6-minute video by David Attenborough on the weird and wonderful life cycle of the knopper gall wasp (Andricus quercuscalicis.) as it provokes an oak tree to produce a gall in which the wasp can lay its eggs safely inside. From the BBC’s ‘Life in the Undergrowth’. The knopper gall wasp is just one of 70 gall wasps which can afflict a single British oak, though many have only a negligible effect on the tree.
Knopper galls develop as a chemically induced distortion of growing acorns on Pedunculate Oak (Quercus robur (L.)) trees, caused by gall wasps which lay eggs within buds using their ovipositor. The gall thus produced can greatly reduce the fecundity of the oak host, making the gall a potentially more serious threat than those which develop upon leaves, buds, stems, etc. The Turkey Oak (Quercus cerris (L.)) introduced into Britain in 1735 is required for the completion of the life cycle of the gall
The word knopper derives from the German word ‘knoppe’ meaning a kind of felt cap or helmet worn during the 17th-century; also a small rounded protuberance, often decorative, such as a stud, a tassel or a knob
Spindle ermines weave silk webs to protect themselves from birds and wasps, allowing them to gorge on leaves for six weeks before transforming into the moth.Not known for being bright sparks, they sometimes mistake other objects for spindle trees such as this car in Rotterdam (Image: Daily Mail).
The Guardian has an editorial this week praising the planting of trees, inspired by a scientific study for the Forestry Commission, calling for the mass planting of trees as a reliable and cheap way of soaking up carbon dioxide.
If Britain planted 23,200 hectares of woodland a year for the next 40 years, this country’s forests could soak up 10% of predicted emissions. That might sound like a lot of trees, but even at this rate woodland would cover only 16% of the land, far below the European average. The way this is done matters: no one wants to see a repeat of the endless dark lines of Sitka spruce which harmed the spirit of Ennerdale, in the Lake District, or drained the life from the peat soil of the Flow Country in Caithness. Read
Some quarters, particularly the forestry sector, are reacting with indignation and protest.In these times of climate change, it is argued, surely woodlands should be preserved, not eliminated.But what the RSPB are doing in Farnham, Surrey, by felling the conifer plantations, is restoring heathland, an increasingly rare habitat in Britain.What’s more, they are lobbying the government to clear more non-native conifers, a move that would favour biodiversity and species such as the nightjar, woodlark, sand lizard and adder, which thrive in more open shrubby areas.
As project manager Mike Coates succinctly puts it, “It should be the right tree in the right place. A field of barley is a field of grass, but it’s not a meadow; it’s a crop. In the same way, these are areas of land dominated by trees, but they are not woods, they are crops.” Photograph: Graham Turner Guardian
The National Trust is embarking on a comprehensive survey to identify previously unrecorded ancient trees on its land. The NT’s land holdings are huge – they include more than 25,000 hectares of woodland, 200,000 hectares of farmland and 135 landscape and deer parks.As many as 40,000 trees are to be classified. Continue reading The National Trust’s ancient trees→
Anyone out of the country that week in October came back to find an altered landscape. An estimated 15 million trees had been toppled, mainly in southern England, which bore the brunt of the hurricane-force winds. The north of Britain is used to ferocious winds, but the south hadn’t experienced anything like it for nearly 300 years. The result was a large population of very tall, old trees that had never been tested by such severe weather conditions. Continue reading Remembering the Great Storm of 1987→
The Fortingall Yew is generally considered as the oldest tree in Britain. Like many yews, it stands in a churchyard. Yews were sacred for the Celts, and the Christian church often found it expedient to take over these existing sacred sites for churches. This oldest of yews is the village of Fortingall in Perthshire. Recent tests suggest the tree is some 2,000 years old, rather younger than the 5,000 years claimed by some, but still probably one of the oldest trees in Northern Europe. The yew was vandalised for tourist trinkets in the 19th century, and its once massive girths is now split into several trunks, giving the impression of several smaller trees.