Are Your Trees Safe? It’s Time to Check If They’re Healthy

Aside from summer and early fall being part of wildfire season, there is another reason for us all to pay attention to the trees around us — invasive insects and fungus. The Coast Live Oak and Monterey Pine are particularly susceptible in the Bay Area, so we spoke with a local arborist about what to look for and how to prevent such damage. Here’s how we can all pitch in to prevent this safety problem. In any of these cases, it’s best to snap a picture of the potential concern so that an expert can diagnose it virtually.

Coast Live Oak

What to Look for:

  • Sawdust at the base of trees from borer beetles that follow Sudden Oak Death fungal infections. 
  • Trees dying yet holding onto their brown leaves. 
  • Quarter-sized oily black spots on the trunk. 

What to Do:

Infected trees likely must be removed. Remove ivy and excess soil from the base of trees. Consult an Arborist to create a management plan. 

Monterey Pine

What to Look for:

  • Signs and symptoms of Red Turpentine Beetles, which can appear as sawdust at the base of trees.
  • Pitch Canker, a fungal disease, which creates tubes at the base of the trunk that look like chewing gum.
  • Excessive cones in the upper canopy.
  • Needles fading from dark green to yellow to brown.

What to Do:

Infected trees can be treated by a professional until the needle color fades dramatically.  Supplemental deep watering once a month can help trees through the summer.

General Tree-Health Tips

  • Water new trees deeply no more than once a week.
  • Have large trees examined every few years by a Certified Arborist.
  • Prune trees that extend over your house every 3-5 years.

Call a Certified Arborist If You Notice:

  • Dead branches, tips or leaves
  • Few or no leaves

How to Help

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Sabrina Tuton-Filson is the Assistant Editor at Marin Magazine and a graduate of Elon University where she studied Professional Writing and Fine Art. Born and raised in San Francisco/Marin, she loves traveling just as much as coming home to the Bay Area. She has curated a sophisticated palate for food, travel and culture and uses her travels as an outlet to develop her photography portfolio and hone her writing craft.