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Posts tagged “Juglans nigra

Mystery Photo: Young Eastern Black Walnuts

7-6-18 black walnuts IMG_8342Congratulations to “Deb” – the first person to correctly identify the subject of the most recent Mystery Photo as young Eastern Black Walnuts!

Eastern Black Walnuts (Juglans nigra) produce abundant tiny male flowers on long, dangling, finger-like catkins. Female flowers, located on the same tree as male flowers, are fewer in number and are slightly larger. Being wind-pollinated, Black Walnut produces female flowers with stigmas (the top-most, pollen-receiving structures) which have a large surface area designed to catch pollen drifting in the wind. (These are the “rabbit ears.”) The stigmas often persist while the fruit matures  — they are barely visible on the left walnut in photo.

By September, the walnuts will have matured. They then fall to the ground where their outer husk slowly decays. The fruits are well-known for leaching chemicals into the soil that inhibit the growth of other plants, an interaction known as “allelopathy” (literally meaning “making your neighbor sick”).

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Red Squirrels Dining on Black Walnuts

1-4-15 black walnut 145The method in which a nut has been opened depends on both the species of nut as well as the species of animal that opened it. To complicate things further, it can be difficult to ascertain who opened a nut as a given species, such as the Red Squirrel, often has more than one way of opening a nut. However, a given squirrel usually chooses one way to open a nut and consistently uses that method, so that if you come upon a pile, or midden, of nuts eaten by a Red Squirrel, the nuts will most likely all have been opened in the same way.

The beveled edges on the hole in the pictured Black Walnut, the fact that it was opened from both sides (leaving the dividing rib between the two sides intact), and the central location of the holes are indications that a Red Squirrel dined on the nutmeat. The chewing of open, jagged holes on either side of a nut is a Red Squirrel’s most common method of opening a nut. Gray Squirrels tend to remove the entire side of a walnut, as opposed to chewing a hole in it.

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Black Walnut

Even though a late spring frost may have reduced this year’s crop of Black Walnuts (Juglans nigra), and even though the few that made it haven’t started falling on the ground yet, squirrels have already located and started consuming this nut’s fatty meat.  Inside the green husk is the actual nut, and if you look closely at the edges of the chewed hole as well as the inner surface of the nut, you will see tiny incisor marks, most likely left by red squirrels.  This particular rodent typically chews a hole on both sides of the nut, so that it can gain access to both halves of the meat.

Black Walnut – Identification in Winter

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Black walnut (Juglans nigra) is a relatively easy tree to identify, as it has so many distinctive qualities. In the summer there are round, tennis-ball-sized nuts, which have a delightful smell.  The bark of black walnut is dark and deeply furrowed.  Best of all are the twigs and buds.  If you cut a twig at an angle, you will see the central portion, or pith, is chambered.  It is also brown.  The only other tree that is chambered (not solid) like this is its relative, butternut (Juglans  cinerea), and butternut’s pith is buff colored.  The buds of black walnut are greyish and fuzzy – lacking bud scales.  By far the most amusing thing about black walnut (and butternut) is its leaf scars – the scar left when a leaf falls off.  The vessels that transport food and water, called vascular bundles, are darker than the rest of the scar, and are shaped in such a way that the leaf scar resembles nothing more than the smiling face of a monkey!  (Butternut leaf scars also look like monkeys, but they have a “furrowed brow” of fuzz on the top edge of the leaf scar.)


Black Walnut

Black walnut (Juglans nigra) is one of the most sought-after native hardwoods.  It has been heavily logged for its fine, straight-grained wood which has been used to make furniture, gunstocks and flooring.  Because it is becoming increasingly rare, black walnut today is used primarily for veneer.  The fruit of this tree is also highly prized, both for its meat as well as its shell, which is extremely difficult to crack, as anyone who has tried to do so by hand knows well.  Because of this hardness, the shell has a number of commercial uses, including metal cleaning and polishing, oil well drilling, paints, explosives and cosmetic cleansers.  If you would like to sample the sweet nut inside this shell, and are fortunate enough to know the location of a fruiting tree, the trick is to beat the squirrels to the nuts.  After the first hard frost, collect the nuts. Eventually the green husks turn black and soften. After rinsing the nuts under water to remove the husks (beware that the husks are a natural dye and will stain your fingers), keep the nuts dry in a cool spot. The biggest challenge comes when you wish to extract the meat – commercial production involves running the nuts between two steel wheels.  Barring that method, a hammer seems to do the trick.