Why Seattle’s Green Factor is Green Washing

What is Green (Space) Factor and why is it Green Washing in Seattle?

“The Green Space Factor (GSF) is a planning policy tool that originated in Berlin and has been adopted and adapted in a number of other cities in Europe and North America to encourage urban greening. GSF schemes work by assigning a factor of between 0 and 1 for various surface cover types, with sealed surfaces given 0 and the most natural cover, 1. To calculate a GSF for a site, the factor for a particular surface cover is multiplied by its area. This is repeated for each surface cover type. The multiplied sums are added together and then divided by the overall site area to give an overall GSF score for a site of between 0 and 1. A planning authority can set a minimum target (typically 0.3, although this varies according to the type of development and class of land use). This can provide certainty to developers as to what is expected from new developments in terms of urban greening. It can also identify planning proposals with insufficient quantity and functionality of greening in order to encourage improvements to a proposal. It can also be useful in determining the scale and benefit of subsequent improvements to plans.”

Why Seattle’s GreenSpace is Green Washing?  They take land with trees on them and remove them to develop a lot.

“A GSF is usually applied to development proposals on previously developed land which has little or no existing natural surfaces. GSF schemes are not an alternative to planning policies that are intended to ensure the protection of a sufficient quantity of existing parks, natural habitats and other green open spaces, however GSF can be used as a tool to show how development may change a site or as a way of comparing proposals for a site.”*

Both quotes from Urban Greening Factor for London, Greater London Authority 7/24/2017

*The highlighting of the second paragraph is mine. Green factor is not meant to be a substitute for a requirement that trees removed from a site and not replaced on site must be replaced elsewhere, which is a policy the Seattle Urban Forestry Commission is on record supporting and what SMC 25.11.090 was intended to do.

Unfortunately for the last 17 years Seattle’s Building Department (currently called Seattle Department of Planning and Development)  has  not consistently enforced this provision or kept a record of where trees planted as a result of this provision might be or of their survival if they were planted. There does not seem to be a fee system to pay the city to replace any of the trees removed if developers can not replant on site which raises the question if the city has planted any trees under 25.11.090.

With the current ordinance updates being considered, the Urban Forestry Commission is recommending that all trees 6 inches DBH and larger removed during development must be replaced on site or a fee in lieu be paid to the city to replace the trees elsewhere. The goal is to be certain our urban forest continues to increase in canopy cover and that is difficult to do if we are achieving a net loss of trees over time.

The Seattle Urban Forestry Commission on July 11, 2018 wrote a letter to the Mayor, City Council and City Auditor urging DCI to enforce the provisions of 25.11.090 and lower the threshold to 6 inches DHH when they update SMC 25.11 – Seattle’s Tree Protection Ordinance. Re:SMC 25.11.090 -Tree Replacement and Site Restoration 


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