The latest report by Michael Walter:
Returning from a few days’ holiday in a glorious part of the Lake District in mid-September, I was quite surprised to note that the development of bracken’s autumn hues of yellow, orange and bronze were more advanced in Blean Woods than in the harsher climate of the exposed fells. I can only assume that the much greater stress from heat and drought down in the soft south was responsible for this discrepancy. Bracken is something of a bête noire amongst conservationists: although undoubtedly native to the British Isles, it is much criticised for the way it can blanket large areas in a monoculture, acidifying the soil and preventing the growth of plants that are deemed to be somehow more worthy of survival. As usual, man has to shoulder much of the blame for its dominance, with harmful practices such as burning, and stock-rearing followed by a cessation of grazing, all liable to enable this aggressive fern to spread insidiously. Thick, fleshy underground rhizomes that may be hundreds of years old enable it to spread over wide areas, and as this vegetative growth is asexual, fronds in a patch occupying hundreds of square yards can all have identical genetic makeup and, effectively, be a single super-individual. It had been controlled by the chemical asulam, often applied by helicopter in remote, hilly areas, but in 2011 the European Union declared it a “not authorised” chemical, due to fears that it could be harmful to humans. Since then the UK has been issued with an emergency authorisation to continue with its application, but it is not clear what the long-term future is for its widespread use in this country. Other methods of control have long been adopted, the commonest being simply to cut the offending plant, but this has minimal effect, as it stimulates the rhizomes to send up new fronds; carried out over a series of years, the bracken will gradually become weaker, but this is evidently not an efficient way of controlling the plant. About 25 years ago a slightly different approach was tested, leading to the invention of a tool marketed as a bracken-bruiser. Dragged behind a quad bike or tractor, it rolls over the bracken, flattening it but simultaneously crimping it at several points along the juicy stems. This weakens the plant, as the carbohydrates produced by photosynthesis tend to bleed out at the injured points, rather than being transported down into the roots; importantly, this method tends not to stimulate the bracken into producing new fronds to the same extent as when it is cut. This technique is now being used at Blean Woods, and you may have noticed flattened stretches of bracken along certain sections of the rides.
Every autumn some continental jays make the journey to England, the numbers varying, depending on the quantity of food available in their breeding quarters in northern and eastern Europe, and this autumn it seems that large contingents are on the move, with 11,000 recorded in the Netherlands in a single day recently. I can’t say that I’ve become aware of increased numbers in Blean Woods yet, but at this time of year, after a summer lurking in the woodland depths, they become more conspicuous, ferrying acorns for temporary burial in favoured “larders”, and so giving the impression of an increased population. It looks as though there is going to be an abundant acorn crop this autumn, which should please the jays, with thousands of nature’s little bullets already forming a layer on the ground. Some sweet chestnuts are also having a fine time of it, their boughs bent down with the weight of the hedgehog-like, spiny nut clusters.
Michael Walter
michaelwalter434@gmail.com
01227 462491
Abundant sweet chestnut fruits in their spiny cases