Trees vs. Solar Access

About two months ago we challenged what we perceive to be a bias in favor of ultra high density, subsidized housing on the part of urban planners who should be engineering cities but often seem to want to engineer society while they’re at it. These comments culminated (for now) with our Critique of New Urbanism (also known as “Letter from Wingnuttia”) posted back on December 13th, 2007.

Want to plant a big tree? Not so fast…

The original inspiration for our critique was a listserve sponsored by, where urban foresters swap advice on how to manage and expand urban forests.

We warned these people who love trees that there is an inevitable conflict between their desire to expand the urban forest and what appeared to be their collective predilection for ultra high density communities.

You can’t cram 10-20 “detached single family homes” onto one acre via infill or within new planned communities and expect there to be room for trees – except of course for trees in public parks and on traffic medians, expensively maintained by public employees. In the urban environment, the private tree on a private lot is an endangered species, and if that sounds hyperbolic, too bad, because it’s true.

Now another threat to the urban forest is upon us, and the only surprise is that it hasn’t happened sooner. Unlike high density “infill” mandates, which we believe are destroying beautiful and irreplaceable semi-rural suburbs under false pretences, protecting solar access is a worthy goal. We have always been enthusiastic about solar power, and the liberating (and libertarian) nature of off-grid, small scale, privately owned energy and water systems.

So when we learned a homeowner in Santa Clara, California, is suing his neighbor because their redwood trees are growing up to shade his rooftop photovoltaic system, there wasn’t an immediate reaction either way. While we lean towards favoring the trees, we can certainly appreciate the concern somebody might feel if they dump $20,000 into rooftop photovoltaics only to see their yields relentlessly lowered in direct proportion to the height of their neighbor’s redwood trees. What do you do?

Rhonda Berry, Executive Director of the Silicon Valley based Our City Forest, was quoted in a report on the lawsuit (S.J. Mercury, “Tree Huggers Should Trump Solar Lovers”) as suggesting “we should develop neighborhood solar hubs – at schools or other public buildings – to provide energy to surrounding homes instead of putting panels on every house.”

Berry is on to something, although this conflict is just beginning and her idea is only part of a possible solution set. But if homeowners invest in solar power systems and reap the payback therein, why should that require them to put the installation on their own roof? Photovoltaics installed on one residential rooftop still cost about $10 per watt, whereas larger scale systems only cost about $6.00 per watt. That is a lot of savings to leverage, and property owners in sunny areas away from prime land, or owners of large commercial buildings with huge rooftop areas ought to be able to capitalize on this.

It’s time for virtual power companies to form. Why should I own a photovoltaic system on my own roof, when I can own a piece of a larger system and make a more cost effective investment – and still enjoy shade from my neighbor’s big urban trees? Is there a business model here?

4 Responses to “Trees vs. Solar Access”
  1. Mark says:

    I read the New Urbanism piece and have to disagree on most of your points. I work extensively in the US, South America and Europe and your piece is very much a narrow American centric view of land use. High density living in most all other countries works very well. The large urban green systems, some centuries old, that result from this development is a hallmark for which planners in the US will eventually turn. Large urban green space in this country pale by comparison. It is the false sense of individual entitlement that makes Americans the grossest consumers from oil to land.

  2. I read the New Urbanism piece and agree with most of it. Americans have different challenges compared to elsewhere in the world. America is a relatively sparsely populated nation compared to Europe, and connecting America’s relatively inefficient energy use to patterns of land use is not necessarily valid. Patterns of energy use are changing because of genuine scarcity and a genuine need for America to be more energy independent, i.e., there are genuine reasons energy costs more. Patterns of land use, on the other hand, are changing because of environmentalist lobbying that exercises inordinate influence over the supply of land, i.e., land costs more for political reasons – there is no genuine shortage of land in America. There’s nothing wrong with high density developments anywhere, including in America. What’s wrong is making high density the only option available for Americans through passing coercive ordinances that make it economically impossible for the people who want large yards to have them.

  3. Chris says:

    Great post, and I could not agree more r.e. community-specific/central vs. home-by-home rooftop installs. Simple model: Have an HOA (in my neighborhood, it’s the “Willowbank Club,” representing about 35 homeowners) host/own/manage the PV system. The economics are simple, and pragmatically ownership/membership/use can transfer with home sales.

    Your post reminds me too of Bill McDonough (the world belongs to the living; there is no end game; it’s an infinite game; if you throw something away, where does it go? Where is away if away has gone away?) and The Lorax, which I wrote about here:

  4. I work with trees.

    Seems our city of Beaverton, Oregon, will be having a tree forum of sorts for 3 nights. I plan to go and share a few ideas.

    Our city has grown a lot, and faces challenges with trees and growth too.

    Right now, if trees are desired in a city, people may have to accept a revolving door policy, where trees are only expected to grow for a certain number of decades.

    A real urban foresty – like urban logging.


    M. D. Vaden of Oregon


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