Firewood – the Environmental Fuel

Occasionally we find people who don’t want to chop down any trees, but logs from the right source are among the most ethical and environmentally friendly forms of heating.

Broadleaved or deciduous trees grow at a yield class of around 10 (that’s tonnes of timber per hectare every year) and conifers perhaps double that.  In a well managed wood, other trees will continue to grow and replace that taken volume, either from remaining trees in a thinned wood, or from young trees replacing them.  Most broadleaves also have the ability to coppice – regrowing from the cut stump or stool, providing there is sufficient light.  Therefore, although carbon dioxide is emitted from the burning of logs, new growth in the wood or forest will absorb carbon dioxide and offset the emissions.

True there are some carbon emissions from the felling, processing and delivery of logs, but these are quite modest, especially if you source your logs from a very local supplier.


Carbon content (%)

Approx. life cycleCO2

Electricity – (UK grid)








Liquid propane gas



Natural gas



Wood chips




Thinning, selective felling or coppicing is also generally good for wildlife, and many nature reserves are managed today with areas of coppice, a traditional form of management dating back to medieval times.  Hazel was frequently cut on a ten to fifteen year rotation, whereas in the south west a thirty year rotation for oak was perhaps more common.  The produce varied from spars for thatching, through fencing stakes, firewood and charcoal.  And the resulting woodland structure was also varied, with relatively open areas good for butterflies, and often an amazing display of spring flowers, while areas a little older were good for songbirds.  A varied woodland structure, with a range of tree ages is usually one of the best for wildlife and nature conservation.  In the past we have coppiced Warleigh Wood for Devon Wildlife Trust and Golitha Wood National Nature Reserve for Natural England, selling the logs to effectively provide a free management service.

So logs are good for reducing global warming and good for wildlife, but what about the cost?  Well it’s a bit hard to compare like with like, but we will have a go.  Remember if you try burning freshly felled logs you will lose half of the energy in drying out the sap in the logs.  Freshly felled logs have a moisture content of around half, whereas a well seasoned log will be close to half that.  So buy your logs well seasoned, or better still store them yourself in a well ventilated shed for a year before you burn them.  A tonne of well seasoned logs will give you over 3.5 mega watts of energy; if you pay say £120, that works out at less than 3.5 pence per unit.  Modern woodburners work at 70% efficiency, which takes the cost up to 5 pence, but still comparable with natural gas, only a third of electricity costs, nearly half LPG and close to two thirds the price of heating oil  (as of October 2012).  So cheap then!  And also a fraction of other renewable energy sources that are subsidised by government feed in tariffs.

But there is one other economic benefit: the multiplier effect.  Buy your logs from a local supplier and he (or she) will spend that money in the local economy.  The money goes around locally to be re-used, rather like spending in the village shop.  No profits to the big city men, or even these days to foreign owned companies.  Western Power Distribution is American owned and EDF Energy are a French company.  Research by the New Economics Foundation has shown that £10 spent with a local grower circulated two-and-a-half times locally, being worth £25 to the local economy. The same money spent in a supermarket left the community much quicker, with a local multiplier of just 1.4, being worth just £14.

Have we convinced you yet?  Well I’ll have one more example to tempt you.  Most of our woods in the south west are on steeper ground, often unsuitable for agricultural production.  So we are getting a sustainable renewable product from an otherwise unused area of farm.  If we can persuade farmers and landowners to once more actively manage these woods, then they will have an additional revenue stream, and the woods will be more valued for that.  On the waste not want not theme, firewood is an excellent use for all the leftovers from forestry.  After that fine tree trunk has been sent to the sawmill for producing the antiques of tomorrow, then the wonky tops and branches can be processed for firewood.

Woodchips and pellets are a growing sector of the firewood market, and are increasingly being installed in commercial buildings.  Pellets especially are a more expensive product, but they are a high quality reliable product and can be fed in by automated processes.  Many of these systems attract government subsidies, via the Renewable Heat Incentive, and indeed there are opportunities for subsidised installation of woodburners for private householders.  However, they are not particularly generous (in my opinion) and require a fair bit of monitoring in return for the grant.  There has also been talk of a second phase of support that will include long-term tariff support for the domestic sector to coincide with the introduction of the Green Deal for Homes. That means ongoing payments for electricity not consumed, but that seems to have gone quiet, and to be honest its more red tape and complication for something we feel everyone should be considering anyway.

So to sum up, renewable, low carbon emissions, good for wildlife, cheap and good for the local economy.  What are you waiting for?  Order a fresh supply today, or look into buying that woodburner that will keep you warm in the winter and also give you a warm feeling for knowing that you are doing something for the environment!

Sources of information