Presented at the Symposium on Multiple-use Management of California's Hardwoods, November 12-14, 1986, San Luis Obispo, California
Acorns are a neglected food for people, livestock, domestic fowl, and wildlife in California. Acorns are easy to collect, store, and process. In addition to the nutritious nut and meal, acorns yield an oil comparable in quality and flavor with olive oil. The existing acorn market could be greatly expanded and provide new income for rural people. A serious effort to identify and propagate the best oak acorn cultivars for these products is long overdue. It is particularly appropriate for this research to be done in California, which once had an acorn based economy.
Acorns have been used as food by Homo sapiens for thousands of years virtually everywhere oaks are found. The worldwide destruction of the acorn resource by mismanagement may well have led to the development of annual plant based agriculture and to civilization as we know it today (Bohrer, 1972; Bainbridge, 1985b). In Europe, Asia, North Africa, the Mid-East, and North America, acorns were once a staple food, (Hedrick, 1919; Loudon, 1844; Brandis, 1972; Lefvebre, 1900; and Bishop, 1891). The Ch'i Min Yao Shu, a Chinese agricultural text from the sixth century recommends Quercus mongolica as a nut tree (Shen Han, 1982). In Spain and Italy acorns provided 20 percent of the diet of many people just before the turn of the Century (Memmo, 1894).
Acorns were perhaps nowhere more important than in California. For many of the native Californians acorns made up half of the diet (Heizer and Elsasser, 1980) and the annual harvest probably exceeded the current California sweet corn harvest, of 60,000 tons. Acorn foods remain on the market not only in Korea, China, and North Africa, but in most major American cities, at Korean food stores (Wolfert, 1973; Bainbridge, 1985a).
A reevaluation of acorns and their uses is long overdue. The acorns of all 500 species should be tested. Although the acorns of some oaks are probably too small or too hard to open for widespread use many species that can and should be planted for use as food. They are also valuable feed for domestic animals and birds, and wildlife.
The factors that made acorns a major food source in California in the past make them attractive candidates for greater use in the future. They often ripen all at once and are easy to collect. They store well and were kept by the native Californians for several years in simple storage bins (Merriam, 1918). They are simple to prepare, even for the varieties that need to be leached. Although most species are bland, as are corn and wheat; some have good flavor and could be used in place of other nuts.
The yield of acorns per acre compares well with grains. When the long-lived, deep-rooted oaks can reach sufficient water; acorn production can be very high, with yields of more than 5,280 kg/ha (6,000 pounds/ acre) (Bainbridge, 1986). High acorn yields can be maintained on hilly lands where annual grain crops cause severe soil erosion (Bainbridge, 1987a).