PTAEDA2V: THE MOST ACCURATE TOOL FOR ESTIMATING VOLUMES IN THINNINGS
Nothing beats PTAEDA2V for identifying trees to be removed
in thinning pine plantations. We emphasize the importance of this
by reporting in a nearby article the sad details of what remained
in a client’s stand after a typical third-row,
operator-selected thinning. But that’s just part of the
story.
As we have written frequently, "selling timber by weight
is tricky business." This is true because the standard
measures of volumes (cords or thousands of board feet) are based
on the dimensions of trees, whereas weights depend upon
the solid-wood content. A recent pulpwood thinning
emphasized the consequence of this.
The 34-acre sale included 9,010 trees containing 79,948 cubic
feet of wood or 802 standard cords, and we asked for bids on a
lump-sum, per-cord, or per-ton basis. The highest per-ton bid was
$8.10, and, using the mill’s cord-equivalent factor of 2.6
tons per cord, indicated that total receipts would be $16,899.
The highest lump-sum bid was $15,646. When all the trees were
cut, weighed, and paid for at $8.10 per ton, however, receipts
were only $14,745, 87.3% of the anticipated amount. Obviously the
lump-sum bid was better.
Calculating the number of pounds offered in the sale
using the formula in PTAEDA2V would have revealed that, at $8.10
per ton, receipts would be $15,302. With information like this in
hand, a landowner could allow bidders to choose any bidding
method (per-cord, per-ton, per-tree, or lump-sum) and yet have no
trouble in detecting the highest bid.
There’s another plus in using PTAEDA2V in such
situations: determining the number of trees by sizes in the first
place. Using PTAEDA2V and the sampling method prescribed by Dr.
Harold Burkhart, we estimated that the sale contained 3,778,284
pounds of wood. The weight delivered to the mill scales was
3,640,738 pounds, 96.4% of our estimate. In our opinion, getting
any closer to the actual amount by any other procedure would have
been very costly. For example, measuring 9,010 individual trees,
as JMV&CO does in sawtimber sales, may have cost more than
total sale proceeds.
|
