18 FORESTS, WOODS, AND TREES 
of improvement in public health due to forest conditions is 
that of the Landes in Gascony. This was formerly a bare 
sandy tract, interspersed with marshes, and reputed to be 
the most unhealthy region in France, the inhabitants being 
very subject to malarial fever, scrofula, and pellagra. Since 
about 1850 the greater part of the Landes, some 1,800,000 
acres, has been afforested with maritime pine; and these 
diseases have practically disappeared, and the district is 
now one of the healthiest in France, the decrease in the 
death-rate being remarkable. This improvement in health 
is no doubt due to various causes, such as the drainage of 
the marshes, the better supply of drinking water, etc., but 
the presence of the pine forest must be recognised as a 
factor which has contributed to the sanitation. Even the 
abundance of cheap firewood has a hygienic effect, as every 
house is now free from damp all the year round, and the 
labourers are able to dry their wet clothes. 
Parks in cities are like the forests. They do not purify 
the air, as was formerly believed, by the functions of the 
leaves. Nevertheless, the air in parks is purer than in the 
dust-laden atmosphere of the streets adjoining, and contains 
fewer bacteria. Belts of trees act as screens, and intercept 
dust and other impurities coming from outside; and it is 
of some importance on this account to make a wall of trees 
around any park or large open space in a city. 
In the preceding pages the direct effects of the forest 
condition upon hygiene are briefly described ; but there are 
many ways in which the presence of woods and trees affect 
indirectly the health of the public, and these will be dis- 
cussed in the subsequent chapters. A great deal might be 
said in praise of the aesthetic value of forests and trees, 
which influence favourably the spirits and consequently the 
health of the people; but a mere mention of this aspect of 
the subject is sufficient. Few will deny its importance. 
NOTES 
1. Frank B. Kellogg, in Proc. Soc. Amer. Foresters, x. 51 (1915), says it 
is well known among dairymen having ranches in Oregon much exposed to 
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