NATURE’S VIEW
Attracted by the habitat and food they provide, the author experimented with planting black walnut trees on his woodlot in Sutton with varying degrees of success.
Imagining a Future Forest While Experimenting with Assisted Migration By Dave Anderson
O
ver the past couple of years, I have collected a few dozen black walnuts from the Forest Society’s Creek Farm Reservation in Portsmouth and planted them on our family woodlot in Sutton. In this experiment with assisted migration—moving a temperate hardwood tree north, but still within its natural range stretching into northern New England and Canada—the walnuts leap-frogged some 75 miles from a former seaside estate to the rugged foothills of the Sunapee-Kearsarge region, 1,000 feet above sea level. Why plant walnut trees in the first place? Because they will grow here, produce shade and valuable lumber, and provide nutritious, edible nuts for wildlife. I have spotted relict American chestnut trees sprouting from blight-resistant 100year-old roots on my woodlot. In the early 1900s, a chestnut blight killed billions of native chestnuts growing in the eastern United States. The loss of the chestnut tree negatively impacted wildlife living in this 20 | FOREST NOTES Winter 2022
country’s original hardwood forest. Animals rely on nuts and seeds for sustenance, and when a food source disappears, it may take a while for nature to backfill that void. Hence, one motivation to plant walnut trees. To begin my walnut-planting foray, I removed the husks and dropped them in a bucket of water to determine their viability. I discarded the floaters and kept the sinkers. Walnuts germinate best after an exposure to cold temperatures for 75–125 days in a process called stratification. Some people stratify walnuts for planting in a refrigerator over winter. It’s easier to direct sow them in late autumn and have nature do the chilling, but squirrels are the issue. These foraging phenoms consumed 100 percent of the first round of walnuts I tried planting. I even caught squirrels inside my garage plucking walnuts from a 5-gallon bucket of water as if they were bobbing for apples at Halloween. To thwart their walnut thievery, I tried pre-sprouting the nuts in springtime, planting them in
4-inch-deep pots. My plan almost worked, though just a measly 2 percent germinated because I hadn’t checked the viability of the walnuts and the pots I used should have been at least 6- to 8-inches deep to accommodate the taproot. To add insult to injury, the squirrels also dug them from the pots in the summer. It was another epic fail. This past autumn, I acquired 1,000 walnuts from a property manager who collected them from lawns to prevent damaging his lawnmower’s mulching blades. I peered into one of the 50-gallon trash barrels containing an estimated 500 walnuts. The tart, citrus-scented walnut husks oozed a brown liquid that stains skin and clothing. The husks contain the chemical juglone, which inhibits the growth of plants looking to set up shop underneath a walnut tree or within their root zone. It’s a classic example of allelopathy: chemical warfare to control competition. Save yourself some time and grief by not composting the walnut husks in compost destined for
