48 TKANSACTIOXS Ol" KOVAL SCOTIISH ARBORICULTURAI, SOCIKTV. 



VI. M. Emil Mer is making in France careful experiments, 

 scientitically carried out, on the effect of thinning. In the first 

 instance, he has simply compared results in thinned and 

 unthinned plots ; the degree of thinning is being tested also, but 

 the results will be published later. In the present instance he 

 has dealt with spruce. 



Three plots, A, B and C, lying together at the foot of a gentle 

 slope facing north-west, on granitic alluvium, were chosen. They 

 were 20 years old in 1886, when the first inventory was taken. 

 A and C had lost a number of stems through snowbreak and 

 otherwise, while B has retained nearly all the original stems. 

 B and C have been left alone ; A was lightly thinned in 1886, 

 but in 1S99 25 per cent, of the material was cut out. Inven- 

 tories were made in 1S86, 1899 and 1907. M. Mer gives his 

 results as follows : — 



1. Early thinnings, made with the view of favouring the stems 

 of the future, by gradually disengaging them from those around, 

 produce not only an acceleration in the growth of these 

 particular stems, but also an increase in material — and still 

 more in value — of the total of the stems of the plot. 



2. The thicket stage passes into the sapling stage some years 

 sooner in a thinned than in an unthinned plot. Since there are 

 fewer trees, these obtain more from the soil and develop a better 

 root below ground and a better stem above ground. 



Here M. Mer states, what is probably true, though not a 

 result of his experiments, namely, that since the soil must not 

 be allowed to be dried up by exposure, we should underplant 

 thinned plots with silver fir. This underplanting would use 

 different layers of the soil from those used by the upper stage. 



3. In favouring diameter-growth the thinning favours still more 

 growth in money value. At each inventory the value (M. Mer 

 must mean "estimated value," one thinks) per cubic metre was 

 highest in the thinned plot, because of the bigger diameter. 

 At 45 years of age the mean girth of A was -56 metre, -54 metre 

 in C, but only -39 metre in B ; while at the beginning it was 

 •35 metre in A and C, and 33 in B. 



4. From 1899 to 1907 each of the 3545 stems of B had 

 arown in value {rapporii':) 19 centime, while each of the 1361 

 stems of A brought in 126 centimes. In the course of this 

 period each hectare (2 47 acres) produced annually 6941 francs 

 in B, and 17525 francs in A — that is more than double. (It is 



