THE AUSTRALIAN NATURALIST. II7 
NOTES ON THE EFFECT OF ARTIFICIAL LIGHT 
ON DECIDUOUS TREES. 
(By HE. Cheel.) 
During the latter end of June, 1910, I was rather sur- 
prised to see one of the Plane-trees in Pitt-street, close to 
the Central Railway Station, with a number of its branches 
bearing many fresh green leaves, whilst the other branches 
were quite denuded. 
Knowing that the Plane-tree belonged to the deciduous or 
leaf-shedding class of plants, and that most of this particular 
species had shed their leaves nearly a month previously, I 
was rather anxious to know the cause of this particular tree ° 
having some of its branches retaining their leaves go long, 
so decided to investigate the matter by closely inspecting the 
other trees in the same neighbourhood. 
In continuing my inspection of those trees along Eddy- 
Avenue, I noticed four others with some of their branches 
still retaining leaves; these, like the one in Pitt-street, were 
all fairly close to the electric lights, so that it seemed to me 
that these artificial lights must have some influence on the 
trees and thus caused them to retain their leaves for a longer 
period than those situated farthest away from the lights. 
A large number of trees are planted along Elizabeth and 
Pitt streets, but as all of these (with the exception of the one 
near the /Pitt-street Railway Enrance) were not near any 
light, the branches in every case were quite denuded of their 
leaves. 
On May 16th, 1911, I examined the trees all around the 
station, and found most of them had,,shed their leaves, but 
here and there a tree had some branches with a few leaves 
still hanging on. Those trees near the electric lights, had 
most of the branches on the side of the trees nearest the lights, 
fairly thickly clothed with quite green leaves. During the 
first week in June, several sharp frosts occurred, and as a 
result, all the trees away from the lights lost their leaves. 
On June 28th, and July 15th, I again examined the trees 
near the lights, and found in every case a few leaves still 
hanging on. Those nearest the lights having more leaves, and 
of a fresher green than the others. On August 2nd, I made 
a further inspection and found that the four trees in Eddy- 
avenue, had at last shed all their leaves, but the tree at the 
Railway Entrance in Pitt-street, still retained a few, those 
on the tips of the branches nearest the light being quite 
fresh and green, so that there can be no doubt that the arti- 
