During the colder winter months, many of our trees are “closed for the season.” Like island businesses, trees will have an “opening date” sometime in spring when flower buds will pop and leaves will unfurl. Exploring the forest in winter can be a fun way to see another facet of island ecology and learn to recognize the details that make tree species distinctive and unique.
Have you ever tried to identify trees in winter condition? This blog article will give you a good start. On Nantucket we have fewer species of trees in our forests than in many mainland locations, so it’s something of a beginner’s paradise. Above is a collage showing twigs of our most common deciduous trees that may be found in areas with mesic (moist) forest, mainly on the northeastern region of the island, such as Squam Farm & Squam Swamp, Norwood Farm, Windswept Bog, and Masquetuck Reservation.
One of the easiest trees to learn how to identify in winter is the Sassafras (Sassafras albidum), which is particularly common in forested areas of Squam. Stands of young sassafras trees have a characteristic upside-down-umbrella theme to their canopies and you can learn to spot them from a distance.
Older sassafras trees become more irregular in their branching patterns and may easily be confused with tupelo, another common tree of our mixed deciduous forests. Take a closer look and Sassafras’s green twigs with large buds alternating on the stem will help you recognize this species at any size. A “scratch-and-sniff” of the inner bark on a twig will clinch the identification–sassafras bark has a spicy lemony scent.
Tupelo (Nyssa sylvatica) is even more widespread on Nantucket than sassafras, and is often found in wetter areas and around ponds. It has many short spur branches that jut out from the main branch at right angles and small nondescript buds. Tupelos often grow in dense stands that are sculpted by the wind. They have a tendency to form a flat-topped tree when growing alone in the open. Cutting a twig open lengthwise reveals that the inner part of the twig is partitioned neatly by tiny walls called septae, clinching the identification on this species.
Another easy to learn tree is the red maple (Acer rubrum) which on Nantucket is mainly found in wet areas, often in low lying spots known as “hidden forests.” Surrounded by vernal pools and mats of sphagnum moss, this tree can be identified from a distance by its red buds and twigs that occur opposite one another on the stems.
Red maple buds are neatly arranged in opposing clusters of three — two small lateral buds flanking a larger central bud on each side of the stem. In late winter, red maple buds become swollen and the red color becomes even more obvious as trees prepare to burst into scarlet flower.
In contrast, oaks have irregular clusters of buds that alternate on either side along the stem. Black oak (Quercus velutina) has large, velvety pointed buds . This species has been plagued in recent years by oak crypt gall wasps, which leaves the trees in poor condition as the insect larvae inhabiting the twigs cause a lot of damage. From a distance you can often spot the knobby deformities on the twigs containing the gall wasp larvae. You can read more about oak gall wasps in a previous blog article: Black Oak Gall & Parasitoids blog. Leaves on this species have sharply pointed lobes and often remain on branches through the winter, as described in an earlier blog post.
White oak (Quercus alba) has smaller rounded buds in clusters, and like black oak, often has some remaining dried leaves long into the winter. Both black and white oak produce copious acorns in some years, but good luck finding any in February, as the squirrels have usually hidden most of them away!
Another tree popular with squirrels is the mockernut hickory (Carya tomentosa), which is usually found in drier upland sites. This species has very thick twigs and large stout buds. The buds themselves are covered in protective scales that have a velvety coating. you can often find remnants of the large nuts on the ground beneath a mockernut, typically just the large watermelon-shaped outer husks. As with the acorns, mockernuts are usually in squirrel food caches by late winter.
American beech (Fagus grandifolia) is easy to recognize by its smooth elephantine grey bark, but a close-up look at the twigs and nuts is a good way to get to know this species better. Beech’s slender twigs have a zig-zag pattern and distinctive long narrow buds. If you happen to find a tree that has had a good fruiting year, you will notice lots of burr-like husks on the ground beneath. Each of these capsules splits open to release small nutlets, each with a triangular cross-section. Beech nuts are popular with wildlife — you guessed it, squirrels, but also a variety of bird species and rodents.
If you’ve enjoyed this intro to Nantucket’s common forest trees in winter, please put your new winter tree ID skills to use and visit one of our island forests for a hands-on look.
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