Why Are There So Few Trees in South San Francisco?

Why are there so few trees in South San Francisco?

This was the very first question a client asked me after hearing I'd become a member of the Beautification Committee.

The next question was, why can't this town look more like Burlingame?

I had moved back to South City in 2004 after going away to school at Sacramento State and living for a short while in San Bruno.  I'd bought my first house, and I wanted to get involved in my hometown. 

As a landscape contractor and designer, I figured the Beautification Committee would be a great place to start. As a new committee member I was not quite sure how to respond to these questions.  But five years later, I can now answer.

The lack of trees has to do with the strong winds that blow through the city.  Not many trees can handle wind, especially all through the year.  Most deciduous trees are fine with winter winds since they have lost their leaves by the time the winds arrive.  But in this town we get wind all year, so by summer trees are showing signs of wind damage.  This can include loss of leaves, misshapen branches and complete branch dieback. 

Historically, the few trees that South City had were willows, alders and cottonwoods that grew along the many creeks and marshy areas.  Others, like oaks, buckeyes and toyons, grew in the coastal scrub where they tended to stay more the size of large shrubs.  Only when a tree was lucky enough to start growing in a wind-protected site did it have the ability to grow larger.

The unfavorable comparison to Burlingame has to do with people's perceptions of trees and their value to the community.  When I suggest to a client the option of having a tree planted in their yard, I sometimes get resistance.  The reasons vary but usually include concerns about how messy trees can be, maintenance costs or how they will create too much shade. 

These are valid reasons, but many times I feel it comes from the client having had a bad experience in the past with trees.  Many of the first trees planted in town were put in to create windbreaks.  These varieties include Monterey cypress, Monterey pine, blue gum and black wood acacia—big messy trees that can be expensive to maintain and create a dark shadow over a property. 

For those reasons, as well as disease, age and safety issues, many of these types of trees have been slowly disappearing from the city.  Since many houses are located on smaller lots, a big tree is not always the best option. 

Another problem is the size of trees that are planted in the city today.  The most common size is a 15-gallon tree, which has a long narrow trunk and a 3- to 4-foot-wide crown.  These trees are used most often because their size tends to make them initially more attractive and less prone to vandalism. 

But a tree this size takes at least three stakes to keep upright and is much more likely to be hurt by the wind.  I usually recommend that my clients in high-wind areas think smaller on the size of the tree and use low multi-trunk types of trees.  This way, by the time the tree is tall enough to be affected by the wind, it has had time to establish a strong root system and adapt to the location.   

I personally like to use large shrubs that can be pruned up as they age, to give the effect of a multi-trunked tree without overwhelming the yard.  I have a big messy tree in my front yard that the original owner planted as a small seedling.  It probably didn't stand more than 3 feet tall when it was first planted, but it's about 30 feet tall now.  I think he was on to something.

Sean Garrone will be writing regularly about gardening and landscaping in South City.