RELATIONS BETWEEN PLANTS AND ENVIRONMENT 71 



the hill, a colony of maples where apparently they have no business 

 being. All around is well drained sandy soil perfectly fitted to the 

 White oaks he sees. Where is the greater water supply maples are 

 supposed to need ? He digs in the soil, and there is the moisture. The 

 geologist explains that ground water seepage is occurring along a 

 strata of impervious shale which out-crops at that point. 



The observer has found a micro-climate ; in this instance a topo- 

 graphic peculiarity has exerted its influence. W T hen an old forest 

 monarch falls, a small clearing results, with greater sunlight, higher 

 temperature, more evaporation, more air movement. This micro- 

 climate soon develops a small plant world of its own. It is more 

 herbaceous than the shaded forest floor. It is controlled by the envi- 

 ronment of the moment, yes, but at once starts a course leading into 

 the climax conditions. In the meantime it will support herb eating 

 animals in greater numbers than will the forest climax. Game man- 

 agers sometimes make clearings in woodland, make micro-climates for 

 a special purpose more game. In the future we will likely see more 

 of this. 



There are scores of these micro-climates on a single farm. The 

 north side of a tree usually provides one, and there certain life forms 

 may live that could not exist a foot away on the south side of that 

 trunk. 



Geography of Plants. It might be expected that wherever on earth 

 similar climates were found, there also would be the same plants and 

 communities. Such is not the case. What we find is very similar ap- 

 pearing vegetation, but the species, in general, differ. What is alike, 

 is the structure of the plants, 3 and their behavior. Sandy deserts the 

 world over exhibit practically the same characteristics. So do all the 

 deciduous forests, the coniferous forests, the prairies, the plains, the 

 scrub areas. 



We have noted that west European farmers on coming to America 

 did not know how to manage the landscape. The Spaniards who 

 moved into the southern California coastal region established them- 

 selves very well, because this area has a Mediterranean climate and 

 vegetation types. The transfer of culture was easy. Protestant Ger- 

 mans from the Rhine Palatinate, who have gained fame for their 

 conservation farming in and around Lancaster county, Pennsylvania, 

 ever since colonial days, represent an unusual type of European farm- 

 er. Victims of religious persecution, they had moved about Europe in 

 search of tolerance. Weary of wandering, they came to America and 

 with great relief settled down, happy to have permanent homes once 

 more. Many of them were familiar with the Alpine storms, torrents 

 and erosion. They were acquainted with Rhine valley terraces, and 

 so, they had an unusual background for dealing with American crops, 

 climate, and agricultural problems. However, even they were not 

 wholly successful in controlling erosion on their rolling southeastern 

 Pennsylvania farms. 



