Tuesday, November 9, 2010

200 Trees for an Urban Forest on Masonic

Panhandle trees looking east from Masonic Avenue

A new urban forest along Masonic with as many trees as the east-end Panhandle

Image: SF Planning Department, SF Municipal Transportation Agency

The Masonic corridor will become a linear forest with 200 additional street trees if the San Francisco Municipal Transportation Agency (SFMTA) proceeds with the Boulevard design proposal. What do 200 trees look like? Imagine the east end of Panhandle Park, starting at Masonic Avenue and continuing east along the north or south trail. Strollers will be in the midst of the 100-year-old Eucalyptus trees, the redwoods, and cypress as they walk toward Central Avenue, then to Lyon Street, and finally to Baker Street at the McKinley Monument. How many trees stand in that large and lush green space three blocks long and a block wide? About 200. Consider transplanting that urban forest to a new landscaped median for the eight Masonic blocks between Fell and Geary. Step back and appreciate how a loud speedway gets transformed into a smooth travelling roadway that is greener, calmer and an antidote to air and noise pollution.

Of course the new Masonic median will not feature enormous 100 year old Eucalyptus trees of the kind that tower in the Panhandle. Instead, young trees of various types will define this new urban forest. Shrubs and grasses, pebbles and boulders will contribute to the mix. The street trees and the landscaping alone -- just one element of the Boulevard design -- will transform Masonic, much as the re-designed Divisadero now looks greener, more attractive and more to scale as a neighborhood thoroughfare.

Street trees function as more than a green softening of the urban environment. A less prosaic notion touted by green advocates is to think of them as "carbon sinks," living organisms that drain carbon dioxide from the air. One tree might remove a ton of CO2 from the atmosphere every year, depending on the size and age of the tree, the amount of pollution, and the length of the leafy season. But even a 1/2 ton removal is impressive.

Critics may argue that a re-designed Masonic will result in more traffic congestion with more frequent stop-and-go vehicles spewing more pollution than while speeding along, but the SFMTA has studied that possibility and thinks that won't be the case. BIKE NOPA will look at the concerns about congestion in an upcoming article. For now, 200 more trees -- equivalent to that half of the Panhandle's forest -- makes a persuasive argument for a better Masonic.

Check here for more stories in the A Better Masonic series.


  1. Moving traffic quickly does not necessarily mean moving vehicles faster. By removing obstacles - such as having dedicated left-turn lanes, or doing away with sudden reduction of lanes - will allow traffic to move more smoothly and faster without increasing vehicle speed. It will also reduce frustration and road rage, which are the main causes of speeding and dangerous driving.

  2. It's not enough just to plant trees: they need appropriate soil conditions. Trees on the panhandle have been able to thrive because their conditions are quite different from those beneath a city street. Pavement requires very tightly compacted soil, and that can kill roots.

    I'm all in favor of more trees, but I would really like to see some assurance from the city that they'll provide enough root space to keep them alive for more than just a few years.

  3. Agreed, and that situation will be confirmed before any planting is undertaken. Another consideration is the existing location of sewer pipes under Masonic. There needs to be enough planting depth above the pipes for trees of substantial size o grow without causing problems to the pipes.But there are obviously various types of trees for different conditions.