PAUL B. SEARS 107 



The problem of man and resources is an exceedingly complicated 

 one. The whole history of the conservation movement has been an 

 evolution from concern with single resources to realization of their 

 interdependence and of the need for viewing the problem in its en- 

 tirety. I am inclined to be patient with those who are on the way 

 but have not yet arrived, despite the difficulties they sometimes 

 cause. 



There are also several philosophical approaches to the problem. 

 One of them, for instance, is by way of the concepts of accounting 

 that identify assets, liabilities, income, expense, and depreciation. 

 One of the common difficulties in dealing with resources is the fail- 

 ure to allow for depreciation (or depletion) in figuring income. On 

 the other hand, it is well known that the outcome of any accounting 

 system varies with its initial assumptions. Plenty of assumptions are 

 involved in dealing with natural resources. 



The estimation of capital resource assets is a thorny job to begin 

 with. Space, which is basic, can of course be measured and we know 

 that the surface area of the earth is finite. Water supply in terms of 

 average rainfall can be computed, but until Thornthwaite's studies 

 of evapotranspiration we were uncertain as to the net amount avail- 

 able for storage and direct use. We know now that for the North 

 Central states this is not more than one-third of the total. 



Estimates of oil, minerals, and forest resources involve not only 

 distribution and extent, but quality as well. For each of these re- 

 sources the standard practice has been one of high-grading, exploit- 

 ing the richest first. Modern technology makes it possible to utilize 

 directly, or to improve, resources of lower grade, but only by in- 

 creasing capital expenditures, as Harrison Brown and others have 

 pointed out. In the case of forest resources such improvement has 

 been rendered especially difficult by the destruction of the best seed 

 stock, as in New England. Soil depletion, for example, in Central 

 America, has often gone so far as to expose parent material beyond 

 any present technical means of restoration. 



The aesthetic approach also has its merits although, as Dr. Gal- 

 braith points out, it is often pressed so hard as to defeat its own 

 purpose. Certainly, sound and satisfying design is integral to good 

 conservation, and it has been true in my experience that Sir Francis 



