Deer
Damage to Commercial Forestry/ Native Woodlands
Poor
deer management in a forestry area can cause deer damage
to commercial forestry and our native woodlands. The main
types of damage are Fraying, Browsing, Bark- Stripping,
Bole-Scoring and Leader-Shoot damage.
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Fraying
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· Species - All Deer (male)
· Time of the Year - Mainly August
to November with a lesser outbreak in spring.
· Description - male deer rubbing
their antlers (and facial scent glands) against
tree stems and foliage cause Fraying. This is mostly
a form of sexual aggression or territory - marking
which occurs during the build up to the rut.
Fraying is recognized, on close examination, by
the presence of hairs in and around the damage,
also by accompanying broken and twisted side-branches
and associated scrapes on the ground. Fraying is
frequently found near to places where deer come
into the open, also on aromatic trees or trees with
a different scent from the main crop, and this fortunately
results in scrub trees (e.g. Willow, Birch, Rowan)
outside the commercial crop being selected if present.
The species of deer responsible can usually be distinguished
as follows: |
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Fallow:
thicker stems (75mm) up to 1.2m, thrashed stems
to 2m.
Sika:
similar height to Fallow; in some populations,
areas of severe bole-scoring recorded on mature
trunks up to 300mm diameter, especially Spruce.
Red:
thick stems with severe damage to branches and
tops, no scrapes associated.
Comment - Although often the most conspicuous
form of deer damage, fraying is usually the least
serious
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Browsing
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Species - All deer (also sheep)
· Time of the Year - Peak of damage
January - May, while other food is scarce and
buds and growing shoots are most tender. Can occur
at all times of the year.
· Description - Browsing is the
nibbling of the buds and shoots of newly established
trees, in particular, for food. Trees browsed
by deer often develop multi-leaders, or in severe
cases come to resemble clipped miniature bushes.
Vulnerability to browsing is mainly relative to
the amount of other browse available, but species
preferred for stripping are also preferred for
browsing, and browsing is also more likely to
occur soon after planting and in certain sites,
e.g. trees planted in clearing to which deer have
become accustomed to grazing, slopes which remain
clear of snow in winter, young plantations surrounded
by thick-stage crop where deer can shelter. It
is essential to be able to distinguish deer browse
from sheep.
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Comment
- Browsing is not as obvious as stripping or fraying,
but builds up during the early years of a plantation,
and becomes a severe form of damage when it prevents
an adequate percentage of leading shoots growing
beyond the reach of deer.
In some areas browsing imposes a 2-4 year delay
on the time taken by Sitka Spruce to grow beyond
reach, greater delays could have serious economic
consequences. Browsing of side shoots is not a
significant form of damage. Prevention is achieved
by adequate culling policy and forest design.
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Bark-Stripping
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· Species - All Deer
· Time of Year - Usually most severe
January- March. Also with Sika deer it can often
occur in the autumn.
· Description - Bark-stripping occurs
when deer shave off tree-bark with their lower
teeth for food. The broad parallel teeth-marks
are often clearly visible, running more or less
vertically.
Thicket-stage plantations are often worst attacked,
but damage may occur on any tree from around seven
years onwards. Highly vulnerable species are Norway
Spruce, Lodgepole Pine (especially thicket stage)
and most hardwoods (especially young Elm). Douglas
and Silver Firs, Lawson Cypress, Hemlock and young
Sitka Spruce, Scotts Pine and Larch may also be
damaged. Brashing of any tree species increases
vulnerability.
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