Oakland, California's Trees

In my son’s neighborhood in Oakland, CA. there is an old home that was abandoned and unkempt. As it is being remodeled, the contractor cut down some trees, and neighbors were concerned whether there was a permit to cut down the trees. I was confused because the trees were on private property. It was explained to me that cutting trees required permits, period. So I did some research on how this came to be and learned a lot about Oakland’s trees!

Conquistadors from New Spain claimed Oakland and other lands in the East Bay area of California. The Spanish crown deeded the East Bay area to Luis María Peralta who called the area Encinal. This was translated more loosely as "Oakland" in the subsequent naming of the town. The name describes the magnificent groves of evergreen oaks which cover the city of Oakland. There are four types of trees most common to the area. Live oak, redwood, eucalyptus, and Monterey pine are the four main trees in this area.

The trees known as California Live Oaks are the dominant overstory plant of the coast live oak woodland habitat. The coast live oak (Quercus agrifolia) is evergreen with spiny leaves. It is one of the two most common oak trees in the East Bay area and the tree that gave Oakland its name. The other is the canyon live oak (Quercus chrysolepis). It is also evergreen but the underside of the leaves is pale blue. Unlike many other oak species, coastal oaks retain their leaves year-round, or at least throughout most of the year. This adaptation allows them to photosynthesize and grow even during dry periods. Coastal oaks can range in size from shrubby forms to massive trees reaching over 80 feet tall. Their crowns are typically broad and rounded, providing ample shade. Coastal oaks play a crucial role in the coastal ecosystem. They provide food and shelter for wildlife, help prevent soil erosion, and contribute to air quality.

The old-growth redwoods played a major role in Oakland's early economic history. A large redwood forest spanned the Oakland hills, with some trees rising to 300 feet. Many of the redwoods were from 12 to 20 feet in diameter, and one was measured at 32 feet. The forest was so prominent that ships entering San Francisco Bay would use it as a navigational landmark. However, increasing numbers of adventurers arrived in the 1840s and began logging without regard to the Peralta family’s rights. The start of the Gold Rush brought a brief lull to logging as loggers headed to the Sierras in search of gold. But the ensuing building boom increased lumber prices ten- to twenty-fold, and logging soon resumed. For some, cutting trees could more reliably produce a fortune than hunting for ever more elusive gold. The Peraltas lost control of the forest. In 1850 the first steam-powered sawmill was erected within the forest, and unfortunately, by 1860 the entire forest of redwoods had been obliterated.

The current East Bay Redwoods are largely in a semi-natural state today. The redwoods seen in the forest today are second or third-growth specimens which are considerably smaller than the former old-growth forest that existed in the canyons. Nestled at the roots of the new-growth redwoods are the hollowed stumps of their once-mammoth forbearers. The original redwoods have sprouted “fairy ring” clones of 10 to 20 second-generation redwoods around the perimeter of the old stumps. This resurrection is an unusual phenomenon for conifer trees, according to California Department of Fish and Game senior vegetation ecologist Todd Keeler-Wolf, as most cone-bearing trees do not re-sprout.

The Oakland redwood forest that has grown in the intervening century and a half is persisting in some of the driest redwood habitats. Redwoods need plenty of moisture for survival, and because the trees in Oakland are not getting enough moisture from rain, the redwoods are instead quenching their thirst with fog. In the summer, Pacific Ocean fogs sweep into the cool San Francisco Bay inland through the Golden Gate, while winter ground fogs known as “tule” fogs come from California’s Central Valley. The redwoods take in moisture from the fog through their leaves, and excess condensation drips down from their leaves.

Eucalyptus trees (genus Eucalyptus), are of the myrtle family (Myrtaceae), and are either an icon in California or a fire-prone scourge. Reaching heights of more than 100 feet, the main kind of eucalyptus you’re likely to find is Tasmanian blue gum, (eucalyptus globulus). They feature sickle-shaped leaves hanging from high branches, and deciduous bark that is forever peeling from their shaggy trunks. Australians were among the throngs flocking to the gold rush. In a place where wood was now in short supply, they brought envelopes of seeds on boats coming to California. Eucalyptus (mainly blue gum) was planted to serve as windbreaks as well as firewood. Blue gum eucalyptus is now classified as a “moderate” invasive.

Monterey Pine (Pinus radiata) is a coniferous evergreen tree growing to 50 - 100 ft in height in the wild, but up to 200 ft in cultivation. It has upward-pointing branches and a rounded top. The needles are bright green, in clusters of three, slender, up to 3 inches long and have a blunt tip. The cones are 3 to 6.5 inches long, brown, egg-shaped, and usually set asymmetrically on a branch, attached at an oblique angle. The bark is fissured and dark grey to brown. Monterey Pine in its native form is a rare and endangered tree; it is twisted, knotty, and full of sap/resin and not suitable for lumber, however in its cultivated form it is a versatile, fast-growing, medium-density softwood, suitable for a wide range of uses and valued for rapid growth, as well as desirable lumber and pulp qualities. The three remaining wild stands of var. radiata (Monterey pine proper) are infected and under threat of extirpation from pine pitch canker caused by Fusarium circinatum, a fungal disease native to the southeast United States. When trees begin to die of the disease, they attract bark beetles which provide a pathway for infection of other trees.

Currently, Oakland's urban forest includes over 200,000 trees. The city of Oakland has developed a method to preserve its trees and its urban canopy. The City of Oakland’s Protected Trees Ordinance requires a permit for the removal of any tree on public or private property. The first protected tree ordinance was passed in 1932. There are two types of Tree Removal Permits: development-related (a project requiring design review or a zoning, building, grading, or demolition permit) and non-development (when a property owner wishes to remove a tree on their property for any other reason). There are also guidelines regarding what size tree may be cut without requiring a permit. A tree less than 4 inches in diameter may be cut.

One non-tree bit of trivia about Oakland: Rocky Road ice cream was created there in 1929!