Imagine being a moose at the end of May: You’ve just survived 200 days of cold and darkness chewing the equivalent of a large garbage bag full of frozen twigs each day.
Now, billions of salad greens are growing from those same woody plants, providing an aroma and texture you savor for an instant before a nod of the moose’s head snaps off a tenuous branch. Throughout Alaska, moose are sucking on new leaves like whales inhaling plankton.
A catkin rises from the stem of a felt-leaf willow, preparing to release someday this summer or fall willow seeds into the air in tiny capsules carried by fluff. (Courtesy photo/Ned Rozell)
The most abundant moose food in the state, and probably the most numerous tree in Alaska, is feltleaf willow, once called Alaskan willow.
As its name suggests, feltleaf sprouts canoe-shaped green leaves that feel fuzzy on the underside. Most feltleaf willows in Alaska are found in areas disturbed by moving rivers, melting glaciers, and human cuttings for roads, homes, and parking areas. They prefer as much sun as they can get.
People would call most of these carbon dioxide-absorbing plants shrubs, since the tallest are only 30 feet tall. Millions of them are much smaller, resembling fields of old orange car antennas sprouting from the gravel bars of waterways large and small.
Willows like the feltleaf (there are over 30 species in Alaska, many hard to tell apart) are the little engines that run the northern forest. The leaves, and in winter the bark, are an important source of protein for moose. Packs of 3-pound stringy muscle and a hint of fat, snowshoe hares eat the bark, leaves, and small twigs. The willow ptarmigan grows so fat from the buds that they have not yet burst as from the leaves.
Individual willows can survive moose ripping off 90 percent of their twigs. They reproduce by the chance encounter of male pollen produced by some willows floating onto the female reproductive parts of others. After that union, caterpillar-shaped catkins form on the stems. Those catkins release seed capsules to the wind in parachutes of fluff.
Willows can also reproduce without the possibility of wind-borne sexual encounters: new plants are sometimes sprouted from stem fragments that find receptive soil after they are broken or cut. It’s probably safe to say that a handful of willows have reproduced in this vegetative fashion somewhere in Alaska as you read this.
Feltleaf willow leaves emerge below where a moose cut the buds during the winter of 2022-2023 in Fairbanks. (Courtesy photo/Ned Rozell)
If you want to succeed as an Alaskan gardener, feltleaf willow seems like a good choice. After the construction of the trans-Alaska pipeline, researchers at the University of Alaska Fairbanks School of Agriculture and Land Resources Management in 1977 led a team attempting to restore feltleaf willows in parts of river valleys Atigun and Sagavanirktok. To lay out the path of the pipeline and nearby roads, workers had dug gravel from the beds of those watercourses, uprooting many willow trees.
After hand-planting thousands of feltleaf willow whips into disturbed riverbeds (primarily as a future food source for North Slope elk), foresters returned nine years later. On his most successful site, more than half of his plantings had grown into tall, healthy bushes.
Somewhere near you, a felt-leaf willow tree has recently grown a few millimeters in height while exhaling oxygen for use. The plant is common almost everywhere in Alaska, except for the Aleutians and a few other West Coast islands. It exists to the southeast in a broad buffer zone along the Alaska Highway and beyond Edmonton, Alberta, but does not grow in the lower 48.
• Since the late 1970s, the Geophysical Institute at the University of Alaska Fairbanks has provided this column free of charge in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.
