252 



FORESTRY AND IRRIGATION. 



June, 



eastern half of the country, has been de- 

 rived from gardeners and nurserymen, 

 and does not usually apply to trees grown 

 under forest conditions. To gather em- 

 pirically definite data as to the behavior 

 of these species under the conditions of 

 a cultivated forest will take a hundred 

 years or more, as it did in Europe. 



In this predicament foresters may de- 

 rive valuable help from a branch of 

 botany which has within the last eight 

 years received an attention much greater 

 than ever before, and promises valuable 

 results for the future, both of a scien- 

 tific and practical nature. This is the 

 science of plant ecology. 



The term ecology is of comparatively 

 recent origin. It may be defined as the 

 science of the manner in which plants 

 adapt themselves to their environment. 

 It may be divided into two divisions. 

 Either one may examine the structure 

 and life history of plants with a view of 

 discovering the structural and func- 

 tional modifications produced in them 

 by the conditions of their life, or he 

 may investigate the distribution of plants 

 over the surface of the globe, and de- 

 termine the manner in which it has 

 been influenced by such adaptations. 

 On the former side ecology is related to 

 morphology and physiology ; on the 

 second to phytogeography. Both sides, 

 however, are so closely connected that 

 it is quite impossible to study the one 

 without the other. 



As yet the study of both sides of the 

 new science is still in its infancy. One 

 may say that so far hardly more has 

 been done than to sketch the outline of 

 its ruling principles, and even that to 

 some extent not more than provisionally. 

 It has been ascertained in a general way 

 that certain structural and physiological 

 peculiarities fit a given species for life 

 under certain conditions of soil, climate, 

 and so forth, and wholly or relatively 

 unfit it for life under other conditions. 

 The detailed knowledge of such struc- 

 tures and life processes has progressed 

 a certain distance ; much more remains 

 to be done. The perfect knowledge, 

 the goal toward which the science works, 

 may be described as the ability to state 

 with certainty, from the character of a 

 plant, to what particular conditions of 



life it is best adapted ; and, on the other 

 hand, from the peculiarities of the con- 

 ditions prevailing in any particular lo- 

 cality, to say with equal certainty what 

 plants are best adapted to grow therein. 



It is evident that long before this goal 

 is reached in fact, from the moment 

 when these questions can be answered 

 with a fair amount of probability such 

 knowledge may be made a valuable 

 guide in the practical work of the for- 

 ester. Of course, in a very general 

 way, the forester has always used 

 ecological data. We have always known 

 that White Oaks cannot be grown profit- 

 ably in a cypress swamp, and that the 

 Mahogany tree of Central America will 

 not flourish in a Minnesota pine barren. 

 But this rudimentary knowledge refers 

 mostly to the great regional divisions of 

 climate and soil condition. The prob- 

 lem that presses upon the forester is r 

 How can I find out what trees generally 

 adapted to the environment of my region 

 are best adapted to each of the great 

 variety of local conditions with which I 

 have to deal ? It is well understood 

 that the mere fact of the prevalence or 

 absence of a species in a given place is 

 no safe criterion of its special fitness. 

 The historical factor, well understood 

 by phytogeographers, may have come 

 into play that is, either the seed of 

 some well-adapted tree may have never 

 reached the place or a tree which was 

 fairly fit may have been driven out by a 

 fitter competitor ; yet this victim of the 

 struggle for existence may be the most 

 valuable for the forester, and may be 

 very well able to reconquer the ground 

 if helped by man. 



To answer this question, ecology will 

 soon be a valuable aid to the forester. 

 Numerous botanists in all parts of the 

 country are now cultivating this field. 

 Many of the data gathered by foresters 

 during valuation surveys and at other 

 times are distinct additions to the data 

 of ecology. Many more could be easily 

 collected by them if their attention was 

 called to the subject. A forester is sup- 

 posed to be a fair botanist, and ought to 

 be easily able to follow the technical dis- 

 cussions of the ecologist. A close alli- 

 ance between the two will be of the 

 greatest mutual advantage. 



