Table 1. Description of the test site.
Placename   San Rossore
Northing   43°41’33.08ˮN
Easting   10°18’30.44ˮE
Slope % 2
Species   Pinus pinea L.
Age years 21
DBH cm 23.1
Height m 10.7
Operation   2nd thinning
Criteria   Selection of candidates
Removal % trees 35–40
Mechanization level Manual Mechanized
System type WT CTL WT CTL
Removal trees ha–1 251a 244a 221a 251a
Removal t ha–1 51a 29.6b 53.9a 33.5b
Tree size kg tree–1 203a 122b 244a 133b
Wood moisture content % 45.8a 47.3a 48.2a 43.5a
Notes: Different letters in superscript indicate that the differences between the mean values presented on the same row are statistically significant at the 5% level according to Scheffe’s multiple comparison test; DBH = diameter at breast height; WT = whole-tree harvesting; CTL = cut-to-length harvesting; Tree size = the mass of the mean tree as it is extracted, i.e with top and branches for WT and without top and branches for CTL.
1

Fig. 1. Farm tractor (a); Feller-buncher (b); Skidder (c); Harvester (d); Forwarder (e); Chipper (f).

Table 2. Technical charecteristics of the machines in the test.
System WT WT CTL CTL WT/CTL WT/CTL
Mechanization level Mechanized Mechanized Mechanized Mechanized Motor-manual Both
Machine type Feller-buncher Skidder Harvester Forwarder Tractor Chipper
Make   John Deere John Deere John Deere John Deere Valtra Erjo
Model   759J 460D 870B 1110B 6400 12/90
Power kW 164 127 114 121 75 370/129
Weight t 27770 12770 13800 13670 4170 30350
Width mm 3050 2880 2510 2710 2340 2890
Length mm 4410 7345 5435 10310 4440 10400
Clearance mm 759 598 570 605 435 600
Head make   John Deere - John Deere - - -
Head model   FR21B - 746C - - -
Cut capacity mm 508 - 500 - - -
Notes: Chainsaws are not included in the table; Chipper size data refer to the complete forwarder-mounted unit; Chipper power figures are provided for both the chipper engine and the forwarder engine, in this order; WT = whole-tree harvesting, CTL = cut-to-length harvesting.
Table 3. Costing assumptions and machine rates.
Unit Chainsaw Tractor Feller Skidder Harvester Forwarder Chipper
Utilization % 46 72 81 90 90 90 83
Investment Euro 1500 55 000 320 000 180 000 300 000 240 000 500 000
Resale Euro 450 16 500 96 000 54 000 90 000 72 000 150 000
Service life years 2 10 10 10 10 10 10
Utilization SMH year–1 1000 1000 1600 1600 1600 1600 1600
Interest rate % 4 4 4 4 4 4 4
Depreciation € year–1 525 3850 22 400 12 600 21 000 16 800 35 000
Interests € year–1 50 1507 8768 4932 8220 6576 13 700
Insurance € year–1 2500 2500 2500 2500 2500 2500 2500
Fuel € year–1 2700 4500 47 840 31 408 27 040 27 040 72 800
Lubricant € year–1 270 450 4784 3141 2704 2704 7280
Repairs € year–1 263 1925 11 200 6300 10 500 8400 17 500
Total € SMH–1 6 15 61 38 45 40 93
Crew n. 2 1 1 1 1 1 1
Labour € SMH–1 32 16 20 20 20 20 20
Overheads € SMH–1 8 6 16 12 13 12 23
Total rate € SMH–1 46 37 97 70 78 72 136
Notes: Cost in Euro (€) as on Sept.18, 2013. 1 € = 1.33 US$; SMH = Scheduled Machine Hours, inclusive of delays; Utilization is the incidence of work time over total work site time: the remaining time is represented by delays. The utilization rates reported in the table were actually measured during the study.
Table 4. Productivity by treatment and work phase.
Mechanization Manual Mechanized
System type WT CTL WT CTL
Felling odt SMH–1 0.9a 0.6b 18.2c 4.9d
Extraction odt SMH–1 2.3a 0.6b 13.5c 6.9d
Chipping odt SMH–1 18.7a 16.7a 15.5a 17.5a
Extraction distance m 233a 140a 189a 174a
Load size odt 0.410a 0.212b 0.958c 3.845d
Notes: Different letters in superscript indicate that the differences between the mean values presented on the same row are statistically significant at the 5% level according to Scheffe’s multiple comparison test; SMH = Scheduled Machine Hours, inclusive of delays; odt = oven-dry tonnes; WT = whole-tree harvesting, CTL = cut-to-length harvesting.
2

Fig. 2. Specific fuel consumption per unit product by treatment and work phase. Notes: Different letters over different bars indicate that the difference between the mean fuel consumption values are statistically significant at the 5% level according to Scheffe’s multiple comparison test; WT = motor-manual whole-tree harvesting; CTL = motor-manual cut-to-length harvesting; Mech. WT = mechanized whole-tree harvesting; Mech CTL = mechanized cut-to-length harvesting; Felling also includes delimbing and crosscutting in the case of CTL harvesting operations.

3

Fig. 3. Thinning cost by treatment and work phase. Notes: Different letters over different bars indicate that the difference between the mean total cost values are statistically significant at the 5% level according to Scheffe’s multiple comparison test; WT = motor-manual whole-tree harvesting; CTL = motor-manual cut-to-length harvesting; Mech. WT = mechanized whole-tree harvesting; Mech CTL = mechanized cut-to-length harvesting; Felling also includes delimbing and crosscutting in the case of CTL harvesting operations.

Table 5. Anova table for the effect of mechanization level and harvesting system on unit cost and fuel consumption.
Thinning cost (€ odt–1)
Effect DF SS η2 F-Value P-Value
Mechanization 1 20003 0.71 113.034 <0.0001
System 1 4863 0.17 27.479 0.0008
Interaction 1 1861 0.07 10.515 0.0118
Residual 8 1416 0.05    
Specific fuel consumption (L odt–1)
Effect DF SS η2 F-Value P-Value
Mechanization 1 17.452 0.22 13.529 0.0062
System 1 40.853 0.52 31.668 0.0005
Interaction 1 10.155 0.13 7.872 0.0230
Residual 8 10.32 0.13    
Notes: odt = oven-dry tonnes.
Table 6. Site impact for the four treatments on test.
Mechanization Manual Mechanized
System type WT CTL WT CTL
Wounding % trees 6.0a 15.7 2.5ab 1.5b
Wound size cm2 433a 407a 106a 431a
Soil density untrafficked g cm–3 1.30a 1.18a 1.25a 1.21a
Soil density trafficked g cm–3 1.28a 1.28a 1.28a 1.36a
Difference % –1.2 8.8 2.5 11.9
t test p-value 0.3462 <0.0001 0.2332 <0.0001
Notes: Different letters in superscript indicate that the differences between the mean values presented on the same row are statistically significant at the 5% level according to Scheffe’s multiple comparison test; p-values in the last row refer to the comparison between untrafficked and trafficked soil density within each treatment; WT = whole-tree harvesting, CTL = cut-to-length harvesting.