BSBINews - BSBI Archive - Botanical Society of the British Isles

Conference Report - 2009 - BSBI Spring Conference on alien trees and shrubs, Berwick 63
Cone size, shape, texture, colour: distinctive
in most genera and species; prickles on cone
scale (e.g. Cupressus, Pinus contorta).
Twig characteristics: pubescence, present or
absent, colour, density, whether in grooves or
all over the twig etc.; peg-like short shoots,
present (e.g. Cedrus, Larix); colour of twig,
especially new growth.
Bud: shape, i.e. pointed or blunt; colour and
layout of bud scales; texture - smooth, resinous,
papery.
Bark: deeply fissured (some Pinus); flaky
(some Pinus, Picea, Abies); soft and spongy
(Sequoiadendron); stringy (Cryptomeria);
presence of resin blisters (Abies).
Finally Cameron stated that there was no
substitute for examining trees in situ and
handling samples back at base to get a real feel
for this group of taxa. Members should run
through one of the field keys which cover
British conifers (e.g. Stace, 1997; Mitchell,
1972 & 1974; Poland & Clement, 2009), and
once the identity has been determined, the
specimen should be re-examined (either whole
tree or voucher) in a more personalised way
and notes made of key features which, to
them, make it distinct from other species.
John Bailey then introduced the last speaker
of the afternoon session, Kevin Rideout, NTS
ranger at St Abbs Head National Nature
Reserve, which was one of the venues for a
meeting on Monday. He gave an entertaining
account of the nature reserve, starting with a
colourful run-through of plants and habitats.
He explained that the headland is a big chunk
of volcanic larva surrounded by sedimentary
rock and the hard volcanic rocks provide
impressive sea cliffs. Thrift, Sea Campion and
Roseroot grow on the cliffs, together with
Scots Lovage, here near its southern limit.
Inland cliffs and rocky outcrops provide
habitats for Spring Sandwort and Purple Milkvetch.
The grassland has been much modified
by human activity but is still species-rich, with
masses of Thrift and Hairbells, and also many
ant-hills with quite a diversity of plants on
their summits, including Wild Thyme and
Lady's-bedstraw. Rock-rose is also prevalent
and is the food plant of the Northern Brown
Argus butterfly.
He explained that sheep were the main
management tools, except in late spring and
early summer. To be successful, overgrazing,
which can open the grassland to erosion, and
undergrazing, which can allow coarse grasses
to proliferate, must be avoided. Sheep must
also be encouraged to graze where you want
them to, not where they want to. With reduced
grazing, Meadow Saxifrage and Common
Whitlowgrass have declined. In the past there
was a tendency to manage too much and the
correct approach now appears to be to 'do
nothing' as the 'default setting' and see how
that works before doing anything else. The
only exception is gorse clearance, which is an
ongoing task.
A large freshwater area used to be bog land
but was drained around 1900, resulting in the
disappearance of Lesser Water-plantain.
However, the aquatic environment has
improved the biodiversity of the site.
Kitiwakes enjoy bathing in the fresh water and
their droppings add nutrients. The ungrazed
side of the mireloch has been given over to
tree planting, during the early 20 th century,
mainly Sycamore, Hawthorn and Grey Poplar.
Then in the 1970s, Sea Buckthorn and
Japanese Rose were planted, mainly to attract
birds, and now the emphasis is on planting
native Oaks and Birch.
The meeting ended with an open forum for
discussion. The many issues raised included:
the need to monitor the spread of Robinia
pseudoacacia; the fertility of Leyland Cypress;
the zigzag branching pattern of Thuja; the
importance of smell in identifying conifers; a
mnemonic for splitting Picea and Abies - E.icea
has 12egs and Abies fl,in't (referring to the
presence or absence of 'pegs' from which
leaves arise); the fact that Roe Deer and a beetle
eat Rhododendron leaves, but not in sufficient
quantity to do any harm; the mounting bureaucracy
in getting grants and planning applications
for planting trees, although it was recognised
that some control was needed; the impending
attack on Aesculus hippocastanum by an
aggressive fungus disease that could decimate
populations in southern Britain, aided by a
small moth from the Balkans whose larvae
were leaf miners; the use of cows instead of