Volume 9 - Electric Scotland

SEED DISPERSAL OF PINUS SYLVESTR1S & BETULA ALBA 45
Yards.
At 266. i Pine, top broken, circumference 8|- inches, still living.
i Birch, height 10 feet, circumference 8 inches, in good
condition, bearing staminate catkins.
,,366. i Pine, height 3 feet, about ten years old.
489. i Pine.
3 Birches, all in good condition.
,,746. i Pine, dead, about seven years old, in damp soil amongst
Erica Tetralix.
,,771. i Pine, dead, about seven years old, in damp soil amongst
Erica Tetralix.
,, 837. i Pine, fourteen years old at least.
,,878. i Pine, height 5 feet, circumference 9^ inches, in good
condition.
,,
886. i
Pine, height 7 feet, circumference i6i inches, about 13
years old, in good condition.
5 Pines, in good condition ;
these were not on the direct
line of measurement, but near the last -mentioned
example, and at much the same distance from the
wood.
Beyond this point no trees were observed, the ground
being composed of loose dunes, and in other ways unsuitable
for the growth of trees.
These observations show that Pine seeds have been
carried as far as 886 yards, and Birch seeds as far as 489
yards.
It will be observed that the trees occasionally occur in
groups separated by long gaps. This is due to the nature
of the ground, which is in the form of alternating ridge and
hollow. The ridges are drier and more suitable for the
growth of trees than the marshy hollows. The dominant
vegetation on the ridges is usually Calluna vulgaris, while in
the hollows Erica Tetralix is the most abundant. All the
trees from i to 500 yards
are associated with Callnna
vulgaris. From 500 to 800 yards the ground is occupied
by a broad marsh with Erica Tetralix^ and there only two
trees were found ;
both were dead, probably having succumbed
to the damp nature of their habitat, which may
lived. From 800
perhaps have been drier while they
to 886 yards the association is
again
that of Calluna
vulgaris, although with some Erica Tetralix mixed and in
; this part eight of the trees were found.