holyoutlaw

A friend recently asked me: How does anybody figure out how much greenspace would be good for a city?

Whenever I’m asked a question, I usually start prattling away, and convincingly sound just as if I know what I’m talking about. I’ll be honest here, though, this question stumped me. It’s not surprising, either, that this turned out to have a complicated answer.

The first thing I thought of was asking around, as it were. For instance, what is Groundswell NW‘s goal for its service area? It wants to create open, public space in every arterial quadrant. That means a green space of some kind will be available to anyone with just a short walk, and without crossing a major street. This plan takes into account topography, bus lines, and so on. “Quadrant” in this case is a square or rectangle formed by four major streets. The quadrant Julie and I live in is four blocks east to west, but 10 blocks north-south. Groundswell is starting an open space survey this year which will count and look for opportunities for more greenspace, including curbside raingardens, greenways (streets modified to encourage bicycle and pedestrian traffic), intermittent use of roadways (Farmers Markets, festivals), and p-patches (public gardens).

The city, working at a different scale, considers its “open, usable space” (OUS) without regard to arterial roads or topography. The city first looks at “breathing room or total open space.” That’s parks, greenspaces, trails, playfields, community centers, and boulevards. Over the entire city, the desirable goal is 1 acre per 100 residents. The acceptable goal is 1/3 acre per 100 residents. This is split up into different types of neighborhoods. For a residential neighborhood, the desirable goal is 1/2 acre within 1/2 mile of all residents; the acceptable goal is 1/2 acre within 1 mile (there are offsets for school playgrounds, among other things). In an urban village, an area zoned for greater density (we live in the Ballard HUV, “hub urban village”), the requirements are slightly more complex: One acre of open space per 1,000 households, and 1/4 acre within 1/8 of all locations in urban village. In the downtown urban core, 1/4 acre of open space per 10,000 jobs. Sheesh. The answer quickly gets pretty arcane and wonky.

Another important consideration is canopy coverage. In fact, as we better understand the value of the urban forest, percent canopy coverage (which includes trees on public and private land) is increasingly important. Seattle’s canopy was measured a couple years ago at 23%. This is done by using software to analyze aerial photographs.

Seattle reLeaf has a goal of 30% canopy cover. Why 30%? It’s a realistic stretch goal, considering our urban density. It also brings us on par with Portland and Vancouver BC, to which we’re always comparing ourselves. Increasing open space will help the city get to 30% tree canopy, but most of this increase is going to come from adding trees to front and back yards and parking strips. That’s why “Trees for Neighborhoods” gives away 1,000 trees a year. There are six or seven different kinds of trees, a few of which are suitable for planting under power lines. Most are deciduous, and usually only one or two are native to the PNW. Native trees, particularly the conifers, are too large for most urban spaces.

Seattle has had a few bold plans for urban greenspace. The Olmsted Brothers firm had a great proposal, but it didn’t get very far, despite their having designed the Alaska-Yukon Exhibition and the University of Washington Campus. The Municipal Plans Commission had another one that was rejected by the voters in the early 20th century. Either one would have made Seattle a much greener city than it is now (but probably also correspondingly more expensive). In the 1990s, Paul Allen (Microsoft co-founder) had a big plan for a park in South Lake Union that was soundly rejected by voters as a billionaire’s park. Alas, I was one of the people who voted against it.

Currently, there is a committee working on a “Parks Legacy Plan” which would, among other things, create a metropolitan parks district with taxing authority. It’s probably the only way to get the funding the parks department needs (lots of deferred maintenance, which doesn’t even include the restoration work people like me do).

This answer only touches the surface of how to figure out what is enough greenspace in a city. I’d hoped to look at it in more detail, but even this little glance is a little intimidating.

Acknowledgments
I’d like to thank Jana Dilley (Seattle Trees for Neighborhoods) and David Folweiler (Groundswell NW) for information they provided for this post. Any errors are mine, of course.

Mirrored from Nature Intrudes. Please comment over there.

Note: On another venue (Dreamwidth), people were declaring December a “topic open house,” and asking for topics to write about. So far, the requests I’ve gotten are on-topic for this blog as well, so I’ll post them here (probably more spread out than every day). The first question was “What is my favorite NW Plant?”

My first thought was: how could I choose between osoberry and skunk cabbage? Both are very early bloomers, the first plants you’ll see blooming in the forest — skunk cabbage starts appearing in early March.

North Beach Park looks like a terrible wreck during the late winter: all the seeps look highly eroded, the leaves have rotted, everything is all twigs and branches. When these plants start appearing, I feel a sense of relief that it’s going to be all right.

But soon enough, osoberry is joined by red-flowering currant (another early-blooming shrub), then a number of shrubs burst out at roughly the same time, and osoberry blends into the shrub layer until late August, when it’s one of the first to drop its leaves.

However, skunk cabbage remains distinctive, and that’s why it’s my favorite. Its leaves are bigger than anything you’d expect outside of a tropical rain forest (four and a half feet/ 1.5 meters), which makes it stand out all season long. In the wet areas it thrives in, there isn’t a whole lot else growing. There have been times when we’ve cleared an area but been unable to plant it in the fall, only to see it come back lush with skunk cabbage in the spring.

Also, I know more of its uses: It was an early-spring famine food, even though it’s not very tasty. The leaves were used to line baskets, berry drying racks, and steaming pits. I like this story, related in Plants of the Pacific Northwest Coast (Pojar & Mackinnon):

In the ancient days, they say, there was no salmon. The Indians had nothing to eat save roots and leaves. Principal among these was the skunk-cabbage. Finally the spring salmon came for the first time. As they passed up the river, a person stood upon the shore and shouted “Here come our relatives whose bodies are full of eggs! If it had not been for me all the people would have starved!” “Who speaks to us?” asked the salmon. “Your uncle, Skunk Cabbage,” was the reply. Then the salmon went ashore to see him, and as a reward for having fed the people he was given an elk-skin blanket and a war club, and was set in the rich, soft soil near the river.

Here are all the photos on Flickr tagged “skunk cabbage.” The variegated purple ones are Eastern Skunk cabbage, and there’s a white one that looks like Calla lilies to me, but the one around the PNW is the yellow-flowered one.

I also have a favorite groundcover, Pacific Water leaf (photos) and a favorite fern, maidenhair fern (photos).

Mirrored from Nature Intrudes. Please comment over there.