These SoCal Trees Had A Sappy, Sticky Summer: Report

SOUTHERN CALIFORNIA — If you've had to traverse viscous tree sap on sidewalks in your neighborhood, you're not alone.

Following an intense September heat wave and warmer-than-usual days in the first few weeks of fall, trees like the cork oak have been producing more sticky sap, LAist reported.

If you've ever made the mistake of parking beneath one of these trees, you may have found it difficult to scrub all of that tarry sap off your car. But this year, these trees have been producing much more sap than usual due to the heat, according to Garrett Crawford, public works administrator for Pasadena and a certified arborist.

Though the cork oak is native to Spain and other southwestern European countries, it is extremely common in Southern California. Some may recognize them from Disneyland or on college campuses such as Cal Poly San Luis Obispo and UC Davis.

Though they are popular for their hardiness and drought resistance, they are also sought after to make corks used in wine bottle stoppers.

Crawford says the state's unusually hot weather is the answer to why these trees are producing so much more sap this year.

“Even though oak trees are fairly adapted to that climate, those sudden spikes and then prolonged heat really stressed out the tree,” Crawford said.

Read more from LAist: You're not dreaming, trees are producing more sap this summer