837. Coast Live Oak

Close your eyes and listen. On most any day at Asilomar, you can hear the ocean breeze fluttering the hardy leaves of the coast live oak. This is one of native trees that grow here. Many coast live oaks at Asilomar are 50 to 150 years old. Now open your eyes. You can recognize this tree by its gray bark; dark green, oval leaves; and of course, its acorns. The coast live oak’s flowers are pollinated by wind, not insects. As you explore Asilomar, you’ll find live oaks in many different shapes. Retired State Park Environmental Scientist Lorrie Madison. MADISON: The more exposed they are to the wind the lower they are, the more wind shaped they are, the smaller the leaves. NARRATOR: Growing lower helps the trees withstand constant and often heavy winds. Over time, coast live oaks have also developed protection from insects and deer. The tough, spiny leaves are high in tannin, which gives them an unpleasant taste. You might notice some light-colored dome-like growths on the branches. They’re called galls. Galls on the coast live oaks can be as small as a dime or as large as a cell phone. They’re self-contained environments -- custom-made hotels -- for a tiny species of wasp called “Cynipidae”. Lorrie Madison: MADISON: The adult female will just dig into the oak tissue a little bit and deposit her eggs and then leave the tissue is stimulated to grow just a tiny little outgrowth to protect the eggs, but then when the larvae hatch they start feeding on the plant tissue and the saliva in their mouth has chemicals it starts creating these huge tumor-like outgrowths to protect the gall wasp larvae. It provides food and shelter – it’s a great gig! NARRATOR: The larvae stay in the gall from a couple of months to a year, feeding on the tree and excreting chemicals that make the gall grow. When they’re ready to emerge, they dig their way out of the dome – if you look closely, you might see these tiny holes. Though these galls look like tumors, they neither help, nor harm, the tree. Another interesting twist: gall wasps have “alteration of generations” – one generation will be all female, and can lay eggs without mating. The next generation will be both male and female.