Proceedings World Bioenergy 2010
Proceedings World Bioenergy 2010
Proceedings World Bioenergy 2010
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m³×PW-hour -1 . The productivity of energy wood<br />
forwarding was assumed 15% lower than pulpwood<br />
forwarding, as suggested by Heikkilä et al. (2005) [15],<br />
who noticed productivity in forwarding whole trees 10-<br />
20% lower than forwarding delimbed wood. The<br />
productivity calculations were made for a forwarding<br />
distance of 200 m and a haulage load size of 8 m 3 solid.<br />
The PW were converted to main work time (MW) [11]<br />
using the coefficient 1.3 for the harvester and 1.2 for<br />
forwarding. The operating costs of the harvester were set<br />
to 80 €×MW-hour -1 and for the forwarder to 70 €×MW -1 -<br />
hour -1 . The transferring costs per machine were set to 200<br />
€ and the thinning stand areal was set to 3 ha.<br />
3 RESULTS<br />
The stem volume of harvested trees ranged between<br />
15 to 84 dm 3 with an average of 38 dm 3 . In average, the<br />
ratio of the harvested biomass to the pulpwood volume<br />
ranged from 1.5 to 2.0 in the “old” stands. The<br />
corresponding ratio in the “middle” age stands ranged<br />
from 2.4 to 2.9 and in the “young” stands it ranged from<br />
4.8 to 7.2. The highest volume ratio was found in the<br />
spruce stands since spruce have a relative higher share of<br />
branches compared to pine and birch. In average the<br />
biomass to pulpwood ratio of the gross income in the<br />
pine, spruce and birch stands was 2.1, 2.9 and 2.3,<br />
respectively (Table I-III).<br />
In pine stands (Table I) the gross income for<br />
pulpwood compared to energy wood was 7% lower in the<br />
“old”, 71% lower in the “young” and 45% lower in the<br />
“middle”.<br />
Table I: Characteristics of pine dominated stands and<br />
harvesting results at a 30% intensity of removal of the<br />
basal area<br />
Initial stand Old Middle Young<br />
Stem volume (dm 3 ) 121 53 35<br />
Basal area (m 2 ×ha -1 ) 31.3 20.2 18.4<br />
Total stem volume (m 3 ×ha -1 ) 229 121 97<br />
Removal<br />
Stem volume (dm 3 ) 79 27 18<br />
Pulpwood volume (m 3 o. b.×ha -1 ) 52 15 7<br />
Biomass volume (m 3 ×ha -1 ) 78 38 33<br />
Volume ratio, biomass/pulpwood 1.5 2.5 4.8<br />
Pulpwood gross income (€×ha -1 ) 1443 420 192<br />
Biomass gross income (€×ha -1 ) 1554 764 658<br />
In spruce stands (Table II) the gross income for<br />
pulpwood was 32% lower in the “old”, 81% lower in the<br />
“young” and 52% lower in the “middle” compared to<br />
energy wood.<br />
Table II: Characteristics of spruce dominated stands and<br />
harvesting results at a 30% intensity of removal of the<br />
basal area<br />
26 world bioenergy <strong>2010</strong><br />
Initial stand Old Middle Young<br />
Stem volume (dm 3 ) 160 58 31<br />
Basal area (m 2 ×ha -1 ) 27.6 20.7 21.5<br />
Total stem volume (m 3 ×ha -1 ) 240 130 100<br />
Removal<br />
Stem volume (dm 3 ) 84 31 15<br />
Pulpwood volume (m 3 o. b.×ha -1 ) 40 19 7<br />
Biomass volume (m 3 ×ha -1 ) 81 54 50<br />
Volume ratio, biomass/pulpwood 2.0 2.9 7.2<br />
Pulpwood gross income (€×ha -1 ) 1101 523 192<br />
Biomass gross income (€×ha -1 ) 1620 1082 994<br />
In birch stands (Table III) the gross income for<br />
pulpwood compared to energy wood was 12% lower in<br />
the “old”, 74% lower in the “young” and 43% lower in<br />
the “middle”.<br />
Table III: Characteristics of birch dominated stands and<br />
harvesting results at a 30% intensity of removal of the<br />
basal area<br />
Initial stand Old Middle Young<br />
Stem volume (dm 3 ) 99 45 33<br />
Basal area (m 2 ×ha -1 ) 29.9 25.1 21.8<br />
Total stem volume (m 3 ×ha -1 ) 172 120 117<br />
Removal<br />
Stem volume (dm 3 ) 52 23 15<br />
Pulpwood volume (m3 o. b.×ha -1 ) 37 18 6<br />
Biomass volume (m 3 ×ha -1 ) 58 43 30<br />
Volume ratio, biomass/pulpwood 1.6 2.4 5.0<br />
Pulpwood gross income (€×ha -1 ) 1025 496 155<br />
Biomass gross income (€×ha -1 ) 1170 865 601<br />
In average the harvesting cost per m 3 (forwarding<br />
included) of the energy wood system was 37 - 40% lower<br />
compared to the pulpwood system. The net income for<br />
the pulpwood system was negative (generating costs) in<br />
all stands. The net income for the energy wood system<br />
was profitable in 67% of the stands; 133 €×ha -1 in pine<br />
stands, ranging from 37 to 145 €×ha -1 in spruce stands,<br />
and 19 to 76 €×ha -1 in birch stands.<br />
4 DISCUSSION<br />
Under current market price conditions the energy<br />
wood system gives in average about 2.4 times higher<br />
gross income than pulpwood in the studied stands. The<br />
systems would give the same gross income if the biomass<br />
to pulpwood ratio equals about 1.4. In the studied stands<br />
this situation would be possible only in the “old” stands<br />
at a harvesting intensity of at least 40% of the basal area.<br />
In present study the current price ratio of energy<br />
wood to pulpwood was 0.7, but market prices fluctuate<br />
and this ratio changes over time. If the energy wood price<br />
would increase with 30%, from 20 to 26 €×m -3 , the price<br />
ratio would increase to 0.9. At this situation, the<br />
differences in net income (€×ha -1 ) between pulpwood and<br />
energy wood, would increase considerable (Fig. I-II-III):<br />
the energy wood harvesting would becomes profitable in<br />
all considered conditions giving a net income ranging<br />
from 120 to 533 €×ha -1 in pine stands, 306 to 556 €×ha -1<br />
in spruce stands, and 139 to 390 €×ha -1 in birch stands.