Skógræktarritið - 15.05.2001, Page 188

Fig. I. Four year old Siberian larch
seedlings, emerged from direct seed-
ing using pyramidal indentations as a
micro site preparation.
There was a significant differ-
ence between the microsites,
both concerning germination
and seedling establishment,
with the Kobresia-heath site giv-
ing much better results. There
were problems scarifying the
Betula Nana moorland site prop-
erly, giving much poorer seed
spots, and seed predation, prob-
ably by mice, was a big problem
there.
Lodgepole pine gave signifi-
cantiy better seedling establish-
ment than the Siberian larch.
When sown in the Kobresia-heath
using plastic cones, 78% of the
Lodgepole pine spots had one or
more living seedling after four
growing seasons, compared to
only 58% of the Siberian larch
spots.
Comparing the results of
seedling establishment for plant-
ing and direct seeding after four
growing seasons, direct seeding
using pyramidal indentions pro-
vides a significantly higher num-
ber of spots with at least one liv-
ing seedling than planting.
The seedlings, both from direct
seeding and planting, had strong
evidenced of stagnated growth,
having yellowish colour and
short needles. The lodgepole
pine seedlings were similar in
size from all seeding methods,
but forSiberian larch, seedlings
in the plastic cones and pyrami-
dal indentations were significant-
ly taller than those in control
spots.
The regeneration trials from
1997 in Mosfell and Höfði gave
generally similar results as those
from 1993 and 1996. Direct seed-
ing after tractor-driven TTS scari-
fication was possible whitout any
significant problems. Using the
plastic cones gave far better
results than the contol and gave
competive results to planting.
There were indications that the
seedlings emerging under the
cones with the fertiliser packs
were larger and better estab-
lished.
Discussion and conclusions
It can be argued that direct seed-
ing of coniferous seeds can give
similar results as obtained by
planting forest tree seedlings in
the cold lcelandic climate (Jón
Geir Pétursson and Aðalsteinn
Sigurgeirsson, 1997). However,
there were enormous differences
between methods and it is evi-
Fig. 2. Stagnated growth („check") of
seedlings was frequently observed in
the trials, like these 4-year-old lode-
pole pine seedlings seen here in
Höfði. There are indications, however,
that this can be alleviated through the
use of slow-reiease fertilisers.
dent that unless some support-
ing method is used, the results
will be very poor. The best overall
results were obtained when
using plastic cones, regardless of
the tree species in question.
Temperature and moisture both
increase under the cones, which
is benificial both forthe seed
germination and seedling estb-
lishment. They also provide shel-
ter for the seedling during the
first two years and prevent seed
predation. Using them, the
amount of seed sown can be
decreased by about a factor of 4
compared to the other seeding
methods.
Seed predetation must be con-
sidered when using direct seed-
ing in Iceland, as in other coun-
tries. The seed predators are like-
ly both mice and birds. The rela-
tively large Siberian larch seeds
are especially vulnerable, but
also to some degree, smaller
seeds like those of lodgepole
pine.
186
SKÓGRÆKTARRITIÐ 2001 l.tbl.