PARK AND CEMETERY. 
157 
EFFECTS OF ESCAPING ILLUMINATING GAS ON TREES 
ber of cubic feet which annually escapes into the soil is quite 
large. 
There are a large number of joints in gas mains in which 
can be detected only slight leakage ; perhaps from two to 
three cubic feet a day. whereas there are others in which the 
leakage is very extensive and thousands of cubic feet of gas 
escape into the soil in the course of a year. Even these 
smaller leaks, where the outflow is only from two to three 
cubic feet a day, are capable of producing injury to trees in 
the course of time, since the soil becomes charged with gas 
to quite an extent in a few years. Should the roots of trees 
happen to be near these leaks, the trees will become un- 
healthy, but will perhaps not die. There are hundreds of 
city trees affected in this manner and gas is seldom suspected 
of giving rise to their sickly condition. In the eastern states, 
at least, there are three kinds of gas used, viz., water gas, 
coal gas, and oil gas. So far as the effects of these various 
gases on trees are concerned, there apparently is little or no 
difference, since they all contain similar elements which con- 
stitute poisons to the tree. 
There are two classes of effects that may readily be dis- 
tinguished as the results of gas poisoning: first, incipient 
cases, and second, pronounced cases. In the first series we 
have those already alluded to as arising from small leaks, 
and the ground in such cases never gets fully charged for 
any considerable distance. This may not result in killing the 
tree directly, but it places it in an unhealthy condition, and 
there is likely to be a large amount of dead wood found in 
such trees annually. Occasionally a large tree may have a 
small leakage and this single root will be affected and por- 
tions of the trunk of the tree in direct connection with this 
root will show effects of gas poisoning. Such trees may 
suffer with what is termed “general debility,” a term which 
is often used to cover up a vast amount of ignorance con- 
cerning trees. In severe cases of gas poisoning, such as take 
place where there is a large leak, effects on a tree are very 
pronounced, and where a tree has once been severly in- 
jured by gas, there is absolutely no hope of its recovery; 
in short, where a tree 'has been defoliated or even half de- 
foliated from the effects of gas there is no hope for such a 
tree, although it might be possible, if one could dig up all 
the soil around this tree and expose it to the air, to eliminate 
much of the gas in the soil, in which case the tree might 
show some attempt at recovery. 
The characteristics of gas poisoning are quite marked and 
can generally be distinguished from other cases of injury 
NDOUBTEDLY a larger 
number of trees suffer 
from the effects of es- 
caping illuminating gas at 
the present time than 
in previous years. The in- 
creased death rate of trees 
from illuminating gas can be 
accounted for by the fact that 
gas is more extensi.vely used 
at the present time, and prob- 
ably there are a larger amount 
of leaks at present than for- 
merly on account of larger 
pipes being in use, together 
with modifications in the meth- 
ods of laying these pipes and 
calking the joints. At any 
rate, it would seem that where 
small pipes have been in the 
ground for many years with a 
coupling joint there is much 
less leakage than where larger 
pipes are used, and where the 
calking is either done with 
Portland cement and oakum, 
or lead. 
There is a large amount of 
gas produced by companies 
that is unaccounted for. Ac- 
cording to the 2ist Annual Re- 
port of the Gas and Electric 
Light Commission of Massa- 
chusetts, the production of gas 
for the year 1905, in this state, 
was 6,418,024,954 cubic feet. 
The amount unaccounted for 
during that year was 622,304,- 
; TREE KILLED BY GAS. ^44 cubic feet. Or in other 
1 ' Photo taken 1 % years words, there was a loss ot 
i after leakage. about lO per cent. Probably 
! I this loss represents more than 
J mere leakage, since part of this loss can be ac- 
R counted for by differences in temperature which the gases 
A kre subjected to when measured. Nevertheless, there is a 
-very large number of leaks existing in gas mains and the num- 
