2018
2018 An operational UAV-based approach for stand-level assessment of soil disturbance after forest harvesting
Bruce Talbot, Johannes Rahlf, Rasmus Astrup
Scandinavian Journal of Forest Research 2018,
The effectiveness of generating virtual transects on unmanned aerial vehicle-derived orthomosaics was evaluated in estimating the extent of soil disturbance by severity class. Combinations of 4 transect lengths (5–50 m) and five sampling intensities (1–20 transects per ha) were used in assessing traffic intensity and the severity of soil disturbance on six post-harvest, cut-to-length (CTL) clearfell sites. In total, 15% of the 33 ha studied showed some trace of vehicle traffic. Of this, 63% of was categorized as light (no visible surface disturbance). Traffic intensity varied from 787 to 1256 m ha−1, with a weighted mean of 956 m ha−1, approximately twice the geometrical minimum achievable with CTL technology under perfect conditions. An overall weighted mean of 4.7% of the total site area was compromised by severe rutting. A high sampling intensity, increasing with decreasing incidence of soil disturbance, is required if mean estimation error is to be kept below 20%. The paper presents a methodology that can be generally applied in forest management or in similar land-use evaluations.
2018 Modifying the settings of CTL timber harvesting machines to reduce fuel consumption and CO2 emissions
Robert Prinz, Raffaele Spinelli, Natascia Magagnotti, Johanna Routa, Antti Asikainen
Journal of Cleaner Production 2018,
The objectives of this study were to examine the possibility of reducing the fuel consumption and CO2 emissions of harvesters during cut-to-length operations by applying various technical settings to the machine through the machine’s own software package. The adjustment of machine settings had an effect on the fuel consumption per unit product (l m−3) and can reduce the fuel consumption and CO2 emissions in cut-to-length harvesting operations. The main factor significantly affecting both fuel consumption and productivity was stem size. The study involved three cut-to-length machines operating in thinning with comparable stand environment and silvicultural prescriptions.
The novelty of this work is in exploring the fuel saving potential of simple adjustments of machine settings in cut-to-length harvesting machines. Such adjustments have an impact on fuel efficiency and may reduce fuel consumption and CO2 emissions in cut-to-length harvesting operations. This work may result in a reduction of energy consumption and environmental pollution, thereby contributing to cleaner production. This study bridges the gaps between research, development and implementation: it offers practical solutions that may affect manufacturers as well as practitioners and entrepreneurs in the field. The outcome of this study may result in innovative technology development with less impact on the environment.
Figure 1: The machines studied in the experiment, upper-left the Ponsse Beaver, upper-right the Ponsse ScorpionKing, below the Ponsse Ergo.
2017
2017 Applications for Remote and Proximal Sensing for Improved Precision in Forest Operations (Review)
Bruce Talbot, Marek Pierzchała, Rasmus Astrup
Croatian Journal of Forestry Engineering (CROJFE) 38(2017)2; 327-336
This paper provides an overview of recent developments in remote and proximal sensing technologies and their basic applicability to various aspects of forest operations. It categorises these applications according to the technologies used and considers their deployment platform in terms of their being space-, airborne or terrestrial. For each combination of technology and application, a brief review of the state-of-the-art has been described from the literature, ranging from the measurement of forests and single trees, the derivation of landscape scale terrain models down to micro-topographic soil disturbance modelling, through infrastructure planning, construction and maintenance, to forest accessibility with ground and cable based harvesting systems. The review then goes on to discuss how these technologies and applications contribute to reducing impacts on forest soils, cultural heritage sites and other areas of special value or interest, after which sensors and methods necessary in autonomous navigation and the use of computer vision on forest machines are discussed.
General characterisation of sensor deployment platform to spatial coverage and temporal resolution (adapted from Pierzchała 2017)
2017 Value Retention, Service Life, Use Intensity and Long-Term Productivity of Wood Chippers as Obtained from Contractor Records
Raffaele Spinelli, Lars Eliasson, Natascia Magagnotti
Forests 2017, 8(12), 503
Acknowledging the absence of up-to-date empirical data on the value retention, service life and annual use of chipping machinery, in 2017 the authors surveyed the records kept by 50 contractors offering biomass chipping services. The machine fleet and operations in this survey could be taken as representative for most of Europe, where the biomass sector is well established and is facing further expansion. Data collection included the whole chipping unit, comprised of chipper, carrier and loader. Manually-fed units were excluded from the survey. The data pointed at a service life up to and exceeding 10,000 h and 10 years, which relieved any concerns about poor durability. Value retention was good, and may exceed that of other mainstream forestry equipment. Engine power was the main explanatory variable in any models to predict purchase price and productivity. The effect of this variable could explain most of the variability (>80%) in the purchase price and productivity data. Results also pointed at the essential equivalence in price and productivity between PTO-driven (i.e., tractor powered) and independent-engine chippers, once differences in engine power are accounted for. However, the distribution of purchase price between different components of the chipping unit was different between the two unit types, with the chipper accounting for a larger proportion of the total investment in independent-engine units. Machine power was also different, with most PTO-driven units being significantly smaller than independent-engine units, due to the limitations of existing tractors. Furthermore, half of the carriers assigned to a PTO-driven unit were subject to flexible use, i.e., they were not solely used for chipping work.
2017 A Robust Productivity Model for Grapple Yarding in Fast-Growing Tree Plantations
Riaan Engelbrecht, Andrew McEwan, Raffaele Spinelli
Forests 2017, 8(10), 396
New techniques have recently appeared that can extend the advantages of grapple yarding to fast-growing plantations. The most promising technique consists of an excavator-base un-guyed yarder equipped with new radio-controlled grapple carriages, fed by another excavator stationed on the cut-over. This system is very productive, avoids in-stand traffic, and removes operators from positions of high risk. This paper presents the results of a long-term study conducted on 12 different teams equipped with the new technology, operating in the fast-growing black wattle (Acacia mangium Willd) plantations of Sarawak, Malaysia. Data were collected continuously for almost 8 months and represented 555 shifts, or over 55,000 cycles—each recorded individually. Production, utilization, and machine availability were estimated, respectively at: 63 m3 per productive machine hour (excluding all delays), 63% and 93%. Regression analysis of experimental data yielded a strong productivity forecast model that was highly significant, accounted for 50% of the total variability in the dataset and was validated with a non-significant error estimated at less than 1%. The figures reported in this study are especially robust, because they were obtained from a long-term study that covered multiple teams and accumulated an exceptionally large number of observations.
