Quercus suber
Other common names
Portuguese: Sobreiro. Spanish: Alcornoque
Origin of species name
Quercus is Latin for oak; suber is Latin for cork
Family
Fagaceae
Dates planted
1917 and 1920
Lifespan
Cork oaks live 150 to 200 years
General description
This is a medium-sized evergreen tree with a broad spreading canopy. It has thick, deeply fissured grey bark which is fire retardant. Its leaves are 4-7 cm long, dark green above and much lighter green beneath. The acorns appear in autumn and held in deep cups fringed with scales. Height 15m. Spread10m.
Natural distribution and habitat
Quercus suber is native to southwestern Europe and northwestern North Africa. It occurs in open woodlands in areas with cold, moist winters and hot dry summers, generally on acidic soils on hills and lower slopes.
A special forest in the Arboretum
The first cork oak seedlings planted at the Arboretum site in 1917 were propagated from acorns sent to Charles Weston at the Yarralumla Nursery by Walter Burley Griffin. These were sourced from the Royal Botanic Gardens in Melbourne. More acorns were collected from the Public Gardens in Kyneton, Victoria and seedlings were also raised from acorns collected on Campbell's property at Duntroon.
By 1920, 9600 cork oaks had been planted in an area covering 8 ha at this location, then known as Green Hills. Some of the area was lost, however, to Glenloch Interchange/William Hovell Drive roadworks in the early 1980s.
From December 2012 to January 2013, volunteers from the Friends of the National Arboretum Canberra surveyed the cork oak plantation that had now become Forest 1 of the National Arboretum Canberra. They counted 2604 live trees, 34 dead trees, 5 fallen trees and 782 tree stumps, accounting for 3420 trees in total.
In 1948, some of the cork oaks were stripped and 19 cwt of the cork was sent to Melbourne GP Embleton & Son, a Melbourne-based firm, who was using imported cork to press into blocks to insulate refrigerator doors. Subsequently, the first cork harvest was sold to Embleton's in May 1951. A second stripping was undertaken in the 1970s and this cork went to Comcork in Melbourne who used it for engine gaskets, cork tiles, heels for shoes and bottle stoppers.
In 1979, ACT Forests did a stripping which yielded 10 t of cork and this was used by potters and model railway enthusiasts. Manuel Silva and Manuel Graca, two cousins from Ponte Des Sor in Portugal's cork-growing region, were brought to Canberra in 2001 by the Portuguese cork company, Amorin. They demonstrated cork stripping at Glenloch Cork Oak Plantation and received much media attention. In November 2005, three Portuguese – Australian men were commissioned by ACT Forests to strip cork over a two-week period and the harvest was sold to plant nurseries for growing orchids.
Conservation status
Not currently recorded as threatened, but cork oak woodlands face an uncertain future due to land use changes throughout their natural range. The international importance of the species is highlighted by its inclusion in the gene conservation network of the European Forest Genetic Resources Program.
Uses
The bark is the world's major source of cork and has been long used for heat and sound insulation, flooring, floats and bottle corks. Portugal currently produces about 50 per cent of the world's cork harvest. Galls produced on the tree are strongly astringent and can be used to treat a variety of ailments. The acorns can be dried, ground into a powder and used as a thickening in cooking or mixed with cereals for making bread.
Planting pattern
A quincunx - one tree at each corner of a square or rectangle and one in the centre.
Further reading
Rushforth, K. (1999). Trees of Britain and Europe. Collins.
Note: Much of the information above is sourced from Susan Parson's Cork Oak tree story.