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Blog - June 2007

The Turkey or Iron Oak - Quercus cerris

The Turkey or Iron Oak – Quercus cerris

by The blog at woodlands.co.uk, 19 June, 2007, 14 comments

The Turkey Oak (or Quercus cerris) is is a fast growing, tough tree; capable of surviving exposure in coastal regions. It was introduced as an ornamental tree into the UK in the eighteenth century,  being native to south east France across to the Balkans and Turkey.   It often has a long straight trunk (or bole), with branches that are somewhat more slender than those seen on English oaks. The leaves are distinctive and different from those of the native oaks (sessile or pedunculate). Whereas the leaf of the latter is quite broad, the leaf of the Turkey Oak is quite narrow and more ‘angular’ (see featured image);  it is also hairy or downy on its lower surface. One of the tree’s distinctive features is the bark, which has orange fissures near to the base of the trunk. Unfortunately, its timber is of little use as it splits and warps during seasoning. [caption id="attachment_37670" align="aligncenter" width="675"] Turkey oak bark[/caption] The Turkey Oak is considered by some to be a "weed species or pest species" because: it is fast growing it will hybridise with the English oak. it is a host to the Knopper Gall wasp Acorns form and mature some 18 months after pollination and are quite large. They may be an orange / brown at the base,  to a green-brown at the tip. The acorn 'cup' is 'hairy' (see image). The galls that form on the tree are abnormal growths.These galls are caused, in this case, by the development of wasp eggs within the plant’s tissues. The wasp (Andricus quercuscalicis) lays eggs in the catkins of the Turkey Oak, these hatch and develop into wasps which in turn lay their eggs in the flowers of the pedunculate oak. The acorns that form are grossly mis-shapen – and are called Knopper Galls. [caption id="attachment_40042" align="alignleft" width="150"] Gall[/caption] [caption id="attachment_40046" align="alignright" width="150"] Gall[/caption]       In some areas there are now systematic attempts to remove Turkey Oak and other non-native species from woodlands and forests.