VI. RESULTS AND DISCUSSION
4. Pulp-chip yield from chipping 1.8m Pinus densiflora logs …
Table 5 shows the result of pulp-chip production with 1.8 m Pinus densiflora logs. As shown in the table, the volume of pulp-chip production gradually increased from 0.015 m3 to 0.681 m3 as diameter class increased. Since the production was estimated assuming that 1 ton of log yields 2.5 m3 of pulp-chip, the recovery rate was the same as 237% in every diameter class.
Table 5. Pulp-chip yield from a given log weight SED
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5. Net profit comparison between lumber production and pulp-chip production
Table 6 shows the result of profitability analysis of lumber production using 3.6 m and 2.7 m Pinus densiflora logs and of pulp-chip production using 1.8 m Pinus densiflora logs.
According to the result, net profits generated from both lumber production cases were higher than pulp-chip production in every diameter class. The average net profit of sawing 3.6 m log was 861% and sawing 2.7 m log was 723% higher than chipping 1.8 m logs (Figure 12).
Between the lumber production cases, sawing 3.6 m log showed higher profitability in every diameter class. The average net profit of 3.6 m lumber production was 24% higher than 2.7 m lumber production.
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Table 6. Net profit comparison between lumber and pulp-chip production with Pinus densiflora logs
SED (cm)
Net profit of lumber production (\) Net profit of pulp-chip production (\) Log length 3.6 m Log length 2.7 m Log length 1.8 m
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Figure 12. Net profit generated from the two lumber production cases and net profit generated from the pulp-chip production
50,000 100,000 150,000 200,000 250,000 300,000
6 <8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Net profit (\)
SED (cm)
1.8m Pulp chip 2.7m Lumber 3.6m Lumber
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6. Production estimation of lumber for wooden cutting board
Figure 13 shows the result of log sawing simulation of 1.8 m Pinus densiflora logs for wooden cutting board lumber. According to the simulation result, lumber (40 × 180 × 1800 mm) for wooden cutting board manufacture was produced from a log 18 cm in diameter.
The number of the lumber production increased from two to twelve as diameter class increased.
In terms of recovery rate, the highest recovery rate was found in between diameter class 32 cm and 36 cm as 56%. The lowest recovery rate was 37% at diameter of 24 cm. However, unlike the previous lumber production cases (3.6 m and 2.7 m lumber production), the recovery rate fluctuated in between diameter classes. Especially, the level of fluctuation was higher in relatively small diameter classes (18 cm-24 cm). The fluctuation can be explained by the same lumber production with the increase of diameter class.
Figure 13. Number and recovery rate of lumber production for wooden cutting board
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7. Production estimation of lumber for wooden tray
The result of log sawing simulation of 1.8 m Pinus densiflora logs for wooden bowl is shown in Figure 14. According to the simulation result, lumber (30 × 120 × 1800 mm) for wooden tray manufacture was produced from a log with diameter of 22 cm and the lumber production increased as diameter class increased.
In terms of recovery rate, similar with the case of the dimension lumber production, it showed a gradual increase as diameter class increased. The highest recovery rate was 59% at diameter 40 cm and the lowest was found at diameter of 22 cm.
Figure 14. Number and recovery rate of lumber production for wooden tray manufacture 0
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Ⅶ. CONCLUSION
This study analyzed the value of Pinus densiflora logs by comparing profitability of lumber production and pulp-chip production with logs in different lengths. In order to estimate the maximum value recovery generated from log sawing, a log sawing simulation model was developed first. The model was based on DP algorithm proposed by Reinders and Hendriks (1989). Since this study assumed that logs had been already bucked into certain lengths, two-dimensional DP algorithm, which breaks down a log into flitches and the flitches into lumber products, was applied.
Using the sawing simulation model, 3.6 m and 2.7 m logs were sawmilled for 3.6 m and 2.7 m lumber products, respectively. 1.8 m logs were debarked and chipped for pulp-chip production. The profitability of the three cases were then analyzed for comparison purposes.
According to the results, sawing the longest log, 3.6 m logs, generated the highest net profit among the three cases. The second highest net profit was generated from sawing logs 2.7 m long, which was the second longest log length of the three lengths of log types applied in this study. The difference of the net profit between the two lumber sawing cases (3.6 m and 2.7 m) were 24% in average. However, the net profit of both lumber sawing cases was 861%
and 723% higher than pulp-chip production with 1.8 m logs. Additionally, when considering by-products such as wood slab and sawdust produced from log sawing, the profitability of sawing Pinus densiflora logs will be higher.
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In addition to the comparative analysis on sawing profitability, the sawing potential of short (1.8 m) Pinus densiflora logs was also evaluated for wooden cutting board and wooden tray manufacture using the log sawing simulation model. According to the result, lumber for wooden cutting board manufacture (40 × 180 × 1800 mm) can be obtained from a log with diameter of 18 cm and lumber for wooden tray manufacture (30 × 120 × 1800 mm) from a log with diameter of 22 cm. The number of the lumber production for both wood products showed a gradual increase as diameter class increased.
The result of this study addresses two important suggestions on the current timber harvesting method and timber sale. First, decisions on bucking patterns have to be in association with timber sale profits. In other words, log buckers who determine where to locate a cut on a harvested tree should consider the end-uses of bucked logs because depending on the location of the cut, the value of each log changes enormously. Second, even if poor bucking patterns have been made in the first place, various end-uses of the bucked log have to be considered in the process of log allocation in order to increase timber sale profits.
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소나무 단목의 경우, 다양한 용도 고찰을 통하여 매각 수익성을 높일 수 있을 것으로 사료된다.