Volume 7, numéro 3, july 1996

EN :

Harvesting production and costs were examined for three alternative silvicultural prescriptions at two sites in the Coast Range of Oregon. Thirty-three-year-old Douglas fir stands were commercially thinned to residual densities of 247,148, and 74 trees per hectare (tph) [100,60, and 30 trees per acre (tpa), respectively]. Detailed time studies were conducted on manual felling and uphill skyline yarding with small yarders. Separate regression equations were developed to predict delay-free felling cycle time and delay-free yarding cycle time. The 74 tph [30 tpa] treatment had the highest production rate and was the least costly to harvest. Total harvesting costs of the other two treatments averaged from 6.0% (148 tph [60 tpa]) to 12.3% (247 tph [100 tpa]) more than the 74 tph [30 tpa] treatment.

EN :

Mechanical failure rates observed in highway accidents involving logging tractor-trailers have fallen significantly since Georgia subjected these vehicles to random roadside inspections. This improvement is attributed to both the regulation and the training efforts aimed at the log trucking community immediately before and after the implementation of the rules.

EN :

Forest roads have long been recognized as the primary source of soil and water disturbance, and other negative site effects, associated with timber harvesting operations. In West Virginia, where slopes are often steep and soils may be unstable, haul and skid road planning, construction, and retirement are particularly important practices. In addition, other challenges related to land ownership and regulations help to form the environment within which forest road practices are performed. However, the scope and relative importance of these challenges have not been studied.

Using a Delphi process, this study pooled the expertise of 10 resource professionals with extensive experience in forest roads, soils, water, and regulations to determine specific challenges and solutions associated with forest roads in the region. Results indicated that among the most significant problems facing forest road construction, as identified by the expert panel, are water management, lack of planning, and topography. Related issues include logger and forester training, adequacy of and compliance with Best Management Practices, constraints on road planning associated with private property boundaries, road costs, and federal and state policies. Results of this study have been used to both guide research priorities and initiate further discussions of important forest road issues.

EN :

Two Waratah 234 single-grip harvester heads were assessed for productivity and log-processing accuracy while working in radiata pine clearfell operations in New Zealand forests.

Estimated productivity, processing stockpiled trees into logs on a landing in a ground-based operation, was 77 m3 per productive machine hour (PMH) in an average tree size of 1.63 m3.

In a yarder-based trial, processing trees into logs on a landing, productivity was 77 m3 / PMH in an average tree size of 3.1 m3.

Length-measuring accuracy in a later trial was shown to be within ± 5 cm for 93% of logs.

In a second ground-based trial, estimated productivity for an average extracted tree size of 1.95m3 was:

51 trees/PMH (100m3) for felling, tree-length delimbing and bunching.

73 trees/PMH (143m3) for tree-length delimbing (butt-first) and bunching of manually felled trees.

EN :

A route selection consists of engineering, biophysical and socio-economic components. A road will generate constraints in one or more of these components. The road proponent then must present the advantages and disadvantages of alternative proposals, the rationale of choosing a particular route and the trade-off made (unavoidable impacts requiring protection planning) on the basis of the best balance and/or the equitable compromise between the engineering, biophysical and socio-economic components. Aerial photography has developed into a standardized, technically mature tool for aerial photo interpretation, reconnaissance and inventory. Traditional procedures of photogrammetric data gathering characterized by interdisciplinary methods, however, may be insufficient to address all of today's environmental protection issues regarding the road planning phase. New scanning sensors and automated imagery data processing software to identify site investigation data in a detailed spatial context have recently become affordable.

In this paper, the present phase of a PC-based imagery data processing system using aerial photography through the application to preliminary road network plans in Mie University forests has been summarized, and some prospective role discussed.