W. Dale Greene

An Interactive Simulation System for Modeling Stands, Harvests, and Machines

An interactive computer simulation program models stand, harvest, and machine factors and evaluates their interactions while performing felling, skidding, or forwarding activities. A stand generator allows the user to generate either natural or planted stands. Felling with chainsaw, drive-to-tree feller-bunchers, or harvesters and extraction with grapple skidders or forwarders are currently modeled in the system and others may be added. Simulations are performed by moving machine images within stand maps on the computer screen. The residual stand, machine running paths, and extraction travel intensity are recorded for later analysis. Examples of simulations with common logging machines are illustrated.

Productivity and Product Quality Measures for Chippers and Grinders on Operational Southern US Timber Harvests

Abstract Growth in bioenergy interests in the southeastern United States has created a need for cost-effective woody biomass harvesting systems. We evaluated three operational systems for their potential production and cost: horizontal grinders fed with residue from roundwood harvests, horizontal grinders fed with residue from clean chipping harvests, and whole tree chippers fed with entire stems. We evaluated three contractors operating each of the three system types over the course of approximately one working week each. Utilization rates for chippers and grinders were 44% and 38% respectively. Hourly production ranged between 22 – 30 metric green tonnes (gt)/SMH and 64 – 70 gt/PMH and did not differ significantly between the three systems. Delivered costs per gt of material were also very similar for the three systems and ranged between

Cost and Productivity Impacts of Product Sorting on Conventional Ground-Based Timber Harvesting Operations

22.68 and

Unused Logging Production Capacity in Northern New England, USA

23.81.

Setting Analyst: An Operational Harvest Planning Tool

The impacts of additional log sorting on production and cost per ton for mechanized, tree-length southern pine harvesting systems were evaluated. The analysis included evaluation of extensive data sets of weekly production along with short-term field time studies to directly measure the impacts of sorting on production. For this study, a product separation, or sort, was defined as a separate pile generated by the loader operator. The data were used to create a model to evaluate log sorting impacts on production and costs. Tree-length harvesting systems encountered weekly production losses when sorting more than six products, while modified tree-length harvesting systems using roadside processors lost production after nine product sorts. Hourly production was significantly impacted by both operator technique and the type of product handled. Operators who processed wood in advance of truck arrivals and loaded trucks from processed piles loaded trucks in 60 percent less time than loader operators who processed stems while loading. Increasing the number of sorts often required more processing while loading since the room to store processed wood under stationary loaders is limited. Adding precut sorts significantly reduced production over that seen with an additional tree-length sort, due to the additional processing and loader movement with multiple stem pieces. With the current product price differentials typical to southern log markets, we did not find increased net revenue to the landowner from additional sorts. In fact, we found that at current prices additional sorts can reduce revenue by 6 to 15 percent.

Safety of Log Transportation After Regulation and Training in the State of Georgia, USA

Abstract Among the costs associated with timber harvesting in northern New England, those related to unused production capacity are among the most poorly understood. Yet research in other regions of the US suggests that idle logging capacity can impose significant costs on wood supply systems, including logging businesses and procurement organizations. Mail surveys of logging business owners and representatives of wood consuming mills were used to understand unused logging capacity in the northern New England states: Maine, New Hampshire and Vermont. Over two-thirds of logging business owners said that they experienced unused production capacity in an “average” year. Weather, poor road conditions, equipment breakdowns, and mill-imposed quotas, were cited most often as causes of unused logging capacity. Results of this study have implications for logging businesses, procurement organizations, and wood supply system efficiency in northern New England.

Productivity of a Tree-Length Forwarder for Logging on Wet Sites

Abstract Operational harvest planning in the southern USA has not been widely used in the past due to a lack of state legislation, non-regulatory water quality protection programs, and relatively easy logging conditions. Increased government regulation and market pressures to document sustainable forest management under various certification standards is increasing the need for harvest planning in the region, particularly on private, nonindustrial timber sales. We developed an ArcView extension, Setting Analyst (SA), to assist harvest planners. SA can use spatial information obtained from scanned air photos or detailed data from a geographic information system. It models travel patterns of ground-based machines and compares different harvest settings based on projected average skidding distance, costs of skidding and improvements, and site disturbance levels. In its current form, it does not account for slope. SA can model settings with complex features such as stream crossings, restricted areas, and skidding on designated trails. Travel intensity is assessed since it is highly correlated with site disturbance and soil compaction. To assess the utility of SA, we used it to model ten actual harvesting settings and contrasted each with two proposed settings. SA produced sale plans that were very similar to those observed on the ground. Its primary advantage is that it conveniently documents each alternative setting considered for the timber sale. These can be kept on file to demonstrate the level of planning used when forest certification audits are conducted. SA offers the most potential to harvest planners that already use GIS or GPS but desire additional analysis and documentation capabilities.

Analysis of Log Hauling Vehicle Accidents in the State of Georgia, USA, 1988–2004

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.

Individual stem value recovery of modified and conventional tree-length systems in the southeastern United States

A GEMCO tree-length forwarder was used to harvest pine from wet sites. It produced payloads of 26.9 metric tonnes with an average cycle time of 72 minutes. Hourly production averaged 32.9 metric tonnes per PMH while addition of the forwarder and a second loader to the system increased system cost by US

Potential for Mechanised Logging Systems in the Republic of South Africa

67.97/PMH. Use of the forwarder was less expensive than building all-weather roads to harvest timber in wet weather where volume accessed was relatively low or an extensive road network was required.