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Trenk, Fred B. (Fred Benjamin), 1900- / Forest planting handbook
(1932)

How fast does a plantation grow?,   pp. 35-42 PDF (2.0 MB)


Page 39


  In Wisconsin, pulpwood is the chief use for small size material,
and this is measured by the cord. The minimum size product taken at
present is a stick four inches in diameter at the small end and eight
feet in length. These dimensions are first attained by pine planta-
tions when the tree is about six inches in diameter breast high. Some
trees of this size will appear in the stand at about 18 years, but the
average time required to attain this diameter is 25 years. Young
plantations of pine produce an eight foot stick with a two inch top at
about 13 years of age. It has been found in a study of a Norway
spruce plantation' that the tops from a four inch diameter point in
the tree to a two inch diameter point contain from one per cent of the
total cubic foot volume for a 10 inch tree to 16 per cent for a five inch
tree. This means that at an age of 30 years and a diameter of six
inches, for every seven cords taken for pulp, one cord is left in the
woods, if the trees are cut to a four inch top instead of to a two inch
top.
Example Plantation*
  This plantation of 0.84 of an acre was planted 38 years ago with
young Norway spruce seedlings, the seed of which had been sent to
this country from Germany. It is probably the only wood lot planta-
tion of Norway spruce of merchantable size in this state. It is grow-
ing on a silt loam soil. Originally Scotch pine was planted inter-
mixed with the spruce, the probable spacing of all species being about
4 x 4 feet. The Scotch pine did not survive and now only the spruce
are left with five European larch which have also made an excellent
growth. A rough eye estimate of the density would place it at ap-
proximately 80 per cent of a fully stocked stand.
   The average diameter of the stand is 7.7 inches diameter breast
 high. Four and one-half cords of eight foot peeled sticks were thinned
 from this stand for pulp during the summer of 1931 and two cords
 were cut about two years previous to this thinning.
   The average growth in this plantation shows that an eight foot
 stick, four inches inside bark at small end, was produced in about 23
 years.
   At present there is left on this small plantation 39 cords of spruce
 figured to a diameter of two inches in the top of the tree, which is
 equivalent to 47 cords per acre. Adding the six and one-half cords
 already removed, there is a total of 54 cords per acre which this
 stand of Norway spruce has produced at a plantation age of 38 years,
 averaging 1.4 cords per acre per year throughout its life. Trees range
 from four to 13 inches in diameter at breast height. The average to-
 tal height is 55 feet, and there is an average of four and one-half
 eight foot pulpwood sticks per tree, when figured to a four inch top.
 The total number of trees now left (acre basis) is 506. Of this number
 438 trees are merchantable and 68 trees are suppressed. The cubic
 volume of the average tree remaining (not includingphe suppressed
   *Norway SprUce Plantation at Prereott. Pierce county, Wisconsin.
                                 39


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