OHESTNUT TREE BLIGHT. ° 9 
How tue Disrase SPREADS. 
The yellow fruiting bodies so common on the diseased trees are 
constantly giving off millions of summer spores all through the grow- 
ing season. These are transported by various agencies to healthy 
trees, where they gain entrance through wounds in the bark. Wind 
is probably the principal agency, but the spores are no doubt carried 
by animals, birds, insects, and by shipment of infected material. 
The disease spreads locally through the gradual distribution of the 
spores from tree to tree, and at a distance chiefly through the ship- 
ment of infected material, such as nursery stock, bark, nuts, and 
other products. There is a possibility that long-distance infection is 
also effected by means of migratory birds. 
There are a number of facts which support the view that the wind 
has been the principal agency in spreading the disease over the pres- 
ent area. For instance, trees in open spaces exposed to winds, such as 
those aléng roads, at the edges of woods, or near streams or ponds, 
are apt to beinfectedsooner than the trees in more sheltered situations; 
trees on slopes or in depressions with diseased trees on higher ground 
near them usually become infected, evidently because they have been 
exposed to the wind-scattered spores from above; and in thinned 
stands, if the disease is present in the neighborhood, almost every 
chestnut becomes nfocted. In this instance the frequency of wounds 
is probably a large contributory cause. Dense woods, as a rule, act 
as a bar to the progress of the infection, except where the disease is 
very prevalent in the vicinity, in which case nothing seems to check 
its spread. 
Amount oF DAMAGE. 
The amount of loss caused by this disease is especially great, because 
it has developed in a region where the chestnut trees are extensively 
used for ornamental and park purposes. For this reason the losses 
have been acutely felt. ere is, of course, no satisfactory basis for 
estimating the value of trees which are useful chiefly for esthetic 
purposes, but the loss is certainly several million dollars. 
In Prospect Park, Brooklyn, there are but 6 chestnut trees left 
alive out of 1,400. In Forest Park, at Jamaica, Long Island, practi- 
cally all the chestnut trees are diseased and many are dead. The 
same applies to Bronx Park in New York City. In Nassau County, 
in western Long Island, few chestnut tracts have escaped serious dam- 
age. In Westchester County, N. Y., it is apparently only a question 
of a short time when nearly all the chestnuts will be destroyed. Many 
estates have sustained losses in scenic beauty which it is impossible to 
estimate. In the part of New Jersey adjacent to New York City the 
damage has been of the same character; parks and country estates 
have lost large number of fine chestnut trees which would not have 
been sold at any price. 
Although so far the injury to ornamental trees has attracted the 
most attention, the damage is not confined to these alone. Indeed, 
a far more serious phase of the epidemic is the menace to commercial 
forest tracts. Already many large tracts in at least five States have 
been attacked, and though great damage has been done in certain 
localities, it is very small compared with what it will be if the disease 
continues to spread. 
