Chestnut Fact Sheet
- Family: Fagaceae
- Genus: Castanea
- Commercially important species:
- American Chestnut; Castanea dentata (practically extinct since 1930's from Chestnut Blight)
- European Chestnut; C. sativa
- Chinese Chestnut; C. mollissima
- Japanese Chestnut; C. crenata
- Related species: Chinkapin (Castanopsis), Oak (Quercus), Tanoak (Lithocarpus), Beech (Fagus)
- Description: Deciduous tree; leaves 5-7 inches sharply serrated, oblong-lanceolate, pinnately veined; bark gray; heights to 100 ft. Male flower = catkin, female flower attached to base of some catkins. Pollen is wind-transferred and often too early for peak female receptivity. Cross pollination between two varieties is therefore required. Terminal bearing; large, starchy nut in a regularly dehiscent prickly burr. Generation time 4-8 years.
- Origin: Scattered native species in europe, Asia, and North America.
- History of cultivation: Domestication still incomplete, but Chestnuts first recorded in China around 900 A.D.
- Current production: 1.2 billion pounds worldwide. China 40%; Italy, Turkey, Japan, Korea around 10% each; U.S. less than 1% of total production.
- Site requirements: Optimum production in deep, alluvial, well-drained soils, pH 60-6.5. Warm growing season; some varieties tolerate lows below 0 F.
Cultivation in California
- History: Scattered single trees and small groves planted throughout Northern California mountains by Chinese immigrants during gold Rush. Also, some trees planted along north and central coast by Italian homesteaders.
- Cultivars: Colossal (European x Japanese) - most common in California; Layeroka, Skioka, and Skookum (all European x Chinese) are considered to be cold hardy and are planted in the Northwest.
- Rootstocks: most California trees on own roots. Difficult grafting; some potential with Maraval, Primato, Tsukuba, Marigoule stocks.
- Propagation: Whip grafting onto seedlings in late Spring.
- Spacing: 25' x 25' (70 trees/acre); pollenizer row every fifth row; hedgerow 11' x 22' (180 trees/acre)
- Irrigation: In dry areas, new trees need 5-8 gallons of water per tree per week in driest months. Coastal plantings may need little or no irrigation following tree maturity.
- Training System: Open center or central leader (self-training)
- Nutrition: Similar to Walnut. Available nitrogen below 2.3%, potassium below 0.9%, zinc below 15 ppm; Toxicities - boron over 300 ppm, sodium over 0.1%, chlorine over 0.3%.
- Harvesting: Hand harvested off ground, ideally every two days during two-week October drop. Prickly burrs still removed largely by hand. Some attempts at using modified walnut sweepers and hullers have had limited success.
- Marketing: Only cottage-scale marketing in California so far. Most chestnuts consumed in U.S. come from Italy. No organized California chestnut "industry" yet.
- Environmental: water stress; nutrient deficiency; soil alkalinity; poor drainage.
- Insect/Pest: Spider mites, shot hole borers, Filbert worm, squirrels, all relatively minor.
- Disease: root rot (Phytophthora), Oak root fungus (Armillaria mellea), Chestnut blight (Cryphonectria parasitica).
- Chestnuts as an Alternative Crop. 9189. Paul Vossen, University of California Cooperative Extension, Sonoma County.
- Growing Chestnuts in Oregon. 1992. Robert L. Rackham.
- The Trees of North America. 1987. Alan Mitchell.
Prepared by Jason Thomas 1995