Nowhere near the greenest city

San Francisco has a “green” reputation, but when it comes to “tree canopy coverage” — the percentage of our land area that’s covered by trees — we’re really far behind.  According to an analysis of aerial photos by the San Francisco Planning Department, only 13.7% of the city is covered by trees.

We don’t compare well with Chicago (18%), Austin (30%), or L.A. (20.6%).  In fact, among the 20 biggest cities in the U.S., only three cities have skimpier urban forests than we do (Phoenix, San Diego and El Paso).

sand covers the future Sunset neighborhood

The Sunset neighborhood, with one of Golden Gate Park’s irrigation windmills in the distance at right.

To be sure, we’ve come a LONG way since the days when we were half-covered with sand dunes.  For example, before trees could be planted in Golden Gate Park, engineers had to figure out how to tame the sand.  They started by planting barley, followed later by yellow lupin and then by sea bent grass, which requires little moisture and sends out strong, fibrous roots.  Only then were the shifting sands sufficiently stabilized that manure and top-soil could be added without risk of erosion by the wind.  Next came more plants, and finally trees.  Phew!

So it’s reasonably impressive that San Francisco has almost 700,000 trees, about 105,000 of which line our streets.  But our streets have space for as many as 100,000 more trees — space that’s currently empty and covered with concrete.  And as you may have heard us say by now, we’re not planting new trees fast enough to keep up with tree mortality.  The City’s urban forestry budget is pathetic, and FUF just doesn’t have the resources to do it all alone.

Once San Francisco achieves a 25% tree canopy coverage, we’ll be a truly green city in every way.  It’s not an impossible goal.  But to get there, we have a LOT more work to do.

About Dan Flanagan, Executive Director

Dan once lived in a treehouse -- really.