40 FORESTS, WOODS, AND TREES 
set apart for its lungs and for recreation grounds. Good 
water supply and sewage, fewer people per house, and good 
ventilation have undoubtedly kept down the death-rate of 
large towns; but there is no means of determining exactly 
how much of this improvement may be due to the extension 
of parks and open spaces. The influence of parks, especially 
if the trees form real woodlands, and give children and 
tired workers pure air, must be considerable. The amount 
to be apportioned in a city, and how much of each park 
should be under trees, is as yet undecided (5). Mr. Holmes 
has secured returns from the fifty chief towns in the 
kingdom, showing that in 1883 they possessed in the 
aggregate one acre of parks and open spaces to 760 people ; 
whereas 20 years later, in 1903, notwithstanding an 
increase in population of 50 per cent, there was one acre 
of parks and recreation grounds to 635 people. In the 
County of London (6) there was in 1883 one acre of open 
space to 950 persons, whereas in 1910 there was one acre 
to 750 people. Birmingham in 1917 had one acre of 
parks and open spaces to 625 inhabitants. 
Mr. Holmes condemns the ordinary school playground 
with its hard surface and high walls as being like a prison 
yard, and no wonder the children prefer the streets. He 
agrees with me that the best form of playground is a grove 
of trees, with a bare sandy surface beneath. The natural 
feature of the larger parks and commons should be carefully 
preserved ; the less elaborate the treatment the better, as 
the public love areas over which they can wander at will, 
and are too often hindered in their games and exercise by 
enclosures, railings, and notices. 
The National Trust for Places of Historic Interest and 
Natural Beauty has done admirable work since 1895 in 
acquiring for the enjoyment of the public many properties 
of interest. Some of these are woodland and of value in 
the wide sense to public health. The most interesting is 
perhaps Box Hill, 234 acres in extent, which was presented 
to the National Trust by Mr. Leopold Salomons in 1914. 
Others are Ide Hill, near Sevenoaks, 21 acres, purchased in 
