Tree planting with climate change in mind

Close-up view of hands surrounding a freshly-planted pine tree seedling

Caption: Close-up view of hands surrounding a freshly-planted pine tree seedling. Photo by USDA Forest Service.

 

Spring is a great time for planting a tree, but timing is just one of many factors that impact your tree’s chances of living a full and healthy life. There’s a lot you can do to help your tree thrive for decades to come — even in the face of a changing climate.

To clear up the mysteries surrounding tree selection and planting, here are some pro tips from two USDA Forest Service staff members based in St. Paul, Minnesota: Jill Johnson, an Eastern Region urban forester; and Leslie Brandt, a Northern Research Station climate change specialist.


Tree and site selection

It’s important to match the right tree to the right site conditions. Narrow down potential trees based on site characteristics, such as soil type, the amount of space you have and whether it is a shady or sunny spot. Consider a species that is relatively pest and disease tolerant.

Before planting, find out your hardiness zone — determined by an area’s average extreme low winter temperature — and consider whether your selected species is suited to it. With climate change, hardiness zones are gradually shifting, so plan your tree planting with that in mind. Check out this Forest Service story map showing how hardiness zones and heat zones will change in your location.

“The greatest benefits come from trees that thrive, not just survive,” said Johnson. “Selecting the right tree for the right place, choosing a high-quality specimen and caring for it properly will increase the likelihood of good health, growth and long life.”

Also consider whether your tree will provide other benefits such as shade, carbon storage, wildlife habitat, biodiversity or pollinator habitat, as well as other concerns such as the level of allergens produced by the tree (wind-pollinated male trees tend to be the most allergenic).


Climate considerations

Climate change will increasingly impact tree health in a variety of ways. Select species that can withstand both current climate and the climate that is expected to occur over the tree’s lifetime.

“Climate change will make growing seasons longer, which could be good for growth,” Brandt said. “However, increased heat and drought during the summer can stress trees and make them more susceptible to pests and diseases. Milder winters may allow us to plant trees from more southern hardiness zones, but also can make conditions more favorable to insect pests that attack trees.”

Keep in mind that climate change may bring more frequent and stronger storm events, leading to breakage that makes trees more vulnerable to disease.


Planting

Planting your new tree at the right depth can make a big difference in its long-term outcome.

“Some people plant way too deep,” said Johnson. “That causes roots to encircle the trunk and, as the trunk enlarges, it eventually meets the roots, which have also enlarged. This compression often kills the tree.”

Instead, before planting, remove excess soil from the top of the root ball. The planting hole should be just deep enough to keep the top of the roots level with the ground surface.


After-planting maintenance

“Watering the right amount is one of the most important things you can do for tree survival,” Johnson said. “Watering too much or too little can kill a tree. Check the soil moisture a couple times a week by poking down 6 inches below the surface.  Water if the soil is dry, even into the late fall up until the ground freezes.”

To help the tree retain moisture, use mulch or ground covering (other than grass) above the root ball. However, be sure that the mulch is not mounded against the tree stem. Do not fertilize the tree for the first year, and never use a weed whip around the tree’s base.


For more information





https://www.fs.usda.gov/detail/r9/home/?cid=FSEPRD906772