408 867-0143 | Since 1973 | ISA Certified Arborist
Saratoga Tree Service

General Report on California Oak Tree


In California, there are just a few native species of oak tree. Of these, are Quercus agrifolia (Coast Live Oak) Quercus lobata (Valley Oak) and the Quercus kellogii (Black Oak). There is also the Tan Oak which is not a true Oak.


Contrary to popular belief, the Live Oak is fairly fast growing and does not live as long as most people believe. I sometimes get comments from clients about their five hundred year old trees and I’m sure they are disappointed to find out differently. There are a few I have seen in this area that are approaching two hundred years of age, but most of the mature Live Oaks are between sixty and eighty years old. The Valley Oak is another native to this area and they can reach ages of two to three hundred years. One of the biggest problems with our old mature trees is the encroachment of buildings, roads and other man made compromises to a root system. Some of the most magnificent trees, now have buildings on their roots. The impact from people shortens the life span of these old trees substantially. Sadly, most of the old trees will die off and the new trees will not live near as long due to the limited space now available for undisturbed growth.


Another big problem to most of these old trees is from the past tree trimming mistakes. Most old pruning cuts were done wrong.  Most old time trimmers used spurs to climb the trees which caused damage. Many trees in the past were topped causing long term decline and decay. Most of the old heritage trees are declining due to the past tree work.


Modern tree procedures have changed dramatically for the companies who are willing to learn.  Sadly, a large number of modern day tree workers don’t care or won’t change. To this day, I still see trees topped and pruned in ways that will lead to an eventual decline.


Many species of trees are real survivors and will endure a whole host of abuse.  As the trees get older, the abuse catches up with them and the trees start to either fail or decline.  Many of the oaks are survivors as well.  I have seen trees that should have died years ago, but are still hanging in there. Sometimes an old oak will be completely hollow but the active growing tissue is just under the bark. The upper canopy will look great but the unknown weaknesses are often a hazard. Hazardous trees don’t linger long in peoples yards and the hazard level often precipitates a removal of a grand old specimen.


There is much talk these days of the “Sudden Oak Death” or SOD. This is a problem that is huge in California and is spreading into Oregon as well. The disease is a variety of Phytopthera that causes a weeping in the trunk.  There is more than one type of Phytopthera and some have similar symptoms. The Live Oaks are susceptible but to date are not as much of a problem, (in our area) as the Tan Oaks. The Tan Oaks have the biggest problem with this disease and they are dying by the millions. Every year, this problem is compounded and there is no relief in sight. The majority of Tan Oaks are living in the forested areas in the Santa Cruz Mountains. I do not see many Live Oaks yet infected with the Sudden Oak Death problem but in other parts of the state, Live Oaks and Black Oaks are dying in great numbers.




Like a tree, this site is growing. Check back often to see how we are evolving.