62 MAN ON THE LANDSCAPE 



serious competition to their lordly parent trees, yet they stand ready 

 to take over the sun energy when the forest patriarchs crash to earth 

 or die and cast little shade. 



This same plant community meets the needs of many animals such 

 as worms, insects, spiders, birds, squirrels, raccoon, deer. Many of 

 these animals in turn render services to the plant community, such as 

 soil improvement, pollination, seed dispersal, and control of injurious 

 life forms. The plant community, by regulating the action of water 

 in and on the soil may maintain permanent springs and streams, 

 which are valuable to both land and aquatic life. 



By this overly simplified example we see that at any point in 

 time, the evolving environment is a complex maze of relationships. 



Life Moves Toward Climax. Though those biologists who are me- 

 chanistic will dispute the idea, many philosophers will maintain that 

 life is driven toward a climax or peak of development. It is driven 

 by the intrinsic forces and reactions of natural phenomena. The 

 jouney has has its sprint and delays, its detours, its rough going. And 

 once the climax is reached there is no assurance that it can be main- 

 tained. Sooner or later some natural force, such as landslide, erup- 

 tion, erosion, or climatic change, may upset the equilibrium and the 

 area must again start its laborious journey upward from whatever 

 point the disturbance dictates. 



Briefly, the development of a climax is this: As a primitive asso- 

 ciation of plants and animals live in a specific area or habitat, the 

 habitat is changed. Soil structure and composition change ; moisture 

 conditions change; sunlight patterns are altered. In general the 

 environment is in time so altered that other associations are enabled 

 to invade the area, in a defined sequence. Finally, if no overwhelming 

 natural force intervenes, a climax balance is established, in which the 

 species present make the most efficient use of the habitat, of minerals 

 water, air and sunlight. Soil formation equals or exceeds natural 

 erosion. A maximum is reached in every department of life and en- 

 vironment. A relatively few species of plants and animals dominate 

 the area. They determine, by the nature of their activities, which 

 ether species can survive there. (Fig. 20.) 



Barring a cataclysm, the climax is (probably) perfect and perma- 

 nent. There is much cooperation and mutual protection between the 

 associated species, but ruthless competition among individuals of a 

 species. 



Life Tends to Overpopulate. Potential reproduction in a climax 

 is more than enough to insure maximum biological activity in the 

 area. A reserve army of seeds and spores is ready to recover quickly 

 any portion of the habitat which may be damaged superficially, as by 

 insects, flood, or lightning fire. Yet, excessive reproduction is con- 

 trolled by natural forces, (Fig. 21) starvation and disease being most 

 common, along with eating of seeds and plants by animals, and mortal 

 combat between animals. 



