Considering buying a local wood to supply our heating needs. The question is how do you work out what sort of size of wood is needed for sustainable harvesting.

A rough estimate is 10 m3 a year (about 4 ton) based on 4.2kWh/kg and bulk density of 400 kg/m3

Locally there are some woods for sale ranging from 1 acre to 15 acres. The larger acreage being a mix of wood/pasture and scrub or river, but having a much lower price per acre.

Perhaps contact..

http://malverncoppicing.co.uk/coppicing_and_firewood.html

Quote:

The coppicing should be in 0.2 to 0.4 Hectare coupes. This will probably require a felling licence. Each 0.4 Hectare will probably produce about 25 to 30 tons of firewood on a forty year rotation. I offer an advisory service on sustainable woodland management planning, woodland creation, felling and potential firewood production.

Posted By: tonyThere are not enough for everyone so it is not a sustainable answer and then there are the health and pollution aspects too ... and more

Tony,

yes you are correct but then I do not think Daysleeper was saying that everyone should use it.

Jonti

Depends also on whether you use brash instead of just logs There is also a difference between coppice or clear fell.

Dont forget fruit and nut trees can also produce firewood from annual pruning.

You need to think about installing a much more efficient "Masonry Heater" to your property and cut down on the usage of the fuel you are thinking about.

Posted By: daysleeperNot sure what is unsustainable about owning a bit of wood

This comes down to your personal views of the over used and misguiding term 'Sustainable'.
I am going to leave CO2 aside, as this is very hard to gauge and there are too many viewpoints on it, but I will say that every time you burn timber you are releasing CO2 into the atmosphere, just that same as when you burn coal, oil or gas.

Let us say that you have 1 hectare of woodland and that can supply all your energy needs.
That ticks the Economic box OK on the face of it, or does it, you could clear the area, install a windturbine or PV panels and produce say 3 times your energy needs (this may well be higher as the conversion efficiency of PV panels is around 20 times that of biomass). You can then sell that excess and have an income stream and supply people that may not have the resources to install their own. So you could make better use of the land if your sole purpose is for energy production. So Economic box not ticked at all.

The Social side is a bit harder to gauge. But we do know that particulates are released when timber is burnt, we also know that they cause health problems, even if they are not right on your door step they will happen somewhere. And as above, you could supply other with energy, so this is not addressed.

Environmental is the very hard one, all depends where you think starting point is, is it the woodland that you wish to buy and change, or a wilderness, one is natural and one will become man made.. It is fairly simple to to put a real value on a patch of land, but depending on the questions asked, this value will change. If the woodland is left as it is, it will go through natural changes depending on the natural variations in the local weather, if you start to fell trees you are changing one ecosystem for another. So it is wrong to think that you are improving the woodland by changing it.

As I said, the term 'Sustainable' has become a bit of a nonsense and is an irrelevance when used to describe energy production. If you want to do the most for your cash, buy the woodland and leave it alone and use a lot less energy at home. That way a natural habitat is preserved and you save money.

Posted By: daysleeperAs for clearing the area to install wind-turbines or PV... firstly you could just buy a bit of pasture instead, secondly funding and finally getting planning permission, particularly for a turbine, might be a bit of an issue.

Or invest the cash into a 'Renewable' fund or shares.
My main point is that timber burning is probably going to become a political issue, just as the London smogs did 50 years ago and absolutely nothing can be justified on the grounds of sustainability.

Have you read through the many threads on burning biomass, growing trees, CO2 absorption etc. You will soon find that it becomes polarised very fast (and just for reference I am against all combustion, not just timber/biomass but I am a very average user).

Comparing your energy use to the UK average is a bit of a red herring, compare it to the world average of 48 kWh/Day, then see if you can use less energy that that in total.

I have similar problems here in Cornwall and this is not a naturally wooded area, plenty of uranium and sunshine though, plus wind, waves, tides.
I considered an ASHP but decided not to pursue that route mainly because of noise and very variable performance.
The UK has set in legislation that it is going to green the grid, so long term I am not worried, though it would be nice to reduce bills (have managed to cut a third off by changing behavour, an extra 30% by insulation and draught proofing, and shall attempt to reduce that further with better controls).

Do you know the heat load that your house uses?

You are in a fortunate position daysleeper, having the woodland close by and having the funds to buy it, I'm envious. You don't say if you intend to use just a couple of stoves or so, or going for a full blown logwood gasification system complete with accumulator etc. If it's the former then a mix of coppice/woodland management brash etc from a few acres would see you self sufficient, especially if you house is well insulated. In addition you'll be doing good for the flora and fauna in the process. If, like me, your house isn't perfect and you want to supply a conventional wet CH/DHW system and you opt for the log-gas set up you may find it more economic to buy the stuff ( in my case, softwood), in bulk and, space permitting just build up a stash. I like your idea of keeping the money "in the pub",- get the priorities right. I've gone down that route to some extent myself. Local woodmen supply my timber and a local guy splits the stuff with his mobile firewood processor just leaving me to do the fancy log stacks. You will of course be left with the annual "hunt" for the subsequent years supplies, but life's never easy.
Mike.

Posted By: SteamyTea

Posted By: daysleeperNot sure what is unsustainable about owning a bit of wood

This comes down to your personal views of the over used and misguiding term 'Sustainable'.
I am going to leave CO2 aside, as this is very hard to gauge and there are too many viewpoints on it, but I will say that every time you burn timber you are releasing CO2 into the atmosphere, just that same as when you burn coal, oil or gas.

Let us say that you have 1 hectare of woodland and that can supply all your energy needs.
That ticks the Economic box OK on the face of it, or does it, you could clear the area, install a windturbine or PV panels and produce say 3 times your energy needs (this may well be higher as the conversion efficiency of PV panels is around 20 times that of biomass). You can then sell that excess and have an income stream and supply people that may not have the resources to install their own. So you could make better use of the land if your sole purpose is for energy production. So Economic box not ticked at all.

The Social side is a bit harder to gauge. But we do know that particulates are released when timber is burnt, we also know that they cause health problems, even if they are not right on your door step they will happen somewhere. And as above, you could supply other with energy, so this is not addressed.

Environmental is the very hard one, all depends where you think starting point is, is it the woodland that you wish to buy and change, or a wilderness, one is natural and one will become man made.. It is fairly simple to to put a real value on a patch of land, but depending on the questions asked, this value will change. If the woodland is left as it is, it will go through natural changes depending on the natural variations in the local weather, if you start to fell trees you are changing one ecosystem for another. So it is wrong to think that you are improving the woodland by changing it.

As I said, the term 'Sustainable' has become a bit of a nonsense and is an irrelevance when used to describe energy production. If you want to do the most for your cash, buy the woodland and leave it alone and use a lot less energy at home. That way a natural habitat is preserved and you save money.

So ST, your take is that felling all the trees and and putting up an eyesore of a wind turbine is more acceptable

But to take your response seriously, it is very one sided in view as you exclude the CO2 capture of the trees when growing and the negative effect of the wind turbine installation. Also, making a lot of money should not be a consideration for sustainability.

Jonti

Posted By: SteamyteaI am going to leave CO2 aside

Because it has been covered to death and is a polarised argument that relies of faulty methodology.
I have no problem with people making money but there are much better methods of supplying a building with heat that buying a wood and setting fire to it

You then need an ever expanding wood, and that is the problem.
We all thought bio-diesel was a good idea until it was analysed properly, look what a mess that has become.

Yes John, very good for farmers, and I don't have a problem with that, but not carbon neutral (though not as bad as alternatives). It is even better for speculators as they drive both the price of food crops and bio-ethanol/diesel up based on nothing that a perception that there are very strong needs for both and there is a shortage of supply.

At the risk of repeating my views from the other thread about this, there was an assumption that every gram of CO2 released from biomass burning would be reabsorbed within the year by biomass, now I agree that the processing and transport emissions are low for biomass, but they are for FF too. What was never taken into account at the time was the CO2 release from ground disturbance, the fact that there is a very limited 'sweet spot' when plants grow well (this is location and weather dependant), but the main fault with the methodology is the time scale. You need to allow for over production (or plant growth) to stay carbon neutral. Or in number terms, for every unit you burn, you have to match that with an equal amount of new growth and then some percentage more to cover the 'costs' or you end up with a diminishing wood, or not being carbon neutral. Now, I think this may be where some confusion lay, I am not saying that it is worse than coal, gas or oil, or a turbine or PV panel, just that it is not carbon neutral when you have a limited area supplying your needs.
New models of biomass carbon intensity are starting to come along and they tend to show that it is not as good as people first thought. This initially started with bio-ethanol and bio-diesel but thankfully is now being applied to all biomass.
To possibly make it clear, think which will capture and store the most carbon, timber burned for heating or timber used for building, it does not have to be a case of either burning or leaving alone, there are many uses of land, some are carbon intensive (heat a leaky house), put PV on it, (no sequestration but it replaces a small percentage of fossil fuel use), farm it (has different levels of emission, cows versus crops) or just leave it alone (which is carbon neutral over about a hundred year timescale.
So all I am saying is that when you do a detailed analysis, timber burning is not carbon neutral for a fixed land area.

Jonti
One of the other threads had some people claiming that burning timber does not produce CO2 at all, all I pointed out was that burning timber does, it is the new growth that that sequesters.
It must be remembered that the energy density is not very high for timber compared to other fuels, so you are burning a greater mass, then comes the diversity issues and the big one is the particulates emissions.
Yes breathing (or living) produces CO2, but then we have anthropomorphed the planet through a naturally occurring economic system that we were pre-destined to follow, there is no getting away from that