Chestnut

Description

Chestnut (Castanea spp.) is a deciduous tree in the family Fagaceae grown for its edible seeds (nuts). The chestnut tree has a thick trunk covered in gray bark. The trunk has an erect growth habit and can grow 2 m (6.6 ft) in diameter. When the tree stands alone, the canopy can spread 15 m (49 ft) across and is made up of glossy leaves with serrated margins and pointed tips. The leaves are hairy with visible glands on the underside. The chestnut tree produces flowers on long catkins and the seeds are produced in clusters of 1–3. The seeds are covered by a thick, spiny bur which is approximately 10 cm (4 in) in diameter. The kernel within is protected by a thin, dark brown shell. Chestnut trees can reach 40–60 m (131–198 ft) in height and can live for in excess of 150 years. Chestnut may also be referred to by variety and includes European, American, Japanese and Spanish chestnut. The tree originates from Asia.


Uses

Chestnuts are commonly consumed after roasting or may be processed to produce chestnut creams and purees or for canning.


Propagation


Basic requirements
Chestnuts are hardy trees which will grow in a variety of conditions. The trees grow best in well-draining, acid loam soils and require a pH between 4.5 and 6.5. The trees perform well when planted on a gentle slope which allows cold air to drain to a lower area as well as aiding in soil drainage. Chestnuts should be planted in full sunlight and open fields are preferred for maximum nut production.Chestnut has poor self compatibility and at least 2 trees are required for nut production.

Propagation
Chestnut trees can be grown from seeds or can be propagated by grafting onto a seedling rootstock. Seedling grown for use as a rootstock for grafting are usually ready to receive a scion when they are two years old. The seedling must have reached a suitable thickness in order to receive a graft (usually when it reaches a thickness similar to that of a pencil).

Germinating seeds
Chestnut seeds germinate readily but not all will produce a seedling suitable for planting and/or grafting. Seeds can be obtained from breeders or collected from chestnut trees in the Fall. Seeds should be kept refrigerated until planting and can then be directed seeded outdoors or grown in containers inside. Seeds should be planted in early Spring as soon as the soil can be worked. The seed should be planted in a hole 7.5 to 15.0 cm (3-6 in) deep with the radicle (embryo emerging from the seed) facing downwards. If planting in a container, be sure to choose one that is at least 30 cm (12 in) deep and 10 cm (4 in) in diameter. The seeds can be planted earlier if the containers are to be kept indoors.

Planting seedlings
Seedlings started in containers can be transplanted after all danger of frost has passed and after hardening. The seedling should be planted in a hole that is at least 1.5 times the size of the existing root ball. Gently remove the remnants of the nut from the roots and place the seedling in the hole. Backfill the hole with soil and tamp to remove air pockets. Seedlings should be planted 10–12 m (33–39 ft) apart, allowing an additional 10–12 m (33–39 ft) between rows. After planting, the seedlings should be watered thoroughly. Continue watering the seed for the first month after planting to help the seedling establish.

General care and maintenance
After planting, the areas around the trees should be kept free from weeds. A layer of mulch spread around the trunks will help suppress weeds and conserve soil moisture. You may have to protect the young trees from pests such as deer which can cause severe damage to the trees. The most effective method of protecting trees is to erect an 8 ft high metal deer fence around the area where the new trees have been planted.


References

Anagnostakis, S. L. (2013). Growing Chestnut Trees. The Connecticut Agricultural Experimental Station. Available at: http://www.ct.gov/caes/lib/caes/docum.... [Accessed 11 November 14]. Free to access

CABI Crop Protection Compendium. (2008). Castanea datasheet. Available at: http://www.cabi.org/cpc/datasheet/16574. [Accessed 11 November 14]. Paid subscription required.

The Pennsylvania Chapter of the American Chestnut Foundation (2006). Planting and Growing Chestnut Trees. PA-TACF Planting Manual. Available at: http://www.acf.org/pdfs/resources/pla.... [Accessed 11 November 14]. Free to access

Vossen, P. (2000). Chestnut Culture in California. University of California Division of Agriculture and Natural Resources. Available at: http://anrcatalog.ucdavis.edu/pdf/801.... [Accessed 11 November 14]. Free to access




Common Pests and Diseases

Blight
Cryphonectria parasitica

Symptoms
Sunken or swollen, yellow-brown, oval cankers on branches or trunk; cankers may girdle stems and result in yellow-brown leaves which remain attached; water may be visible below cankers
Cause
Fungus
Comments
American and European chestnuts are susceptible to the disease; Japanese chestnuts have some resistance; the fungus was introduced to the US via imported chestnuts and completely devastated the population of chestnut on the east coast
Management
Infected trees must be removed and destroyed to prevent spread

Leaf spot
Marssonina ochroleuca

Symptoms
Small, circular, yellow-brown spots on leaves which may have concentric rings; holes in leaves as lesions dry and drop out; premature leaf fall
Cause
Fungus
Comments
Management
No control methods are currently recommended

Japanese beetle
Popillia japonica

Symptoms
Leaves skeletonized (only veins remaining); flowers and buds damaged; plant damage may be extensive; adult insect is a metallic green-bronze beetle with tufts of white hair protruding from under wing covers on each side of the body; adult beetles are approximately 13 mm in length; larvae are cream-white grubs which develop in the soil
Cause
Insect
Comments
One beetle generation every 1-2 years; pheromone traps may actually attract more beetles to home gardens and should generally be avoided; beetle overwinters as larvae in soil; beetle has an extensive range of over 300 host plants
Management
If beetles were a problem in the previous year, use floating row covers to protect plants or spray kaolin clay; adult beetles can be hand picked from plants and destroyed by placing in soapy water; parasitic nematodes can be applied to soil to reduce the number of overwintering grubs; insecticidal soaps or neem oil can help reduce beetle populations

Chestnut weevil (Lesser chestnut weevil, Larger chestnut weevil)
Curculio sayi
Curculio caryatrypes

Symptoms
Nuts on ground with small circular hole bored from the inside; adult insects are dark brown beetles with protruding snouts; larvae are creamy white grubs
Cause
Insect
Comments
Female weevil lays her eggs in the shell of the nut and larvae hatch and feed inside; larvae exit the nut through a small hole bored in the shell and enter the soil when the nut falls to the ground; most larvae pupate after one year
Management
Chestnuts should be picked daily and, after curing, should be heated to 60°C (140°F) for 30 minutes to kill off any larvae inside nuts; collecting the nuts promptly after they have fallen prevents larvae from leaving the nut and entering the soil