Regardless of the type of construction and logging equipment used in a particular project, harvesting operations themselves remain difficult, often hazardous operations that can cause substantial damage to the forest ecosystem unless environmentally sound practices are followed. In particular, road construction in mountainous terrain can inflict scars on the landscape which can seldom be remedied at a later stage and only at much higher costs.
Therefore, the selection of construction machinery as well as all other harvesting equipment should not only be guided by short-term economic benefits but should take account of environmental considerations.
The road construction equipment described below was used at the studied construction sites.
Table 12. Construction equipment used in the road projects under review
| Kharungla road | Korila extension | ||
| Equipment features | Caterpillar 320B L | Dresser TD 12 | Unit |
| Type of tracked equipment | Excavator | Bulldozer | |
| flywheel power | 95.5 | 82.0 | (kW) |
| Operating weight | 20 700 | 13 172 | (kg) |
| Overall width | 3.18 | 3.83 | (m) |
| Overall track length | 4.46 | n.a. | (m) |
| Overall length with blade | n.a. | 4.89 | (m) |
| Ground pressure | 45 | 67 | (kPa) |
| Fuel tank refill capacity | 290 | 246 | (l) |
| Maximum travel speed | 3.4–5.5 | 10.0–11.7 | (km/h) |
| Gradability | 70 | 70 | (%) |
| Pry-out force | 120 | n.a. | (kN) |
| Penetration force | 104 | n.a. | (kN) |
| Bucket capacity (heaped) | 1.10 | n.a. | (m3) |
| Maximum reach at ground level | 9.31 | n.a. | (m) |
| Maximum digging depth | 6.29 | 0.49 | (m) |
It should be noted that although road construction is machine-intensive, labour remains the most critical element for achieving the goals of environmentally friendly engineering practice. Only if operators are competent in their skills, and motivated to work properly and efficiently can they be expected to contribute effectively to these goals (FAO, 1996).
The following sledge winch was used on both logging sites, the Korila and the Helela site, where work and time studies on long-distance cable logging were carried out.
Table 13. Cable crane unit used at study sites
| Kharungla/Helela logging site | ||
|---|---|---|
| Equipment features | Gantner USW 60D 1000 | Unit |
| Type of winch | single drum sledge winch | |
| Power | 60 | (kW) |
| Operating weight | 1 500 | (kg) |
| Payload | 2 500 | (kg) |
| Mainline - diameter | 12 | (mm) |
| Skyline - diameter | 24 | (mm) |
Since diesel engines lose considerable power with increasing altitude (about 30 percent at 3 000 m above sea level), this more powerful 60 kW winch, as used at the study sites, should be used at high altitudes (2 000–4 000 m above sea level). The much cheaper 45 kW winch should be adequate in the lower areas like in the Geruwa-Demula FMU and most of Lingmethang FMU of TFDP (Roetzer, 1996).
