Every spring, at about this time, there is a day when I step outside and find my olfactory senses drowning in a spicy sweet aroma. The scent is so powerful that it blocks out all other senses, the brain focusing on this and this alone. The fragrance brings to mind dark rooms filled with incense, or images of the ancient orient, and yet its source is completely and wholly native: balsam poplar (Populus balsamifera), an otherwise unassuming pioneer species of the boreal forest.
It took me several years to discover the source of this fragrance. I first encountered it while working in The Great Swamp in New Jersey. No one there knew what it was. I didn’t smell it again until I came to the Adirondacks, and that first spring, there it was. My head snapped up and I looked around. “I’ve smelled this before,” my nose was telling me. Scent is a powerful memory stimulant, and this scent is one of the strongest. My search for an answer began.
Because I could smell it right outside the main building of the Visitor Center, I knew the source had to be close by. I went from tree to tree until I found the culprit, a smallish tree with light grey bark. The newly emerging leaves were dark and shiny, and the stems to which each leaf attached were slightly sticky. Now all I had to do was identify it. In short order I had a name and the mystery was solved.
Now, you may be wondering how or why a boreal species would be growing in New Jersey. I’ve been wondering this, too. At first I thought that maybe what I’d smelled were trees of a remnant population, descendants of pioneer ancestors that moved into the swamp after the glaciers retreated all those thousands of years ago. But as a pioneer species, balsam poplar ameliorates a site and in fairly short order more shade-tolerant and cooler soil species move in, making the site unfriendly to the poplar. Even if disturbances were frequent, allowing the tree to continually colonize new areas via suckers or seeds, the odds of it still growing there would be very long indeed.
So I made a call to my former place of employment. No one knew of balsam poplar growing in The Swamp, or at least not naturally. Back in the 1970s some no doubt well-meaning folks planted a few non-native species of trees (like bald cypress) thinking they would be nifty additions to the swamp ecosystem. It is possible balsam poplar was planted as part of this campaign, for it likes wet soils and does well in disturbed areas. The tree can tolerate summer temperatures upwards of 104 degrees Fahrenheit, so it’s not out of the realm of possibility that they survive the heat and humidity of The Great Swamp.
Let me take you through a year in the life of this tree. Winter is the time to look at the buds, for they are thickly coated with a sticky, aromatic gum that gives these trees their common name (balsam). The terminal bud (the one at the end of each twig) is quite large, making it rather distinctive.
Before the buds open in the spring (releasing their delightful fragrance), the male trees produce their catkins. These male flowers grow two to three-and-a-half inches long and appear red thanks to their brightly colored stamens. The female trees also produce catkins, which grow four to six inches long and are more of a yellow-green color. Soon after the male catkins release their pollen, they fall off the trees and decay. The female catkins remain on the trees until their seeds are disbursed, which can last well into June or even July. Warm, dry weather is best for seed dispersal, for each seed is attached to a tuft of silky thread and blows away on the wind.
When autumn comes around, the shiny green leaves turn yellow. In our mixed forest, autumn is dominated by the reds and oranges of maples, so the golden poplars don’t stand out as much. But travel further north across Canada, where this is the only hardwood around, and solid stands of balsam poplar produce a beautiful golden glow in the autumn sunlight.
Locally, balsam poplar isn’t considered to be a tree of much worth. According to one former Finch Pruyn employee, when the bark is removed from the tree in the pulping process, the rest of the tree falls apart. Even so, it does have a place in the hardwood industry. Some of its uses include pulpwood (the short, fine fibers make good tissues), veneer, and boxes and crates (the soft, lightweight wood is ideal for these), although other related species, like cottonwood and aspen, are preferred for these uses. It apparently makes an excellent waferboard, but it requires special treatment to get the final product. Up north, its logs are milled for building houses and other structures.
Historically, the resin was used medicinally. If you chew on a twig, you will notice it has a bitter, aspirin-like taste. This is because it contains the same base compound of many members of the willow family: methylsalicylate. It is not surprising, therefore, that the resin found use, by Native Americans as well as settlers, in the treatment of various ills, like sore throats, congestion, coughs, and rheumatism.
Balsam poplar is a delightful tree, and one I encourage everyone to get to know. I leave you today with this quote from Donald Peattie’s wonderful 1950 book A Natural History of Trees:
“Those who have ventured beyond the great North Woods, out on the arctic prairies, where all the rivers fall into the polar sea or Hudson Bay, tell us of the surprising beauty of the isolated groves of Balsam Poplar there. How fair it must look then is something we can hardly realize when we encounter this species in the United States, for even when it is a fine tree…it is still a forest tree, crowded upon by others…”