Proceedings World Bioenergy 2010

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