58
M. E. D. P O O R E
into account in a classification of the forest. The confusion which arises
when an attempt is made t o classify phytocoenoses using all the constituent synusiae is illustrated by Cain and de Oliviera Castro (1959)
from data from the red spruce association (Piceetum rubentis) of the
Great Smoky Mountains in which a possible total of 256 separate
phytocoenoses might occur, all with the same superior arborescent
layer but with various combinations of layer-societies in the four lower
strata. It may sometimes be convenient t o study the phytocoenose,
sometimes the synusia, but the principles which are applied t o the
classification of one may not necessarily apply t o the other.
Some systems of classification have arisen in the attempt t o produce
a world-wide or continental conspectus of vegetation ; such for example
are the works of Schimper (1898), Schimper and von Faber (1935),
Weaver and Clements (1938) and Rubel (1930). Others have arisen by
generalizing from more local studies, as has that of Braun-Blanquet
(1951). That these do not altogether coincide in their higher units may
be due t o the fact that the same methods are not appropriate for
extensive and more local analysis. The highest unit of the BraunBlanquet hierarchy, being, as it is, floristically based, is the Community
circle (Gesellschaftskreis) which is essentially a plant geographical unit.
This is defined as: “The final unit is a system of vegetation based on
floristics. It is characterized by the total complement of all species and
communities which are peculiar t o or favour one natural Gesellschaftskreis (Vegetation region) and derives its most comprehensive value
through an independence which is partially based on climate and
partially on floristic history.” Similarly in his approach t o the classification of Malaysia, van Steenis (1950) uses the same concept. But the
higher categories of Schimper and Rubel transcend these floristic
barriers.
A. B I O C O E N O S E A N D G E O B I O C O E N O S E
Attention is being increasingly drawn t o biocoenoses as a subject for
study. Sukachev (1944) has extended this concept t o include the
physical elements associated with living organisms in any one site.
Only in the geobiocoenoses can the interrelationships of rock, soil,
plants and animals in all their complexity and the energy relationships
between them be studied.
There are real difficulties at present in the way of a classification of
biocoenoses. This is partly due t o the divergent developments of plant
and animal ecology and partly t o problems raised by the behaviour of
the animal component, many of which move daily or at particular
seasons from one biocoenose t o another and must properly be considered
a part of both. To what biocoenose, for example, do migratory flocks of
geese belong or swarms of the desert locust? It is by no means clear on
M. E. D. P O O R E
into account in a classification of the forest. The confusion which arises
when an attempt is made t o classify phytocoenoses using all the constituent synusiae is illustrated by Cain and de Oliviera Castro (1959)
from data from the red spruce association (Piceetum rubentis) of the
Great Smoky Mountains in which a possible total of 256 separate
phytocoenoses might occur, all with the same superior arborescent
layer but with various combinations of layer-societies in the four lower
strata. It may sometimes be convenient t o study the phytocoenose,
sometimes the synusia, but the principles which are applied t o the
classification of one may not necessarily apply t o the other.
Some systems of classification have arisen in the attempt t o produce
a world-wide or continental conspectus of vegetation ; such for example
are the works of Schimper (1898), Schimper and von Faber (1935),
Weaver and Clements (1938) and Rubel (1930). Others have arisen by
generalizing from more local studies, as has that of Braun-Blanquet
(1951). That these do not altogether coincide in their higher units may
be due t o the fact that the same methods are not appropriate for
extensive and more local analysis. The highest unit of the BraunBlanquet hierarchy, being, as it is, floristically based, is the Community
circle (Gesellschaftskreis) which is essentially a plant geographical unit.
This is defined as: “The final unit is a system of vegetation based on
floristics. It is characterized by the total complement of all species and
communities which are peculiar t o or favour one natural Gesellschaftskreis (Vegetation region) and derives its most comprehensive value
through an independence which is partially based on climate and
partially on floristic history.” Similarly in his approach t o the classification of Malaysia, van Steenis (1950) uses the same concept. But the
higher categories of Schimper and Rubel transcend these floristic
barriers.
A. B I O C O E N O S E A N D G E O B I O C O E N O S E
Attention is being increasingly drawn t o biocoenoses as a subject for
study. Sukachev (1944) has extended this concept t o include the
physical elements associated with living organisms in any one site.
Only in the geobiocoenoses can the interrelationships of rock, soil,
plants and animals in all their complexity and the energy relationships
between them be studied.
There are real difficulties at present in the way of a classification of
biocoenoses. This is partly due t o the divergent developments of plant
and animal ecology and partly t o problems raised by the behaviour of
the animal component, many of which move daily or at particular
seasons from one biocoenose t o another and must properly be considered
a part of both. To what biocoenose, for example, do migratory flocks of
geese belong or swarms of the desert locust? It is by no means clear on