1067-4136/01/3206- $25.00 © 2001
Russian Journal of Ecology, Vol. 32, No. 6, 2001, pp. 393–399. Translated from Ekologiya, No. 6, 2001, pp. 427–433.
Original Russian Text Copyright © 2001 by Khutornoi, Velisevich, Vorob’ev.
The external morphology and viability of woody
plants at the timberline reﬂect the dynamics of environ-
mental factors, on the one hand, and plant response to
them, on the other (Gorchakovskii and Shiyatov, 1976).
Owing to a high ecological ﬂexibility, Siberian stone
pine has an extensive range and is one of a few tree spe-
cies growing at the timberline. The speciﬁc distribution
of this species implies the existence of certain metabolic
mechanisms providing for a high degree of adaptation to
extreme conditions of growth. It was noted that changes
in ecological conditions at different elevations in the
mountains lead to signiﬁcant changes in metabolism and
coordination of growth processes and generative devel-
opment in Siberian stone pine (Vorob’ev, 1967, 1977).
Specialists devoted much attention to studies on the
effects of external factors on the growth and develop-
ment of conifers at the upper limit of their distribution
(Tranquillini, 1979; Holtmeier, 1981), some problems
of needle and shoot damage (Hadley and Smith, 1986),
the relationship between the growth of terminal and lat-
eral shoots (Weisberg and Baker, 1995), and distur-
bances of reproductive processes (Zemlyanoi, 1975);
there are numerous descriptions of crown forms in dif-
ferent coniferous species along the altitudinal gradient
(Vorob’ev, 1967; Wardle, 1968; Alexandrov, 1971).
However, mechanism of crown formation in high
mountains remains obscure.
Today, there is no generally accepted theory of mor-
phogenesis in tree species forming the timberline, and
the corresponding data are fragmentary. This is evidence
for the necessity of studies in this ﬁeld, especially those
concerning the adaptation capacity of the tree crown
with respect to its morphological pattern as the factor
determining yield structure and providing for realization
of the processes of organogenesis.
OBJECTS AND METHODS
An ecological proﬁle established in the high-moun-
tain belt of the central Altai began at the southwestern
foot of Mount Sarlyk (1700 m a.s.l.) and ran through
the Seminskii Pass to its top (2506 m a.s.l.). More than
30 test plots were established along this proﬁle
, 2000), and four of them are considered
in this work (plots nos. 3, 2b, 2e, and 1a).
Plot 3 is situated at an elevation of 1700 m. This is a
typical subalpine parklike stand consisting only of Sibe-
rian stone pine. Plot 2b is at an elevation of 1850 m, at
the timberline. Trees grow in rows or strips arranged in
the prevailing wind direction (Vorob’ev, 1967; Khutor-
noi, 1997). The trees are very close to one another,
which creates conditions for strong competition but, on
the other hand, promotes their survival (Galazii, 1954).
Plot 2e is at an elevation of 1900 m, in the zone of the
so-called crooked forest, or krummholz (Holtmeier,
1981). In our opinion, this place is at the upper bound-
ary of species reproduction and the upper boundary of
tree as a life form (Serebryakov, 1952). The stand in the
plot loses its structure: parts of tree rows and individual
trees separate and disperse. Plot 1a is at an elevation of
2170 m, at the upper boundary of the distribution of
Siberian stone pine as a species in the study region.
In this plot, Siberian stone pine is usually represented
by single sterile plants of cushionlike prostrate form
0.5–1.5 m in height, which correspond to the forma
depressa variety of this tree species (Vorob’ev, 1967).
Below, these plots are referred to as the subalpine stand,
strips, krummholz, and cushions, respectively.
Model plants for analyzing the morphological struc-
ture of the crown were selected in two stages. At the
ﬁrst stage, core samples were taken to determine tree
age. Then, having analyzed the age structure and taxa-
tion parameters of the stand, we chose one average
Ecological Variation in the Morphological Structure
of the Crown in Siberian Stone Pine at the Timberline
O. V. Khutornoi, S. N. Velisevich, and V. N. Vorob’ev
Sukachev Institute of Forest Tomsk Branch, Siberian Division, Russian Academy of Sciences, Akademicheskii pr. 2,
Tomsk, 634021 Russia
Received March 28, 2000
—The structure of the crown and branching; the growth, development, and ontogeny of branches; and
organogenesis and growth of female shoots in the model Siberian stone pine trees were studied in four types of
habitats at the timberline in the central Altai Mountains (1700–2170 m a.s.l.). The results provided evidence
that the ecological forms of trees appear due to changes in the pattern of branching as well as to the decreased
rate of vegetative (primarily apical) growth. The diameter of the shoot pith is one of the most variable characters
reﬂecting the deterioration of environmental conditions at higher elevations.
: Siberian stone pine, timberline, morphological structure of tree crown, branching.