Coast Live Oak Woodlands

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Their graceful limbs are impossibly mighty, and they hold them wide. Their branches are more outstretched, more parallel to the ground than upright. Within a short distance of the City of Santa Cruz, there are hundreds of coast live oaks large enough provide shade for 20 picnicking people. These trees invite climbing and most groves have a tree with a branch large enough, and slung low enough, to invite you to lie on its mossy arm. While you lie there, looking up through the dappled light, you will notice a world of life also sheltered by these friendly trees: clouds of insects zip and zag in and out of the shade, lichens cling and drape all around, and there are so very many birds!

To Know Them is to Love Them

The coast live oak species (Quercus agrifolia) is one of several live oaks that co-occur in our area. Live oaks are called that because they keep their leaves year-round: these are evergreen oaks. The telltale sign of coast live oak is on the underside of its leaf, where the side veins meet the midvein: there, find tufts of hairs ‘hairy armpits’ – no other oak has those. The oak that is most easily confused with coast live oak is the much rarer Shreve oak, which has dark furrowed bark and stands much more upright and has deeper green more persistent leaves. Canyon live oak has golden fuzz covering the undersides of its new leaves. Coast live oak is the only oak with that characteristic smooth, white bark in large smooth plates separated by dark cracks that aren’t very organized. Learning to identify these three live oak trees is a good and doable challenge for everyone living around here.

Planet Ord’s Oaks

It is not hard to find coast live oak woodlands, but there are several kinds, each with its own characteristics and place. I find the most enchanting stands of coast live oaks to be behind Marina and Seaside at the Fort Ord National Monument. There, ancient rolling dunes are covered with thousands of acres of coast live oak woodland with miles of easily accessed trails. Fort Ord’s coast live oak forests are nice to visit this time of year, soon after or during a rainstorm. Dripping water falling through live oaks is particularly percussive, as drops hit the waxy tough leaves on the trees fall to the big drifts of dead crunchy leaves below. The coast live oaks at Fort Ord are relatively short and almost always have many trunks- 3 to 6 normally, sometimes more. Right about now, treefrogs are living up to their name, calling to each other with their odd croaking squinchy noise from up in the canopies of oaks. The forests there are particularly densely festooned by long draping lacy lichens.

Oaks Just North of Ord

North of there, and much less accessible to the public, similarly old sandy soils support coast live oak woodland in the hills around the Elkhorn Slough and in the foothills north of Watsonville. The Elkhorn hills aka “Prunedale Hills” have some remaining coast live oak forests where agriculture hasn’t taken them out, and the Elkhorn Slough Reserve is a great place to walk around to experience those. More north still but mostly inaccessible to the public, in the area between the Freedom Boulevard and Buena Vista exits off Highway One, there’s something called “San Andreas Oak Woodland.” Both of these types of coast live oak woodlands are taller than Fort Ord’s, though the presence of multiple trunks, a sign of previous fire, is also common.

The Majestic Oaks of Santa Cruz

Closer to Santa Cruz, in many public parks you can enjoy that relatively narrow band of majestic coast live oaks ringing most every large meadow. Sometimes, these oaks grow right out of the grasslands, so you can walk right up to their trunks without braving brambles or poison oak.

In this photo, Sylvie Childress is enjoying lounging on a large coast live oak limb. Look at all those ephiphytes!

Sadly, long gone are the once magnificent coast live oak groves in the flood plains of the San Lorenzo River and many of the larger North Coast streams. But you might still encounter a coast live oaks blanketing the bottoms of drainages, mainly in thick, upright and impenetrable thickets wound through with tall poison oak.

Roosting Birds in Fall Oaks

Like coral reefs, coast live oaks attract a vast array of other life that unfolds before you the more you keep looking. As an example, I visit a couple particularly dense teenager coast live oaks at dusk to watch a particular wildlife drama unfold. These trees are only about 20’ around, but with canopies so dense you can’t see into them, even from underneath. Each evening, golden crowned sparrows flap noisily into these trees coming solo or in twos and threes. Forty birds later, this gets quite raucous – apparently there is a pecking order for who gets to sit where through the night. Sometimes, a bird decides to go to some other roost, popping into sight again and jetting off somewhere. The sparrows come early as the sun is setting, hanging out in the middle of the tree canopy. While the last sparrows are straggling in, right after sunset, quail whir into the top of the tree, settling into the upper part of the canopy. Now the squeaky chips of the sparrows are joined by the lower chucks of fussy quail. There’s a bunch of fluttering wings bashing about in the leaves and against one another, but eventually everything calms down then goes altogether quiet just as it is getting dark. This repeats every night, same trees, same drama. The night shelter of dense oaks is only one of the many services of coast live oaks…they also make acorns!

Harvesting Acorns

Jays and acorn woodpeckers are harvesting the last of the acorn crop in the next couple of weeks. I have been watching a family of scrub jays carrying around acorns far from the nearest tree. A bird can only carry one acorn at a time, and it looks a bit silly with it…and sounds even sillier when it tries to call with its mouth full (which they do). Holding one of these oak nuts, a jay tilts its head back and forth, jumping around the ground memorizing the coordinates before it pushes it into the soil. I am careful to remain hidden watching this; if a jay sees me watching, it will shriek, dig up the acorn and disappear with it…headed to a more secret location. They are very wary of potential acorn thieves. I recall research suggesting that jays can bury hundreds of acorns a day, and they recall the location of 80% of them. Acorn woodpeckers also guard their acorns, but they do so communally. It takes a tribe to guard the cache, which they do in ‘granaries’ – often several adjacent trees that have thousands of holes pecked out that are just the right size to store acorns.

The Coming Wind

One wonders how the giant crowns and sprawling branches of coast live oaks fare in the wind. With global warming, we expect more frequent and more severe windstorms, and the windstorms of the last several years have knocked down some very old coast live oaks across the North Coast. They topple sideways and pull up a huge amount of the mudstone substrate, holding onto their root wads, which stand at least 10’ tall, full of jumbled rock and debris. Those wide roots provided for stability for more than a hundred years. May they keep the big trees upright for many more! I hope that this winter’s coming winds are not too harsh…

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