Why UC Berkeley’s Prof. McBride Wants to Save Mt Davidson
August 1, 2013 5 Comments
We’re very concerned about the SF Rec & Park plans, under the Natural Areas Program, to fell 1600 trees on Mount Davidson.
We were pleased to learn of a letter Professor Joe McBride wrote to Phil Ginsburg, General Manager of SF Rec & Parks after assessing the situation on Mount Davidson. He presented a strong case for leaving the forest alone.
(Professor McBride is Professor of Environmental Science in the College of Natural Resources at University of California, Berkeley. He is the author of many studies of urban forests, several of which he cited in his letter. He is particularly expert on the failure of trees caused by extreme wind conditions.)
Mount Davidson falls under the Natural Areas Program (NAP) of the SF Rec & Parks Department. Some years ago, NAP issued its Significant Natural Resource Area Management Plan (SNRAMP, “Sin-Ramp”). The NAP – and the Sin-Ramp – cover 32 parks. In total, the Sin-Ramp looks to cut down 18,500 trees; close ten miles of trails, restrict access and remove up to 80% of dog-play areas, and use growing amounts of toxic pesticides.
The Sin-Ramp is currently on hold. A Draft Environmental Impact Report (DEIR) has been prepared. The City’s planning department, which is managing the process, received a large number of comments on the DEIR, and they are employing a consultant to respond to them. Once they respond, the DEIR will need to be certified, and then implementation of the Sin-Ramp is possible. However, some work is already being done as parts of other projects such as trails or construction.
Mt Davidson stands to lose more trees than any other NAP park (though UCSF’s Mt Sutro, also a dense historic eucalyptus forest, is threatened with even more tree removal).
TEN KEY POINTS
Professor McBride’s assessment differed sharply from what we’ve been hearing from supporters of the tree-cutting. Those talked about invasive and overcrowded trees strangled with ivy, a lack of biodiversity, and imminent forest destruction. By contrast, here are the main points Professor McBride made.
1) Historic importance and Visual Value. The eucalyptus forest on Mount Davidson was planted under the direction of Adolph Sutro, philanthropist and former Mayor of San Francisco. The hilltops covered in eucalyptus trees and Monterey cypress are a distinctive feature of San Francisco’s landscape. They’re been there for a hundred years and are an important historical heritage.
2) Eucalyptus is not invasive. The Plan frequently refers to these trees as “invasive.” Prof. McBride’s studies indicate that eucalyptus does not invade adjacent grasslands; and this is also obviously true on Mt Davidson, where a stable boundary exists between the forested and unforested areas.
3) Eucalyptus groves are biodiverse. Eucalyptus groves are richer habitats for vertebrates than either redwood or Monterey cypress/pine forest; and are similar to dry chaparral and grasslands.
4) More Pesticides. Removing the number of trees shown in the Plan will expose the ground to more light than existing understory plants can tolerate. In the disturbed ground and increase light conditions, existing exotic species will proliferate and will have to be controlled by using even more pesticides.
5) Increased wind-throw and breakage of remaining trees. Removing trees in this windy area will affect the trees that remain, which are not wind-hardened. More trees will go down.
6) Reducing a wind-break. This is a very windy part of the city, with winds blowing in straight from the ocean. Walking recreationally on Mt Davidson will be a less pleasant experience.
7) Reduction in habitat. The Plan’s assumption that birds will quickly adjust to removal of 1600 trees is unfounded. Many birds return to the same nesting site each year. Cutting down large numbers of trees displaces these birds, and also causes a great deal of disturbance. Bird protection plans usually call for a 300-foot radius of protected area around a nest.
9) Ivy is not a problem. English and Algerian ivy climbs up the trees, but cannot smother the trees by growing into the canopy. The only snags covered in ivy were those that had been girdled.
10) Regeneration is a 22nd Century issue. It’s been argued that the understory of ivy, Cape ivy, and Himalayan blackberry may restrict the establishment of eucalyptus seedlings. If so – and it’s possible – this is a problem for the next century. The forest, though 100 years old, is comparatively young. This could be revisited in another 100 years or so. Meanwhile, the understory provides an excellent food source and cover for wildlife.
Here’s the conclusion to Prof McBride’s letter:
I conclude that the Significant Natural Resource Areas Management Plan for the removal and thinning of different portions of the eucalyptus plantation on Mt. Davidson is not justified. The plantation serves an important role in the history and visual characteristics of the city. Trees and the existing understory provide habitat for wildlife and wind protection for walkers. The justifications for the management prescriptions have not been properly developed. Furthermore, the cost of removal of the trees seems unjustified in view of other priorities in the San Francisco budget.