Extent and severity of damages caused to spruce roundwood by harvesting heads in standard versus debarking configurations

Labelle, Eric R.; Breinig, Lorenz; Spinelli, Raffaele

doi:10.1007/s10342-018-01161-3

Cited by 3 publications

(7 citation statements)

References 17 publications

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“…However, as reported by van der Merwe et al (2015), more severe damages on the log surface and loss of biomass can occur. When the number of passes is limited to three (as in our study), Labelle et al (2019) reported that the frequency and severity of penetrations into the wood caused by the feed rollers were actually deeper under standard configuration (8.7 mm) than with the debarking configuration (6.7 mm). The fact that two of the summer tests had to be performed within spruce bark beetle stands added important information about the performance of the setups within this field of application, but basic information on the performance of S2 and S3 modifications under undisturbed summer conditions is lacking.…”

Section: Study Design and Modificationssupporting

confidence: 47%

In-stand debarking with the use of modified harvesting heads: a potential solution for key challenges in European forestry

et al. 2019

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Modern forestry is increasingly confronted with challenges that appear with intensive forest management and the progression of the effects of climate change. The forestry sector is able to react to the changing conditions by adapting management plans, forest structure or planting tree species with a higher stress resistance. However, during stand management activities, silvicultural treatments and harvesting operations can have an impact on the further development of the remaining forest ecosystem. In Germany, the most widely used harvesting system for thinning operations is a single-grip harvester used for felling and processing trees followed by a forwarder for timber extraction from the machine operating trails to roadside. In this research project, debarking rollers and other modifications designed for Eucalyptus harvesting heads were tested on conventional harvesting heads for the first time to assess the possibility of adding debarking to mechanized forest operations under Central European conditions. Seven field tests with varying tree species, diameters and age classes, were established within German state forests in Lower Saxony and in Bavaria. These tests were repeated in both summer and winter seasons to evaluate the influence of associated tree sap flows on debarking quality. Three different harvesting heads were modified to assess the altered mechanical characteristics and setups. To assess debarking ability originating from head modifications, a photo-optical measurement system developed within the scope of the project was used. The results demonstrate that especially for summertime operations, simple modifications to currently used harvesting heads are able to provide an average debarking efficiency up to 90% depending on the modifications. Another key finding is that a negatively affected sap flow, experienced during wintertime operations, resulted in 46% lower debarking efficiency, while spruce bark beetle infestations only resulted in a wider spread of the variation. Additionally, the vertical position of the log within the tree proved to have an influence on debarking efficiency, resulting in 15% lower average debarking for butt logs and 9% for top logs as compared to middle logs. Since a debarking process requires the stem to be fed through the harvesting head on multiple occasions to remove bark, average harvesting productivity might be reduced by approx. 10% compared to productivity measured with conventional harvesting heads. Considering the results and the extent of the modifications, the system proved to be a potential addition to existing harvesting methods facing changing challenges in future forestry.

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Section: Study Design and Modificationssupporting

confidence: 47%

In-stand debarking with the use of modified harvesting heads: a potential solution for key challenges in European forestry

et al. 2019

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“…Damage to the stem surface was recorded in 50% of produced logs. Labelle et al [19] identified the damage as damage II, which was localized on 18-23% of stem area with a depth up to 18.9 mm. In our measurements, we recorded a damage depth in the order of centimeters.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the harvester head fell in the third category and its modifications are shown in Figure 2A-C. After the modification of the harvester head, the technology of stem processing is different to the standard procedure [18,19]. The cut tree is pulled through the harvester head for delimbing and the first debarking throughout its full length without crosscutting.…”

Section: Harvestersmentioning

confidence: 99%

“…A total length of the record was 120 min for each research plot. The obtained recording of the manufacturing process was then analyzed by the respective work operations: After the modification of the harvester head, the technology of stem processing is different to the standard procedure [18,19]. The cut tree is pulled through the harvester head for delimbing and the first debarking throughout its full length without cross-cutting.…”

Section: Time Studymentioning

confidence: 99%

“…The use of debarking heads has so far been limited only to eucalyptus plantations due to the problematic bark bond strength, which is extremely sensitive to moisture content [19]. Logs are best debarked right after felling and the consumption of energy is lower [20,21].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Efficiency of Harvester with the Debarking Head at Logging in Spruce Stands Affected by Bark Beetle Outbreak

Mergl

Zemánek

Šušnjar

et al. 2021

Forests

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This paper deals with the use of debarking modifications of the conventional harvester head in the conditions of felling due to bark beetle calamity. For this purpose, a time study was established, in which the conventional heads were compared with the heads with debarking modifications on four research plots and two harvesters. The measurements were taken from August to September 2018. Harvester efficiency with the use of the head with the debarking configuration ranged from 41.2% to 41.8% from the efficiency of a machine with the conventional head, depending on the felling type. It was also demonstrated that the quality of debarking does not depend on the trunk moisture content in the growing season. In terms of diameter, it was found that the best debarked parts of the stem were those occurring in its middle. Specifically, in the central part of the stem with a diameter of 13 to 23 cm, 91.0% of the stem area was debarked in the main felling and 76.6% in the thinning. In contrast, the top parts of the stem (trunk diameter up to 13 cm) were the least debarked. In the main felling, it was 74.2% of the stem area and in the thinning, only 52.2%.

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Moisture Content of Fresh Scots Pine Wood in Areas near Damage Caused by Harvester Head Feed Rollers

Tomczak

Latterini

Smarul³

et al. 2023

Forests

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By damaging bark, mechanized harvesting deprives wood of its natural mechanical barrier. This study concerns the effect of this damage on the changes in moisture content that occur near the damaged areas of Scots pine (Pinus sylvestris L.). This study was carried out using 45 randomly selected 11 m long logged pine stems. Additionally, the effect of bark thickness on the depth of damage was measured. To determine the influence of the location of the damage and bark thickness on the wood moisture near the damaged region, wood samples were collected from two sections. The first was located one meter above the log’s base, while the second was located one meter from the end of the log. Two increment cores were taken by a Pressler borer in each section: one from the damaged wood zone and the second from the undamaged wood zone. The average bark thickness one meter from the base of the log was 11.2 mm, which decreased to 1.8 mm in the samples taken one meter from the top of the log. The average depths of the damage caused by feed roller spikes in the two sections were 3.9 and 3.8 mm, respectively, indicating that there was no significant effect of bark thickness on the depth of the damage. The wood samples collected near the damaged wood zone (DW) had about 13 percent lower moisture content than those taken from the undamaged zone (UDW). This difference was statistically significant. We observed greater mean moisture content closer to the top of the log for both the samples taken near the damaged zone and the samples taken from the undamaged zone. One meter from the base of the log, the moisture content difference between the DW and UDW was 9.8 percentage points, which was statistically insignificant. By contrast, significantly lower moisture content (−16%) was observed in the DW one meter from the top of the log.

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Extent and severity of damages caused to spruce roundwood by harvesting heads in standard versus debarking configurations

Cited by 3 publications

References 17 publications

In-stand debarking with the use of modified harvesting heads: a potential solution for key challenges in European forestry

In-stand debarking with the use of modified harvesting heads: a potential solution for key challenges in European forestry

Efficiency of Harvester with the Debarking Head at Logging in Spruce Stands Affected by Bark Beetle Outbreak

Moisture Content of Fresh Scots Pine Wood in Areas near Damage Caused by Harvester Head Feed Rollers

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