Tag Archives: Bench

Nature Reserves

A Hot Day Down at the Reserve … to Rebuild a Bench

The old bench by the pond had been getting very rotten and rackety, so the back, seat and one of the sides (yeah, 60% of it then) were taken off and the team had the job of putting it all back together using new wood and a bag of coach bolts.

If only things were that simple. Cutting the wood to length wasn’t too complicated. The side stretcher was angled but I managed to measure that with the saw and a pencil and marked holes from the bolts of the surviving stretcher. The bolts were too long, so they had to be cut down with a hacksaw to make it possible to use a socket spanner to tighten them.

DSCN4513 Rebuilding the pond bench

Then we marked the position of all five timbers for the back and seat, marked the bolt holes, and drilled them. The two for the back were countersunk for the heads, and fitted to the posts. The bolts were heavier than the old ones, giving us trouble trying to tighten them in the small countersunk space available. I widened the gap with a bit of chiselling and managed to tighten the nuts using a pair of grips. The bolts weren’t long enough for the seat timbers and the thickness of the stringers so we drilled the timbers with starter holes (very narrow) and nailed them down with six-inch nails, a considerable effort.  The vibration made the timbers climb up the nail, so when the nail was seemingly fully down, it in fact still had an inch to go and the timber was way adrift of the stringer. We thumped the thing down with a lump hammer and then continued tapping away on the nail with an ordinary hammer. The engineer’s maxim, ‘when all else fails, use b****y great nails’ did come to mind. It was very hot in the sunshine and we gratefully shared a thermos of iced water between us.

The pond bench rebuilt
The pond bench rebuilt

The bench actually looked quite new and professional. Of course if the old posts fall to bits, we’ll have to start over, but it* should last a few more years yet.

* It – the bench – is now officially a “Grandad’s Axe”. You know, grandad’s axe is over 70 years old, and has had seven new shafts and two new heads over the years…

Natural History

Not every day I’m seen wheeling a bench about a nature reserve

Wheeling a bench ...
Wheeling a bench …

Well, it’s not every day one wheels a robust two-legged bench about a nature reserve. The team of three however managed to think of a way of balancing the bench on a wheelbarrow using a bit of four-by-two to prop up the legs, and thus poised it turned out to be quite easy to trundle along, carefully dodging trees and bushes along the way.

The holes were just the right depth, so all we had to do was drop in the bench, level it, pour in some water and add rapid-setting post concrete. The bit we had left turned out not to be enough, so after struggling in vain with additional pebbles, we propped it up and those with bicycles went round to the hardware store to fetch some more concrete.  Second time proved lucky, the ‘crete set like custard without enough milk added, and very soon we were shovelling the spoil into the holes and stamping it down.

New bench on the mound
New bench on the mound
Conservation, Natural History, Nature Reserves

Giant Ichneumon in London Reserve

A terrifying monster stalks the suburbs. Silently and with unerring accuracy, it scans the surface, using its advanced sensors to detect and identify targets buried deep below. Once a target has been located, the hunter drills down to find it, deposits the payload, and leaves in search of the next. It could be a cyber-borg or pilotless military vehicle. Actually, it’s Rhyssa persuasoria, the giant Ichneumon. And giant or not, it’s about 30mm long.

Rhyssa persuasoria, side view
Rhyssa persuasoria, side view

Rhyssa is a parasitic wasp, a solitary hunter distantly related to the social, black-and-yellow striped wasps. Her prey are the larvae of other insects which burrow in dead wood for food and safety. Only when she is above, safety below is hard to find. For Rhyssa‘s weapon is as long as her body: her ovipositor is greatly elongated into a precision instrument that can drill deeply through wood and into the body of the larva. Once there, she lays a single egg down the ovipositor tube. The egg hatches inside the still-living larva, and devours it from the inside. The larva dies (so Rhyssa is a parasitoid, not a true parasite that avoids killing its host) and a young Ichneumon emerges.

Rhyssa persuasoria dorsal view
Rhyssa persuasoria, dorsal view: in search of a host

Today at Gunnersbury Triangle we erected a new bench, to allow visitors to relax and enjoy a quiet moment in nature. It sounds a trivial task. If only. Two volunteers spent a day putting the “ready to assemble” kits together. All the supplied bolts were the wrong size, so they had to ream out all the pre-drilled holes to the larger size. Meanwhile, that day, I dug out the well-embedded MetPosts remaining from a previous bench. Then we dug 2 holes for the new bench: they promptly filled up with water, and the deeper we dug, the more the local weakly-cemented gravel (our local rock, when it isn’t sticky clay) collapsed into the hole, making it wider at the bottom. It was clearly hopeless.

So today we spent an hour prospecting for a drier place that would also be aesthetically pleasing, not harm the rare ferns nor disturb the nesting Blackcaps, and be close to an existing path. Then we started digging holes all over again. This time they didn’t fill up with water, much: just the bottom 10 cm or so. To keep the sides from crumbling, we avoided digging with spades: we lay on bin-bags, and wearing rubberised gardening gloves, scooped out handfuls of wet gravel. Then we levelled the two holes, cast a base of PostCrete in each, let it cure — at this point everybody disappeared for a cup of tea, leaving me in the wood guarding the site. I sat on a coppiced Willow trunk, and was approached by the giant Ichneumon when I least expected it. Luckily my little camera was not far away — you can readily imagine why I wouldn’t want the big camera with me while working.

The team reassembled, we gingerly lowered the bolted wooden creation into place, wedged it tight with broken bricks, and fixed it in place with plentiful PostCrete before cunningly sloping the top to shed rainwater. Needless to say, during this procedure we accumulated more and more tools all round the excavation site. If only it were as simple as drilling for an unseen caterpillar and laying an egg in it. But then, Rhyssa has the jump on us, with millions of years of evolution in her hunting technique.