Mid-Peninsula bring more than just heat—they bring risk. Extended drought and increasing fire pressure mean some trees on your property may be more vulnerable than others. Whether you live in Woodside, Portola Valley, or Palo Alto, knowing which species are most at risk can help you act before peak fire season. 

What Makes a Tree Fire-Prone? 

Several factors increase a tree’s fire risk: 

• Dry, resinous wood (like pines or eucalyptus) 
• High oil content in leaves 
• Excessive deadwood or unpruned branches 
• Proximity to structures or other vegetation 
• Drought stress that weakens natural defenses 

Trees at Higher Risk in Our Region 

In our local landscapes, we often see these trees in high-risk zones: 

1. Pines (especially Italian Stone Pine) 

• Highly flammable due to dry needles and resin 
• Frequently hosts red turpentine beetles during drought 

2. Eucalyptus 

• Fast-burning oils in leaves 
• Common along older rural properties and roadsides 

3. Coast Live Oak 

• Native but vulnerable when crowded or defoliated by pests like the oak worm 
• Deadwood buildup increases fire load 

4. Olive Trees 

• Can become brittle and flammable when stressed 
• Often neglected ornamentals in estate settings 

Overgrown ornamentals (Cedars, Junipers, Cypress) 

• Hold onto dry foliage and build up dead branches 
• Frequently planted as privacy screens too close to structures 

Drought Stress Increases Risk—Even for Healthy Trees 

When trees are drought-stressed, they: 

• Lose canopy density, drying out inner branches 
• Divert energy away from pest/disease defense 
• Become more susceptible to bark beetles, borers, and decay 

Add summer heat and you’ve got a recipe for ignition. 

How to Reduce Fire Risk and Support Tree Health 

Now is the time to prepare. Here’s how: 

1. Create Defensible Space 

• Remove ladder fuels and prune low-hanging limbs 
• Clear debris and deadwood from under trees 
• Maintain 100 feet of clearance around structures (especially in WUI zones like Woodside) 

2. Prioritize Strategic Pruning 

• Remove crossing limbs, dense growth, and deadwood 
• Open up canopy airflow to reduce heat stress 
• Avoid aggressive summer pruning of already stressed trees 

3. Support Hydration 

• Use mulch to conserve moisture 
• Schedule bio-hydration for severely stressed trees (especially oaks and redwoods) 
• Water early morning or evening, slowly and deeply 

4. Monitor for Pests 

• Look for boring dust, sap bleeding, and canopy thinning 
• Catch infestations early to avoid tree loss 

Not Sure Which Trees Need Help? That’s Where We Come In. 

At Urban Tree Management, our certified arborists specialize in evaluating drought and fire risk across estates, residential landscapes, and wooded properties throughout the Mid-Peninsula. We’ll help you create a plan that protects your trees and your home. 

📞 Call us at (669) 639-0521 to schedule a fire-readiness inspection, or
🌐 Learn more at: https://urbantreemanagement.com/ 

Pro Tip: Mulch isn’t just for moisture—it reduces weed competition, regulates soil temperature, and improves soil structure over time. Aim for 2–4 inches deep, but keep it away from the trunk flare.