Black Walnut Traditional Cache

Black Walnut is near parking on Keith Lane, but grab your stick for stability. I am glad I did.

Juglans nigra, the eastern black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to eastern North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.

Black walnut is an important tree commercially, as the wood is a deep brown color and easily worked. The fruits, walnuts, are cultivated for their distinctive and desirable taste. Often, trees are grown for both lumber and walnuts simultaneously and many cultivars have been developed for improved quality nuts or wood. Black walnut is currently under pressure from the thousand cankers disease which is causing decline of walnuts in some areas. Black walnut is also allelopathic, which means that it releases chemicals from roots and other tissues which harm other organisms and give the tree a competitive advantage, this is often undesirable as it can harm garden plants and grasses.

Black walnut nuts are shelled commercially in the United States. About 65% of the annual wild harvest comes from the U.S. state of Missouri, and the largest processing plant is operated by Hammons Products in Stockton, Missouri. The nutmeats provide a robust, distinctive, natural flavor and crunch as a food ingredient. Popular uses cakes, cookies, fudge, and pies, during the fall holiday season. The nuts' nutritional profile leads to uses in other foods, such as salads, fish, pork, chicken, vegetables and pasta dishes.

Nutritionally similar to the milder-tasting English walnut, the black walnut kernel is high in unsaturated fat and protein.

Tapped in spring, the tree yields a sweet sap that can be drunk or concentrated into syrup or sugar which is not unlike the sap of sugar maple.

The extraction of the kernel from the fruit of the black walnut is difficult. The thick, hard shell is tightly bound by tall ridges to a thick husk. The husk is best removed when green, as the nuts taste better if it is removed then. Rolling the nut underfoot on a hard surface such as a driveway is a common method; commercial huskers use a car tire rotating against a metal mesh. Some take a thick plywood board and drill a nut-sized hole in it (from one to two inches in diameter) and smash the nut through using a hammer. The nut goes through and the husk remains behind.

While the flavor of the Juglans nigra kernel is prized, the difficulty in preparing it may account for the wider popularity and availability of the Persian walnut.

Hands after removing the husks from 500 black walnuts

Three boards of black walnut showing the color and grain.

Black walnut drupes contain juglone lumbagin (yellow quinone pigments), and tannin. These compounds cause walnuts to stain cars, sidewalks, porches, and patios, in addition to the hands of anyone attempting to shell them.The brownish-black dye was used by early American settlers to dye hair. According to Eastern Trees in the Petersen Guide series, black walnuts make a yellowish-brown dye, not brownish-black. The apparent confusion is easily explained by the fact that the liquid (dye) obtained from the inner husk becomes increasingly darker over time, as the outer skin darkens from light green to black. Extracts of the outer, soft part of the drupe are still used as natural dye for handicrafts. The tannins present in walnuts act as a mordant, aiding in the dyeing process, and are usable as a dark ink or wood stain.

Walnut shells are often used as an abbrasive in sand blasting or other circumstances where a medium hardness grit is required. The hard black walnut shell is also used commercially in abrasive cleaning, a filtering agent in scrubbers in smoke stacks, cleaning jet engines, cosmetics, and oil well drilling and water filtration.

Black walnut is highly prized for its dark-colored, straight grained, true heartwood. It is heavy, strong, shock resistant and yet can be easily split and worked. Along with cedars (Thuja spp.), chestnut Castanea spp.), and black locust (Robinia pseudoacacia) black walnut is one of the most durable hardwoods in the US. The wood can be kiln dried and holds its shape well after seasoning with makes this wood even more attractive for wood working.

Walnut wood has historically been used for gun stocks, furniture, flooring, paddles, coffins, and a variety of other wood products. Due to its value, forestry officials often are called on to track down walnut poachers; in 2004, DNA testing was used to solve one such poaching case, involving a 55-foot (16-m) tree worth US$ 2,500. Black walnut has a density of 660 kg per cubic meter (41.2 lb/cubic foot), which makes it less dense than oak.

Black walnut is allelopathic as it excretes chemicals into its environment which harm competition. While many species of plants are allelopathic, walnuts are particularly famous for it, records of walnut toxicity to other plants have been observed as far back as the first century when Pliny the Elder wrote: "The shadow of walnut trees is poison to all plants within its compass." Walnuts have since been observed as being toxic to many plants including herbaceous and woody plants

Like other walnuts, the roots, innerbark, nut husks, and leaves contain a nontoxic chemical called hydrojuglone, when exposed to air or soil compounds it is oxidized into juglone which is biologically active and acts as a respiratory inhibitor to some plants. Juglone is poorly soluble in water and does not move far in the soil and will stay most concentrated in the soil directly beneath the tree. Even after a tree is removed the soil where the roots once were will still contain juglone for several years after the tree is removed as more juglone will be released as the roots decay. Well drained and aerated soils will host a healthy community of soil microbes and these microbes will help to break down the juglone.

Symptoms of juglone poisoning include foliar yellowing and wilting. A number of plants are particularly sensitive including: apples, tomatoes, pines, and birch are poisoned by juglone, and should not be planted in proximity to a black walnut.

The cache is a camoed "micro" pill bottle with double arrows on the lid. That means you have to push down hard, both to open and close. It contains a rolled log with a rubber band in a tiny plastic bag. Please keep track of it all and return as you found it. BYOP and No Tweezers, please.