volume: 39, issue: 2
The performance of a harvesting crew in terms of its ability to transform inputs into outputs
is influenced by discretionary factors within the unit’s control, such as the selection of machines
and operators. However, factors associated with the operating environment, such as
terrain slope and tree size that are outside the direct control of management, can also influence
harvesting system efficiency. Using data on forest harvesting operations in New Zealand, this
paper applies an established four-stage Data Envelopment Analysis (DEA) procedure to estimate
the managerial efficiency of independent forest harvesting contractors, while taking into
account the influence of the operating environment. The performance of 67 harvesting contractors
is evaluated using seven inputs, one output (system productivity) and three operating
environment factors in an input-oriented, variable return to scale DEA. The results show that
the operating environment including terrain slope, log sorts and piece size influence the efficient
use of inputs by harvesting contractors. A significant difference is observed between the
mean managerial efficiency of the crews before and after controlling for the influence of the
operating environment, the latter being higher by 11%. This study provides evidence that
without accounting for the influence of the operating environment, the resulting DEA efficiency
estimates will be biased; the performance of crews in favourable operating environment
would be overestimated and those in unfavourable environment underestimated.
volume: 42, issue:
Technology development, in terms of both capability and cost-effective integration, is moving at a fast pace. While advanced robotic systems are already commonplace in controlled workspaces such as factories, the use of remote controlled or autonomous machines in more complex environments, such as for forest operations, is in its infancy. There is little doubt autonomous machinery will play an important role in forest operations in the future. Many machine functions already have the support of automation, and the implementation of remote control of the machine where an operator can operate a piece of equipment, typically in clear line-of sight, at least is commonly available. Teleoperation is where the operator works from a virtual environment with live video and audio feedback from the machine. Since teleoperation provides a similar operator experience to working in the machine, it is relatively easy for an operator to use teleoperation. Autonomous systems are defined by being able to perform certain functions without direct control of a human operator. This paper presents opportunities for remote control, teleoperated machines in forest operations and presents examples of existing developments and ideas from both forestry and other industries. It identified the extraction phase of harvesting as the most logical placement of autonomous machines in the near-term. The authors recognise that, as with all emerging technologies and sectors, there is ample scope for differences in opinions as to what will be commercially successful in the future.
volume: 42, issue:
Fires in forest machines are typically catastrophic in terms of machine destruction and can develop rapidly to be a risk to the machine operator. They are an issue worldwide and there can be larger consequences such as starting a major forest fire. This paper describes trends in machine fire occurrences in the New Zealand forest harvesting sector. A total of 224 machinery fire incidents were recorded over an 8 year period from 2007 to 2014. Trends in forest machinery fires in the sector were identified and summarized. Late morning (10 am-noon) and mid-afternoon (2–4 pm) showed the highest incidence of machine fire, corresponding to periods with the highest level of work. Excluding the main holiday months, there was a correlation of machine fires to average monthly temperature. Summary statistics on causes of fire ignition showed that 40% were attributed to electrical and hydraulic faults; however, some remain unidentified as the fires commenced after work was completed. A short survey of industry managers was carried out to ascertain machine fire perceptions. 67% agreed that machine fire was an issue, and only 33% thought the current industry procedures were sufficient to mitigate them. The report concludes with proactive measures to reduce the incidence of forest machine fire risk.