30 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
they continued their ravages until whole woods were denuded of 
their foliage, and looked as bare as in mid-winter, and so annoying 
were they that labourers could not work in the woods. They also 
attacked the hazel under the oak, surrounding some of the bushes 
with their webs as if in a glass case. It was only in the close 
woods where the ravages took place, isolated oaks not being 
touched, The trees which enjoyed immunity, although surrounded 
by infested oaks, were the elm, beech, sweet chestnut, and the 
Turkey oak, and the ash partially. During the height of the 
attack I passed through a wood composed of Q. sesst/iflora, which, 
although the attack had been begun, they had left off evidently 
either poisoned or starved. This fact has also been noticed by a 
resident in the Forest of Dean, who, in writing of 1881, says, “ It 
was strikingly evident last summer that the Q. robur pedunculata, 
or old English oak, was attacked by blight more severely than the 
Q. r. sessiliflora. Single trees and groups of several together would 
be seen in full foliage, or but slightly injured, and, when examined, 
these were found to be of the last-mentioned variety, while all 
around them Q. 7. pedunculata would be leafless and bare.” This 
is another proof that sesst/iflora is distinet from pedunculata. On 
the 2d of July 1888 very heavy rain began to fall, and continued 
at intervals for a week. Then the trees that seemed to be dead 
began to sprout, and the mid-summer shoots soon clothed them in 
verdure again. Many of these shoots measured from 12 to 18 
inches in length. 
Of the causes, or a cure for such a devastating attack, little can 
be said. A mild winter is generally reckoned a predisposing cause, 
but the winter of 1887-88 was not what might be called ‘ mild.” 
An analysis of the 61 days previous to the attack—that is, from 
the Ist of April to 1st June—shows that there were 18 days 
of frost, 2 on which snow fell, 20 on which rain fell, and 8 classed 
as cold or ungenial, thus leaving only 13 days of moderate 
temperature, or warm, June 5th was remarkably cold, and snow 
fell in Scotland and parts of England. Now this record is not 
consistent with the ‘‘ mild season” theory. A writer, in noticing 
the attack of 1848 in the Forest of Dean, says, “‘'There seems to 
be no method of checking their ravages. The rooks come in great 
numbers, and they and other birds destroy great quantities.” But 
the report of the visitation of 1881 in the same forest says, ‘‘ The 
very rapid and destructive nature of the blight this season may 
have been caused by the absence of large flocks of rooks, jackdaws, 
