30
DAVID M. GATES
be done since one must understand the structure of the plants of the
community. One must know the height of the plants, something concerning their spacing, the leaf size, shape, orientation and exposure, and
the canopy structure. Once these basio featuree are specified and the
degree of i.ariation occurring among them recognized, the mathematical
models can be formulated and the computatiom made. Subsequent field
observation and qresaurement may confirm the predictions, in which
case the investigator should be careful that it is not a fortuitous agreement. If the field measurements reject the predictions then the investigator m-at inspect the mathematical model and locate the point at
which the model departs from reality. Perhaps it is because the stomates
of fully sunlit leaves close in midday and thereby make the diffusion
resistanca very high for a few hours, or perhaps the statistical treatment of large numbers of leaves was done camledy, or some more subtle
detail not taken properly into account.
By means of mathematical models which are based on reality, by
means of repeated field observations and measurements, and by subsequent correction and refinement of the model it is possible to test
various arrangements of plant types, sizes, and distributions for optimum ubilization of the available energy. For a region with specific
edaphic and climatic characteristios is it poeeible to derive from basic
principles a unique structure for the vegetation which oould establish
itself? Is it possible to derive h m baeic prinoiples the fact that one
region will have a beeoh-maple climax, another aa oak-hickory o h x ,
and anc ther a pine climax? Much is now known about the differenoea in
mil type. moisture, and climate in these vegetation types, but can these
differences in vegetation be predicted from the proper analytical formulation bawd on physical principles and physiological responses? Or will
it only be possible to eatablish principles for major differences in vegetation types such sa g r d a n d s , chaparral, coniferous forests and deciduous forests. One does not lack descriptive information concerning
various plant communities and ecosystems. The climates, mil characteristics, seasonal moisture amounts, and plant species compositions are
well documented. Yet this is about aa far 8~ one can go without a
working model b d on physical and biological principles.
D. SUCCESSION
How does plant succeesion p r o d ? What determines the rate of
plant succession?
If a mathematical model is formulated which can simulate a simple
plant wmmunity and reeults in verifiable predictions concerning competition for water, light, carbon dioxide, etc. then the next logical step
DAVID M. GATES
be done since one must understand the structure of the plants of the
community. One must know the height of the plants, something concerning their spacing, the leaf size, shape, orientation and exposure, and
the canopy structure. Once these basio featuree are specified and the
degree of i.ariation occurring among them recognized, the mathematical
models can be formulated and the computatiom made. Subsequent field
observation and qresaurement may confirm the predictions, in which
case the investigator should be careful that it is not a fortuitous agreement. If the field measurements reject the predictions then the investigator m-at inspect the mathematical model and locate the point at
which the model departs from reality. Perhaps it is because the stomates
of fully sunlit leaves close in midday and thereby make the diffusion
resistanca very high for a few hours, or perhaps the statistical treatment of large numbers of leaves was done camledy, or some more subtle
detail not taken properly into account.
By means of mathematical models which are based on reality, by
means of repeated field observations and measurements, and by subsequent correction and refinement of the model it is possible to test
various arrangements of plant types, sizes, and distributions for optimum ubilization of the available energy. For a region with specific
edaphic and climatic characteristios is it poeeible to derive from basic
principles a unique structure for the vegetation which oould establish
itself? Is it possible to derive h m baeic prinoiples the fact that one
region will have a beeoh-maple climax, another aa oak-hickory o h x ,
and anc ther a pine climax? Much is now known about the differenoea in
mil type. moisture, and climate in these vegetation types, but can these
differences in vegetation be predicted from the proper analytical formulation bawd on physical principles and physiological responses? Or will
it only be possible to eatablish principles for major differences in vegetation types such sa g r d a n d s , chaparral, coniferous forests and deciduous forests. One does not lack descriptive information concerning
various plant communities and ecosystems. The climates, mil characteristics, seasonal moisture amounts, and plant species compositions are
well documented. Yet this is about aa far 8~ one can go without a
working model b d on physical and biological principles.
D. SUCCESSION
How does plant succeesion p r o d ? What determines the rate of
plant succession?
If a mathematical model is formulated which can simulate a simple
plant wmmunity and reeults in verifiable predictions concerning competition for water, light, carbon dioxide, etc. then the next logical step