White and red oak acorns from Browne Preserve collected by Chris Schipper

As our deciduous trees shed their leaves each fall, they also drop an abundance of seeds in the form of acorns, nuts, and samarras. This seed crop, referred to as mast, is defined as the dry fruits of woody plants. In our eastern woods and on NCLT’s preserves, the most significant mast-producing trees are oaks, hickories, beeches, and maples. Their mast provides a major source of fall and winter food for birds and wildlife.

In Connecticut, oaks are the most important wildlife trees. Acorns, which are high in protein and fat, can make up to 50% of the winter diet of white-tailed deer and wild turkeys. White oaks produce sweet-tasting acorns every year. Red oaks, on the other hand, produce a bitter-tasting crop that matures over two years. White oak acorns are generally preferred and eaten first, while red oak acorns are left for later and are often the only ones on the ground towards the end of winter.

White oak acorns are elongated with knobby caps; red oak acorns are rounder with larger scaly caps

Ripe acorns are brown or tan. An abundance of green acorns that drop prematurely can indicate that the tree is stressed and is allocating its resources away from seed production. This can be due to drought, too much rain, or other adverse weather conditions.
Hickory nuts with outer husks and inner shells
Hickory nuts are high in fat and nutrients. They have a tough outer green husk and an inner shell that protects the nut meat. They are favored by rabbits, field mice, squirrels, foxes, deer, wild turkeys, and bears. Hickories belong to the walnut family and are related to pecans. They are sweet-tasting and totally edible by humans. In former times, hickory nuts were an important high calorie winter food for rural Americans and farmers often planted rows of the trees at the edges of their pastures.
Beech nuts are also a high-fat and nutrient-dense food. Beech trees produce nuts every other year. These feed all kinds of rodents, deer, bears, turkeys, bluejays, and other birds. As our beech trees are currently stressed due to beech leaf disease, they do not appear to be putting energy into seed production. If they were to disappear from the forest, in the same fashion as the bygone American chestnut, their demise would impact wildlife that depends on this valuable food source. The demise of the American chestnut in the last century had a devastating effect on both wildlife and rural populations, especially those living in Appalachia who relied heavily on chestnuts to add protein to their winter diet.

Beech nuts

Maple samarras

Maple samarras, sometimes called ‘whirlybirds’ or ‘helicopters’ germinate and fall once a year. These dry fruits are soft and slightly bitter tasting, yet palatable to small mammals, such as chipmunks, squirrels and other rodents, cardinals, grosbeaks, and other birds.

Every 2-5 years, mast trees produce a bumper crop. These surpluses are referred to as ‘mast years.’ Scientists are uncertain as to what triggers the increased production of acorns, nuts, or samarras in any given year, but there is an ecological advantage to this binge reproduction. Boom years produce many more seeds and nuts than can be consumed by wildlife, therefore there is a better chance that more seeds will survive and sprout.

Mixed hardwood forests with several kinds of mast-producing trees are the most beneficial to wildlife habitats. If one kind of tree produces a scant mast crop one year, another species may prove to be more bountiful. To everything, there is a season.