Message to UCSF: Do the math!!

We are reprinting, with permission, the following article from the Million Trees blog.


UCSF has sent an email to its neighbors about its plans for the Sutro forest in which they say, “Contrary to rumors being circulated, there is no plan to cut down 30,000 trees in the Mount Sutro Open Space Reserve, and it is unfortunate that this misinformation continues to spread.”

Our response is, Do the math!!

The Draft Environmental Impact Report (DEIR) claims that the thinned forest will have 62 trees per acre. (DEIR Appendix F) The DEIR arrives at this figure by assuming that each tree will occupy a circle with a radius of 15’. In fact, it is not possible to pack circles into another geometric space, whether it is a bigger circle, a rectangle or a square without wasting space. Therefore, this calculation arrives at a bogus answer which is larger than is physically possible.
We have calculated the number of trees remaining in the thinned forest based on the number of squares in an acre that are 30’ X 30’. Such calculations of tree density are found in books regarding arboriculture, which corroborates that we are using a standard calculation used by the timber industry and the DEIR is not. (1)


43560/900 = trees per acre if 30 feet apart (the proposed plan)


43560/3600 = trees per acre if 60 feet apart (the proposed plan)


Total number of trees existing now on 61 acres (according to UCSF)


46 acres X 740 trees/acre = Number of trees existing in project area


44 acres X 48 trees/acre = thinned forest with 30’ spacing


2 acres (Demo Area #4) X 12 trees/acre = thinned forest with 60’ spacing


Existing Trees – Thinned Forest = Trees Removed in Project Area


Trees Removed/Existing Trees in total forest = Percent of Trees Removed in Total Forest

If UCSF wishes to reduce the number of trees that will be removed by the proposed plan, it can do so by reducing the spacing between the trees or the number of acres to be “thinned.” All other numbers used to arrive at an estimated number of tree removals are straight-forward mathematical calculations based on the information provided by UCSF.

UCSF would be wise to read the DEIR for its project, which says, “Under full-implementation or worst-case implementation of management activities under the proposed project, approximately 60% of all existing trees, including large and small trees, could be removed.” UCSF reports that there are 45,000 trees in the Mount Sutro Reserve presently. Sixty-percent of 45,000 is 27,000 trees. We think UCSF’s estimate of tree removals is just a few thousand trees less than what is actually planned. What are we quibbling about?

Once again, we invite UCSF to revise its proposed project to reduce the number of trees that will be removed.

(1) Ecology and Silviculture of Eucalypt Forests, R.G. Florence, CSIRO, Australia

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3 Responses to Message to UCSF: Do the math!!

  1. dolan eargle says:

    I’m getting “UCSF says “this or that” but just WHO is UCSF? Names and addresses and if possible status within the University.

  2. Pingback: UCSF’s Mt Sutro DEIR: How Many Felled Trees – 30,000 or 22,000 or zero? | Save Mount Sutro Forest

  3. Pingback: Sutro Stewards: The Good, The Bad, and the… ??? | Save Mount Sutro Forest

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