West of Twin Peaks Central Council opposes Natural Areas Program, Part 2: Trees and Pesticides

This article continues the West of Twin Peaks Central Council (WTPCC) letter opposing the Natural Areas Program (NAP). Emphasis has been added.

Click here for the beginning of the letter.

Click here for Part 3, Park Access and Habitat & Wildlife.


WTPCC opposes NAP plans to remove healthy trees simply because they are non-native or simply to allow more sunlight to reach newly planted, sun-loving natives on the forest floor. We fully support the removal of hazardous trees in our parks, but NAP’s plans go far beyond that.

We are concerned that the actual number of trees removed will be much higher than the 18,500 listed. NAP does not include any trees or saplings less than 15 feet tall in its count of trees to be removed, yet the SNRAMP makes clear that these “smaller” trees or saplings will be cut down along with the taller ones. A 2007 US Forest Service report noted that just over half (51.4%) of the trees in San Francisco are less than six inches in diameter at breast height. This diameter corresponds to a tree less than 15 feet in height. The removal of these smaller trees will significantly amplify the impact of the removal of the taller trees on aesthetics, erosion, and windthrow in natural areas, yet the Draft NAP DEIR did not consider these additional impacts.

WTPCC is concerned that claims in the Draft DEIR that trees cut down will be replaced on a one-to-one basis by native trees are misleading. The SNRAMP makes no promise to replace trees. In particular, the SNRAMP specifically states that the 15,000+ trees removed at Sharp Park will not be replaced since the natural area will be converted to coastal scrub. In addition, there were few native trees in San Francisco before the Europeans settled the area; the climate was too harsh. Native trees do not grow well in the windy, foggy, sandy or rocky soils present in most natural areas. For example, about a decade ago, NAP planted 25 oak trees at Tank Hill to replace 25 trees cut down by NAP. Only 5 of the replacement oak are still alive, and only one of those has grown.

Our concerns about the 1,600 tree removals planned for Mt. Davidson in particular include:

  • Increased erosion from the loss of the trees
  • Increased water runoff during storms and the potential for damage to park neighbors’ property from the water or mudslides

These concerns were not adequately addressed in the DEIR.

WTPCC is also concerned that the DEIR does not adequately address impacts on carbon sequestration and global warming from NAP’s plans to cut down 18,500 trees. A 2007 US Forest Service survey of San Francisco’s urban forest notes that our trees store 196,000 tons of carbon, adding 5,200 tons of carbon to the storage each year. When a tree is cut down, it releases its stored carbon into the atmosphere (as carbon dioxide) as it decays. California State Law requires the state to reduce greenhouse gas emissions;

NAP’s plans seem to be at odds with this goal. In addition, grassland does not store as much carbon as forests of trees, and the DEIR does not adequately address the impacts on this of NAP’s plans to replace non-native trees with native grasses.


WTPCC opposes repeated applications of herbicides in natural areas to remove non-native plants. Applications of herbicides in NAP-managed areas have increased by 330% over the last four years (from a total of 26 applications in 2008 to 86 applications in 2011). Applications will continue to rise, since NAP plans to use repeated herbicide applications to kill the roots of the thousands of trees it plans to cut down. The Draft DEIR does not consider impacts from this increase in usage.

We are also concerned about inadequate and incorrect signage by NAP when it applies herbicides in natural areas. For example, a recent sign warned that herbicides would be applied “throughout” McLaren Park, with no more specific information on where other than “throughout.” People walking in the park had two options – continue to walk in the park and risk exposure to herbicides (since you can’t know from the sign exactly where in the park they were applied) or leave the park. This inadequate signage essentially closed access to large areas of McLaren Park for a period of time as people tried to avoid exposure.

WTPCC is also concerned that NAP applies herbicides incorrectly, causing needless exposure and risk to people, pets, and wildlife from unnecessary spraying. For example, in December 2011, NAP posted a sign that it planned to spray a mixture of glyphosate and imazapyr to eradicate cape ivy in Glen Canyon.

However, the California Invasive Plant Council website says spraying to destroy cape ivy must be done in the late spring, when the plant is “photosynthesizing actively but is past flowering, so the active ingredients [in the herbicide] move down with the sugars that are transported to underground storage organs.” The spraying should never have been done in December when it would not be effective. NAP essentially put people, pets, and wildlife at risk of exposure to the herbicide for no reason, and ensured they would have to reapply the same herbicides a second time in the late spring if they want to kill the cape ivy.

It is not enough to say that NAP herbicide applications are approved as part of the SF Integrated Pest Management Ordinance that governs herbicide use by city agencies and are therefore okay, as the Draft DEIR does. The DEIR should study the application records more closely. There are many cases where NAP usage violated IPM rules. For example, NAP applied imazapyr in 2008 and 2009, two years prior to its approval for use by SF IPM in 2011. NAP “sprayed” Garlon in years prior to 2011, even though SF IPM had approved its use only by “dabbing and injection.” NAP sprayed herbicides containing glyphosate near the water at Lake Merced, even though US Fish and Wildlife regulations ban the use of that herbicide (and many others) where there is red-legged frog habitat; Lake Merced is red-legged frog habitat.

(To be continued: Read HERE for Part 3, Park Access and Habitats & Wildlife.)

This entry was posted in "Natural" Areas Program, Applies Pesticides, Fells Trees and tagged , , , , , . Bookmark the permalink.

4 Responses to West of Twin Peaks Central Council opposes Natural Areas Program, Part 2: Trees and Pesticides

  1. Pingback: “Rethink Support for Natural Areas Program” – West of Twin Peaks Central Council letter Part 1 « San Francisco Forest Alliance

  2. LC says:

    Kudos to WTPCC for standing up for what’s right for San Francisco and its citizens, and NOT the supporters of chemical companies like Monsanto and Dow, who care for nothing except money, even if their products sicken or kill us all. Many of the native-only plant racist group are unwitting dupes of the chemical companies.

  3. Pingback: West of Twin Peaks Central Council opposes Natural Areas Program, Part 3: Park Access, Habitat & Wildlife « San Francisco Forest Alliance

  4. Pingback: West of Twin Peaks Central Council opposes Natural Areas Program, Part 4: Poor Public Process « San Francisco Forest Alliance

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