SAP-STAIN, MOLD, AND DECAY IN GREEN WOOD. 
29 
THE EXPERIMENTAL STEAMING OF RED-OAK AND WHITE-OAK BLOCKS AT THE LABORATORY OF 
FOREST PATHOLOGY, MADISON, WIS. 
During the spring of 1919 the writer performed several series of 
experiments at the Madison laboratory to determine the efficiency of 
steam at atmospheric pressure in destroying mold and sap-stain fungi 
in artificially infected red or white oak blocks 2| by 2^ by 10 inches. 
Incidentally the rate of drying and the amount of checking were 
noted in connection 
with the steaming. 
The blocks were 
sawed from the sap- 
wood of summer-cut 
logs, weighed, and 
then sprayed with a 
water suspension of 
spores taken from 
cultures of mold 
fungi originally de- 
rived from infected 
material sent in by 
the writer. A list 
of the fungi used in 
these experiments 
follows : 
Aspergillus flavus. 
Aspergillus niger. 
Cephalothecium roseum. 
Ceratostomella sp. 
Citromyces sp. 
Graphium sp. 
Monilia sitophila. 
Mucor sp. 
Penicillium asperulum. 
Penicillium divaricatum. 
Penicillium luteum. 
Penicillium pinophilum. Fi g. 10. — Square billets close piled in a box car. This type 
Penicillium rugulosum. of raw stock suffers considerably when piled in the 
~ 7 7+" manner shown here. Stripping or cross piling while in 
kyncephalastrum sp. transit or storage is essential if losses from fungi are 
Trichoderma sp. to be avoided. 
The sprayed blocks were then placed in a tile chamber, which 
served as an incubator. After several weeks in this chamber, where 
an average relative humidity of 95 per cent and an average tempera- 
ture of 70° F. prevailed, the blocks became well infected and de- 
veloped countless numbers of the fruiting bodies peculiar to the fungi 
mentioned above (PI. II, fig. 1). 
