Methodology for Assessing and Managing the Environmental Performance of Skidding and Feller Buncher Tractors

Round 1

Reviewer 1 Report

72-77. In my opinion, this problem is well recognized. I suggest including some articles in the literature review and discussion:

Kormanek, M., Banach, J., Sowa, P., 2015. Effect of soil bulk density on forest tree seedlings. Int. Agrophys. 29: 67-74.

Kormanek, M., Głąb, T., Banach, J., Szewczyk, G., 2015. Effects of soil bulk density on sessile oak Quercus petraea Liebl. seedlings. Eur. J.

Forest. Res. 134: 969-979.

Kulak, D., Stańczykiewicz, A., Szewczyk, G., 2019: Disturbance to outer soil layers depending on the season of timber harvesting. Baltic Forestry. 25 (2): 289-295.

Kulak, D., Sowa, J.M., Szewczyk, G., Stańczykiewicz, A., 2020. The accessibility of post-fire areas for mechanized thinning operations. Forests, 11, 471; doi: 10.3390 / f11040471.

Kormanek, M., Dvořák, J., 2021. Ground Pressure Changes Caused by MHT 8002HV Crawler Harvester Chassis. Croat. j. for. eng. 42 (2): 201-211

32, 34. I am not sure that the terms "environmental efficiency" and "ecological efficiency" are the most appropriate. “Efficiency” relates rather to labor productivity, which has not been studied.

34. I suggest removing the term "skidding tractors" - it is used in the title of the work.

44-45. I think this sentence needs to be corrected. I would delete the word "deforestation" and comment on "improper timber harvesting ..."

78. Error - need to remove "l".

78-82. In my opinion, this provision should be corrected. The main purpose of the study was to determine the impact of machines on forest soil. Only one factor influencing soil compaction was also assessed - the machine's running gear.

85-129. This large fragment of the work is not closely related to the research carried out. I suggest shortening it and placing it in chapter 1.

159-162. It is necessary to provide the exact location of works, number and size of research plots. Did you measure soil moisture, soil compaction? What instruments did you use? Did the machines move along the operational routes with branches after delimbing? Were the wood storage sites located directly next to the logging routes? How was the timber stored (spacing, size of the timber bundles, etc.)?

173-174. The variants compared are probably inconsistent. In the "logging with feller buncher and tractors with pincer grab" variant, soil compaction is related to the passage of felling and logging machines. In the "Felling with gasoline powered saws, skidding with choker skidding tractor" variant, soil compaction is only associated with logging. What do the terms "freshly cut" and "wet" mean? There is no "wet" variant in the second technological variant. How was the density of skidding trails determined?

242-251. Are the references to agriculture correct?

271-272. Not all data presented in Table 5 were discussed in the study. This should be clearly stated in the text.

Author Response

1. 72-77. In my opinion, this problem is well recognized. I suggest including some articles in the literature review and discussion

The following was added: The impact of dry soil compaction on the growth of beech and pine seedlings was studied [17]. It was established that increased soil density adversely affects the development of the root system, particularly for small-diameter roots [18]. Another study was carried out on soil compaction in the cold season. Thus, compaction in winter was reported to be mostly surface, affecting roots much less than in summer [19]. It has been demonstrated that there is no significant difference between the compaction of arable land resulting from logging in post-wildfire and control areas [20]. Studying the effect of tracked skidders allows stating that the soil compaction degree depends on the weight of the log transported and the extension length of the crane [21]. 

2. 32, 34. I am not sure that the terms "environmental efficiency" and "ecological efficiency" are the most appropriate. "Efficiency" relates rather to labor productivity, which has not been studied.

The wording was replaced with environmental effect, ecological effect

3. I suggest removing the term "skidding tractors" - it is used in the title of the work.

The term was removed, as suggested

4. 44-45. I think this sentence needs to be corrected. I would delete the word "deforestation" and comment on "improper timber harvesting ..."

The term was replaced with "extraction of timber."

5. Error - need to remove "l".

The error was corrected

6. 78-82. In my opinion, this provision should be corrected. The main purpose of the study was to determine the impact of machines on forest soil. Only one factor influencing soil compaction was also assessed - the machine's running gear.

The corresponding correction was made: c) analyzing tractor landing gear and other impacts on the soil that reduce damage to natural regeneration and remaining stands in logging operations.

7. 85-129. This large fragment of the work is not closely related to the research carried out. I suggest shortening it and placing it in chapter 1.

Corresponding changes were made: The operation of forestry machinery, including skidding tractors, can be represented as a process consisting of individual technological operations. The operation of the winning machinery in general and the carrying out operations related to technological winning should be considered based on a systematic approach [17]. A systematic approach to examining the operating efficiency of the skidding tractor was applied in [18].

Thus, an inclusive approach was used to study the forest/technological process/machine-tractor unit/finished product system [19]. It comprises subsystems with objects, properties, connections, and functions performed by the forest machine. Each subject of this system is regarded as an independent low-level system or subsystem. Every object is a set of interrelated elements, each directly or indirectly linked to other components.

Potential properties, including numerous parameters and characteristics of specific units and whole machines, which determine service properties and reliability of the skidding tractor, are grouped and presented in the flowchart below. The system of indicators and factors specifying the operating conditions of the skidding tractor is illustrated in Figure 1, and its service properties and operational effectiveness are presented in Figure 2 [20].

Figure 1. Indicators characterizing the system's service properties and operational effectiveness.

The operating scheme of the skidding tractor developed during the study of its operational efficiency [21] was complemented by the factors affecting environmental efficiency. With the methodology adopted in the study of mobile systems and an inclusive approach, the operation of a skidding tractor can be depicted as a system object.

Figure 2. Features characterizing the operating conditions of skidding tractors.

8. а) 159-162. It is necessary to provide the exact location of works, number and size of research plots.

The moisture content of the soil was not precisely measured.

The following was added: Tests were performed on 1-hectare plots in the territory of the Yakutsk forestry.

1. b) Did you measure soil moisture, soil compaction? What instruments did you use?

The following was added: Soil density was measured with an SC 900 penetrometer (Spectrum Technologies, USA)

1. c) Did the machines move along the operational routes with branches after delimbing?

We added: The tractors moved along the standard logging routes in this area.

1. d) Were the wood storage sites located directly next to the logging routes? How was the timber stored (spacing, size of the timber bundles, etc.)?

The wood conservation sites were in strictly defined locations - apart from the sites, the maximum distance was 1.26 km. This remark may be a topic of new work and requires further consideration.

9. a) 173-174. The variants compared are probably inconsistent. In the "logging with feller buncher and tractors with pincer grab" variant, soil compaction is related to the passage of felling and logging machines. In the "Felling with gasoline-powered saws, skidding with choker skidding tractor" variant, soil compaction is only associated with logging.

In both cases, soil compaction was caused by timber transportation. For "logging with feller buncher and tractors with pincer grab," – compaction is due to the action of tractor wheels. And "Felling with gasoline-powered saws, skidding with choker skidding tractor" means that compaction occurs through skidding the wood on the ground.

1. b) What do the terms "freshly cut" and "wet" mean?

The term "freshly cut" refers to newly felled timber that was transported immediately after felling. The term "wet" means that the logging had been done earlier.

1. c) There is no "wet" variant in the second technological variant.

After manual logging, the trees were immediately loaded onto the tractor.

How was the density of skidding trails determined?

Soil density was measured with an SC 900 penetrometer (Spectrum Technologies, USA)

10. 242-251. Are the references to agriculture correct?

We believe that references to agriculture are correct because soil density methods for forests and fields are not significantly different.

11. 271-272. Not all data presented in Table 5 were discussed in the study. This should be clearly stated in the text.

The table was removed. The text was changed and moved to the conclusions: In order to improve this work, the factors for optimizing the logging system, valuation indicators, and the transport routes of tractors must be studied in more detail.

Author Response File: Author Response.docx

Reviewer 2 Report

A revision of the article is provided in the Annex.

Comments for author File: Comments.docx

Author Response

1. Line 135, 140 and 145, adjust the equation as instructed by the editor.
Corresponding changes were introduced.
2. Line 149,150, What are these Tractors? The technical parameters that affect the passage and thus the measurement are not clear. It would be appropriate to specify at least the basic technical parameters of the machines.
The following was added:
Table 1: Technical specifications and dimensions of skidding tractors

Reviewer 3 Report

The manuscript is aimed to actual and interesting topic related to environmental performance of skidding tractors. The paper requires a major revision and corrections to improve the overall readability. I have following questions and suggestions for the authors:

L2 - I suggest the authors to change the title to something more precise - the environmental performance of skidding tractors can be also measured thru the energy return on investment (EROI), greenhouse gases (GHG) emissions, particulate matter (PM) emission, non-renewable (NR) energy consumption etc. In the title there is a skidding tractor phrase, and in the result part there is a data regarding feller buncher?!

L 27 - different units for tire pressure!? Taken from results chapter “the weight of the wheels is approximately 46.5 kN. Therefore, the pressure of a ground grip on the solid support surface 196 shall be 196 kPa.” Please correct the sentence construction from the abstract!

L34 – keyword “operation of forestry machinery” is unnecessary, maybe it is better to put e.g. “soil impact”!

In introduction chapter, did I miss disposition paragraph?

L45 – is the used word “deforestation” the most appropriate choice in a sentence; L86 – is “winning machinery” the most appropriate choice in a sentence; L173 - in the table 3 is “Freshly-cut and wet” the most appropriate choice; L 257 – is ”slaughter of winter” the most appropriate choice in a sentence - throughout the paper it is necessary to correct terms related to professional terminology!

L88-89 - the sentence is not complete!

L120 - the text related to the title of Figure 4 is redundant!

I miss a paragraph about the analysis procedure/method you are using for data processing!

In the chapter Materials and Methods, through the table, it is necessary to state the basic specifications of the machines used in the research! Please include the above in the paper!

What is needed to present the knowledge gap addressed, and make sure you have a purpose that is precise! Does it make sense to compare indicators related to soil changes in different machines used for different work processes, and which have different undercarriage (wheels or tracks)?! Please clarify!

In the chapter Materials and Methods, it would be useful for readers to visually display the polygon area and the manner in which the experiment was conducted! Please include the same in the paper!

A lot of citations of the results of previous research (L192, L216, L218) are included in the results chapter! The sources cited should be included in the discussion section! Please rewrite the discussion!

I think that the authors missed some important papers that have recently been published e.g. in Croatian Journal of Forest Engineering!

L283 – 284: which confirms the claim in question in the chapter conclusions?

I would like to see more precise conclusions, evidently matching your purpose.

Where are your limitations? Where are the suggestions for further studies?

Author Response

1. L2 - I suggest the authors to change the title to something more precise - the environmental performance of skidding tractors can be also measured thru the energy return on investment (EROI), greenhouse gases (GHG) emissions, particulate matter (PM) emission, non-renewable (NR) energy consumption etc. In the title there is a skidding tractor phrase, and in the result part there is a data regarding feller buncher?!
The following changes were introduced: Methodology for assessing and managing the environmental performance of skidding and feller buncher tractors
2. L 27 - different units for tire pressure!? Taken from results chapter "the weight of the wheels is approximately 46.5 kN. Therefore, the pressure of a ground
grip on the solid support surface 196 shall be 196 kPa." Please correct the sentence construction from the abstract!
The data was changed to: 46.5 kN – 45 kPa
3. L34 – keyword "operation of forestry machinery" is unnecessary, maybe it is better to put e.g. "soil impact"!
The wording was changed to "soil impact".
4. In introduction chapter, did I miss disposition paragraph?
The text was added: the following section describes the methodology of the experiments. Section 3 presents the results of this work. In Section 4, the data obtained are discussed, adding relevant literature sources and providing examples of applying results obtained for subsequent research works. In the final section, we present the final findings of the study.
5. L45 – is the used word "deforestation" the most appropriate choice in a sentence; L86 – is "winning machinery" the most appropriate choice in a sentence; L173 - in the table 3 is "Freshly-cut and wet" the most appropriate choice; L 257 – is" slaughter of winter" the most appropriate choice in a sentence - throughout the paper it is necessary to correct terms related to professional terminology!
Corresponding changes were made.
6. L88-89 - the sentence is not complete!
The sentence was completed: A systematic approach to examining the operating efficiency of the skidding tractor was applied in the paper [23].
7. L120 - the text related to the title of Figure 4 is redundant!
The redundant text is removed, as requested
8. I miss a paragraph about the analysis procedure/method you are using for data processing!
The following text was added: All measurements were performed three times to statistically process the data (calculate variance).
9. In the chapter Materials and Methods, through the table, it is necessary to state the basic specifications of the machines used in the research! Please include the above in the paper!
We added: Table 1: Technical specifications and dimensions of skidding tractors

10.What is needed to present the knowledge gap addressed, and make sure you have a purpose that is precise! Does it make sense to compare indicators related to soil changes in different machines used for different work processes, and which have different undercarriage (wheels or tracks)?! Please clarify!
Our objective was to estimate if soil compaction depended on the type of logging operations, including the tractors used, which is provided in the conclusions: Evaluation of the skidding tractor's efficiency showed that using machines with pressure not more than 70 kPa for tracked and 150 kPa for wheeled vehicles at average load during forest thinning is preferable. It has been established that when the 33L-32 tire of a wheeled skidder interacts with the soil with the ground grips fully immersed, the pressure exerted on the soil is lower than recommended for logging and thinning techniques.
11.A lot of citations of the results of previous research (L192, L216, L218) are included in the results chapter! The sources cited should be included in the discussion section! Please rewrite the discussion!
Corresponding changes were made.
12.I think that the authors missed some important papers that have recently been published e.g., in Croatian Journal of Forest Engineering!
The following was added: Studying the effect of tracked skidders allows stating that the soil compaction degree depends on the weight of the log transported and the extension length of the crane
Kormanek, M., Dvořák, J., 2021. Ground Pressure Changes Caused by MHT 8002HV Crawler Harvester Chassis. Croat. j. for. eng. 42 (2): 201-211
13.I would like to see more precise conclusions, evidently matching your purpose.

The following was added: The higher number of passes by skidding tractors leads to greater soil compaction (by 25% for loam and 2% for sandy soils). Additionally, the maximum load of operating equipment increases tire pressure by more than four times, which is more damaging to the ground.
14.Where are your limitations? Where are the suggestions for further studies?
In order to improve the quality of this work, the factors for optimizing the logging system, valuation indicators, and the transport routes of machinery must be studied in more detail.

Round 2

Reviewer 1 Report

I believe that the work is suitable for printing in its current form

Author Response

Thank you for your positive feedback!

Reviewer 3 Report

Include mass (kg) for tractor models in table 1!

Author Response

Mass for tractor models was added to table 1.