J. Puumalainen, OPTIMAL CROSS-CUTTING AND SENSITIVITY ANALYSIS FOR VARIOUS LOG DIMENSION CONSTRAINTS BY USING DYNAMIC-PROGRAMMING APPROACH, Scandinavian journal of forest research, 13(1), 1998, pp. 74-82
An application of a forward reaching algorithm of dynamic programming
is presented for cross-cutting trees. Sensitivity analysis was applied
for evaluating the effects of various log length and dimension constr
aints on the produced yield and the relationships between the timber v
olumes obtained and the dendrometric properties of the data were analy
sed. The data used consisted of 3283 Scots pine (Pinus sylvestris L.)
stems collected from 52 forest stands located in seven regions in Finl
and, The timber grades used were branchless logs, logs with living bra
nches, logs with dead branches, pulpwood and waste. It was shown that
the volumes of different grades vary considerably when different dimen
sional criteria are applied and that log length constraints seem to af
fect the yield more than the limit for the minimum top diameter. By re
ducing the minimum log length from 37 dm to 22 dm the volume of the br
anchless log grade was tripled in some stands. The volume gain obtaine
d by loosening the dimension constraints was generally largest iu stan
ds of poor quality. The average height of the lower part of the dead c
rown was found to be the best indicator for the amount of the branchle
ss timber obtained in a stand. In general. the timber volumes obtained
varied a lot between the stands of a region as well as within a stand
. Especially between-tree variation within a stand makes the estimatio
n of the timber volume unreliable without some measurement data.