WHAT IS POTENTIAL FOREST LAND? 



By Crosby Hoar 

 Forest Examiner, U. S. Forest Service 



Interpreted literally, the question means not what constitutes Na- 

 tional Forest land, but forest land anywhere. Let us consider it briefly 

 from that standpoint and ask what is meant by the term "potential 

 forest land" in its broadest sense. I shall try to define it as "land 

 suitable for the growth of tree species in stands." 



I did not say suitable for continued growth, because where one crop 

 of timber has grown, another should ordinarily be able to follow. Any 

 unusual interference with natural reforestation, unless it destroys the 

 soil, will only postpone, but not prevent, the second crop. Therefore, 

 nine times out of ten, if a tract has once been forested, it is still poten- 

 tial forest land. 



The definition specifies tree species, but we need not split hairs in 

 trying to distinguish between trees and shrubs. Possibly some of the 

 oaks in the Rocky Mountains deserve to be classed as trees. If so, 

 such oaks form forests, and their habitat is forest land. This is only 

 another way of saying that such oaks, when in stands, perform the 

 functions of a forest, both as regards their mutual interdependence and 

 in their effect upon run-off soil formation, etc. 



It will be noticed that the definition requires potential forest land to 

 be suitable for the growth of tree species in stands. The insistence 

 upon stands is important ; not the requirement of actual existing stands, 

 but the ability of the site to produce them. By stands is meant a col- 

 lection of trees of one or more species growing in such proximity that 

 they mutually influence each other. This would classify as non-forest 

 the ledges and cliffs upon which an occasional tree gains a footing and 

 maintains a precarious existence, too far removed from its neighbors to 

 influence them in any way. On benches or pockets in such a formation, 

 or wherever trees could grow in stands, there might be potential forest 

 land. 



Finally, the definition given supposes the growth of trees in stands 

 only under natural conditions or such artificial conditions as are 

 economically practicable. Lands requiring irrigation or artificial drain- 

 age to grow trees are not potential forest lands within my meaning. 

 The fact that planting or seeding may be in prospect does not alter the 

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