Chinese Chestnut is a large flowering, deciduous tree in the Fagaceae family that is native to parts of Asia, including Korea and China.
Tree Identification
Bark – Juvenile Chinese chestnut trees have very smooth, gray bark that slowly develops fissures with age. Mature specimens have very deeply fissured and plated bark, with a grayish brown color. It is very common for green lichens to grow on the trunk and branch bark, as well as for moss to grow on the more damp bark located on the north facing buttresses or root flare of the tree, at the base of the trunk.
Leaves – Medium to large in size, with toothy serrations along the edges. Color ranges in various shades of green. Generally the lower leaves on the tree, or the shade leaves, are quite large and dark green whereas the leaves higher in the canopy in full sunlight are smaller and lighter green.
Flowers – The male flowers are long clusters of yellow or cream colored catkins. Female flowers are much smaller and less conspicuous, located at the base of the male flower and develop into the spiny green husk that houses the chestnut fruits. Insects are an important pollinator of chestnut flowers, including native insects such as the Goldenrod soldier beetle.
Fruit – Medium to Large brown or russet nut (a chestnut). Generally each spiky green bur contains 2 to 3 fully developed ripe chestnuts that fall at the end of September. Due to the many different cultivars, nut size can vary greatly but is generally quite large. Considered to be one of the best tasting nuts in the chestnut family, Chinese chestnut is highly coveted for their taste and size.
Tree Characteristics
Chinese chestnut trees have been selectively cultivated for many thousands of years in eastern Asia and are thus a very developed orchard tree. Given their consistent large annual harvest of nuts, they make for a very suitable planted specimen or orchard tree. They are commonly grown in hunting plots for animal mast and forage, specimen trees in parks and homes, and in large orchards where the nuts are harvested for commercial purposes.
Lifespan – Chinese chestnut trees have a very long lifespan in the range of 200 to 1000 years, with living specimens being confirmed as over 800 years old. Many sources elsewhere erroneously underestimate or understate the longevity of this tree, but given proper care, they can easily live for hundreds of years, just like European, or Sweet, chestnuts (Castanea sativa) can.
Growing zone – Generally a very hardy tree, they grow well in USDA Hardiness zones 4-10. In the colder regions, harsh winters and late frosts can damage the juvenile wood and buds; whereas in hotter regions they are susceptible to drought. Chinese Chestnut can generally be grown in the entirety of eastern America and in many parts of the Central and Western states as well.
Soil – They can grow in virtually any soil type, but prefer sand or loam, which drains much faster than clay soils. The soil should not be waterlogged; ideally the trees are located on ridges or slopes where water quickly drains away from the roots. Chestnuts are very susceptible to root rot in such damp soils and thus this growing condition should be avoided if possible. Additionally, it is very important to keep the buttress roots of the trunk, also known as the root flare, free of soil and mulch surrounding or in contact with it. This allows for the tree roots to respire, or take in oxygen, freely as well as keep damp soil from inducing rot in the bark of the trunk or root flare, which stabilizes the tree.
Light requirements – Can tolerate anywhere from dense shade to full sunlight, and all conditions in between. Fruit production will be much greater and occur sooner in chestnut trees grown in full sunlight. Chestnut trees grown in the understory will stay significantly smaller and shorter until “released” from surrounding shade and allowed to grow in sunlight.
Water requirements – In the early juvenile development period, they require consistent moderate amounts of water and can be significantly impacted by drought. Mature trees are very hardy and can be considered drought tolerant.
Size – Chinese chestnut grows into a large 40 to 60 foot tall, with an equally large canopy spread, specimen tree if left unpruned. If regularly pruned in an orchard manner, it can be kept to a more manageable size of 20 to 30 feet in height. The trunk of the tree grows quite rapidly in its juvenile years, often adding as much as one inch per year to the diameter of the trunk. Once the trunk reaches around 24 inches in diameter, it starts to slow down, taking many years to achieve a maximum trunk width of around 4 or 5 feet in exceptionally old specimens.
Growth rate – Reasonably moderate to fast growers, young Chinese chestnut trees will often grow 12 to 24 inches per year for the first few decades, before slowing down considerably once reaching around 30-35 feet in height. Depending on the genetics of the tree, they will grow very little once reaching around 40 or 50 feet in height, instead focusing most of the tree’s resources on maintaining the large canopy and nut production.
Pathogens and Pests – Remarkably hardy trees, they generally have very little problems with disease or insects. The chestnut blight only affects them very marginally, and any small orange cankers quickly heal over with callus wood. Chestnut weevil can develop within the fruit of the tree, but it does not harm the nut whatsoever.
Overall, the Chinese Chestnut tree is very valuable for those who enjoy the taste of their sweet, large fruit. A mature tree can drop anywhere from 50 to 200 pounds of nuts during the harvest, generally at the end of September. It can become a magnificent shade or specimen tree as well; many huge mature Chinese chestnut trees line part of Leakin Park in Baltimore, Maryland. Provided it is well cared for and not overly pruned or subject to root damage, these trees will easily give shade and joy for countless generations.
