While out on Saturday taking photos for a presentation on trees in winter, I was driving towards Wheeler Natural Area in South Burlington when a stand of sumacs caught my attention. I think what drew me in was a particular grace to the trees, an element of symmetry, orderliness, something so rare to find, particularly in sumacs. Staghorn sumacs are named after the velvet that adorns the most recent year’s growth, much like the velvet on a deer’s antlers (see image below). But the name, I think, equally draws connection to the contorted growth, which resembles the twisting forks of a deer’s antler.
Sumac is dioecious, meaning that an individual plant or colony can be either male or female. Their seeds are covered by an extremely tough seed coast, which prevents germination unless the seed is scarified. A seed coat acts as a barrier to water and oxygen, preventing environmental cues for the seed to germinate. Scarification is the break down of the seed coat, which make it permeable to water and gases. Scarification may be physical (involve abrasion) or chemical (as when a bird swallows the fruit and it passes through its digestive tract). However, I rarely see pure stands of either male or female sumacs. Germination rates of seeds are vastly greater after scarfication, which breaks down the extremely tough seed coat. The seeds are not
a preferred food source for many birds and their red cones are persistent throughout winter and only really get eaten in early spring when other food sources are rare and the early migrants, like robins, are returning.
One thing that struck me was how different the ground cover was under the sumac stems. There was almost nothing growing in the understory and there was very little leaf litter either. Sumac stands can block nearly 90% of light from hitting the forest floor.
Younger sumac stems are relatively easy to age without cutting them down to count the rings. The most recent year’s growth is always fuzzy. This is followed by an abrupt change in color.
