The sweet chestnut tree (Castanea sativa Mill.) is a medium-large deciduous tree that may reach 30-35 m. The tree is long-living and can live up to 1 000 years, when cultivated. It can also reach a significant circumference (up to 12 m at breast height). The bark is brown-greyish, leaves are oblong-lanceolate (8-25 cm long, 5-9 cm broad) with a dentate-crenate margin and a brighter green upper leaf surface. This species tree is monoecious and flowers develop in late June to July and may be pollinated by wind (more usual in case of dry weather during flowering) or insects (dominating in wet weather conditions).
The broad diffusion and active management by man resulted in the establishment of the species at the limits of its potential ecological range, which makes difficult to trace its original natural area. The present distribution ranges from North-Western Africa (e.g. Morocco) to North-Western Europe (southern England, Belgium) and from south-western Asia (e.g. Turkey) to Eastern Europe (e.g. Romania), the Caucasus (Georgia, Armenia) and the Caspian Sea. In Europe the main chestnut forests are concentrated in a few countries such as Italy, France and the Iberian Peninsula.
The sweet chestnut is a warm-temperate deciduous species that likes a mean yearly temperature ranging between 8 and 15 °C and monthly mean temperatures over 10 °C during 6 months. The species needs a minimum rainfall that ranges between 600 and 800 mm according to its distribution and interaction with temperatures. The lowest elevations are recommended for the highest latitudes and vice versa. The chestnut tree displays a high sensitivity to summer droughts issuing from the combination of high temperatures and lack of precipitation. It does not thrive on limestone, preferring well-drained, from very acidic to neutral soils and nutritionally poor sites. Due to the strong cultivation pressure, it is very difficult to define natural chestnut stands with consociated tree communities. In fact in about 90 % of chestnut forests, this tree is pure or the dominant species. With time over-aged and oversized chestnut orchard trees and coppice stools become unstable and tend to uproot, disrupting the original chestnut structures within the post-cultural ecosystems.
This has caused a severe decrease of biodiversity in the affected regions and reduced ecosystem service provision. Further threats for chestnut trees include the ink disease (Phythophtora spp.), the spread of the newly introduced chestnut blight (Cryphonectria parasitica), and the impact of the Chinese gall wasp (Dryocosmus kuriphilus).
In Europe the sweet chestnut covers an area of more than 2.5 million hectares. Most of the area (89 %) is concentrated in just a few countries (France, Italy, followed by Spain, Portugal, and Switzerland) with a long tradition of chestnut cultivation. Due to its multipurpose character, the chestnut tree has always been cultivated in different management systems,
according to the targeted products and services. Chestnut wood is particularly suitable for external use, thanks to its natural high tannin content that acts as a protection against decay. In former times tannin extraction was also a very common use of the timber. Due to its high re-sprouting capacity, coppice represents the main type of forest management with about 80 % in cover of the chestnut forests, supplying principally fire wood, charcoal, poles (fence, pit-props, etc.), and wood for small products (barrels, shingles, sleepers, etc.). Pure chestnut high forests are rare with a cover of about 10 %, producing timber wood for construction, furniture or long poles. Traditional chestnut management approaches (i.e. coppices, high forests, orchards) requires continuous cultural inputs. In the absence of management, chestnut stands tend to be invaded by other species and to evolve towards mixed deciduous forests.
Important source of economic loss for the chestnut growers are fruit damaging insects such as the chestnut weevil (Curculio elephas) and tortrices (Cydia splendana; Cydia fagglandana; Pammene fasciana).
According to Food and Agriculture Organization of the United Nations, Statistics division (FAOSTAT) top three exporters of chestnut in Europe in 2013 where Portugal, Italy and Spain. At the same time, Italy was number one importer worldwide (China being 2nd) with over 30 000 tons of imported chestnut.
In 2013 there was a significant increase in demand for chestnut products, resulting in increase of import in the European Union by more than 10 000 tones.
- San-Miguel-Ayanz, J., De Rigo, D., Caudullo, G., Houston Durrant, T., Mauri, A., European Atlas of Forest Tree Species, Publication Office of the European Union, Luxembourg. ISBN: 978-92-79-36740-3. DOI: 10.2788/038466, 2016
- Idžojtić, M., Dendrology – flower, cone, fruit, seeds, University of Zagreb, Faculty of Forestry, 2010