Mount Sutro Forest has approximately 45,000 trees in the 61 acres belonging to UCSF, and designated as an open space reserve. This dense forest, with an estimated 740 trees per acre, a sub-canopy of acacia, an understory of blackberry and nearly a hundred other plant species, is functionally a cloud forest. All summer long, it gets its moisture from the fog, and the dense greenery holds it in. Where it isn’t disturbed, it’s a lush beautiful forest, providing habitat for birds and animals, and a wonderful sense of seclusion from urban sounds and sights.
THE TREE REMOVAL PLAN
UCSF now has published a Draft Environmental Impact Report (DEIR) on a project to remove over 90% of the trees on three-quarters of the area. Only 15 acres – on the steep western edge of the forest – will remain as they are. Tree-felling could start as early as Fall 2014
2013. [Note: Owing to the large number of comments on the DEIR, which UCSF must respond to, this has been postponed by a year to 2014 after the nesting season ends around mid-August.]
[Edited to Add:
Here is the PDF of the DEIR. Mount_Sutro_EIR_1-16-13_with_Appendices
Comments were due on March 4th, but because of the length and complexity of the document, neighbors asked for, and got, an extension. Comments are now due before March 19, 2013.]
On most of the forest (44 acres), UCSF plans to cut down trees to achieve a spacing of 30 feet between trees – the width of a small road – and mow down nearly all the understory habitat. On another 2 acres, they will space the trees 60 feet apart.
The stumps of the trees will be covered in black plastic, or else poisoned with Garlon to prevent re-sprouting. Eventually, this will kill the roots, which will start to decay. We’ll address some of these issues in more detail in later posts.
Right now, we want to talk about the number of trees that will be felled. A spacing of 30 feet between trees gives about 50-60 trees per acre. A spacing of 60 feet gives 12-15 trees per acre.
(The easiest way to think about it is that each tree occupies a 30 x 30 foot space, or 900 sq ft. An acre is 43,560 sq ft, so this would give 48.4 trees to an acre. The DEIR calculates it as 61 trees per acre, assuming each tree occupies a circle that’s 30 feet in diameter, 707 sq ft. But there’s no way to arrange circles without wasted spaces between them, so this doesn’t exactly work.)
So on 44 acres, they will retain maybe 50 trees per acre (or maybe fewer). On two more acres with a 60-ft spacing, they will retain 12-15 trees per acre. All the rest will be cut down. Even using the DEIR’s overly optimistic calculation, they will be felling some 31,000 trees. Our calculations are closer to 32,000. Either way, it’s a huge number.
That means that in the 46 acres where UCSF will be felling trees, they will remove more than 90% of the standing trees.
The DEIR says that they will start by cutting down trees that are dead or dying. Aside from their value as habitat (some birds like woodpeckers depend on them), there are not all that many of them in Sutro Forest, which despite everything that has been claimed to to opposite, is a thriving forest. Next in line will be trees with diameters under 12 inches, or roughly 3 feet around – as thick as an adult’s waist. Then they’ll start on the larger trees. Since it’s going to be 90% of the trees, we expect thousands of large trees to be removed.
IT GETS WORSE
However, this is not all. We expect further tree losses for four reasons:
- Wind throw. Since these trees have grown up in a dense forest where they shelter each other, removing 90% of the trees exposes the remaining 10% to winds to which they’re not adapted. This can be expected to knock down a significant number of the trees not felled. Since the Plan only calls for monitoring the trees and felling any that seem vulnerable to wind-throw, it’s unlikely any vulnerable trees will be saved.
- Physical damage. Damage done to the remaining trees in the process of removing the ones they intend to fell. With such large-scale felling, damage to the other trees is inevitable, from machinery, erosion, and falling timbers.
- Pesticide damage. This forest has an intertwined, intergrafted root system. When pesticides are used to prevent resprouting on tree-stumps and cut shrubs and ivy, it is quite possible for it to enter the root system and damage remaining trees.
- Loss of support. Compounding the effects of the wind-throw, the remaining trees will suffer from a lack of support as the root network dies with 90% of the trees being removed. This could destabilize them, and make them more likely to fail.
What remains will be a seriously weakened forest with a greater risk of failure and tree-loss, not the healthier forest that the DEIR claims. It is likely that the long-term impact of the Project will be the elimination of the forest altogether, and instead will be something like Tank Hill or Twin Peaks plus a few trees.
IMPLEMENTING THIS PLAN
The project is to be implemented in two phases. In the first phase, trees will be felled and the understory removed in four “demonstration areas” totaling 7.5 acres. They are shown on the map below in yellow, as areas #1-#4. (One of these, #4 “East Bowl”, is the two-acre area slated to have only 12-15 trees per acre.
One area (#5 on the map) is supposed to be a “hands off” area to demonstrate the untouched forest. However, a trail has already been punched through it in November 2011, even before the DEIR had been published.
During this phase, they would experiment with the 3 acres on the South Ridge, just above the Forest Knolls neighborhood. On 1 acre, they would use tarping to prevent regrowth of felled trees; on 1 acre, they would use pesticides, particularly Garlon; and 1 acre they would trim off sprouts by hand. They could also use pesticides on the understory “consistent with city standards” – presumably those of the Natural Areas Program (See article on NAP’s Pesticide Use.)
In the second year, the plan would be extended to the remaining forest, with the proviso that not more than a quarter of the forest would be “thinned” at “any given time.”
[Edited to Add the ways to help, below]
HOW YOU CAN HELP
You can help by writing to the Regents; commenting on the EIR in writing and at the Public Hearing on Feb 25, 2013; and signing the petition to save the forest.
The details are in our next article, HERE.
And most of all, you can help by getting the word out! Most people – even those who hike in the forest and love it don’t know what’s planned for Mount Sutro Forest.