Helicopter Logging Research Articles

Light-lift helicopter logging operations in the Italian Alps: a preliminary study based on GNSS and a video camera system

Terrain access is a critical factor influencing the feasibility of forest operations in steep mountainous terrain. Long extraction distances coupled with terrain obstacles can favor the use of helicopters in timber extraction in such areas. However, helicopter logging in the Italian Alps is not commonplace when compared to other Alpine regions, for example, in Switzerland and Austria. The use of light-lift helicopters has recently caught the attention of practitioners as an alternative to more traditional medium- to heavy-lift aircraft in the Alps. This article reports the findings of two preliminary case studies using light-lift helicopters for the extraction of high value timber and fire-damaged timber subsequently exposed to bark beetle disturbance. In order to provide a comprehensive analysis of the factors affecting helicopter logging productivity, the two case studies were separately analyzed using time-element analysis supported by on-board global navigation satellite system (GNSS) devices. Additionally, an external video camera was used to continuously monitor the operations. The payload utilization was 86% for the extraction of high value timber and 70% for fire-damaged timber subsequently exposed to bark beetle disturbance. Variation in the turn time was mostly related to the hooking, choker return, and load times, as well as flying distance. Above all, the load hooking time explains c. 27% of the variance, revealing its critical influence on logging productivity.

Long-term productivity of helicopter logging in Sarawak

Management of natural forests in the tropics generally involves some type of single-tree selection system that has only a few trees removed per hectare. To reduce the impact of harvesting on the residual stands, logging operations are increasingly moving to low-impact harvesting systems that work with single-tree selection. One low-impact harvesting system is the use of helicopters. However, helicopters are significantly more expensive than ground-based systems, and understanding the factors that influence productivity is critical to profitability of operations. This paper provides an analysis of logging productivity in the tropics using data from four different timber licenses operated by WTK in Sarawak over an 18-year period and using Sikorsky 61F, 64E, and 64F and Kamov KA-32 helicopters. The results show that productivity, measured as average volume produced per hour, is a function of the number of turns per hour, the number of productive hours in a day, the proportion of choker turns, and the type of helicopter. The relatively even hourly production through balancing log size and use of chokers also shows the effect of proper planning in helicopter harvesting.

Using Linear Mixed Effects in Helicopter Logging Data

Abstract This article applies a linear mixed-effects model (LME) to an unpublished helicopter logging productivity data set. The data were clustered in units, and the silviculture treatments varied between units, where units are cutblocks. When the covariance matrix was considered, it was found that the interunit variance was significant and the intraunit variance was heterogeneous. The significant interunit variance results in significant intraunit correlation, and this indicates the need to use LME to analyze these data. When turn time was considered, unit 4, which had the lowest level of group retention, had a conditional predicted value that was significantly less than the marginal predicted value. When turn weight was considered, unit 2, which had small patch cuts, had a conditional predicted value that was significantly less than the marginal predicted value, and unit 4 had a conditional predicted value that was significantly higher than the marginal predicted value. When productivity was considered, the conditional predicted value for unit 4 was significantly greater than the marginal predicted value, and unit 2 was significantly less than the marginal predicted value. In this data set it is interesting to note that productivity is independent of the number of logs in a turn and that turn weight was relatively insensitive to the available explanatory variables.

An Analysis of Utilizing Helicopter Logging in Turkish Forestry

An Analysis of Utilizing Helicopter Logging in Turkish Forestry

Helicopter Logging Productivity on Harvesting Operations in Southeast Alaska, Using Ecologically Based Silvicultural Prescriptions

Abstract This study examines production rates and costs for felling and helicopter yarding on eight units harvested in accordance with ecologically based silvicultural prescriptions in southeast Alaska. The prescriptions included harvesting to create gaps, harvesting to leave trees in clumps, individual tree selection, and combinations of these treatments. In combination, the treatments represented five levels of basal area (BA) retention. The levels of retention had irregular spatial arrangements caused by gaps and clumps that ranged from 0% retention (clearcut) to 75% of BA retained. Turn time (TT), as adjusted to a standardized distance, and turn weight were used as the basis for estimating productivity. There were statistically significant differences in adjusted TT, depending on the treatment. Areas with higher levels of removal tended to have lower adjusted TTs. With the exception of one unit with a short yarding distance, average turn weights increased as levels of retention decreased. Weighted average cost per thousand board feet (mbf) harvested was $322. The cost per mbf for cutting and yarding together ranged from $305 to $353.

Evaluating the Salvage Value of Fire-Killed Timber by Helicopter—Effects of Yarding Distance and Time Since Fire

Abstract Recently, large areas of federal lands in the western United States have been subject to wildfire. Concerns about hastening restoration, soil disturbance, and road building have prompted consideration of helicopter logging. Normal planning procedures on federal lands are not sensitive to the rapid decline in the recoverable economic value of fire-killed timber. The economic value of fire-killed timber is dependent on logging costs and time since tree death. A model is developed to calculate value of fire-killed timber as a function of time since death and yarding distance using helicopters as the preferred logging method. Applications of the method to tactical planning are discussed.

Alaska's model program for surveillance and prevention of occupational injury deaths.

The National Institute for Occupational Safety and Health (NIOSH) established its Alaska Field Station in Anchorage in 1991 after identifying Alaska as the highest-risk state for traumatic worker fatalities. Since then, the Field Station, working in collaboration with other agencies, organizations, and individuals, has established a program for occupational injury surveillance in Alaska and formed interagency working groups to address the risk factors leading to occupational death and injury in the state. Collaborative efforts have contributed to reducing crash rates and mortality in Alaska's rapidly expanding helicopter logging industry and have played an important supportive role in the substantial progress made in reducing the mortality rate in Alaska's commercial fishing industry (historically Alaska's and America's most dangerous industry). Alaska experienced a 46% overall decline in work-related acute traumatic injury deaths from 1991 to 1998, a 64% decline in commercial fishing deaths, and a very sharp decline in helicopter logging-related deaths. Extending this regional approach to other parts of the country and applying these strategies to the entire spectrum of occupational injury and disease hazards could have a broad effect on reducing occupational injuries.

IMPROVING AQUATIC HABITAT CONDITIONS OVER TIME WHILE PRODUCING WOOD PRODUCTS: AN EXAMINATION OF OPTIONS1

ABSTRACT: A land management activity scheduling model that can perform a multi‐period, simultaneous evaluation of aquatic habitat quality and commodity production goals was used to identify alternatives which would allow the improvement of aquatic habitat conditions over time, while producing wood products. The scheduling model has the ability to use stream sediment index levels, stream temperature index levels, and equivalent clearcut acres (ECA) levels as primary goals. A secondary goal imbedded in the model is the achievement of an even‐flow of timber harvest volume, and a tertiary goal is the achievement of maximum efficiency (maximum net present value). The scheduling model utilizes a heuristic programming technique (Tabu search) to guide the selection of timber harvests and road standards. A 14,643 acre case study watershed in eastern Oregon is used to illustrate several policy scenarios. Activities considered include: clearcutting and partial cutting; cable, skyline, ground‐based, and helicopter logging; road obliteration; requiring lower truck tire pressures on forest roads; and tree planting in riparian areas. The scheduling model produced land management plans which were spatially and temporally feasible over ten ten‐year time periods. Stream temperature was shown to be dramatically reduced if tree planting is performed in all riparian areas, regardless of whether harvesting activities occurred, and including meadows and forested areas where shade density is low. Timber harvest volume levels decreased 31 to 43 percent, and net present value levels decreased 36 to 46 percent, from an unconstrained case, when any of the following occurred: ECA was constrained to 15 percent, sediment index levels were required to decrease by 1 percent per decade, or temperature levels were constrained to “no harvest” levels. The use of a heuristic programming technique is a departure from traditional techniques that are commonly used in management plan development. Yet the heuristic technique allows the inclusion of complex management goals, many of which may be prohibited when using more traditional mathematical programming techniques. In addition, decision variables which require spatial information, requiring them to take on integer or non‐linear representations, can be accounted for without realizing the limitations of the traditional techniques.

Epidemiology and Prevention of Helicopter External Load Accidents

From 1980 through 1995, there were 230 helicopter external load accidents resulting in 57 fatalities and 74 serious nonfatal injuries in the United States investigated by the National Transportation Safety Board (NTSB). Helicopter external load operations, such as helicopter logging, place unique demands on the aircraft helicopters and the pilots who fly them. A descriptive analysis of NTSB “accident briefs” indicates that mechanical failure, pilot error, and maintenance errors were cited as the most common probable causes of the accidents. Recent experience in Alaska has shown that by adhering to existing regulations and manufacturer recommendations, and by implementing improved training and frequent maintenance, helicopter external load operations are safer with fewer accidents, crashes, and injuries. Published by the National Safety Council and Elsevier Science Ltd

Hydrologic and Erosional Responses of a Granitic Watershed to Helicopter Logging and Broadcast Burning

Abstract Forest land managers are concerned about the effects of logging and site preparation on erosion, site productivity, streamflow, and water quality. Effects of helicopter logging and prescribed burning on streamflow and sediment yields from headwater drainages in the Idaho Batholith were evaluated, using paired watersheds monitored from 1966 to 1986. In the fall of 1976, 23% of a 162 ha watershed was clearcut. All the cutting units were located on south-facing slopes. Helicopter logging was followed by broadcast burning on the cutting units. Streamflow parameters showed little change in response to the logging and burning. However, total annual sediment yields on the treated watershed increased an average of 97% in the 10 yr following logging, with the largest increases occurring in the years of highest sediment yields. Increased sediment yields did not appear to result from accelerated channel erosion; rather, about 94% was attributed to accelerated surface erosion on the cutting units, and 6% was contributed by a single mass erosion site. Accelerated erosion persisted on the cutting units throughout the study period. The accelerated surface erosion occurred primarily as a result of the prescribed burning (rather than the helicopter logging); surface erosion rates on the burned areas were about 66 times greater than those on undisturbed slopes. The accelerated rates of erosion and sedimentation have potentially serious implications for on-site productivity and downstream resources. For. Sci. 41(4):777-795.

Soil Temperature and Organic Matter in a Disturbed Forested Wetland

AbstractSoil temperature and organic‐matter content are useful indices of ecosystem recovery after disturbance. This study was designed to evaluate soil temperature and organic‐matter changes associated with different levels of disturbance within a forest wetland. Soil temperatures and organic‐matter contents were monitored in a palustrine water tupelo (Nyssa aquatica L.)‐baldcypress (Taxodium distichum [L.] Rich. var. disticum) wetland forest in southwestern Alabama for two growing seasons following timber‐harvest‐related disturbances. Three forms or levels of disturbance were applied: helicopter logging, rubber‐tired skidder logging, and helicopter logging followed by herbicide application. An adjacent undisturbed stand served as a reference area. Analyses of post harvest data revealed that during the 2‐yr postharvest period, soil temperatures in the reference area were coolest, helicopter and skidded areas were warmer, and herbicide plots had the warmest soil temperatures. Soil organic matter followed the same trend. Both parameters were related to vegetative cover and indicated recovery following timber harvest.

REMOVAL OF FLOODWATER SEDIMENTS BY A CLEARCUT TUPELO‐CYPRESS WETLAND1

ABSTRACT: A palustrine water tupelo (Nyssa aquatica L.)‐baldcy‐press (Taxodium distichum (L.) Rich.) swamp in southwestern Alabama was subjected to three types of disturbance, including helicopter logging, rubber‐tired skidder logging simulation, and helicopter logging followed by an herbicide application. An adjacent undisturbed stand served as a control area. Post‐harvest collection of sedimentation data revealed that the herbaceous and woody vegetation regrowth within the helicopter and skidded clearcut areas trapped more sediments than did the control or herbicide treatment areas. Clearcutting, followed by plant regrowth, improved the wet‐land's capacity to remove sediments from overbank flow flood waters.

Helicopter Logging of Valuable Furniture Timber from Natural Rain Forest in the Southern Cape

SYNOPSIS The use of helicopters to extract valuable furniture timber from ecologically sensitive or inaccessible parts of the natural rain forests managed by way of a single-tree selection sylvicultural system was attempted for the first time during 1983 and has been used as an economically feasible method from 1985 to 1988. In this system, single logs are successfully lifted by helicopter through gaps in the forest canopy as narrow as about 5 m.

Helicopter Logging of Baldcypress in Southern Swamps

Abstract A Boeing Vertol-107 II helicopter with support men and equipment, yarding large baldcypress (Taxodium distichum (L.) Rich.) from a southern swamp, hourly produced 2,773 ft3 of wood at a cost of $2,087. The average payload was 120 ft3 or 7,747 lb, 70% of the machine payload capacity, with an average cycle time of 2.57 min. The cycle elemental times were poorly correlated with yarding distance, payload weight, stems flown, and density altitude. Positioning, descent, hooking, and ascending with the logs accounted for most of the variation and length of the average cycle time. A predictive equation of per cycle cubic foot volume as a function of payload weight and the number of stems flown was developed. South J. Appl. For. 10:92-95, May 1986.

Simulating Changes to Helicopter Logging Operations

Simulating Changes to Helicopter Logging Operations

Helicopter Logging Moves East — Trial Results

ABSTRACT ENCOURAGED by results of helicopter logging tests in other parts of the country, loggers in the East have been lending a keener eye toward heli-copter logging by performing their own trials. There have been few such logging operations in the eastern United States, but a recent test in the Allegheny National Forest was efficient. There were few delays during the cycles we observed. The average daily production rate for the yarding operation was 205.90 m3; at an average daily cost to the lumber company of $4,327.20.

Prebunching to Reduce Helicopter Logging Costs

Abstract This paper describes one effort to quantify rates and costs of helicopter production for thinning young-growth Douglas-fir (Pseudotsuga menziesii) in Oregon. The logs in a small sale (21 acres) were skidded to landings within the sale area by horses (prebunching), and then flown about 2,400 feet across a steep canyon by helicopter. The helicopter moved about 5,050 board feet per flight-hour and 3,320 board feet per total work-hour. Total logging costs were about $265 per MBF. Had the sale been yarded conventionally, total cost might have been as high as $440 per MBF.

Advanced Logging System-I: Helicopter Logging: Advantages and Disadvantages must be Weighed

Advanced Logging System-I: Helicopter Logging: Advantages and Disadvantages must be Weighed