I helped my father plant a Chinese chestnut tree in our front yard when I was growing up, and another nearby for pollination purposes. He had ordered it through the mail, from a nursery catalog. As it grew, we couldn’t eat or give away all the nuts it produced. I hurt my feet more than once on the burs that encased the nuts, and there was leaf and bur litter to contend with each autumn. However, the tree looked very nice and enabled many, like me, to see how chestnuts looked and tasted. The native American chestnut, Castanea dentata, which once was as common as oaks, hickories, and pines, had by my time been devastated by Chinese blight. It is sad that my father’s chestnut tree was such a novelty.
China and Korea are the largest producers of chestnuts in the world. The Chestnut species that contribute to worldwide chestnut production are European chestnut, Castanea sativa, Japanese chestnut, Castanea crenata, and Chinese chestnut, Castanea mollissima. The Chinese chestnut is native to East Asia, which includes the countries of China, Taiwan, Korea, and Japan. In the 1890’s, or shortly before, chestnut tree nursery stock from East Asia were imported to the United states to grow as orchard trees. Some carried Cryphonectria parasitica, a bark fungal chestnut blight disease. American chestnuts quickly succumbed to the disease. Since Chinese chestnut trees had coexisted with the fungus for many years in Asia, and had developed some resistance to the disease, this tree became the main source of chestnuts for Americans. A cross and back-breeding program using the Chinese chestnut is in its last stages and will soon bring the native tree back in a more disease-resistant form. (For detailed differences between Chinese and American chestnut trees see American Chestnut Foundation.) The American chestnut is sure to become an important contributor to worldwide chestnut production in the future.
Chinese chestnut trees are grown around the world, and in America they are frequently seen from Maine to Florida. They can be understory trees, but they prefer full sun and acidic, loamy soil. Soil that is well drained and moist, but not wet, is good. Heavy clay and any soil that is poorly drained invites root rot. Established trees are drought tolerant, but stressed trees do not grow as well and produce fewer and smaller nuts. Shade also decreases nut production. Trees are heat tolerant, and also cold hardy to -20 degrees F.
Size of the Chinese chestnut tree is 45 to 50 feet in height, and width may be wider. They have spreading branches that droop. Growth is at a medium rate. In comparison with American chestnut trees, these trees are shorter and wider. Bark is gray, and deeply furrowed. Roots are not considered a problem.
Branches of Chinese chestnuts are smooth and gray. Stems are tan to pea-green, hairy, and have lenticels which appear as small bumps. Stipules, appearing as tiny, broad leaves, cover the buds until late summer. Petioles are thick, and measure about ½ inch long. Leaves are alternate and oval, and measure 4 to 8½ inches long and 1¾ to 3 inches wide. The leaf base is rounded and the tip is pointed. A large leaf mid-vein feeds smaller veins, which end in spiny teeth at the margins. Top of leaf is glossy dark green, thick and waxy-feeling. Leaf underside appears whitish due to many hairs, and leaf veins there are also hairy.
Buds on Chinese chestnuts form in late summer, and appear rounded. The following spring, from late May through June, shoots emerge from these buds with two kinds of catkins appearing along the shoots. This picture of catkins was made first week of June. Male or staminate catkins are positioned on the proximal end of shoots, and bi-sexual catkins are at the base. Catkins can measure 1½ to almost 8 inches long. Flowers in the catkins are primarily wind pollinated, and the odor given off by the flowers may be considered offensive to some people. The tree is not self-fertile, but requires two or more varieties planted within 200 feet of each other to produce fruit.
Chinese chestnuts are encased in burs that have a dense mass of short, thick and sharp spines. They mature in late September through October. Pictures made were in early September. The burs are 1½ to 3 inches in diameter, and the spines are about .3 to .8 inches long and .04 inches thick. Contact with burs can be painful, so it is important to dispose of burs if people will be about the tree. Even remaining burs from previous years are sharp enough to hurt. There are 2 to 3 nuts in each bur, and they measure 3/4 to 2 inches in diameter. Each nut has a leathery skin which is glossy brown. Nut tips are rounded and hairy. On the opposite side from the tip, vascular bundles can be seen in a diffuse pattern.
Chinese chestnuts taste sweet, and many favor them above other chestnuts. At harvest, they are best when allowed to “cure” for a few days to reduce moisture content and increase sugar content. Chestnuts are 40-45% carbohydrates, 5-8% protein, 2-3% fat with no cholesterol, and about 44% water. Due to water content, chestnuts will spoil if not refrigerated or dried. Dry chestnuts are rock hard and can’t be eaten, but they can be rehydrated in boiling water or ground into gluten-free chestnut flour. Lactose-free milk can be made from this, as well as pancakes, muffins and pastries. They can also be made into soups, poultry stuffing, and many desserts. With many vitamins and minerals, and no cholesterol or gluten, chestnuts are healthy to eat.
The wood of chestnut trees has up to 20% tannin content, the highest of all tree species, making it extremely rot resistant. Easily split, the wood makes excellent posts. The wood has been used for bridge timbers, beams for houses and barns, railroad ties, exterior siding, flooring, exterior trim, doors and windows, furniture, caskets, shingles. Tannin for use in the tanning industry is extracted by soaking finely ground wood in water. Chestnut timber can be harvested in 50-70 years. A coppiced tree produces trellises and stakes after 2-3 years, and fence posts after 10-20 years.
There are herbal remedies made from the Chinese chestnut tree. Chestnut leaves have up to 95% tannin, and high amounts of vitamin K. Teas from the leaves have been taken as a remedy for respiratory diseases such as whooping cough. Adding thyme to the tea produces a remedy for cough, diarrhea, and backache. Tea made from the flowers has been used for sinusitis, and chestnut flower honey has been used for gastritis and liver problems.
It would be hard to find a more useful tree. Provided burs are kept cleared from the area, the Chinese chestnut tree can make a nice shade. It has attractive form, coarse texture, and interesting catkins and burs for use as an ornamental. The nuts are delicious and healthy to eat. They help make gluten-free and lactose-free dishes and drinks, for those having this necessity. The wood has high tannin content and splits easily, making it important for uses where rot resistance is important. Many trees have none, one, or some of these uses, but to my knowledge only the Chinese chestnut has them all.