Mysteries of the Sinodun Hills

By the session leader:

It was a beautiful sunny spring day as we waited for the site warden to turn up in his Land Rover.  We were not sure what was involved in today’s work as all we had to go on was his cryptic message:   

This time we will be working to protect some of the trees we coppiced during the winter from being eaten by the deer.

No idea how we were to do this, although we did get a clue when he rolled up with the large trailer piled with old fence posts.

When we reached the site where we had coppiced, we found it still had logs and brash everywhere.  So the first task was to pile up some of the sawn logs to give us some working space:

 

Once the area was clear enough to work, the fence posts were unloaded – initially by carrying them down the slope, but this was quickly overtaken by two people ‘tossing the caber’ from the trailer.  The latter was very effective, but the rest of the team kept well clear.

Then a production line got going:

Stacking the posts

Sawing off the rotten ends

Chopping the ends into points

Level 1 completed

The tea break was badly needed at this point.  Just as well, for the next stages were even more strenuous.  Each clump of coppiced trees had to have three or four holes spiked around it:

 

In turn each hole had a post pushed in and then thumped into place.  Thankfully, the ground was damp.  This would have been very difficult in mid-summer:

The ladies proved that they were just as good at post-thumping as the men:

By the time we had finished, the site looked like a fortress to keep elephants out let alone deer: 

Another group will have the gentle task of wrapping netting around each group of posts.

As one green-gymmer said afterwards, “That was the best all round exercise for a long time:  carrying, sawing, chopping, spiking, and thumping.”

As for the other mystery – the geology of the hills, which had intrigued volunteers at a previous session – one of our members had thought to look it up in The Geology of Oxfordshire by Philip Powell (thank you, Tony!) and tells us that:

The main bulk of Sinodun Hills is comprised of Malmstone, a pale, fine-grained rock which looks like Chalk, but is really a type of sandstone largely made up of grains of silica derived from the spicules of sponges.  The sands originate from a mass of higher ground over Cornwall carried here by marine currents when the sea returned to southern England in a series of pulses 114 million years ago.

The sandstone is capped with a layer of Lower Chalk, a grey, impure, clayey chalk with no flint.

On top of the chalk there are patches of pale-brown quartzite and white quartz gravels brought here during the more recent ice ages by ancient rivers from glacial deposits in the west midlands.

So now we know.