858 JOIIKNAL ()\- F()Ki:STR\- 



lieavier rainfall and higher temperature produced somewhat superior 

 material. In fact, the differences in strength values are somewhat 

 larger than one would be willing to attribute to the comparatively small 

 difference in climatic conditions. Material from the region of Golden, 

 1>. C. seems to be intermediate between the coast and true mountain 

 types and compares closely with Douglas fir from the coast region of 

 California. 



Maximum and minimum values for the localities are in the same 

 order as averages, but tables of data show that some material from the 

 locality giving the lowest average is better than some from that giving 

 the highest ; hence source is not a criterion of either excellence or in- 

 feriority of material, and the need for a quality classification of Doug- 

 las fir, such as has been advocated by the United States Forest Service, 

 is again illustrated. One of the conclusions reached by the authors is 

 that "it would appear that a grading rule based on density, as visually 

 indicated by the amount of summerwood, is a promising possibility for 

 Douglas fir, as for certain other species, and that a clause in such a rule 

 specifying the minimum number of growth rings per inch for material 

 of first grade would be of value." 



Comparisons with data from the United States Forest Service show 

 that Canadian Douglas fir has practically the same strength value as 

 Douglas fir from the corresponding type of trees grown on our side of 

 the boundary. 



A map shows the origin of the three shipments of material and nu- 

 merous diagrams illustrate the effect of drying, the correlation between 

 strength values and various physical factors, and the variation of me- 

 chanical properties with position in the tree. 



An appendix of some 20 pages explains and illustrates the selection 

 of test material, the methods of tests, and testing apparatus, all of 

 which are closely patterned after — in fact, with the exception of some 

 unimportant details, are identical with — the working plan adopted by 

 the United States Forest Products Laboratory as a standard for testing 

 American species. The use of these common methods and standards 

 is of great advantage, as it makes the results obtained at the two forest- 

 products laboratories concerned with the testing of North American 

 woods directly comparable. 



It seems unfortunate that our Canadian friends are apparently un- 

 willing to accept our standard nomenclature as given in Forest Service 

 Bulletin 17. but prefer to use the species name inner onata for Douglas 

 fir. T. R. C. W. 



