1067-4136/04/3504- © 2004
Russian Journal of Ecology, Vol. 35, No. 4, 2004, pp. 224–229. Translated from Ekologiya, No. 4, 2004, pp. 259–265.
Original Russian Text Copyright © 2004 by Tsvetkov.
The boreal forests of central Siberia are mostly larch
forests. Growing in the permafrost zone, they fulﬁl
environment-forming and protective functions and
maintain the unstable natural equilibrium under the
extreme conditions of the North. It is known that exter-
nal stress factors may cause long-term degradation of
boreal forests, which lose their stability and ecological
potential. Fires are one of the factors that have pro-
foundly and diversely affected boreal forests through-
out their history. Practically every spot of forest has
been exposed to the pyrogenic factor at least once.
Therefore, the spatial arrangement, formation and
development of forest ecosystems have been directly
and indirectly affected by periodic ﬁres for a long time.
Forest ﬁres are a natural, unavoidable, and cyclic
(nonperiodic) factor of the life of forest ecosystems
(Sannikov, 1992). They play a priority role in both evo-
lutionary and forest-forming processes, determining
the cyclicity of the latter. Therefore, they may be
regarded as one of the exogenous, evolutionary ecolog-
ical factors determining the life of forest communities
in the northern regions of central Siberia.
(Rupr.) Rupr. is the most
common tree in central Siberian boreal forests.
Although larch forests are highly sensitive to external
factors, their geographic range, which almost coincides
with the permafrost zone, is conserved. Therefore, the
main purpose of this study was to determine how this
species survives under the conditions of the permafrost
zone and periodic ﬁres. I focussed on one extremely
important aspect of this problem, namely, the pyro-
phytic properties of
as the main forest-form-
ing species of northern taiga ecosystems.
Here, I will use, after Sheshukov and Peshkov
(1984), the following terms for characterizing species
resistance to forest ﬁres at different organizational lev-
els: at the level of an individual tree,
at the level of a tree stand,
; and at the
level of a forest ecosystem,
also use the generic term
the Greek roots
(born, origin); i.e.,
the properties caused by (originating from) exposure to
ﬁre—to refer to all three terms.
was proposed by Sannikov
(1973) to mean a species that is highly resistant to ﬁre
and well adapted to the conditions of burned-out areas.
This property implies that the substrate must be prelim-
inarily exposed to ﬁre for the site to be prepared for nor-
mal natural forest regeneration. Thus, the pyrophytic
properties of a species characterize its ability to spread
to burned-out areas due to good adaptation to the new
conditions of the ecotope.
Many Russian researchers have reported that the
larch is highly pyrophytic. The studies performed by
Tarabukina and Savinov (1990) in Yakutia, Krasno-
shchekov (1994) in Mongolia, and Prokushkin
(2000) in Evenkia demonstrated that soil acidity
decreased and the gross nitrogen and exchangeable-cat-
ion contents decreased in soils after forest ﬁres, which
promoted the formation of a substrate favorable for for-
est renewal. Larch rapidly spread to the spots with this
Foreign researchers also observed improved
edaphic conditions in burned-out areas. For example,
the studies performed by Scotter (1971) in northern
Canada showed that the amounts of exchangeable cal-
cium, potassium, and phosphorus increased and the
acidity decreased in the upper layers of soil after forest
ﬁres. Payette (1992) reported on “bursts” of natural for-
est regeneration after ﬁres in North American boreal
Pyrophytic Properties of the Larch
in Terms of Life Strategies
P. A. Tsvetkov
Sukachev Institute of Forestry, Siberian Division, Russian Academy of Sciences,
Akademgorodok, Krasnoyarsk, 660036 Russia
Received May 12, 2003
—The pyrophytic properties of the larch
(Rupr.) Rupr. growing in the northern taiga of
central Siberia have been studied. It has been found that, although the trees are highly combustible and ﬁre resis-
tance of tree stands is low, the species is highly pyrophytic, which allows it to retain its geographic range. At
early stages of postﬁre successions, the larch exhibits characteristics of pyrogenic explerent and is subject to
selection. When forest restoration is close to completion, the species passes into the patient state and acquires
properties subject to
: permafrost zone forests, larch, pyrophytic properties, life strategies.