Undermined by rains this winter, a huge oak tree crashed through the roof, killing a Bay area woman. Except for their beauty, trees are generally not of prime concern for most home buyers or owners; however, noticing the type, size and condition of trees on your lot is vitally important and may even save your life.
Monterey pines and eucalyptus are two species often cited by arborists as dangerous because of their potential for falling and fueling fires. Since they constantly produce litter in the form of leaves or needles, cones, branches and sap, all highly flammable, they are referred to as "dirty" trees.
The Monterey pine is said to have existed at least a million years ago. In the East Bay, they have a lifespan of 60 to 80 years and can reach heights from 50 to over 100 feet.
Older Monterey pines are especially susceptible to serious infestation and disease; among those are turpentine bark beetle and pitch canker fungus. In 2003, a 100-foot Monterey pine in San Francisco's Golden Gate Park was discovered to be toppling. Less than an hour later, it gave way and snapped a nearby, mature redwood in half. Fortunately, no one was hurt.
Although they are beautiful and can help any landscape become more appealing, Monterey pines should be viewed with a cautionary eye. Even if only young, small ones are on your property, it might make sense to have a competent tree specialist take a look and provide you with a professional opinion of their present and future impact. This will give you knowledge about safety and other issues, such as view obstruction.
Rather than removing the tree, pruning may be an option. Trimming back, however, could create its own problems. I was recently told by an experienced arborist that pruning large Monterey pines requires extreme care and specific experience. An imprecise “haircut” could actually cause the tree to die, and, eventually, fall.
Eucalyptus trees were brought into California from Australia well over 100 years ago. These fast growers can live more than 100 years, but may fail in a much shorter time span.
It is an invasive tree, notorious for its combustible bark and leaves, with an oil that ignites quickly. Eucalyptus can grow to 120 feet or more, allowing for the rapid spread of “crown fires.” These are dangerous and difficult situations for firefighters, where the fire moves through treetops, irrespective of the fire below. Our Australian imports were a major contributor to the East Bay hills firestorm of 1991.
Eucalyptus have been called “widow makers,” because their unpredictable falling branches can severely injure or kill people near them. They also have a negative environmental effect by crowding out native species.
Another sad, but not well known, disadvantage of these trees is that many of our local birds, while foraging in eucalyptus, are killed by a tar-like substance which suffocates them. If their bills are not long enough, their nostrils (nares) can get clogged by the tar.
Local governments consider eucalyptus a weed, putting no restrictions on their removal. Unfortunately, they are difficult to eradicate because new growth sprouts from stumps. One tree can become two, then four, which explains why many of these volatile trees have reappeared in the fire area.
Depending on its size, condition, location and proximity to high power lines, the removal of a big tree by a reputable firm can cost from $2500 to more than $10,000. Before hiring anyone to cut down or prune a tree, make sure the company is licensed, insured and the person you are dealing with is a certified arborist. This will give you assurance about technical knowledge; it should also afford some protection in case of future liability issues with neighbors.
Check with the city or county to determine if there is a hazardous tree ordinance and confirm that cutting down a specific species does not conflict with local code. For Oakland, refer to . It defines hazardous tree conditions and addresses ways of mitigating them.
Trees are some of nature's most lovely, living sculpture. Nonetheless, some, such as Monterey pines and eucalyptus, can be dangerous and destructive. Increasing your awareness could protect your property and prevent serious injury, or worse, to you, your family and neighbors.
