This week in the woods, white green-algae coral (Multiclavula mucida) appeared beside a beaver pond as it often does: regularly distributed across a decaying, moist, barkless log crusted with algae. The late-fall lichenized fungus’s Latin name reflects its appearance: multiclavula for “many clubs” and mucida for “slimy.”
Last week, we discussed hardwood trees’ susceptibility to damage from ice storms. Their leaves’ high surface area means that they risk accumulating heavy snow and ice and catching high winds. In part to avoid breaking their limbs this way, ashes, maples, birches, and other deciduous species drop their leaves in advance of the colder months. Still, many oaks and American beeches – like this one, caught in freezing rain on Sunday in Topsham, Vermont – keep their dead, brown, rustling leaves into wintertime. We don’t have definitive explanations for this winter leaf retention (called marcescence), but in the Winter 2010 Northern Woodlands issue, Michael Snyder offers some possibilities: keeping the leaves off the ground could slow their decomposition until a tree drops them in the spring, when it most needs their recycled organic material on low-nutrient sites; it could trap snow at the base of the tree, providing the roots with more moisture come spring; and it could protect buds from both frost and browsing deer. The fact that these species often outcompete other overstory species in dry, infertile, deer-infested environments supports these hypotheses. Alternatively, it could also be less of an adaptation than a vestige of beech and oak’s evergreen evolutionary history (and, in the case of beech, of only a relatively recent arrival from points south).
An actual evergreen, maidenhair spleenwort keeps its rosette of slender, black-stemmed fronds lush-looking throughout the year. This miniature fern may look delicate but endures winter on rocky, calcium-rich cliffs and outcroppings, often interspersed with mosses. Its name derives from its sori (clusters of spore-producing structures) shaped like spleens. The Greeks once thought that this resemblance indicated that the plant could heal diseases of the spleen.
This drab moth photographed by Ann Little could be either the invasive winter moth (Operophtera brumata) or the native Bruce spanworm (Operophtera bruceata). The latter also goes by the common name hunter’s moth, reflecting its presence in the woods during deer-hunting season, and, confusingly, it also goes by winter moth, the same common name as O. brumata. These late-flying moths are indistinguishable visually and told apart only upon examination of their genitalia or DNA analysis. Both pests defoliate hardwoods, although Bruce spanworm does so through natural cycles of boom and bust. As Bryan Pfeiffer describes in an Outside Story article from 2009, Bruce spanworm can survive low temperatures by way of energy-conservation strategies: flightlessness for the females, and for the males, a high proportion of muscle mass to body weight and low “wing-loading,” which means that they have low total weight in comparison to the wings’ surface. By now, many insectivorous birds have migrated and allowed these male moths to flit about low to the forest floor, desperately in search of wingless mates; note the sizable antennae, best for picking up the females’ pheromones.
Unlike winter moth and Bruce spanworm, the very similar downy woodpecker and hairy woodpecker can be told apart without work in the lab. The two species diverged 6.5 million years ago (about as long as chimpanzees and humans did) and have less genetic similarity with each other than with other woodpecker species. However, recent research suggests that the downy’s appearance has evolved to match the hairy’s appearance; this similarity benefits the smaller downy, which can make other rival birds mistake it for the larger, more dominant hairy and scare them off. If you can’t see both the downy and hairy at once and compare their sizes, you can still note the sizes of their bills relative to their own heads: the hairy’s beak is about as long as the distance from the base of the beak to the back of the head, and the downy’s is shorter, only about half as long. Additionally, while the hairy tends to be “shier” than the downy and dwell deeper in the woods and away from human activity, it still has the louder call: a peek given sharply (vs. the downy’s softer, more even pik).
What have you noticed in the woods this week? Submit a recent photo for possible inclusion in our monthly online Reader Photo Gallery.