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Posts tagged “Fagus grandifolia

A Promising Fall Beechnut Crop

Beechnuts, high in protein and fat, are the primary fall and winter food for many forest wildlife species including Red, Gray and Flying Squirrels, Eastern Chipmunks, Black Bears, Blue Jays, Tufted Titmice, Wild Turkeys, and Ruffed and Spruce Grouse.  The dependence of these animals on this food source makes them vulnerable to the American Beech’s cyclical nut production.

In the Northeast, American Beech (Fagus grandifolia) mast crops (amount of beechnuts produced by beech trees) have a two-year cycle: one year they produce an overabundance of nuts and the following year very few. Among other animals, Black Bears rely on these nuts to sustain themselves over the winter.  That a bear’s nutritional health affects its reproductive health was documented in  a study in Maine that showed that the mean proportion of female bears producing cubs decreased to 22% when a denning period followed a poor beechnut crop. During denning periods following good beechnut production, 80% of the productively available females produced cubs.

Many American Beech trees in the Northeast suffer from Beech Bark Disease which has seriously compromised their ability to produce nuts.  Invasive scale insects (Cryptococcus fagisuga) invade a tree. Through a presently unknown mechanism, excessive feeding by these insects causes two different fungi (Neonectria faginata and Neonectria ditissima) to produce annual cankers on the bark of the tree. This disease decreases nut production, and eventually lesions around the tree girdle it and causes the tree’s death. The diminishing number of healthy beech trees will have a significant effect on consumers of beechnuts as well as a broad array of other organisms.

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Next Year’s Buds Already Formed

11-7-18 A. beech bud _U1A1228Because tree buds tend to swell and increase greatly in size in the spring, this is often the season when we first notice them and assume that this is when they are produced.  However, if you look in the axils of leaves on any deciduous tree right now, you will see full-size buds that were formed this summer.   These little packages of miniature leaves, branches and sometimes flowers, will remain on trees all winter, tightly closed and often protected from the elements by modified leaves called bud scales.  Come spring, when trees are once again taking up quantities of water, their buds will swell, scales will fall off (leaving bud scale scars), and tiny, pristine leaves or flowers will appear.  (Photo is of American beech, Fagus grandifolia, bud.)

Just a quick reminder that the NC Calendar ordering deadline is November 10th.

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Beechnuts & Black Bears

11-22-17 black bear scat and beechnuts 049A7821One need look no further than this Black Bear scat to know that American Beech (Fagus grandifolia) nuts (hard mast) are a preferred food for Black Bears, both in the fall and spring. They are an important food source for other wildlife as well, including White-tailed Deer, Fishers, Wild Turkeys, Ruffed Grouse and many small mammals and birds.

There are very good reasons why beechnuts are a preferred food for so many creatures. They have about the same protein content as corn but five times the fat content. Compared to acorns, beechnuts have nearly twice as much crude protein, twice the fat of white oak acorns and about the same fat content as red oak acorns. Research on the importance of beech mast for Black Bear reproduction shows that in northern Maine, 22% of the female black bears that were reproductively available reproduced following falls when beechnut production was poor. The proportion of reproducing females increased to 80% following falls when beechnut production was high. (Photo:  Black Bear beechnut husk-filled scat, 1 1/2″ diameter)


Bud Scales

bud scales 147Much of this coming summer’s woody plant growth is contained in embryonic form inside a tree’s buds. Buds contain an undeveloped shoot, leaf, and/or flower. Formed last summer, these buds must survive the freezing and fluctuating temperatures, relatively dry air and the potential insect, bird and fungal damage that may occur during the fall, winter and early spring.

Bud scales, which are small, modified leaves, cover and protect many of these buds. The number of scales, their arrangement, color, presence or absence of hairs or sticky substances are often distinctive. Willows have one visible bud scale (actually two fused into one), whereas pine and fir buds may have anywhere from 100 to 350. The scales on a bud can either be arranged in pairs facing each other edgewise (American Basswood, pictured) or overlapping like shingles (Sugar Maple, pictured). Colors range from the wine-colored bud scales of Striped Maple to the mustard yellow Bitternut Hickory scales. The texture of bud scales has great variation, including the satiny-smooth hairy bud scales of Box Elder (pictured). Many bud scales, such as poplars, are covered by a gummy substance which serves as added protection.

A few trees and shrubs have buds that lack scales. These are referred to as “naked” buds, and often the embryonic leaves are quite hairy. Witch Hazel, Hobblebush and Staghorn Sumac (pictured) are species of woody plants lacking bud scales.

Most buds have multiple scales which, upon falling off when the bud opens, leave a series of horizontally-elongated scars on the surface of the growing stem. By means of these scars one can determine the age of a young branch, since each year’s growth ends in the formation of a terminal bud which produces an additional group of bud scale scars. Continued growth of the branch causes these scars to be indistinguishable after a few years so that the age of older branches cannot be determined by this means.

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Beech Bark Disease

 Anyone familiar with the beautiful, smooth, gray bark of American beech is well aware that the forest landscape is changing, in part due to the disease that is affecting American beeches. Beech bark disease is caused by not one, but two, agents – an insect and a fungus.  The bark of an American beech is initially attacked and altered by the soft-bodied scale insect, Cryptococcus fagisuga, after which it is invaded and killed by fungi, usually Nectria coccinea var. faginata or N. gallegina. This scale insect was accidentally introduced to Nova Scotia around 1890 and since then has spread far and wide, affecting large American beech trees (over 8 inches) the most.  Pale yellow eggs are laid by the yellow female scale insects (there are no males – they reproduce through parthenogenesis) on the bark of beech trees in mid-summer and hatch in the late summer or fall.  Larvae begin to feed on the bark until winter when they transform into a stage that has no legs and is covered with wool-like wax. The white wax secreted by beech scale insects is the first sign of the disease – heavy infestations of beech scale can cover tree trunks with white wax. Serious damage results only after the invasion of the bark by either one of the fungi mentioned, presumably through injuries made by scale feeding activity.

 


Tree Bud Formation

 

Because tree buds tend to swell and increase greatly in size in the spring, this is often the season when we first notice them and assume that this is when trees produce them.  If you look in the axils of leaves on any tree right now, you will see full-size buds that were formed this summer.   These little packages of miniature leaves, branches and sometimes flowers, will remain on trees all winter, tightly closed and often protected from the elements by modified leaves called bud scales.  Come spring, when trees are once again taking up quantities of water, their buds will swell, scales will fall off (leaving bud scale scars), and tiny, pristine leaves will appear.  (Photo is of American beech, Fagus grandifolia, bud.)

 

 


Beechnuts

Birds and mammals that rely on beechnuts as a staple of their diet include black bears, white-tailed deer, fishers, porcupines, wild turkeys, ruffed grouse, wood ducks, tufted titmice, and numerous small rodents, to name but a few.  There is a good reason for this – beechnuts have about the same protein content as corn, but five times the fat content.  Beechnuts also have nearly twice as much crude protein and twice the fat of white oak acorns and about the same fat content as red oak acorns.  Given the number of husks and nuts that are on the forest floor this fall, it appears that this is a good year for beechnut mast, or seed production.  Research has shown that high beechnut production in the fall is correlated with a high percentage of reproducing female black bears in the coming winter.