Published at 11:06, Thursday, 28 June 2012

I HAD a letter some weeks ago from Donald Piggott, former professor of plant biology at Lancaster and one of our best field ecologists.

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He had read my past articles regarding Great Wood by Derwent Water with its wych elms and tree lunworts, as well as our much more local, splendid and mysterious Haile Great Wood.

He tells me that the wood by Derwent Water is the finest example of a place dominated by wych elm in the whole of the Lake District. He goes on to say he had visited Haile Great Wood as a boy in the war and had I found small leaved lime there?

I have never seen it thereabouts. He knows it from Wasdale and Eskdale as well as one old tree by Linbeck, which flows from Devoke Water down to the River Esk – an old record from the days of the Norsemen.

We know from pollen analysis that it was especially common in the warmer Atlantic period between 7,500 and 5,000 years ago, occupying great swathes, especially across northern Britain and down into Wales. Even today there are ancient coppice woodlands of small-leaved lime in Suffolk and it occurs occasionally in south Cumbria – witness names like Lindale, the vale of the linden tree, its old mediaeval name.

If we look in Oliver Rackham’s excellent book Trees and Woodlands in the British Landscape, a map shows regional variations in the pre-historic wildwood, with the pre-eminence of small-leaved lime.

The town lime was extensively planted by the Victorians, especially in parks and avenues, as it was found to be easily propagated by cuttings. I recall there are some in Whitehaven park. It forms groups of drooping flowers in July as does the very rare large-leaved lime which does not grow in our area but I have found it on the Silurian limestone of Wenlock Edge.

By contrast the small leaved lime forms erect groups of flowers. It may also have smaller leaves. Professor Piggott informs me there are pollen records from Ennerdale, but it does not grow there now. The colder climate of the last 2,500 years is thought by Dr Rackham to be a factor in its decline.

In spring, the deep lake at Ennerdale begins to stratify into a warmer upper layer and a deep cold underlying one, the hypolimnion. Other lakes at our latitude do the same, due to water having greatest density at four degrees centigrade. Yet Ennerdale is unique in lakes in mainland Britain in possessing a larger Arctic estuarine crustacean, thought to have become entrapped in glacial lake Ennerdale at the end of the last Ice Age, when the water was connected to the open sea.

With guidance from the Freshwater Biological Association at Windermere, we put down baited traps in the deepest part of the lake, off Angler’s Crag. We also trawled a large net behind a tiny rowing boat in the inky darkness of the lake. The animal – which is quite an active swimmer – is said to come near the surface at night. The animal is Mysis relicta. In such a brief shot-in-the-dark 24-hour period, we didn’t catch any Mysis.

The difficult and modestly risky field work, was made possible by the sterling assistance of young students from Whitehaven College, with their practicality and resourcefulness. Public access to the lake by boat is strictly prohibited (we did our little study back in the 1970s). It was impracticable to do this over many weeks.

In 1981 I gave evidence at the Two Lakes public inquiry opposing the raising of the lake level which would have had a devastating effect on its ecology and wildlife. This was in Whitehaven Civic Hall. I published my evidence in a paper A Reprieve for Ennerdale, Ecologist 15(4)177-181 (1985.) As for Mysis, as far as I know it is still there.

Published by http://www.whitehavennews.co.uk