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Butternut Tree - Juglans cinerea
Walnut Family: Juglandaceae
Butternut grows to 60 feet. Its lemon-shaped, citrus-scented fruit
contains a sweet, oily seed responsible for the tree's common name.
Also commonly called white walnut or oilnut. |
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Butternuts |
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Leaves are alternate, pinnately compound, with 11 to 17
oblong-lanceolate leaflets with serrate margins; rachis is
stout and pubescent with a well developed terminal leaflet;
green above and paler below. Flowers are monoecious; male
flowers are single-stemmed, yellow-green catkins, 2 1/2 to 5
1/2 inches long; females are on a short spike near the end
of the twig, green-yellow in color, appear in mid to late
summer.
Fruit: Oblong (lemon shaped), with a yellow-green sticky
indehiscent husk; husk contains an irregularly-ribbed nut
containing sweet, oily meat; mature in late summer. Fruit
husk has citrus-like odor. Twig: Stout, may be somewhat
pubescent, yellow-brown to gray, with a chambered pith that
is very dark brown in color; buds are large and covered with
a few light colored pubescent scales; leaf scars are
3-lobed, resembling a "monkey face"; a tuft of pubescence is
present above the leaf scar resembling an "eyebrow".
Bark: Light, ashy gray, with flat top, shiny ridges,
developing diamond shaped patterns. |
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No, this tree does not actually grow horizontally
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Butternut grows rapidly on
well-drained soils of hillsides and streambanks in mixed
hardwood forests. This small to medium-sized tree is
short lived, seldom reaching the age of 75. Butternut is
more valued for its nuts than for lumber. The soft
coarse-grained wood works, stains, and finishes well.
Small amounts are used for cabinetwork, furniture, and
novelties. The sweet nuts are prized as a food by man
and animals. Butternut is easily grown but must be
transplanted early because of the quickly developing
root system.
Flowering and Fruiting- Butternut flowers from
April to June, depending upon location. The
species is monoecious; male flowers are slender
catkins that develop from axillary buds and
female flowers are short terminal spikes home on
current year's shoots. Flowers of both sexes do
not usually mature simultaneously on any
individual tree. The fruit is an oblong-ovoid
pointed nut, 3.8 to 5.5 cm (1.5 to 2.2 in) long,
that matures in September and October of the
year of pollination. Nuts occur singly or in
clusters of from 2 to 5. The kernel or seed of
the nut is sweet, oily, and edible. The nut is
enclosed by an indehiscent husk that contains a
glandular pubescence on the surface. The fruit
usually remains on the tree until after leaf
fall.
Seed Production and Dissemination- Commercial
seed-bearing age begins at about 20 years and is
optimum from age 30 to 60 years. Good crops can
be expected every 2 to 3 years, with light crops
during intervening years. Thrifty trees may
yield 9 to 35 liters (0.25 to 1 bushel) of
cleaned seeds. A high percentage of mature seeds
are sound, but high premature seed losses in
butternut have been reported. Possible causes
include consumption by insects, birds, and
rodents as well as natural pollination failures
due to a lack of pollinating trees in the
immediate vicinity. Upon ripening, seeds are
dispersed by gravity and by squirrels and other
rodents. At this time, the seeds are dormant.
Cold stratification for 90 to 120 days at
temperatures of 20° to 30° C (68° to 86° F)
overcomes dormancy.
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Butternut Trees |
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Damaging Agents- Insect enemies
of butternut are often pests of associated trees as
well. Some insects commonly found on butternut
include wood borers, defoliators, nut weevils,
lacebugs, husk flies, and bark beetles. The most
serious insect pest at this time is the butternut
curculio (Conotrachelus juglandis), which injures
young stems and fruit (8,21). The most serious
disease of Juglans cinerea is butternut decline or
butternut canker. In the past the causal organism of
this disease was thought to be a fungus, Melanconis
juglandis; but now this fungus has been associated
with secondary infections and the primary causal
organism of the disease has been identified as
another species of fungus, Sirococcus
clavigignenti-juglandacearum. Symptoms of the
disease include dying branches and stems.
Cultivars of this species have been selected for nut
size and for ease of cracking and extracting
kernels. Several cultivars have been named. Nuts are
especially popular in New England for making
maple-butternut candy. Small amounts of wood are
used for cabinets, toys, and novelties.
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