Portland-area communities look to thicken tree canopy

In a world of people and plants, trees stand out as solid citizens. They clean and cool the air. They slow water runoff. They make neighborhoods feel like neighborhoods.

During the past century, however, humans felled many of the trees that once greened the Portland region and soaked up its abundant rainfall.

The gray result: concrete mega-projects such as Portland's $1.4 billion Big Pipe, tunneling alongside the Willamette River to control millions of gallons of storm water that run off the unforested urban landscape each year.

Yet, like a leaf starting to unfurl, tree-thinking is changing.

Recognizing that they can help combat climate change, and ultimately save society billions of dollars in combination with more conventional "gray" infrastructure, jurisdictions are stepping up to save existing stands and replant trees in urban areas.

Their overarching objective: filling in the canopy of sparsely treed neighborhoods, perhaps most urgently east of the Willamette, where the deficiency of trees stands out on maps. Some researchers have dubbed that area "the big white pork chop," because of its shape and less-treed appearance.

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