[Vol. io, 
408 
AMERICAN JOURNAL OF BOTANY 
Table 3. Data taken from Tiemann's curves of temperature and humidity in characteristic 
dry-kiln runs ( 8 , pp. 277-285) for comparison with data in text figure 1 to show 
probable effect of kiln-drying on wood-destroying fungi within the wood 
DRY HEAT 5 
Curve 
no. 
Kind of Wood 
Entire Run of Kiln 
Probable Killing Effect as Taken from 
Curve in Text Figure i. 
Temper¬ 
ature (C.) 
No. of 
Days 
I 
i-inch hardwood 
50-65° 
20 
None of the fungi would be killed. 
2 
1-inch hardwood 
50-70° 
14 
None of the fungi would be killed. 
3 
i-inch hardwood 
77-80° 
7 
None of the fungi would be killed. 
4 
2^-inch hardwood 
43° 
64 
None of the fungi would be killed. 
5 
i-inch conifer 
75° 
10 
All but Lenzites trabea would probably be 
killed. 
6 
i-inch conifer 
57-77° 
10 
No killing effect. 
7 
i-inch conifer 
82-93° 
4 
L. trabea would not be killed, others 
might be. 
MOIST HEAT 
Wood at Fiber-saturation Point 
1 
i-inch hardwood 
50° 
6 
2 days at this temperature would probably 
kill all fungi. 
2 
i-inch hardwood 
50-55° 
8 
2 days at this temperature would probably 
kill all fungi. 
3 
i-inch hardwood 
75° at 
least 
3 
12 hours at 55° kills all fungi. 
4 
2^-inch hardwood 
45° at 
least 
25 
4 days kills all in f-inch material; 25 days 
should kill all mycelium in 21-inch 
stock. 
5 
i-inch conifer 
75° 
2-3 
2 days at 50° kills all fungi. 
6 
i-inch conifer 
57° 
2-5 
All killed in 12 hours at 57°. 
7 
i-inch conifer 
82-88° 
15 
lb days at 52° kills all fungi. 
the run until the time when the water content of the wood goes below the 
fiber-saturation point. In the second contingency, the air within the wood 
is saturated with moisture, and hence the heat applied acts as moist heat 
regardless of the external humidity, which is, however, high for most of 
the period. 
Taking the results upon five fungi, it appears from the two sets of data 
(text fig. i and table 3) that such a procedure may be counted upon to kill 
the mycelium of most if not all species in i-inch stock. Counting the heat 
applied in these kilns as absolutely dry heat over the whole period (which it 
certainly is not), it is seen that in most of the cases the mycelium would not 
be killed. On the other hand, it is seen that moist beat is acting upon the 
mycelium in the wood ‘in all of these seven conditions (table 3) sufficiently 
5 It is of course understood that the heat for the entire run of the kiln cannot be dry. 
It is considered as dry for the purposes of this treatment, solely for comparison with the 
data on dry heat presented and because there are no data available for humidities between 
dryness and saturation of the air. See text for discussion. 
