Tree Facts

There's always a big argument whenever trees are cut down in cities to build something, including housing. Seattle architect and urbanist Matt Hutchins posted an interesting set of datapoints about this topic a week or so ago:

I hate whenever urban trees get cut down — it is a visceral loss. But let’s put the problem of tree canopy loss in perspective. In 5 years we [Seattle] lost 0.0229% of our tree canopy during development and could easily be offset with new public trees.


It isn’t the biggest crisis we need to plan our future for.

Now imagine those 40,000 homes don’t get built in Seattle, in an urban area, because we can’t bear to sacrifice any canopy — and instead are built as sprawl in a clear-cut ex-urban forest at 10 dwelling units per acre.

For those 35 acres of urban canopy lost, we preserved 4,000 acres of forest.

In answering a question about how the other 1.4% of trees were lost, Hutchins answered, "Age, disease, hazard." 

Here in the Twin Cities, we've had a large number of trees lost to an invasive insect called the emerald ash borer, which arrived here about 25 years ago. That's an example of the kind of thing that has a much bigger impact than development on our tree canopy.