Wednesday, June 11, 2014

Smokin'! Making Charcoal



Part of the longer term vision for Fox Wood is to produce charcoal from any of the wood that doesn't have a primary use, so a couple of weeks ago I took the plunge and did my first charcoal burn. I did it under the tutorship of Greg Humphries, a friend who is also a woodsman and runs courses in Cornwall.

First of all Greg cut up a load of willow branches that he had collected. The wood can be any type, but must be properly seasoned and of approximately equal thickness.




Proper charcoal kilns are expensive (the one I have my eye on is £1,300) but you can make your own one for free by using an old oil drum. Garages often want to get rid of them, so ask around, but make sure there is no residue or paint on it by having a hot fire in it first. Then you just need to cut vents in it using an angle grinder.



We selected a site for the burn and dug out the earth. It should be away from trees as the process gives off a lot of noxious gases as the resin in the wood is burned.




The kiln needs to be propped up on blocks to keep it stable and to form the basis for channels for the air vents, and then soil is packed in around so that air can get in from four directions.




 Next we need to load up the kiln.


The wood is packed in like a 3D jigsaw puzzle, leaving as little space as possible left over. At the bottom is a mix of dry willow sticks, newspaper and wood chips to help start the fire. A plastic tube is inserted down the centre which will be removed when the kiln is full. This provides a central chimney from which the smoke can escape.


 When the kiln is full and the chimney pipe has been removed it is lit using embers from a hot fire.



Now is the exciting part. For the best part of three hours the kilns will be burning and a huge amount of smoke is produced (you must inform the local fire service in advance or face the embarrassment—and cost—of having them turn up to extinguish your kilns). During the burn the wood is turned to pure carbon and to do this you must make sure it burns in an even manner throughout the kiln. Too hot and with too much oxygen and it will turn to ash, too cold or without enough oxygen and you will end up with scorched wood. It's a constant process of monitoring and adjusting air vents and the only way to learn it is by doing it with someone who is already good at it. The fire must burn evenly throughout the kiln so it is a case of paying attention to the colour of the metal and noting where it is hot or cool. Water can be splashed on the kiln if it is too hot in one area, and vents can be opened up a little if it is too cool. An uneven burn is what we are trying to avoid.

With larger kilns the burn will take all night (or day) but oil drums are smaller and therefore take less time. Traditionally, charcoal burners have lived in the woods for this very purpose, and sat on one-legged stools so that they would fall over if they fell asleep. Of course, if you don't have a full-sized kiln but still want to produce a decent amount of charcoal you could have lots of oil drums in a circle and achieve the same volume in a lot less time.

During the burn the lids are placed on the kilns and grass sod is placed around the edges to keep it on tight and to form top vents. It is a very smoky few hours!



When the smoke becomes thin and bluish it means that this stage of the burn is almost complete. More soil is placed on the kilns and the lower vents are blocked off to prevent any more oxygen getting in. It's quite fiddly and time-consuming this stage but if any oxygen gets in at all then all the charcoal will turn to ash so it's worth getting right. If we were using purpose-made charcoal kilns we wouldn't have this problem as the lids seal shut.



Then we simply go away and come back the next day. In our case it was two days later, and when the kiln was opened you could immediately see that 2/3 of the volume of wood had disappeared (gone up in smoke). If you open it up too soon the rush of oxygen will cause the whole thing to ignite and you'll have a large and unexpected barbecue on your hands.


In this case the burn had gone well, with not too much ash and not too many scorched bits of brown wood. The next stage was to break the larger chunks up by hand and then put the charcoal through a metal sieve to get rid of the pieces that are too small. These bits that are left over can be pulverised into biochar, or they can be spread on paths to deter slugs and snails.



All that remains is to put it in bags and sell it! These ones are for sale at a local farm shop near Penzance, but there is plenty of scope for selling them to holidaymakers at campsites. They go for £7 a bag, and when you consider that a single oil drum produces about four bags per burn you can see that it makes sense to produce larger volumes of charcoal rather than smaller. A large kiln would probably produce 50-60 bags per burn.


If you're in Cornwall Greg runs lots of different woodland-related courses from his base at Plan It Earth, near Penzance. You can wild camp there too - or stay in the hobbit house.



Tuesday, April 1, 2014

Life Returns



The picture above shows one of the sweet chestnut stools in Fox Wood coming back to life. If you remember, I cut down these trees in early January - and now the sap is rising again and the trees are starting to produce new shoots as they come back to life.

I have been busy! Looking after a woodland can be a lot of work - especially at this stage when I am trying to get things established. I have planted around 180 trees in the last month, and have been working very hard to get all of the cut wood stored and fences built so that the rabbits do not get to eat the new shoots and destroy all my work. What follows is a selection of pictures from Fox Wood that I took today. There are quite a few of them ...

A little beautification project was needed at the field entrance. The soil I used was dug out from the basement of our house 10 miles away. It has not seen the light of day since 1880 and is full of clay pipes and horse shoes.

Some idiot dumped a load of old tyres in a hedge. I wish I had caught them ... I would have thanked them and asked if they had any more.

This is the site of the future poly tunnel. I'm levelling the ground so that it is not so steep.

A silver birch coming to life again.

The half-finished pond is due for completion this year. At the moment it is acting as a nursery for about 300 oak seedlings, which I will use for hedging and exchange/sale.


A willow in bud.

It doesn't look like much but this is the new edible hedge. I only had enough cash for a 10m section this year, but in it are apples, pears, crab apples, hazel, oak, sycamore and plums. In a few years it will be awesome.

This is the beginning of a large wind break of Italian alders that stretches about 150m. There are 150 trees planted here and they will shield the orchard from the strong southwesterlies that blast the field. These trees get really big really fast, and they fix nitrogen as well.

This apple had been attacked by (very large) rabbits last year and seems to be dead. All of the branches are brittle and there is no sign of life ...

... until I removed the spire guard and noticed this. It's really hard to kill a young tree!

This almond is the first tree to blossom. There are plenty of bees and other pollinators around, so hopefully it will produce some fruit this year (yes, almonds are fruits - closely related to peaches).

This is the section of the field where I killed the grass by covering it with silage plastic for six months. I have removed the plastic now and have sown clover seeds to fix nitrogen and out-compete the grass. I've also sown a load of old veggie seeds randomly to see what does well. There are lettuces, carrots, radishes, coriander and a few other things just tossed in. You can tell I've been reading Masanobu Fukuoka's 'The One Straw Revolution' !

Here's an insect hotel I made. Several bees have moved in already - so they must like it.

This is a small stand of hazel that I planted for coppice. Because the whips are so small at the moment I had to devise a method of keeping them from falling/blowing over, so I tied string around them between two poles. 

Some purple flowers that just popped up in the grass.

The edge of my land and originally a gateway. I've planted common alder here to block this off. They grow quite fast and they are wide and thick. They are forever spraying chemicals on this field and I'm trying to stop them drifting onto my land on the wind.

A sycamore sapling unfolding its leaves.

Sycamore leaf emerging.

The kids' vegetable plots.

Down in the coppice wood.


Patches of bluebells are appearing.

A close-up of the woodland floor.

And another one.

This might not be obvious but a natural pond has started to form here. Ancient maps reveal that this used to be an animal pen a few hundred years ago. It's right at the bottom of my land and the valley - a fast running stream with little beaches is just beyond!

And this, which runs down one side of the woodland, used to be a drovers track in times past. This area has been farmed for at least five thousand years and the land is criss-crossed with tracks if you know what you are looking for. You can see that (wild) animals are still using it and leaving tracks.

A bit of dead wood. Although I have an itchy chainsaw finger, standing deadwood is excellent habitat for insects and grubs and enhances the biodiversity of the woodland immensely. I've heard it said that you should leave at least 10% of the wood dead. Fungus loves it too.

An elder bush coming into leaf. I love elder so I'm encouraging it wherever I see it growing. You can make great wine with the flowers and the berries, and the plant generally has more uses than you can shake a stick at ... not all of them wholesome.

Looking at trees, you get to see the forces that shaped them. This one clearly shows how the wind rushing along the valley has given it a distinctive shape.

This row of alder was planted before the rest of the woodland, about 25 years ago. It would have grown faster than the oak and chestnut maidens, shielding them from strong winds. We felled one of them and the wood is dark orange for a few weeks. I will grow mushrooms in the logs and one section is being given to a green woodworking friend who will make bowls from it.

Ferns unfurling.

Not sure what this is ...

This chestnut tree has grown a lot of side sprouts, for some reason. They will need to be cut off otherwise the  tree will be outgrown by those surrounding it and it will lose the battle for light and die. 

This is what happens when you let low side branches grow. Is it me, or does it look a bit like a rhino?

This is squirrel damage. Grey squirrels are prolific here and I will have to control them if I want the coppice wood to be a success. 

Within the wood is this row of hazels. I'll probably coppice them next year as the new shoots they produce are extremely useful.

Oak being strangled by ivy. 

I've cut many of the ivy stems, so hopefully the old oak trees will be saved. 


I love the way hazel looks like rippling muscles.


Some of the wood I cut, stacked up in different sized piles.

I'm experimenting with growing vegetables in the newly-coppiced forest area. These are potatoes coming up.


The coppiced cant. I moved all the remaining wood today - by hand. One of the joys of coppicing is that you don't need heavy machinery. It is a human-sized job.

I have built hedges with the brash to deter deer and act as a store for firewood. Actually, most of this will get turned into charcoal in a couple of years, but for now the birds seem to love it and robins are busy building nests in it.

Some of these are HEAVY. Still, being on a slope, I just rolled 'em down it.

A lone chestnut standard amidst its fallen comrades.  I wonder, does it feel survivor guilt?

I have more wood than I know what to do with. Luckily, a couple of buyers have already stepped forward for some of it.



Another pile.

During the extreme 'worst in 250 years' storms of the winter, I lost only one tree. This was an old hawthorn that was covered in ivy. I chopped it up and it will be fed into our wood burner next winter.

One of the bird boxes that my daughters made.

Orange blossom. Yes, that's right.

Baby oranges. I also have lemons, olives and avocados - although they'll need to go in the poly tunnel next winter.

The new steps. I've sprinkled wildflower seed on the (probably) sterile soil, so soon this should be a riot of colour.