Hot, Dry Weather Can Stress Recently Planted Trees
Our stretch of hot and dry weather means many of Portland’s recently-planted trees may not be getting enough water on their own, according to Portland Parks & Recreation (PP&R)’s Urban Forestry division.
“Maintaining a mature and healthy tree canopy is one of our City’s key livability goals,” says Jenn Cairo,Portland’s City Forester. “It’s important for folks to get out and water their newly planted trees during the dry season. Good watering practices increase the trees’ chances of survival and helps with vigorous, well-formed root development, so that the trees will be around and beautiful for years to come.”
Older, more established trees are more hardy and resilient, adds Cairo. But whether your thumb is green or anything but, PP&R Urban Forestry offers these tips:
To keep your newly-planted trees in top shape:
Newly-planted trees generally need about 10 to 30 gallons of water each week in dry conditions. Healthy, mature trees generally don’t need to be watered. Our climate in Portland generally means that watering in the rainy winter is not necessary, regardless of when the tree was planted.
Water for three to six minutes with a hose to produce about 15 to 30 gallons per tree, depending on the flow volume. Watering tubes and 5-gallon buckets with holes in the bottom placed next to the tree trunk are other ways to deliver water to your tree.
Although it is possible to overwater a new tree, in a dry Portland summer, it’s pretty hard to do. PP&R experts say, “When in doubt, water.”
If water starts to run off the surface, water at a slower rate, water on the other side of the tree, or loosen up any hard surface so water can percolate into the ground. Don’t be afraid to dig into the soil and see if the water is penetrating the surface.
Watering a tree deeply about once a week is generally better than providing a shallow watering more frequently. Deep watering encourages deeper root growth, which in turn creates stronger trees, better able to withstand windy conditions and future dry seasons.
It can take up to about five years for a newly-planted tree to establish itself in its new environment. Good watering practices during the establishment period are very important to the tree’s survival, so keep at it in future summers.
When watering, take advantage of the looser, wet soil, and pull up the weeds and grass from around your trees. By reducing the competition for the water, you won't have to water as much. You can also add mulch around the tree. Mulching improves the soil, deters grass and weeds, reduces the need to mow near the tree which can damage the bark and eventually kill the tree, and does a great job of retaining water in the soil.
Watering your trees and thinking about what the tree will look like in 10 years is all part of the joy of nurturing a tree!
More tree facts to “leave” you with:
Portland is green, and is getting greener. New data from a Portland Parks & Recreation’s aerial imagery study show thatPortland’s urban tree canopy has grown by 2.6 percent over the past 10 years, and now covers nearly 30% of the city.
“A lush, greener Portland is a fabulous place to live,” said Cairo. “Results are positive and encouraging that our canopy growth is moving in the right direction.”
There are currently around 240,000 street trees in Portland, and approximately 1.2 million trees in Portland’s parks. The City and valued partners such as Friends of Trees are continuing strong efforts to plant more trees. http://www.friendsoftrees.org/
A 2009 City of Portland study valued the ecological benefits of Portland's street and park trees at $27 million annually!
Trees soak up rainwater and improve the quality of water. They help to assure the retention and stability of soil, improve air quality, regulate heat in the city, provide wildlife habitat, and make life more pleasant. Trees also increase property values of both residential and commercial property and make communities more livable.