Been spending some time crawling under manzanita recently and continually come across these piles of branches and twigs. Searching online led me to them. I've read stories / post online regarding them stashing shiny stuff in their houses. I would never tear one down to look inside but found it interesting what Wikipedia has on them.
Woodrats build extensive nests in trees, on the ground, and on bluffs with dense vegetation or rock cover. The conical shaped nests can be two to eight feet tall and are made of sticks, bark, and various plant matter. One nest can house successive generations of woodrats, with offspring adding to nests making them larger. The nests can have many rooms used for food storage, resting, nurseries, and protection. Nests can be built in harsh, inaccessible places such as thorny brush or poison oak patches. Dusky-footed woodrats of California have been found to selectively place California bay leaves (Umbellularia) around the edges of their nest within their stickhouses to control levels of ectoparasites such as fleas. The leaves contain volatile organic compounds which are toxic to flea larvae. Among the terpenes most toxic to flea larvae in the bay leaves are umbellelone, cineole, and cymene. Wood rats are believed to have evolved this behavioral adaptation to cope with the environmental stresses posed by ectoparasites.
Reading accounts of the old 49ers in the gold discovery area of California, they suffered mightily with fleas. You would have thought some of them would have caught on to the bay leaves idea from these critters.
This lead me down the next rabbit hole.
Umbellularia californica is a large hardwood tree native to coastal forests of California, as well as to coastal forests extending into Oregon. It is endemic to the California Floristic Province. It is the sole species in the genus Umbellularia.
The tree was formerly known as Oreodaphne californica. In Oregon, this tree is known as Oregon myrtle, while in California it is called California bay laurel, which may be shortened to California bay or California laurel. It has also been called pepperwood, spicebush, cinnamon bush, peppernut tree, headache tree, mountain laurel, and balm of heaven.
The tree's pungent leaves have a similar flavor to bay leaves, though stronger, and it may be mistaken for bay laurel. The dry wood has a color range from blonde (like maple) to brown (like walnut). It is considered a world-class tonewood and is sought after by luthiers and woodworkers.
The tree is a host of the pathogen that causes sudden oak death.
Umbellularia has long been valued for its many uses by Native Americans throughout the tree's range, including the Cahuilla, Chumash, Pomo, Miwok, Yuki, Coos, and Salinan people. The Concow tribe call the plant sō-ē’-bä(Konkow language).
The leaf has been used as a cure for headache, toothache, and earache—though the volatile oils in the leaves may also cause headaches. Poultices of Umbellularia leaves were used to treat rheumatism and neuralgias. A tea was made from the leaves to treat stomach aches, colds, sore throats, and to clear up mucus in the lungs. The leaves were steeped in hot water to make an infusion that was used to wash sores. The Pomo and Yuki tribes of Mendocino County treated headaches by placing a single leaf in the nostril or bathing the head with a laurel leaf infusion.
The chemical responsible for the headache-inducing effects of Umbellularia is known as umbellulone.
Nearly ripe bay nuts being prepared for roasting.
Both the flesh and the inner kernel of the fruit have been used as food by Native Americans. The fatty outer flesh of the fruit, or mesocarp, is palatable raw for only a brief time when ripe; prior to this the volatile aromatic oils are too strong, and afterwards the flesh quickly becomes bruised, like that of an overripe avocado. Native Americans dried the fruits in the sun and ate only the lower third of the dried mesocarp, which is less pungent.
The hard inner seed underneath the fleshy mesocarp, like the pit of an avocado, cleaves readily in two when its thin shell is cracked. The pit itself was traditionally roasted to a dark chocolate-brown color, removing much of the pungency and leaving a spicy flavor. Roasted, shelled "bay nuts" were eaten whole, or ground into powder and prepared as a drink which resembles unsweetened chocolate. The flavor, depending on roast level, has been described variously as "roast coffee," "dark chocolate" or "burnt popcorn". The powder might also be used in cooking or pressed into cakes and dried for winter storage. It has been speculated that the nuts contain a stimulant; however this possible effect has been little documented by biologists.
The leaf can be used in cooking, but is spicier and "headier" than the Mediterranean bay leaf, and should be used in smaller quantity. Umbellularia leaf imparts a somewhat stronger camphor/cinnamon flavor compared to the Mediterranean bay.
Roasted bay nuts ready for eating, or grinding into a powdery paste for beverages and cooking
Some modern-day foragers and wild food enthusiasts have revived Native American practices regarding the edible roasted fruit, the bay nut.
U. californica is also used in woodworking. It is considered a tonewood, used to construct the backs and sides of acoustic guitars. The wood is very hard and fine, and is also made into bowls, spoons, and other small items and sold as "myrtlewood". It is also grown as an ornamental tree, both in its native area, and further north up the Pacific coast to Vancouver in Canada, and in western Europe. It is occasionally used for firewood.
According to a modern Miwok recipe for acorn soup, "it is essential that you add a generous amount of California laurel" when storing acorns to dry, to keep insects away from the acorns.
One popular use for the leaves is to put them between the bed mattresses to get rid of, or prevent, flea infestations.
The wood is used as lumber in furniture making, especially highly figured specimens.
"Myrtlewood" is the only wood still in use as a base "metal" for legal tender. During the 1933 "interregnum of despair" between Franklin Roosevelt's election and his inauguration, the only bank in the town of North Bend, Oregon—the First National—was forced to temporarily close its doors, precipitating a cash-flow crisis for the City of North Bend. The city solved this problem by minting its own currency, using myrtlewood discs printed on a newspaper press. These coins, in denominations from 25 cents to $10, were used to pay employees, with the city promising to redeem them for cash as soon as it became available.
However, when the bank reopened and the city appealed for people to bring their myrtlewood money in to redeem it, many opted to keep their tokens as collector's items. After several appeals, the city announced that the tokens would remain legal tender in the city of North Bend in perpetuity. The unredeemed tokens have become very valuable, because of scarcity and historical interest. Fewer than 10 full sets are believed to exist.
Interesting that a pile of twigs and sticks can lead you into more knowledge of local vegetation. I may have to try some cooking (er, the wife to try).
Also, if you use Wikipedia, please donate.