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Please
click here for the latest report from
Professor Ted Collins, from Reading University,
on the current state of the market for
coppice products.
Ted
edited and part wrote the ‘Crafts in the
English Countryside’ Report, available
at www.craftsintheenglishcountryside.org.uk
Maximising
the Quality of Produce from Hazel Coppice
Click
here for Stool Density as a Factor
in the Quality of Hazel Coppice by
Rebecca Oaks
Rebecca
Oaks' dissertation explores the relationship
between hazel stool density and the quality
of the yield. She also presents a series
of useful recommendations for improving
hazel quality. Rebecca is an experienced
coppice worker based in Cumbria.
(by Edward Mills, Project Manager,
Cumbria Broadleaves)
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Coppicing has been traced
back to Neolithic times
by archaeologists who have
excavated wooden tracks
over boggy ground made
entirely of coppiced material.
There are written records,
going back to at least
1251, which describe the
value and type of material
cut for woods in East Anglia.
Coppicing can provide a
constant supply of material
for a wide variety of uses.
The material is of a size
which is easily handled.
This was very important
before machinery was developed
for cutting and transporting
large timber, when anything
more than 20 miles from
a large river could only
be used locally. Through
the 18th and 19th centuries,
coppiced woodlands provided
industrial charcoal for
the smelting of iron, and
bark from which tanning
liquors were prepared.
However, by the mid-twentieth
century coppicing was in
rapid decline and many
coppice woods were replanted
with conifers, or simply
neglected.
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Coppicing occurs when a tree is
felled and sprouts arise from the
cut stump (known as a stool). This
process can be carried out over
and over again and is sustainable
over several hundred years at least,
the stool getting ever larger in
diameter. The shoots arise from
dormant buds on the side of the
stool or from adventitious buds
developing in the cambial layer
below the bark. Root buds can produce
coppice shoots when close to the
stump, especially in birch and
hazel. The development of the buds
is initiated by a change in plant
hormone levels following removal
of the crown or stem.
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All broadleaves coppice
but some are stronger than
others. The strongest are
ash, hazel, oak, sweet
chestnut and lime whilst
the weakest include beech,
wild cherry and poplar.
Most conifers do not coppice.
The number of shoots per
stool depends on the species,
its age and size. A large
number emerge in the first
year - up to 150 in some
cases, but these quickly
die off in following years
as self thinning takes
place. By mid rotation
5-15 are left. The final
number depends on the rotation
length and species. Sweet
chestnut coppice cut in
its 16th year has about
5,000 stems/ha.
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| Oak,
hazel and lime commonly
grow a metre in their first
year; ash and willow can
grow much more and in the
second year growth is generally
greater. From the third
year, growth slows dramatically. |
Depends on the rotation length,
site and species.
Indicative yields are as follows
:-
Oak 2-4 tonnes per hectare per
year over a 30 year rotation
Sweet chestnut up to 10 tonnes/ha/yr over a 15 yr rotation
Mixed species 3-5 tonnes/ha/yr or 45-75 tonnes at year 15 and 90-115 tonnes
at year 30
Hazel 25 tonnes/ha at year 10 of a rotation
Oak and ash usually grown on a
25-35 year rotation:- 200-500 stems/ha
Sweet chestnut usually grown on a 15 year rotation:- \tab 8000-1000 stems/ha
Hazel usually grown on a 7-10 year rotation:- 1500-2000 stems/ha
Usually established on a new site as per a normal plantation and then cut back
at year 3 or 4 to begin growing a new crop.
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Coppice is normally divided
into coupes (otherwise
known as a fell, a cant,
a hagg, or more simply
a compartment). If cutting
neglected coppice, it is
usual to cut the most neglected
areas first, but if usable
material is required straight
away, some better coppice
will need to be cut as
well.
As a rule of thumb, coupes
should be at least 0.5
ha. However, under the
UKWAS certification standard
no more than 10% of semi-natural
woodlands over 10 ha in
size should be felled in
any 5-year period. Large
coupes have the advantage
of deterring deer from
entering.
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There are two systems - coppice
and coppice with standards. The
former has no standard or maiden
trees (i.e. no trees which are
not coppiced). The coppice with
standards system is much more common
in Cumbria. Oak normally makes
up the standard trees but they
could consist of ash or, less commonly,
birch. Standards should be retained
at a density of about 30-100 per
ha (a 10-18m spacing), and should
consist of a variety of age ranges.
Try to leave a few of the very
oldest trees to grow on to become
veteran trees.
Up to 40% of the canopy can be
occupied by standards. When coppicing,
look out for seedlings to protect
and allow to grow on to form standards.
Too many standards retained will
result in poor coppice regrowth
due to insufficient light reaching
the ground.
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A sloping cut is traditional
as it was thought to shed
water and prevent fungal
decay. However, there is
no evidence that a sloping
cut minimises fungal attack.
A low cut maximises the
yield and encourages shoots
to develop their own roots;
it is also safer to work
when stumps are cut low.
The bark below the cut
should not be damaged.
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Work traditionally takes
place during the winter
- October to the end of
March. There is no silvicultural
reason for this but coppice
which is cut during July,
August and September will
produce shoots which are
not frost hardy. Coppicing
during the spring will
disturb nesting and trample
the ground flora. Coppice
material cut in the winter
works better and lasts
longer than that cut when
the sap levels are higher.
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In Cumbria, especially in the
south of the county, the deer
population is usually too high
to risk coppicing without suitable
protection from browsing. The
protection can take several forms:
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Exclude all livestock from
the wood
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Stacking brash over stumps
works where deer pressure
is low, but is generally
not effective
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Erect a brash deer barrier
if manpower, materials and
time allow - this can be
effective for long enough
for the regrowth to get away
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Erect deer fencing if the
site makes this practicable
and expense allows
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Erect individual tree shelters
over regeneration or rabbit
net protection around coppice
stools if only protecting
a few. Small circular fences
of chestnut paling are thought
to keep deer out (no more
than 20m across). This type
of fencing need only be temporary
and can be used several times
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Electric fencing is quite
effective but requires regular
maintenance
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Control deer if numbers
are high; professional help
must be sought for culling
- Repellents work for a short
time but require regular replacement
as high rainfall washes away
the active ingredient
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