Q is for Quercus

‘Quercus’ is the genus name for all the species of oak trees or shrubs; Wikipedia states there are about 600 species. Many will think of the ‘English Oak’ (Quercus robur, also known as ‘pedunculate’ oak) as Oak trees but at least 20 other species can be seen at Ipswich Arboretum and Christchurch Park, most looking very different. English oaks are numerous throughout Suffolk and in A Flora of Suffolk Martin Sanford and Richard Fisk mention ‘veteran’ oaks including the ‘Queens Oak’ at Huntingfield, the ‘Tea Party Oak’ in Ickworth Park, and the loss of the ‘Gospel Oak’ at Polstead which collapsed in 1953. They mention that place names like Oakley, Occold and Eyke may be based on ‘Oak’ and perhaps also Copdock (“meaning pollarded oak”).

Letters patent licensing the imparkment by Sir Thomas Kitson of Hengrave Park, 1587 (HA528/30)

Letters patent licensing the imparkment by Sir Thomas Kitson of Hengrave Park, 1587 (HA528/30)

Oak trees have been significant in the history of Suffolk providing wood for the many ‘timber frame’ houses built here; there are many pictures of them in Suffolk Record Office collections including the Suffolk Photographic Survey (K681) at Ipswich. Oak was also used for shipbuilding in Ipswich and no doubt elsewhere. However Oak has also played another very significant but less obvious part in the history of Suffolk: in the ink used to write a large proportion of the manuscript documents, maps and drawings that form the record of history. Documents for many centuries have been written with iron-gall ink, and as the name suggests the ink is made with oak galls and iron.

Oak galls are caused by gall wasp insects embedding their eggs into host plants. When the grubs hatch the host plant (in this case oak trees) form a growth around it which provides food and protection. When the larvae has pupated into a wasp it exits through a ‘flight hole’ and files off. Many types of galls form on oaks, roses and other trees and shrubs, each particular to the insect species. The gall wasp Andricus kollari forms ‘marble’ oak galls which are rich in tannins. During ink-making an extract of the tannins is mixed with an iron-rich material, usually ferrous sulphate and during use the dark pigmented colour of the ink evolves.

Marble galls can be found on ‘Turkey’ oaks (Quercus Cerris) and ‘English’ Oaks.