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are so irregular that this diameter class was dropped from further consideration. In estimating, the possible amount of wood from trees less than 2.5 inches D B h can be considered as a margin toward conservatism.

Purely as a check on the work done so far, the volumes given in Table II were used in computing a table of merchantable form

TABLE II
VOLUME TABLE FOR RED MAPLE IN CUBIC FEET

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.4

.5

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

.25 .6 1.0

1.15

.8 1.25 1.95 3.0

.9 1.5 2.3 3.5 4.8 6.4 8.1

1.3 2.1 3.1 4.4 5.9 7.9 10.3 13.1 16.6 20.7 25.2 30.0

3.9 5.2 7.0 9.1 11.8 15.0 18.4 22.3 26.5 31.2 36.0 41.5

6.5 8.2 10.5 13.2 16.5 20.2 24.2 28.7 33.7 39.1 45.0

9.4 11.6 14.4 17.6 21.5 25.8 30.8 36.5 43.0 50.5 58.0

41.5

factors (see Table III), since it was thought that in this way any large errors would become apparent. The form factors proved to be surprisingly regular except for the larger diameters in the fifty foot height class. No adequate explanation of the high values in these cases can be given. At eleven inches, the form factor is above 500, but the average form factor for the four trees of this diameter and height actually measured is 527. More data must be collected before the results for the diameters above nine inches in the fifty foot height class can be accepted without caution, or completely rejected.

The next step in the preparation of the volume table is based on admittedly scanty data. An attempt was made to secure average figures for the proportion of wood in piles each containing the bolts from trees of one diameter class. Ordinary commercial practice was followed in splitting large bolts. Measurements of only nine piles were taken, but the resulting averages, curved, are at least

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approximately correct for average conditions on the Harvard Forest. The influence of crown class was found to be very strong in even the small amount of work done, since overtopped and intermediate trees usually have few limbs and the bolts are fairly smooth, while dominant trees often have heavy crowns which yield knotty and crooked bolts. One pile made from overtopped six inch trees had over seventy per cent wood, although the average for this diameter was well below sixty per cent. In estimating, this variation should be kept in mind, especially where suppressed or intermediate maples are to be taken out of a pine or chestnut stand in thinning. The proportions used are given in Table IV.

TABLE IV

PER CENT OF WOOD IN PILES OF RED MAPLE CORDWOOD

Based on 9 piles of 2 to 4 cord feet each. Harvard Forest, Petersham, Mass.,

1910-11

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Based on Measurements taken in 1910 and 1911. Harvard Forest,

Petersham, Mass.

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46

.009
.014

3 4 5

.010
.016

.012
.018
.028
.042

.013
.022
.033
.049
.065
.083
.101

7 8 9 10 11 12 13 14 15 16 17

.019
.030
.044
.061
.079
.102
.128
.156
.191
.230
.275
.321

.055
.072
.094
.118
.147
.179
.211
.241
.290
.334
.380
.434

.090 .110 .136 .164 .197 .232 .270 .314 .359 .413 .471

.127 .150 .179 .210 .247 .288 .336 .391 .455 .529 .604

27 34 38 20 32 24 11 18 6 3 3 1

.444

Or

2 Total, 267

• This volume table is computed with the standard cord of 128 cubic feet. In places where extra beight is required to allow for shrinkage, the volumes given should be reduced proportionally.

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The cubic volume for trees of each diameter and height class given in Table II was then divided by the percentage for the corresponding diameter class given in Table IV, and the quotients multiplied by 109 to find the space, in cubic feet, occupied by the tree in a pile. This figure was again divided by 128, and the quotient taken as the fraction of a cord of merchantable wood in the tree. The volume table was then rewritten in cord measure, and is given as Table V.

The custom on the Harvard Forest is to measure cordwood promptly after it is cut, using as the unit of measure the standard cord (a pile four feet wide, four feet high and eight feet long), containing 128 cubic feet. The wood is usually sold without remeasurement. The foregoing table has been made for use under these conditions, and the volumes given should be discounted for use in localities where choppers are required to make their piles four feet four inches high to allow for shrinkage. This discount may also be made by using the table as it is, but reducing the total indicated volume of the stand. A discount of ten per cent would be liberal, and eight per cent should ordinarily be sufficient.

Possibly the following general statement may be remembered
for use when the table is not at hand.
Red maples of good height for their diameters should run:

If 4 inches D B y about 50 trees to the cord.
If 6

20
If 8

9 If 10

6 If 12

4 If 14

3

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66

66

FIRE PROTECTION

RICHARD F. HAMMATT, B.S.F. 1906

SOME six years' work, mostly administrative, in the United States Forest Service, has impressed me more and more with the vital importance of the fire problem, particularly from the lumberman's and forester's view points.

To the progressive lumber or pulp concern, or the forester going into either private or Government administrative work, fire protection is, in a way, the basis of all operations. What concern can hope to get a second cut from its logged over lands, if they are burned over every five or ten years? What good does it do for the forester to determine quality classes or rate of growth, to figure on yield per acre, rotation, or annual cut, if continued fires are going to upset all his calculations and burn all his work ? The prospective forester must understand that it is up to him to so protect the holdings in which he is working that his other work will be of some value.

There are now a number of schools and colleges in the United States giving instruction in lumbering and forestry. There are, annually a large number of men attending such schools. Do these men realize how much more true fire protection means than getting men, supplies and tools to a fire as soon as it is reported, and then putting it out? Did it ever occur to you that, as the man in charge, you should know, not only every square mile of the physical features of your country, but that you should know, too, the climatic, moisture and wind conditions, and the amounts and kind of brush and debris as well as the timber?

Nearly every one realizes, of course, that time, money, and loss of life and property can be avoided by roads, trails, and telephone lines. Did you ever try to work out a complete and cconomical plan for such improvements covering a broken area of one and onehalf million acres? You know that to get the fullest benefit from such a system there must be a force of men placed at strategic points throughout the dangerous season. Did you ever try to pick

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