“…reduce parking and the mature specimen cedar gets to live.”

To a large extent, this is the cause of much or our urban canopy problem. The rules that require parking have knocked down mature evergreen trees and made the new development really ugly. I applaud the efforts by the developers of the last ten years. They have managed to create relatively nice places despite the stupid rules. But the development that took place in the 80s and 90s was really ugly. We got density, but we got a lot of concrete with it. We lost trees and nice landscaping. This made for neighborhoods that are no longer nice to wander. Much of the “anti-density” attitude started with such eye sores.

I’ve said it once and I’ll say it again: this should be a high priority for the new administration. Much of what we would like the city to do will require money. However, changing the development rules will actually help homeowners, developers and renters:

1) Allow more mother-in-law apartments
2) Allow more backyard cottages
3) Ease up on the parking requirements for new developments

At a minimum, perhaps we should try and kill two birds with one stone: How about easing the parking requirements if trees are preserved (or planted). That would have made perfect sense for the example given.

In the last 40 years, tens of thousands of street trees have been planted, in some neighborhoods producing canopy that covers the entire street right of way. Yes, we’ve lost some greenbelt acreage and trees on vacant lots have been cut down, but it’s hard to imagine that those loses are not more than offset by the tremendous number of trees now lining city streets and arterials.

Seattle’s tree canopy is less functional because we have replaced evergreens with deciduous street trees and lost most of the value of our tree canopy in the process.

Deciduous street trees, in our weather area:

1. Have 50-60% less stormwater retention
2. Fail at scrubbing small particles from the air during the winter when we most need that service because of climatological patterns
3. Fail at wind screening, which is the most important energy saving aspects of trees in our area because they have no leaves during our highest power usage times.

If you’re inclined to read the science in this area, I’ll give you a free tip: You have to read both the methodology and the measurement method in urban forestry scientific papers. Most of the errors I read above are due to well-meaning people not getting past abstract or summary data.

For example, almost all of the stormwater retention data comparing deciduous to evergreen concludes the difference between the two is minor. The error in applying this to Seattle is the bulk of our rain comes when there are no leaves on the trees. SPU has a most excellent summary scientific review on this subject that is worth reading as a first step before reading other scientific papers on the subject.

Every city in our area, and international favorites mentioned here often, have stronger tree regulations than Seattle. Stronger tree regulations are not a barrier to density. To the contrary, strong tree regulations make it more likely people want to live and shop in our urban villages because it preserves tree canopy. The scientific data on this are very clear.

That urban tree preservation is a NIMBY issue is a flat-out falsehood. Sure, some NIMBYs use trees to argue against development but that does not make tree preservation a NIMBY goal.

Take the Roosevelt/Cicely property example. There was no reason to take down the significant cedar there. Shrink the unit sizes by single digit percentages and reduce parking and the mature specimen cedar gets to live. Smaller units are cheaper and more energy efficient. No parking is needed at that location because it is blocks from the Roosevelt light rail station.

Saving the Roosevelt tree would have made the resulting MF development less auto-centric, more energy friendly, and likely more affordable (by unit rent and/or cost to maintain over time).

1. Less auto centric
2. More energy friendly
3. More affordable

If I understand correctly, those are three pretty important urbanist goals.

Yet people decried those trying to save that tree as “NIMBYs”.

1) Big additions (as already mentioned) in Discovery and Magnuson Park plus a smaller addition due to Freeway Park.
2) Losses due to bigger houses. Seattle is a nice place to live so wealthy people have moved here. Many of them have cut down old trees (on their lot) and expanded their house.
3) Suburban style expansion. Much of the city is (or at least was) suburban in nature. Their was some old fashioned, suburban style growth in the North, South and West (Magnolia) end of the city. Not as much as Bellevue, certainly, but enough to move the numbers a bit (probably similar to the loss due to bigger houses).
4) Conversion to apartments, condos, or multiplexes. As much as I believe in density, I have a hard time believing that we didn’t see a net loss of trees in, say, Ballard. A lot of houses with trees got replaced by condos and multiplexes with concrete. But here is where the same folks who complain about loss of tree canopy are dead wrong about their policies. It is the policies which lead to the concrete (for parking) not the density. The developers would have loved to save the trees (or plant some new ones) and not worry about the parking. The neighbors might have complained about the parking (eventually) but they wouldn’t have complained about the new development (since it would have been much nicer). The answer is obvious, get rid of the parking requirement; get rid of the restrictions on mother-in-law apartments; get rid of the restrictions on backyard cottages. All of those changes will be good for the trees (and homeowners and renters). Oh, and since we’ll have a lot more people in the city, we’ll be able to better afford a lot more park land. Perhaps we could make a nice big park downtown, by Westlake (oops — too late) or maybe a nice “public commons” by South Lake Union (oops, too late again). All kidding aside, the argument that increased density in Seattle will lead to a huge loss of tree canopy is rather absurd.

It could not do so.

Period.

Go ahead and repeat my experiment. If you get some hard facts which relate to Seattle, and/or which prove things one way or another, please share it.

•••

And let’s remember why this issue is important. It goes back to Dan’s critically-important statement that it is crucial to dissociate the idea that increased urban density means declining quality of the natural environment (in this case the urban forest.)

My belief is that a fair-handed study of the Seattle situation will show just the opposite: that increased urban density is consistent with increased urban tree canopy and not just in theory — but in fact.

Go get ‘em, academic researchers in geography, urban planning, forestry. Let the facts fall where they may.

I think if we could compare satellite photos from 1970 with today, we could quickly put the kibosh on the city claims.

…must resist clicking the link to the satellite-imagery-based study that is the basis for the city’s claim.

The amount of tree canopy in Seattle is truly mindboggling to someone who watched the city develop between 1970 and 1995. In the 70s and 80s it was physically painful to see wooded land developed, not least because it happened in the city’s “greenbelts”, which were never owned by the city, but just marked on maps as places where they thought development was unlikely.

Compared with 1970, Seattle is incredibly dense and developed- as is the tree canopy. Apparently a goodly number of trees grew up.

I think if we could compare satellite photos from 1970 with today, we could quickly put the kibosh on the city claims. The potential problem is real, though, because trees are high-maintenance in the urban environment, and they can’t fight back when some bozo wants to improve his view or park on the sidewalk.

In general, you can’t go far wrong if you fight like a tiger to protect greenspace. There will always be lots of people with money, many of whom don’t even live here, looking to make a quick buck. No harm in making them work a little harder and build their development up instead of out.

“My only thought on the 1960s tree canopy mystery is that the single largest change since then has been more space for cars: new freeways, surface parking lots, wider streets for driving and parking, curb cuts for driveways and garages in Craftsman neighborhoods, and so on”.

The reference date used by the City in the loss of urban forest claims is 1973 which post-dates freeway building in Seattle by a decade. The rest of your ideas are plausible but for one thing: it didn’t happen that way. The city you see now was in its physical form the same one I saw in 1973. Few streets have gotten wider, curb cuts are inconsequential in number etc…

Think about the claim the City makes: ONE HALF of the tree canopy has disappeared since the early-mid 70s. Try to imagine the scale of that change. If it were true it would be huge and would imply the cutting of a huge number of trees. Where were those trees? My assertion is that those trees existed only in the imagination of people too young to remember Seattle in the 1970s or people who simply weren’t here.