Eastern white cedar is on the rise as a commercial tree species. We have lots of it in Ontario, and its wood resists rot, making it useful for docks, decks, posts, shingles, cabin logs, and more. It’s also a valuable tree for wildlife food and shelter; drive along any forested highway in Ontario and you can see that the cedar are lacking foliage up to the height that deer can reach. And it’s a popular yard tree, as it makes an excellent green privacy fence.

OFRI summer experience student Meghan Garside uses callipers to measure the diameter of an eastern white cedar stem at OFRI's arboretum in Sault Ste. Marie.

However, eastern white cedar has been studied less than more popular commercial species such as black spruce and jack pine, so less is known about how to manage it. Several MNR studies are underway to determine how best to grow, harvest, and regenerate cedar.

In 2011, OFRI researchers Tom Noland and Rongzhou Man began a new study to determine how well this species tolerates the herbicide glyphosate, applied in varying concentrations and and at differing times of the year. Glyphosate is the herbicide used most often in Ontario’s forests to control plants that compete with crop trees.

“A critical part of regenerating forests after harvest is managing vegetation that competes with young seedlings,” Noland says. “Vegetation management helps ensure that you end up with the right mix of species—in this case a healthy eastern white cedar component—rather than having less desirable, more aggressive species, such as balsam fir, crowd out the cedar.”

Not much is known about whether cedar tolerates glyphosate, Noland says. For this study, researchers planted 1,000 cedar seedlings at OFRI’s arboretum outside Sault Ste. Marie. The arboretum has a deer fence, allowing researchers to focus on effects of the herbicide without interference from deer.

“This year we’re letting the cedar plants establish,” Noland says. “Next year, we’ll let competitor plants establish and apply glyphosate at three different rates at three times during the year and compare that with doing mechanical control and doing nothing. We’ll assess the seedlings in the fall and see how well they grew and whether they are showing signs of stress. We’ll do a final assessment of growth in the fall of Year 3.”

Results of this work, available by 2014, will help improve decisions about managing cedar regeneration after forest harvesting.

For more information, contact Tom Noland. Michael Irvine, provincial vegetation management specialist, MNR’s Forest Health and Silviculture Section, also contributes to this project.

Related articles:
Eastern White Cedar: Researchers Set Out to Solve the Mystery of a Promising but Low-Profile Commercial Tree Species
Ontario Tree Atlas: Eastern White Cedar
Related research report: Silvicultural Practices for Eastern White Cedar in Boreal Ontario
Landowner Resource Centre—Extension Note: Eastern White Cedar
 

Did you know...? Facts about eastern white cedar!

• University of Guelph researcher Douglas Larson discovered that eastern white cedar is Ontario's longest-lived tree species by a long shot. The oldest eastern white cedar, growing on the Niagara Escarpment, sprouted in the year 688, making it more than 1,324 years old in 2012.
• He also discovered that eastern white cedar is the world's slowest growing tree. One 155-year-old cedar weighed only 11 grams, suggesting it grew only 0.1 grams per year. That is about 10,000 times slower than a Douglas fir grows. (Read more about Larson's work in The Last Stand: A Journey Through the Ancient Cliff-Face Forest of the Niagara Escarpment.)
• You can tell eastern white cedar along roads by the fact that they are evenly trimmed to the height up to which deer can reach. An eastern white cedar grove is like a deer food court.
• Planting eastern white cedar close together creates a beautiful green fence.
• Eastern white cedar resists rot, so it's good for making fences, docks, saunas, and shingles. While exploring the St. Lawrence River In 1536, French explorer Jacques Cartier took the advice of native people and boiled cedar needles for tea to save his men who were dying of scurvy.