A tough city for trees
Life for trees on San Francisco streets isn't easy--they compete with ozone, exhaust fumes, cigarette butts, trash, urine and feces, soil compaction, drought stress, wind, tiny tree wells, overhead wires, fog, months without rain, and always too much concrete. Dying branches, diseased foliage, early leaf drop, or stumps leftover from cars running into or "dooring" trees are routine.
No water in medians
Trees in medians face an even greater challenge, because they are effectively stranded in the middle of the street. Some medians (Dolores for example) get additional water--but most don't.
Trees on San Jose/Guerrereo--unlike most city streest--are selected, planted, and maintained by DPW. Maintenance is done according to a schedule--or by calling 28-CLEAN in an emergency.
Street trees may not be planted within:
Standard trees for sidewalks
Right now, the only trees allowed on San Jose/Guerrero sidewalks are the tristania laurina or the tristania conferta--selected by DPW for consistency, ease of maintenance, size and hardiness.
Trees in the median: 2005
There is no standard for trees in the medians, and the existing 4-foot medians pose the toughest possible environment for trees. However we're working with DPW and Guerrero Street Gardens on a pilot project to "green" the existing medians.
Read Michael Sullivan's book!
For a wonderful book on the trees of San Francisco, try Michael J. Sullivan's The Trees of San Francisco, Pomegranate Press.