TOWARD UNDERSTANDING ECOSYSTICMS
21
air temperature, radiation, relative humidity, and wind within the
unit. The temperature and transpiration rate are then cdculated for
the “characteristic” leaf of each foliage unit. The total water usage of
each unit is obtained by multiplying the transpiration rate of the
“characteristic” leaf by the number of leaves within the unit. The total
water usage of the tree is obtained by summing up the water usage of
each unit. Not only is the total water usage of the tree estimated but the
contribution by each foliage unit is realized. When there is a change of
climatia conditions some of the foliage unifs are more strongly affected
than are others.
D. STANDS
One can extend the analytical method from the single plant or tree
to an array or stand of plants or trees. This would appear to some as a
tedioua procedure, but it is an approach which msy indioate many
things concerning climate, water usage, and the competition of neighboring individuals for water. A single tree in the open, without neighboring trees, has certain values of the climatic factors for each of the
foliage units. As soop as other trees are plaoed nearby they partially
shade bhe sun from some of the foliage units, modify the wind flow and
the ail temperature and thereby change the climate of some or all of
the foliage units. These changes of climate show up aa a change in the
water usage of the foliage and of the entire tree. olie can begin now to
inspect the whole process of mutual interference and of competition
on a qcantitative and an analytical basis. There are really very few
other possible methods for doing this. An analytical, mathematical
model utilizing the convenience of a large computer, for facilitating the
arithmetic, is very useful when tempered by judgment bawd on field
obeervrttions and experience. Therefore, in line with the p r o d u r e
suggebted here one can synthesize the entire vegetation structure leaf
by lea.f, foliage unit by unit, plant by plant, and finally for an entire
stand. Plants with leaves of various sizea, various orientations, and
various diffusion resistances to transpiration will respond in very different ways to the climatic conditions prevailing. The important point
to make here is that the techniques for working out the response of the
vegetation, such aa the water usage or net photosynthesis and productivity, are now available and can be done. Mistakes will be made,
important factors left out, but certain basic underlying causes and
effects will be discovered for the first time from such fundamental
physical models.
21
air temperature, radiation, relative humidity, and wind within the
unit. The temperature and transpiration rate are then cdculated for
the “characteristic” leaf of each foliage unit. The total water usage of
each unit is obtained by multiplying the transpiration rate of the
“characteristic” leaf by the number of leaves within the unit. The total
water usage of the tree is obtained by summing up the water usage of
each unit. Not only is the total water usage of the tree estimated but the
contribution by each foliage unit is realized. When there is a change of
climatia conditions some of the foliage unifs are more strongly affected
than are others.
D. STANDS
One can extend the analytical method from the single plant or tree
to an array or stand of plants or trees. This would appear to some as a
tedioua procedure, but it is an approach which msy indioate many
things concerning climate, water usage, and the competition of neighboring individuals for water. A single tree in the open, without neighboring trees, has certain values of the climatic factors for each of the
foliage units. As soop as other trees are plaoed nearby they partially
shade bhe sun from some of the foliage units, modify the wind flow and
the ail temperature and thereby change the climate of some or all of
the foliage units. These changes of climate show up aa a change in the
water usage of the foliage and of the entire tree. olie can begin now to
inspect the whole process of mutual interference and of competition
on a qcantitative and an analytical basis. There are really very few
other possible methods for doing this. An analytical, mathematical
model utilizing the convenience of a large computer, for facilitating the
arithmetic, is very useful when tempered by judgment bawd on field
obeervrttions and experience. Therefore, in line with the p r o d u r e
suggebted here one can synthesize the entire vegetation structure leaf
by lea.f, foliage unit by unit, plant by plant, and finally for an entire
stand. Plants with leaves of various sizea, various orientations, and
various diffusion resistances to transpiration will respond in very different ways to the climatic conditions prevailing. The important point
to make here is that the techniques for working out the response of the
vegetation, such aa the water usage or net photosynthesis and productivity, are now available and can be done. Mistakes will be made,
important factors left out, but certain basic underlying causes and
effects will be discovered for the first time from such fundamental
physical models.