Category Archives: Conservation

Conservation, Gardening

How to Prune a Fruit Tree

Ice patterns in puddle, Huckerby's Headows
Ice patterns in puddle, Huckerby’s Headows

I arrived at Huckerby’s Meadows in the crisp early morning. No, I hadn’t heard of it either: it was round the back of the industrial estate at Cranford, squeezed in between the edge of London and the perimeter of Heathrow airport. The puddles were interestingly frozen, the looping pattern suggesting successive stages of freezing.

Wheels down: right under the flight path at the end of Heathrow's north runway
Wheels down: right under the flight path at the end of Heathrow’s north runway

The meadows have miraculously survived untouched by the rushing development all around them. In fact, it protected them – nobody wants to live exactly under the end of the flight path, just before the planes drop over the airport fence and shriek to a halt on the runway; and the airport itself may well have had designs on the land, buying it up just in case, but not sure what to do with it. Huckerby’s meadows are now leased by the airport authority to London Wildlife Trust. It discovered a hidden corner of England, taken over by wildlife: I saw muntjac deer prints, jays, a green woodpecker, mallard ducks, a singing song thrush, and fieldfares chattering in the hedges.

A carpet of crab apples - surely there for a reason
A carpet of crab apples – surely there for a reason

The meadows had become seriously overgrown with brambles, creeping across the grass from the hedges. Volunteers have now cleared most of them, revealing a curious sight: the meadows contain a large number of big, old crab apple trees in their midst, nowhere near the hedgerows, so they must have been there for a purpose. A possible clue is in the carpet of fallen crab apples: perhaps old Huckerby found them useful fodder for his pigs? The crab is so sour that it is barely suitable as human food – crab apple jelly about covers it – but pigs will eat them as a change from the swill they were presumably fed on, in those days.

We volunteers had been lucky enough to get a place on a fruit tree pruning course, run jointly by London Wildlife Trust and the London Orchard Project. The course tutor, Bob, had come down from Norfolk to get us up to speed. The pole saws we had to use were remarkable, extending to 12 foot long, with a viciously sharp curved saw at the far end – think of the scythe in the hands of the black-cowled figure of Death, and you have the general idea. Bob effortlessly lopped off an offending branch ten feet above his head. We wore awkward goggles and hard hats; fresh, sharp-edged sawdust falling in your eyes means an instant visit to casualty, and of course as you saw something and look up, that’s just where the stuff is going to fall.

Er, how do I hold this? LWT volunteers trying out pole saws for the very first time
Er, how do I hold this? LWT volunteers trying out pole saws for the very first time

Bob explained remedial pruning; you don’t want ‘a tree on top of a tree’, a new vertical shoot rising from the end of an exposed branch, or the tree will get topheavy and split. You can’t just hack away: the tree will go into emergency overgrowth mode if you cut away more than 20% of the branches in a year. If an individual branch is heavy, just slicing away from the top means it will split when you are halfway through, letting wet and fungi into the wound, so it is best to cut in stages, reducing the weight by cutting smaller branches further out. Then you can cut the main branch part-way through from the bottom, finishing off from the top for a neat job, a cut surface that will shed rainwater cleanly. And you want to shape the tree neatly, with no crossing branches: they should radiate out tidily, giving each other space. Suddenly there was a lot to think about, and we looked at trees with newly informed interest. Then it was time to try it for ourselves. It was a lot harder than watching Bob do it; the poles were tricky to manoeuvre through the tangle of branches, the sun was in our eyes, and sawing at a distance felt nothing like holding a handsaw. But with supervision and encouragement we got the hang of it, and were soon bringing sizeable lumps of wood safely down to earth.

Bob also answered our questions about fruit trees – I needed something to pollinate my Cox’s Orange Pippin apple as it wasn’t bearing much fruit. The pollinator needs to be a suitable variety, so the flowers are open at the same time and the pollen is not rejected as being the same – Coxes do not self-pollinate. Lord Lambourn, for instance, is a good choice, as it is a useful cooking apple to complement the sweet eating Cox, and the two varieties pollinate each other as the bees fly about the garden visiting flowers.

By the end of the day, I had learnt a great deal, realising that I was only just beginning to grasp the rudiments of a fascinating subject. Maybe I’ll try grafting next year.

Conservation, Wildlife

Building a Stag Beetle Loggery

Packing the Logs in Tight

Today was an amazingly hot day for mid-March. It dawned foggy and chill, but quickly warmed up. Down at the Gunnersbury Triangle, a big pile of coppiced willow logs and some birch trunks were waiting to be built into a loggery. This is by intention a home for the stag beetle, which happens to have its British stronghold centred pretty much on south and west London. The stag beetle larvae are soft, white helpless grubs, a ready meal for a fox or a hungry bird – except that they live underground, or rather in timber which is in contact with the ground. They tunnel through the dead wood with their only really hard dark parts, their mouthparts, grow fat, split their skins and continue eating wood and tunnelling along, gradually making holes of larger and larger diameter. After some years – it can be up to seven – they metamorphose into handsome adult beetles with their black and shiny chestnut carapaces, walk or fly, mate, lay eggs in dead timber which is in contact with the soil, and die.

DSCN0268 Completed Trench for Loggery;
Completed Trench for Loggery

To accommodate this bizarre life history, we dug a trench somewhat more than knee deep – quite a feat in the sticky brown clay with some flint gravel – and packed in the logs as tight and close as we could get them.

DSCN0275 Shovelling earth into all interstices
Shovelling earth into all interstices

We then jammed short lengths of smaller wood in between the logs to prevent them from wobbling, and finished up by shovelling earth and clay into all the gaps and stamping it well down.

DSCN0276 Completed Loggery
The Completed Loggery

The rest is up to the beetles – millions of years of evolution has given them a superb ability to find suitable places to lay their eggs – and then with luck in a few years’ time we will see some shiny new stag beetles walking heavily about the reserve.

Conservation, Wildlife

Not much to see at this time of year?

A fine filmy Slime Mould on leaf litter
A fine filmy Slime Mould on leaf litter

After the brief heatwave it feels like March again. In the Gunnersbury Triangle nature reserve, willow buds are starting to open but only the evergreen trees like the native yew and holly, and the invasive holm oak (from the Mediterranean) are in leaf. Not much to see, then? Not a bit of it.

In the leaf litter under the forest canopy, a large and handsome white slime mould was spread out, draped over some twigs in a fine shiny film. In detail its surface seems almost fractal, full of rounded holes at different scales like a Sierpinski Triangle if you know what one of those is. The individual cells – I’d almost call them animals – of the slime mould signal to each other with a chemical (AMP), which causes them to aggregate; they slowly ooze along like amoebae, eventually forming fruiting bodies rather like small fungi. It’s an extraordinary process, and in an odd way quite beautiful.

Leaf Miner, probably Ectoedemia heringiella on Holm Oak
Leaf Miner, probably Ectoedemia heringiella on Holm Oak

Meanwhile, the large holm oak by the picnic meadow looks utterly extraordinary, something like the horse chestnuts that have been attacked by plagues of leaf miner moths. Almost every leaf of the holm oak is scarred yellow and brown with the wandering trails of the moth caterpillars, making the tree look multicoloured and very badly battered. This is probably the work of Ectoedemia heringiella, according to the RHS.

A filzgall, Aceria ilicis, on Holm Oak leaf
A filzgall, Aceria ilicis, on Holm Oak leaf

Many of the leaves also have squarish brown furry patches (a filzgall or erineum ) on the underside; the leaves are naturally fluffy, with a tiny gall mite, Aceria ilicis, causing overgrowth; the thickened, darker hairs are too tough for the insect to eat, so the plant’s reaction works as a defence.

And that is not all; there are also a fair number of much larger pupae, probably of another moth species, wrapped in partly-rolled leaves, tied up with silk threads. We used to think of the holm oak as a useless non-native species with no pests or predators: not any longer, it seems, though at least the leaf-miner is a recent arrival itself.

Down at the pond, there are masses of frogspawn; at least a dozen large frogs, with at least four mating pairs, were responsible. When we came over the mound they must have seen us as there was a remarkable amount of splashing; even in amplexus they are capable of emergency diving: this is just as well, as much of the weed and reed has been cut during the winter.

Conservation, Wetlands, Wildlife

Slimbridge, home of Peter Scott’s original ‘Severn Wildfowl Trust’

Flamingoes at Slimbridge

I had the good luck to be able to visit Slimbridge this week with a friend. Back in 1946, Peter Scott founded the ‘Severn Wildfowl Trust’, setting up an observatory to study the White-fronted Geese and the Bewick’s Swans, and to help save other wildfowl from extinction. The geese and swans happily remain on the reserve today; there were 20 Whitefronts, as well as a hundred or more Barnacle Geese out on the marsh, not to mention plenty of Greylags and Canada Geese in the bright sunshine on the scrape.  And as the sun sank in the western sky, the collection Flamingos glowed in the warm light – no need for Photoshop tricks there.

The star of the show, though, was one of the European Cranes, tall and elegant with its tail ‘bustle’ like an late Victorian lady’s; incongruously, it was also wearing a radio transmitter and three coloured rings, such has been the excitement at the raising of these rare British birds from the egg, and allowing them to fly off as wild birds – only for one or two to pay a return visit. Meanwhile, a genuinely wild flock of cranes has established itself in Norfolk, so Britain once again has this beautiful and distinctive species breeding in its wetlands. The number of places, even near London, with ‘crane’ in their names is striking – Cranfield, Cranbrook, Cranford to name a few. I once imagined this was simply a confusion or word-shift, the bird having been a grey heron all along: but no, cranes were once common, as were wetlands and damp flowery meadows. Let’s hope they will be again.

Conservation, Wildlife

What are we conserving?

Kings Cross Development looms over Camley Street's new Viewpoint
Kings Cross Development looms over Camley Street’s new Viewpoint

Everyone in the packed council chamber turned to look at the chairman of the planning committee. The members had voted 6-6: a tie. “As chair with the casting vote, I am voting for the development.” There was stunned silence. The developers said nothing. We objectors took a deep breath and said nothing. Gunnersbury Triangle Nature Reserve would never be the same again.

London Wildlife Trust’s other central London reserve at Camley Street is also changing. A 10 storey block has cut off the view. Were all our reserves being trashed? Were we fighting for nothing? 30 years ago a passionate campaign saved the Gunnersbury Triangle from becoming four industrial units. Miraculously, with a huge input of volunteer effort, it became a wet woodland with little meadows, grassy banks, leafy paths, a handy pond for school pond-dipping. Now it’s surrounded by 4, 6, 8-storey buildings. The latest one at Colonial Drive is right up against the reserve boundary — at the top of a ten-foot bank. The quiet meadow and scrubby corner where the whitethroats nested will be illuminated 24 hours a day by stray lamps from a wall of flats. “I’m desperately saddened at the insensitive nature of the development — it robs local people of the sense of countryside,” says long- time campaigner and Gunnersbury Triangle committee member Jan Hewlett.

Certainly, the reserves will feel different. But Camley Street has a new ‘Viewpoint’, an architect-designed floating open-air classroom. It will be beautiful to sit and learn on the canal, in the little watery oasis in the midst of the busy city. At Gunnersbury Triangle, too, the blackcaps and thrushes will delight our hearts in springtime. School groups will still lie down on the boardwalk we built and enjoy catching newts, dragonfly larvae and ramshorn pond snails.

Our reserves must change with our great city. They do not feel like forgotten corners of countryside any more. They are little oases, islands in a sea of noise and pollution and traffic. They are special exactly because they are right in the heart of our vibrant capital city.