If you were asked what trees grow in the hills surrounding Scotts Valley, you’d most likely – and correctly – answer with the names of some of our native conifers such as the Coast Redwoods, Douglas fir, and our own special sandhills species of Ponderosa Pine.
If you looked around again though, you’d begin to notice how many oaks trees occur in and around the town. By far the most prolific oak species you see around Scotts Valley is the Coast Live Oak, Quercus agrifolia.
Coast Live Oak is an evergreen oak found from Mendocino County into Baja California. Its leaves are spinose (having spines), especially on younger trees and lower branches to discourage predation. Leaves on the underside of the tree’s canopy tend to be larger and thinner with only one layer of photosynthetic cells to capture the sunlight; whereas outer leaves are smaller and thicker with three layers of photosynthetic cells – and a concave shape to distribute the sun’s rays in the heat of summer. Like most oaks, it has an obligate relationship with mycorrhizal fungi, which provide critical moisture and nutrients
If you are fortunate enough to have Coast Live Oaks surrounding your house you will know that this privilege is a mixed blessing as the oaks are constantly dropping their leaves - no sooner do you sweep the deck than it’s ready to be swept again! However, it’s worth the work, because living beneath these great oaks also allows you to enjoy a parade of creatures - including wild turkeys, gray squirrels, band-tailed pigeons, native wood rats, Steller’s jays and acorn woodpeckers - who depend upon them for food and shelter.
Scotts Valley boasts some large Coast Live Oak specimens: a particularly beautiful tree can be found here in front of the Recreation Department at Skypark; the Glenwood Preserve boasts many large groves; and on the hillside to the north of the former Polo Barn is a lone oak we can only hope is spared by the developers who dismantled the Polo Barn.
Sadly one of the town’s largest Coast Live Oaks to the north of City Hall was cut down last year due to its shedding branches. Ironically the tree could well have lived another 200 years – there is an old saying about Coast Live Oaks that they “live for 200 years and die for 200 years.” It’s important if you have a Coast Live Oak in your yard, that you do not water it within its drip line as this can increase the likelihood of rot and infection by soil-borne pathogens such as sudden oak death.
Many animals depend upon Coast Live Oaks, the dominant tree of the coast live oak woodland habitat, for food and shelter. The California oak moth caterpillar lives solely on the leaves of the tree. Every eight to ten years the caterpillars will emerge in sufficient numbers to denude the oaks – which recover, sending out new leaves after the infestation. It’s thought that this may be a mutually beneficial relationship, the oaks receiving fertilizer and the caterpillars’ sustenance.
Acorn woodpeckers are also dependent upon Coast Live Oaks; these are unique birds considered to have social structures as complex as those of humans. A breeding pair will create a nesting cavity in a dead tree in which a group of adults participate in nesting activities. Breeding groups range from monogamous pairs to breeding collectives of three females, seven males and up to 10 nonbreeding helpers.
Acorn woodpeckers create granaries called "acorn trees" by drilling holes in dead trees, dead branches, telephone poles, and wooden buildings. Acorns are then collected and stored in the drilled holes. As the acorns dry out, they are moved to smaller holes. Because granary trees are so important to the acorn woodpeckers’ survival, it is sometimes recommended that when a conifer dies, twenty or thirty feet of it be left in place to act as a habitat tree.
Coast live oak acorns were used by as many as twelve Native American cultures as a staple food source. Later settlers used the wood for charcoal and for shipbuilding; but the greatest negative impact upon oak woodlands was their clearing for towns such as San Diego and San Francisco.
Scotts Valley is fortunate in having a healthy urban population of relatively young Coast Live Oaks – which given time – will grow to be as large as the magnificent specimens that graced the golden hills of California in bygone days.
