(iS8 



JOURNAI. OF FORESTRY 



Lnrcli, 

 -foot clas 



Scots pine, 



England, 

 50-foot class 



Scots pine, 



Scotland, 

 50-foot class 



Spruce, 

 1-foot class 



Height in feet. 



Height in feet 



Mean quarter-girth (inches) 

 Number of stems per acre.. 

 Basal area per acre (square 



feet) 



Vohmie per acre (cubic feet) 



Height in feet 



Mean quarter-girth (inches) 

 Number of stems per acre.. 

 Basal area per acre (square 



feet) .....I 



Volume per acre (cubic teet) | 



391^ 



800 



100 



1460 



74 

 934 

 220 



AC.Ii 10 YEARS. 



10 10 



AGE 30 YEARS. 



31 31 



334 334 



1040 1230 



93 116 



1130 ' 1300 



AGE 70 YEARS. 



621^ i 63 J/^ 



9'/ I 9J^ 



270 , 325 



147 

 3910 



169 

 4060 



199 

 4880 



36^ 



4 



1310 



14.6 



2140 



75 



230 



224 

 6730 



At 30 years of age the average quality class of larch produces a 

 greater volume than the average quality class of Scots pine, but in later 

 life the position is reversed. 



Comparison with foreign tables is rendered difficult by the absence 

 of a common standard. "Quality I" means a different thing in every 

 table. In the British tables the method of classification adopts the same 

 criterion for all kinds of trees, namely, a standard height for each 

 quality class at 50 years of age, and in the statement below there have 

 been selected from the Continental tables those classes whose mean 

 heights at 50 years most nearly approximate to the corresponding 

 British classes. 



The yield tables show that the volume produced at 50 years by the 

 110-foot quality class of Douglas fir exceeds that of the 80-foot quality 

 class larch by about 75 per cent, and a comparison between the other 

 pairs of quality classes shows an even greater difference. 



With heights of 103 feet and 90 feet respectively for Douglas fir at 

 50 vears, the U. S. A. quality classes I and II correspond closely with 

 British classes II and III." The U. S. A. quality III (70 feet at 50 

 years) is below anything found in Great Britain as yet, though doubt- 

 less in the future, when the tree is planted more extensively, poorer 

 growth will be obtained in some localities. 



See Hanzlik's tallies, For. Quart. XII., p;i. 440-452. 



