With some information now at our disposal concerning the structure of vegetation and its organization into plant communities, associations, formation-classes, and biochores, we can study the environmental factors which require vegetation to assume such varied forms.
The four main classes of environmental factors are
(1) climatic,
(2) geomorphic (related to land form).
(3) edaphic (related to soil), and
(4) biotic (related to living organisms).
Although we treat each of these classes of factors in turn and examine each factor separately, it must be kept in mind that the basic concept of ecology is that many factors act simultaneously and that factors affect one another in a most complex interrelationship. The very plants that are affected by environmental factors may react in such a way as to modify the environment and thus change the factors themselves.
In considering how various factors of the physical environment influence plant structures and distributions, two scale ranges can be treated. One is essentially the global scale and consists of such climatic factors as the seasonal and latitudinal patterns of insolation, light and darkness, temperature, precipitation, and prevailing winds. The other scale of consideration is that of variation of the physical environment found within a relatively small habitat and between adjacent habitats. Thus although there are vast global climate patterns of deserts and humid regions, we may also find within a region of generally humid climate a few small habitats (such as dune or cliff) which are extremely dry places for plants to live.
"The world is a book, and those who do not travel read only a page", St. Augustine said. Here at www.travel-university.org we believe that every page must be read and explored. Travel is an avenue of learning that no text or classroom can teach. The world is a living classroom and you the student. We invite you to the www.travel-university.org library where you can read general interest and detail oriented articles.
