VANCOUVER, Wash. — Trees provide a long list of scientifically proven benefits.
They cool the air, which saves energy by reducing the need for air conditioning and also takes the edge off global warming. They filter out air pollution. They soak up rainwater, which helps keep creeks and rivers clean. They provide animal habitat. They improve human health by reducing stress.
All are reasons why the United Nations has launched a campaign called the “Trees in Cities Challenge.” Vancouver Mayor Anne McEnerny-Ogle has signed on to this tree-planting pledge.
Vancouver, which typically sees 800 trees planted a year, will aim to get 1,000 trees in the ground in 2020, said Jessica George, education and outreach coordinator for Vancouver’s Urban Forestry Program.
November through March is the optimal time to plant trees here, George said.
The city works with the Portland-based nonprofit Friends of Trees to organize tree-planting events like one last weekend in southeast Vancouver. Friends of Trees, which has more planting days in the coming months for other Vancouver neighborhoods, offers reduced prices on trees and marshals volunteers to plant them for you.
The urban forest needs all the help it can get. Vancouver’s tree cover fell from 19.7 percent in 2003 to 18.6 percent in 2011, the last time it was studied. The city expects to measure tree canopy again next year, George said.
If you want to help by planting a tree at your home, here are some tips.
Check the rules
Vancouver and most cities require a permit to plant or cut a tree in the public right of way. Not only should you inquire with your local jurisdiction, if you have a homeowners association, make sure you know what its rules are for trees.
Think beyond maples
People like maples because of their gorgeous fall colors, but they are overrepresented in the urban forest, George said. Asian longhorn beetles have infested hardwood trees in Massachusetts, New York and Ohio. The pests, which prefer maples, may make their way West.
“We don’t want our urban forest to be decimated because it’s dominated by one tree,” George said.
If you like fall color, George recommends black tupelo. The tree grows 30 to 50 feet tall, and the leaves turn yellow, orange, bright red, purple or scarlet.
Urban foresters’ mantra is “the right tree, the right place.” You should think about how big the tree will grow and its placement in relation to structures, property lines, utilities and sunlight, George said. But that doesn’t mean you have to rule out big trees. One of George’s favorites is giant sequoia, which can grow to 100 feet tall.
“It’s a large-form stately tree with great structure, and you don’t have to give it a lot of maintenance,” George said.
Erica Timm with Friends of Trees loves Oregon white oak, which is slow-growing but reaches 50 to 90 feet when mature.
“It’s a common misconception that a large tree can’t work in a small yard,” Timm said. “If you plant a tree that can grow taller, you can prune branches up and it creates an umbrella over your yard.”