sults. A similar 
FOREST DISEASE SURVEYS. 91 
Schroeder and Reuss in 1883.1. Other works by Schroeder and 
Schertel in 1884? and Borggreve in 1893* also give maps in connec- 
tion with studies of smoke, the latter maps being uncolored. No 
references were found which contained colored maps of the dis- 
tribution of forest-tree diseases. 
In the making of timber-survey maps, type boundaries are indi- 
cated by continuous dotted lines inclosing within the areas so °* 
formed the figures 
indicating type 
mixture, density, 
and age class, the 
age class also being 
separated by dotted 
lines. Very often 
these areas are col- 
ored by the use of 
wash inks or cray- 
ons, so as to make 
a greater distinc- 
tion between them. 
A number of stand- 
ard colors are used 
and are applied 
upon white prints, 
which are found to 
give the best re- 
method is proposed 
for use in making 
pathological maps, 
the only variation 
being the addition 
to the type-sheet 
maps of boundary 
lines indicating the Fic. 21.—Cronartium coleosporioides, pine rust, gall form, 
infected areas and on young lodgepole pine. The two galls on the main stem 
: are fruiting. Note the small white cups scattered over the 
a special set of col- 
: ; : surface of these two galls. 
ors indicating va- 
rious diseases. In the pathological maps only those colors denoting 
the various infections should be used, leaving the type areas uncolored. 
1 Schroeder, Julius von, and Reuss, Carl. Die Beschaidigung der Vegetation durch 
Rauch und die Oberharzer Hiittenrauchschiiden. 333 p., 2 maps (colored). Berlin, 18838. 
2 Schroeder, Julius von, and Schertel, A. Die Rauchschiiden in den Wiildern der 
umgebungder physikalischen Htittenwerke bei Freiberg. Separat-Abdruck Jahrb. Berg. w. 
- Hiittenw. Konigr. Sachsen, 1884, p. 938-120, map (colored). 1884. 
3 Borggreve, B. Rauchbeschidigung in dem yon Tiele Winkler’schen Forstreviere 
Myslowitz-Kattowitz. 236 p., 2 maps. 1898. 
