246 
PRUNING AND THINNING. 
[Part IV. 
Measurement 
and longevity 
of trees. 
I never dare touch sycamore or walnut except 
in summer. I have never known any tree bleed 
when in full leaf. I have known sycamore and 
walnut bleed when pruned at Christmas, which 
corroborates the idea of a winter circulation of 
sap ; but perhaps we have an undue horror of 
bleeding from pruning. The southern vineyards 
are always pruned in the bleeding season ; and 
the more freely they bleed, the better the sign. 
I object to autumnal pruning, because the 
boughs are full of elaborated sap due to the 
root. These observations apply to pruning 
hardy forest-trees for wood, not to pruning for 
fruit 
The largest sound tree I have ever measured 
is “the grindstone oak” in the Holt Forest.* 
It is thirty-five feet in girthing at three feet 
from the ground. It is dead, and was appa¬ 
rently lately dead when I first saw it, since the 
bark was still on it: I think it has been origi¬ 
nally a 'pollard (polled or headed) ; and the 
largest sound timber I have ever seen in Eng¬ 
land has been old pollards, allowed to grow up 
in our forest grounds, after the pollard system 
* Unhappily burnt by a thoughtless boy some 5th of 
November, since this was published in 1844. 
