COMMENTS ON TERMINOLOGY 



In accordance with the suggestion of the chairman of the Com- 

 mittee on Terminology that those who find difficulty in accepting the 

 committee's rulings should come forward with arguments for their 

 own choice of other terms or of new terms, space is provided in the 

 Journal for discussion of the proposed forest terminology. It is hoped 

 that only through such a discussion forest terms may finally be accepted 

 by the profession and a healthy growth assured. 



Prothingha'm: 



It seems to me that the term "crown density," as now used, is am- 

 biguous, covering two closely related but still distinct conceptions: 

 (1) crown closure, and (2) shade density. These two, together, com- 

 prise "crown density" ; but I believe that the latter term will be 

 much more comprehensible and useful if factored, in the nomen- 

 clature, into its components. Both "crown closure" and "shade density" 

 can be expressed in tenths, if desired. The standard of classification 

 of "crown closure" would be ocular or diagrammatic ; that is, it would 

 be a matter of estimate or of charting and measurement by means of 

 planimeter, or otherwise. "Shade density" might be estimated on the 

 basis of the difference between full light and the condition under 

 heaviest shade, such as that of hemlock under pine or hardwoods ; but I 

 believe some photometric scale of classification must soon be worked 

 out for it. 



I would suggest a rewording of the term "crown density" and the 

 introduction of the two new terms "crown closure" and "shade density," 

 complete cross reference to be made between them. The definition 

 of these terms would be as follows: (That for "shade density" was 

 formulated by C. G. Bates.) 



Crown density. The compactness of the crown cover of the forest, dependent upon 

 (1) the distance apart, and (2) the compactness of the individual crowns. A 

 loose term, combining the meanings of crown closure and shade density (cf.)._ 



Crown closure. 1. The closing together of the crowns of trees in a forest, as in the 

 youth of the stand, or after thinning. 



2. Any stage in this process; by extension of the term, the proportion of the 

 ground area covered by the aggregate vertical projection of all the crowns in the 

 crown cover, regardless of whether these crowns may be expected to complete the 

 closure. The degree of crown closure may be determined diagrammaticaUy or by 

 ocular estimate, and may be expressed by the following terms and decimal 

 equivalents: 



Closed — .8 to 1. G., geschlossen. F., plein. 



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