This is some of the woodfuel for next winter - harvested from the coppiced woodland along the trail (under a management agreement with the Northern Devon Coast and Countryside Service who manage the trail)......No chainsaws....(only bowsaws allowed)......No trucking.......(only biketrailers)
This fuel powers the woodburner in the bunkhouse - for hot showers, cooking and space heating
Aha.......we hear you say, but you're releasing a load of carbon by burning all this wood aren't you?
Well yes but the stumps (coppice stools I think they're called) left behind after harvesting magically start sprouting new stems and in 8 years or so there's a new crop of timber waiting to be harvested.
So......the carbon released by burning one harvest is balanced by the carbon taken up by the regrowth from the old stools.
That's one way we're trying to reduce the carbon emissions from our activities. We've still got a long way to go in the cafe (calor gas oven, electric coffee machine, water boiler) but as you'll see below, the bunkhouse is doing pretty well on carbon reduction as shown by our Energy Performance Certificate:
The Timber Bunkhouse
What is now the bunkhouse was,
until 2006 a former chicken shack of ramshackle but to some, quite
picturesque appearance. John Hooper whose family owned Yarde Orchard
for over a hundred years, remembers reconstructing this building in the
1960’s after purchasing it from a military depot in Newport Pagnell
from where it was brought to Yarde in a dismantled state – all the way
by train!
Beneath the floor was a rich depth of straw and dried chicken manure which was carefully bagged up for future horticultural use
Sadly, little of the tin
and timber fabric was serviceable and the present timber framed and
clad structure was set up during 2007. Plans to source the majority of
timber from Devon trees have not, for a variety of reasons, been fully
realised though the exterior boarding is all mid-Devon grown Western
red cedar.
Whether local or not, the substantial quantities of timber in the building constitute a fair mass of locked-up carbon, at least for the life
span of the building. Energy consuming concreting has been limited to
12 concrete pads which bear the main posts.
In these and other respects, the building exemplifies a range of small scale sustainable and green technologies.
These technologies include:
Composting/reedbed water treatment
Warmcel insulation
Solar water heating
Wood-fuel boiler/cooker
Rainwater harvesting
Poos ‘n wees ‘n showers and stuff….. …..waste water treatment using separation, composting and reedbed
While staying in the
bunkhouse, nothing will be wasted, not even your poo! The water
treatment system uses standard flush toilets (though flushed with
rainwater from the roof for most of the year rather than mains water)
but the drainage then passes to a sealed composting chamber outside the
building. Here is a magical device from Sweden called an Aquatron,
which, without any use of external energy, sets your poo, wee, shower
water etc. into a mad spin and using only gravity, centrifugal force
and surface tension separates solids down onto the compost heap to be
consumed by eagerly awaiting wriggly red worms. Composted solids, after
a sufficient period of time, warmth and gobbling, form a safe, nutrient
packed fertiliser similar to peat in appearance.
The separated liquid
component passes down the site to a settling tank then into a second
tank which fills then flushes out through a perforated pipe and is
spread evenly over a sand bed which supports a stand of
Phragmites communis
(the common reed). The sand
and roots filter, oxygenate and take out excess nutrients which would
otherwise over-feed and de-oxygenate the watercourse into which the
reedbed discharges.
(The system was designed by Dr Chris Weedon of Watercourse Systems e-mail: WEEDON@compuserve.com)
The joy of the system is that
water cascades through it under gravity with no pumping or electrical
energy and the water which drains out of the reedbed base is not
dissimilar in quality to the pristine rainwater flowing into the toilet
cisterns.
Low carbon warmth……. …….solar, woodfuel and insulation solutions
The energy systems in the
bunkhouse alternate seasonally between a solar based system for the
summer months and a wood based system for winter. The south facing half
of the pitched roof has three large Genersys solar panels which feed to
one of two coils in the hot water tank. While these provide background
warmth on cloudy days, the backup immersion heater is needed to top-up
when the solar heat alone is insufficient.
In winter, the main source of space and water heating is a Wamsler
wood-fuelled range stove which also has provision for cooking. The
extent to which wood burning can be considered carbon neutral depends
on the source of wood supply. There are two sources close at hand which
arguably tend towards carbon neutrality.
One is prunings from the orchard trees where burning of old growth in
the stove is balanced by carbon uptake by the regenerated tree. A more
substantial source of wood fuel is the old coppiced ash, willow and
hazel woodland adjoining the trail. Much of this has not been regularly
coppiced since the former railway along the Tarka Trail closed in the
early 1980’s. This overgrown coppice is much in need of management to
maintain the species rich coppice habitat and to prevent the Trail from
becoming too overgrown and obscuring views from the Trail.
We now have a management agreement with The Northern Devon Coast and
Countryside Service to coppice 30metre compartments annually along the
trail near Yarde on a 10 year rotation. Again, a carbon balance can be
achieved by setting the emissions on burning harvested coppice wood
against the carbon uptake during coppice regeneration.
All the voids in the timber
frame (roof, floors, external and internal walls) are stuffed full of
“Warmcel”, an insulation medium derived from recycled newsprint,
treated with a fire retardant (borax). This grey fluff is sprayed into
the voids once one of the surfaces has been clad, it’s cohesion
enabling the mass to support itself even on vertical wall surfaces.
Warmcel is said to offer comparable insulation properties to sheep wool
batts while avoiding the environmental drawbacks of glass-fibre or
polystyrene.
