Connecting with nature

by Jenny Rigby

On a summer’s day at Irvine Regional Park or Bommer Canyon, you might be drawn to the cool shade offered by coast live oaks. The massive trees can reach a height of 75 feet and are identified by their gnarled limbs and dark canopy of leaves.

While you’re there, look around. Coast live oaks can be home, roost and pantry to over 300 species of birds, reptiles, amphibians, mammals and thousands of invertebrates.

The trees also serve as shelter. Like an apartment tower, a single oak offers multiple levels of housing, from roots in the soil and cavities in the wood to the highest reaches in the canopy. Some animals live in the oaks. Others pass by, traveling along branches and limbs.

Tough and leathery, the dark green leaves of coast live oak have a spiny margin, or edge. Their underside contains dense tufts of “hair.” Unlike other oaks in its botanical group, a coast live oak produces acorns that take just one year to mature.

Take time to savor these trees. After a few minutes of sitting quietly under one, you might be treated to a wildlife sighting.

Resembling an apple, though hardly a fruit, this particular gall is produced by the tree in response to having a tiny cynipid wasp lay its eggs in it. The site swells, forming a growth that supplies the growing wasp larvae with food.

Jenny Rigby directs The Acorn Group, a design firm dedicated to interpreting natural history.


 

IN A SINGLE BOUND - The acrobatic gray squirrel moves in the higher reaches of oaks, leaping 20 feet from tree to tree. Watch for them racing up or down the trunks, each cheek pouch stuffed with an acorn. Gray squirrels cache acorns in the ground as their winter food supply.
“WAKA-WAKA-WAKA” - Where there are acorns, acorn woodpeckers follow. Dead limbs of oaks and sycamores offer space for their acorn caches, or granaries. Watch for this red-capped, clown-faced bird high in the oaks and listen for its loud waka-waka-waka call.
EARLY RISER - Oak trees provide cover and food for mule deer. The deer feast on the fall acorn crop, taking advantage of a high-energy food with a fat content that ensures energy and insulation. Watch for deer in early morning and late afternoon.
JUMPIN’ JAY FLASH - Watch for a flash of blue as the raucous California scrub-jay hops along the ground or darts from branch to branch. In their pursuit of gathering and caching acorns, scrub-jays play a key role in the propagation and dispersal of oak trees.