326 



Exotic Conifers in Britain. 



or removed in the thinnings. The average height of the wood 

 would therefore be not 60 feet, but 80 feet ; hence it follows 

 that in converting the results of arboricultural treatment into 

 terms of sylvicultural treatment we should take as the basis of 

 our calculations not the average but the largest trees. I am 

 aware, of course, that " specimen " trees are usually set out in 

 good soil and in well-sheltered and otherwise favourable situa- 

 tions, but, on the other hand, they lack the " drawing-up " 

 influences of a closely stocked wood. 



In the following tables it will sometimes be found that a 

 young tree has attained to greater dimensions than an older 

 one. The reason for this may be explained. In dealing with 

 any particular species the choice of specimens decreases with 

 age, that is to say, whereas we may have twenty measurements 

 of twenty-year-old trees from which to select, we may not have 

 more than one or two in the case of sixty-year-old specimens of 

 the same species. The chances of being able to record the 

 dimensions of a " dominant " tree of the latter age are, therefore, 

 relatively small. 



In compiling the following tables, free use has been made of 

 Mr. Dunn's census,* though other reliable sources have also been 

 drawn upon. In many cases I have been able to secure 

 measurements in June, 1903, of the same trees whose dimen- 

 sions, in the spring of 1891, were recorded by Mr. Dunn. In 

 this way a record of the growth made during the last twelve 

 years has been obtained. In some cases the particular tree has 

 lost its top in the interval between the two measurements, which 

 accounts for the height recorded in 1903 being sometimes less 

 than that given in 1891. 



Abies amabilis, Forb — Quite hardy, though not very common. 

 The following measurements are recorded : — 



* Jour. Roy. Hort. Soc. 1891, Vol. xiv., p. 481. 



