Fen Management Handbook - Scottish Natural Heritage

‘Bird-eye’ and incineration A
tracked excavator working on
mats is fitted with a special ‘birdeye’
cutting head consisting of
one spinning disc which fells
trees up to 75 cm diameter and
grinds stumps. Once trees are
felled, they are placed within a
large portable incinerator where
they are reduced to ash. Initial
trials suggest that 1 hectare
of scrub can be cut within 4-6
days, with an incineration rate of
a further 4-6 days.
The excavator has a ground
pressure of 1.5 psi. The
incinerator itself can be moved
around the site using the
excavators, although a new
system of locomotion is being
investigated for use in the
Broads using an experimental
air platform, i.e. similar to a
hovercraft. The incinerator has a
ground pressure of 0.8 psi with
floats, and 1.3 psi without floats.
Winches used to drag trees
Sky line extraction which
partially suspends the cut trees
and scrub
Helicopter extraction, usually of
bundled tree trunks
6.5.3 Chemical control
Wide reach and low
number of passes causes
little damage to peat
surface.
Grinding process kills
many stumps, especially
if they are flooded at the
time or shortly afterwards.
Complete burn by the
incinerator enables huge
amounts of material to be
reduced to manageable
proportions.
The cutting machine and
incinerator carry large
reserves of fuel and one
refuelling trip per hectare
is anticipated.
Reduces damage from
dragged material
Minimises damage from
dragging
Some stump re-growth
may need treating.
Norfolk and Suffolk
Broads where bird
eye cutting has
been combined with
a large portable
incinerator to dispose
of woody material.
Fenn’s and Whixall
Mosses, Clwyd
Very expensive Roudsea Moss,
Cumbria
Stumps should normally be treated immediately after cutting with an approved
chemical to prevent regrowth. Stumps should be cut as low as possible to minimise
the treatment area and as much herbicide as possible applied to the stump and basal
bark without risk of liquid running off. The technique of ‘drill and kill’ before felling
and physical removal has recently been used with some success on Portmore Lough
in Northern Ireland (see Case Study 7.2) and has the potential advantage of reducing
the amount of re-growth from tree stumps/roots left in the fen.
Formulations containing ammonium sulphamate (commonly marketed
as Amcide) or glyphosate (Roundup) are the most common herbicides
used for stump treatment, but recommended herbicides and their use
are tightly controlled to avoid risk of pollution or other environmental
damage. Details of herbicides suitable for use on nature conservation
sites are listed in Natural England’s Information Note 125 The Herbicide
Handbook – Guidance on the use of herbicides on nature conservation
sites. If in doubt, always seek expert advice.
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