A3 
size material, or about 6,000 feet B. M. In the old woods as tbey stand, 
the trees above sapling size represent the great mass of the wood mate- 
rial, and therefore the growth of wood is largely on trees nearing or 
already of log size, so that the same amount of growth per acre here 
adds more saw timber than in the young grove above considered. For 
this reason a good thicket of pine 60 years old may not cut much more 
than 6,000 feet per acre, since much timber is under size, but the same 
stand at 120 years would easily cut 15,000 to 20,000, in spite of the fact 
that over half the trees that were found in the 60-year grove have died 
before this age is reached. From this if would appear that 100 feet 
B. M. per acre and per year on sapling timber is probably a safe esti- 
mate for the growth in this region. About the same conclusion will be 
reached if a grove of old hard woods is considered. Such a grove, 
which may cut 6,000 feet per acre, will be found to consist largely of 
young trees, among which there may be 20 to 50 good size older trees, 
and if examined, it will be found that the age of the oldest is not over 
150 years, so that here about one-third or less of all the trees standing 
on the acre have produced the 6,000 feet B. M., which we are taking 
for lumber, in 150 years; the whole acre, therefore, may be assumed to 
be able to produce this amount in one-third this time, or, in other words, 
the same acre might be logged over for 6,000 feet about every fifty 
years. Such an assumption is fully supported also by comparing the 
cross sections of the Pine and hard wood, which shows that though 
growing rather slowly (for hard woods), nevertheless, Oak, Basswood, 
ete., in Wisconsin, equal and excel Pine in rate of growth. 
If, then, 100 feet B. M. per acre and year be assumed as an average 
estimate of growth for this region, the total annual growth over the 
whole may be set at about 900,000,000 feet B. M., which is distributed 
among the different kinds according to their ascertained acreage, as 
follows: 
Million feet. 
Rahnicranaslveda GO wiay i liNO~ see seesaw ce hoe ect e ws sade t-te cee ce 250 
UE GIR PTE: Sy eee ae ee Se See To eee IRD a I, Riga ar 5 A Ce SR a ee 30 
PS ESTI@GE “2 SS Se ee ae nee ae ae er een 
“SETS TPA REL Sk AS Se re a 30 
WO EDGNP oo cies AES 5 Bek eR Ee ea I pa cae es Ue vane toy ee ee 20 
uae CHUM Eye LSU arer ete ete ee, ene Ste Ee LS cet e cee Seis 10 
Pier RUMOOU Sea eee TS SAGE a oak: Ge ed Nic hg ON Ur Oe ome Ook TA 500 
EOUEN 2 che eb, G2 RS LEE iS a ae ey 915 
From this growth must be deducted the loss by decay or natural 
waste, which in all wild woods necessarily equals growth when large 
areas and long periods are considered. For White Pine, Red (Norway) 
and Jack Pine, also Tamarack and Cedar (Arborvite) in Wisconsin, 
nearly half the present growth takes place in young, immature timber, 
since this largely prevails. With Pine in the hard-wood forest, and 
still more with Hemlock, decay proceeds faster than growth; for Spruce 
and Balsam an increase is doubtful, and with the hard-wood forests in 
