PAPERS ON BIOLOGY AND AGRICULTURE 191 



recounting the ravages of such fires. They cannot be ac- 

 counted as having been less than catastrophic in their 

 nature. 



Today, however, the factor of man's activities that ap- 

 pears to be that most actively operative is the grazing of 

 domestic stock in woodland areas. About the entire gamut 

 of grazing is being run — cattle, horses, pigs, sheep, goats, 

 and deer. It is extremely rare to find any place where graz- 

 ing is practiced where the number of grazed animals has 

 been held down to such a number as would cause little or no 

 deterioration of the fodder plants, not to speak of the native 

 vegetation as a whole. The consequence is that not only 

 has the grazing been impaired but the productiveness of 

 the land itself has become impaired, except where it was 

 shortly converted into fann crop land. Back from the Rock 

 River in many or most of the farm woodlots. where, ap- 

 parently, the purpose is to obtain permanent pasturage for 

 domestic stock, the areas have been so reduced and im- 

 paired by overgrazing as no longer often to afford pasturage, 

 having been reduced merely to shaded places for stock. 



The effect of all these matters, when considered from the 

 point of view of their action on the habitats involved, is be- 

 lieved by the writer to be chiefly of an edaphic nature, a 

 matter of affecting the soil moisture content. For more 

 complete elucidation of the numerous questions involved the 

 line of attack would have to be a series of investigations 

 planned for quantitative work. On the basis of data fur- 

 nished by observational investigations such further ques- 

 tions might be determined. 



Perhaps it will some day be recognized generally in this 

 country that, as the elder CockajTie, a foreign botanist, has 

 said — "The yield per acre in crop or meat is primarily a 

 matter of the plant covering of the farm," that "facts based 

 upon the study of a virgin vegetation and on that of an ar- 

 tificial or modified vegetation are of equal value, the same 

 laws governing both," and that, hence, "the ecology of vir- 

 gin land is. then, the ecology of the farm, except that on the 

 latter man can purposely alter the conditions to which the 

 plants are subject in order to increase their economic ef!i- 



