SELLINGLUMBER 89 



"Is the growth of a tree from the outside alone? If so, 

 what turns the coarse-grained sapling into a close-grained virgin 

 tree?" 



The growth of a tree is always upon the outside ; that is, 

 it takes place between the very inner portion of bark and the 

 wood. Now, the rate of growth of practically all of the pines is 

 determined by two factors : First, there is a certain periodicity, 

 which is annual; and in the second place, by soil conditions, and 

 by the two factors of the amount of annual rainfall and the wind 

 velocity. A pine sapling usually starts under conditions where 

 there is plenty of light, the trees not shading each other, and 

 where they are not subject to the wind stresses. They usually 

 have plenty of rainfall and the result is they generally make, in 

 periods from seven to seventeen years, a rather rapid rate of The Tree 

 growth. Then, almost invariably, irrespective of moisture con- Grows on 

 ditions or other factors, they will start to slow down; and par- 

 ticularly where they grow close, with other trees close to them, 

 they tend to develop a crown high up in the air; and the result 

 is the growth will slow down and for the next twenty, thirty or 

 forty years or more the growth per year will be very small, and 

 consequently will make very fine rings on the tree. That is not 

 always the case. The exceptions are, trees in an open field, 

 old field pine, or rosemary, which will make very rapid growth 

 for forty or fifty years, due to the fact that they have no com- 

 petition for light and air. 



"What is the meaning of a specification which reads, 'All 

 timber used must be long leaf yellow pine or Douglas fir, con- 

 forming to the standard heart specification'?" 



That is a specification which I recognize is found very fre- 

 quently in both architectural and engineering contracts. If I 

 should interpret that I would say that the standard heart specifica- 

 tion refers to the standard adopted by some national technical 

 organization. The only two that really have adopted any standard 

 heart specification are the American Railway Engineering Asso- The "Standard 

 ciation, and the American Society for Testing Materials, and they 

 usually mean 70 to 85 per cent heart, depending upon the class of 

 timber to be used. In other words, they will allow a higher 

 percentage of sap in struts than they will in stringers and caps, 

 but will even require 85 to 95 per cent heart. 



