Apr. 15,1925 TJse of Liability Ratings in Forest Fire Protection 
759 
VALUES OF YOUNG GROWTH 
The timber value of young growth 
depends upon its species and the 
stage of development which it has 
reached. This value is the value of 
the accrued net return on the capital 
value of the forest, for a number of 
years equal to the economic age of 
the stand. For natural stands, such 
as practically all of those on the 
national forests, it can be expressed 
by the formula: 
Here Y is the value of the final crop 
(for the sake of simplicity no allowance 
is made for intermediate returns from 
thinnings), .Op is 3 per cent, m is the 
economic age of the stand, and n is 
the number of years in the rotation. 
The value of Y depends upon the 
stumpage value per thousand board 
feet and the amount of timber that 
will be produced during a rotation. 
For the purpose of establishing stand¬ 
ard values for young growth, arbitrary 
rotations and yields were used, with 
the stumpage rates given in Table VIII. 
Because we know very little about what 
rotations will actually be used for stands 
now below merchantable size, it seemed 
advisable for the present purpose to use 
a uniform rotation period of 100 years, 
regardless of forest type, in the regions 
where growth is moderately fast 
(regions 2, 3, 4, 5, 6, 7, 8, 16, and 17), 
and 150 years where it is slower 
(regions 1, 9, 10, 11, 12, 13, 14, 15, 
18, 19, and 20). For the Lake States 
(region 21) a 70-year rotation was 
used. 
In order that the field men may not 
have to estimate the ages of the 
stands, and to reduce the division into 
age classes to the simplest practicable 
terms, only three age classes of young 
growth are recognized, and these are 
expressed in terms of size, rather than 
of age. They are: Reproduction 
(stands below 4 inches d. b. h.); 
small poles (4 to 7 inches d. b. h.); 
and large poles (8 to 11 inches d. b. h.). 
In stands classed as “all-aged,” young 
growth of all sizes will be lumped 
together. For computing values by 
the formula, the average ages of these 
size-classes were assumed to be: For 
150-year rotation, 20, 40, and 70 
years, respectively; for 100-vear rota¬ 
tion, 15, 30, and 50 years; and for 70- 
year rotation, 10, 20, and 35 years. 
Besides the timber, or product, 
value of young stands, there is their 
value as part of the forest capital. 
The destructible part of this value 
(aside from soil productivity, which 
will not be considered) is the cost of 
establishment. That is to say, when 
a new stand has been established on the 
burned area, the forest capital (but 
not the accumulated product) has been 
restored. If a destroyed stand is 
quickly replaced by natural reproduc¬ 
tion, it is considered that no capital 
loss has been suffered; but where 
natural restocking does not follow, 
the capital loss, equal to cost of re¬ 
planting, must be added to the pro¬ 
duct loss. Standard costs of planting 
have been given in Table IX. For 
the sake of simplicity and uniformity, 
it has been assumed that stands of 
young growth covering less than 10 
acres, and also young growth of any 
area under merchantable stands or 
scattered through all-aged stands, will 
be replaced by seeding from the sides 
or from above if desHwed by fire, 
and that areas greater than 10 acres 
(except where mixed with older tim¬ 
ber) will not restock naturally. Burns 
smaller than 10 acres, within more 
extensive stands of young growth, 
can not be depended upon to restock 
naturally within a reasonably short 
period; therefore damage in such 
cases will include the capital loss. 
Exceptions to the above assumption 
are: the western yellow pine in regions 
14, 15, 18, 19, 20, where it was assumed 
that only one-half of the destroyed area 
will restock even in stands smaller than 
10 acres; Douglas fir in the same 
regions, where it was assumed that 
only two-thirds of the destroyed area 
will restock in stands smaller than 10 
acres; the woodland types in all re¬ 
gions, where only one-half will restock 
in stands under 10 acres in extent; 
lodgepole pine and jack pine stands of 
the ‘Targe pole” class, where it was 
assumed that half the burns will restock 
naturally even in stands larger than 
10 acres; and the hardwood and 
aspen types in all regions, which will 
restock entirely, even on large burns. 
INTANGIBLE VALUES 
There appear to be no data upon 
which to base valuations of watershed 
protection, recreation values, or other 
similarly intangible benefits due to the 
presence of a forest cover, or to esti¬ 
mate what part of such values might 
be destroyed by a fire. It seems fairly 
reasonable to suppose that in most cases 
where reproduction will follow naturally 
almost immediately after the burn, the 
damage to such values is comparatively 
small; where such restocking will not 
take place, the damage estimates 
