1887-88.] Annual Increase in Girth of Trees. 



251 



the branches and foliage. As there was not a single eligible 

 specimen in the Botanic Garden, five trees were selected at 

 Craigiehall, where oaks are both numerous and fairly well 

 grown, although many of them are " stag-horned," and display 

 the other faults just mentioned. The selected trees vary 

 in girth from 5 to 10 feet, and all stand clear, or nearly so, 

 of other trees, Nos. 10*, 11*, and 16* in the park, the two 

 former close to the river, the latter at a considerable height 

 above it, and Nos. 16*, 17*, also on low ground near the 

 river. 



The average annual rate of increase w^as only 0'35, and 

 excluding No. 16*, which grew nearly twice as fast as the 

 best of the others, the average of the remaining four is but 

 0"25. This evidently abnormally low rate was no doubt pro- 

 duced by the disastrous and lasting effects of the low winter 

 temperatures at the beginning of the period, and particularly 

 in 1880, for if we take the year 1878, which preceded these 

 disastrous seasons, and rejecting the low increase of 010 in 

 No. 11'"" as altogether exceptional in a year of universal 

 prosperity, substitute O'SO, its increase in the subsequent 

 year, we get the average of 0-71 for the three trees then 

 under observation. Moreover, we know that No. 16*, the 

 largest of the five, actually did grow at the rate of 0-09 all 

 through the decennial period. 



The individual range varied between 50 to 0"00 in 

 No. 11* and I'OO to 045 in No. 16*, which in this, as in 

 all other respects, comes out the best. The aggregate range 

 in the three trees measured throughout lay between 1-75 in 

 1878 and 0-65 in 1880; for the five trees measured for the 



