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6. STUDY METHODOLOGY AND ANALYSIS OF DATA

Item

Conventional logging - Plot/01

(without tree location map)

Planned harvesting - Plot/02

(with tree location map)


Work time

8 h 22 min

6 h 55 min

Non-work time

54 min

1 h 06 min

Workplace time

9 h 16 min

8 h 01 min


Trees felled and bucked

39

43

Trees bucked only*

1

1

Total

40

44


Trees hung up during felling due to lianas

2

4 (2)

Trees rejected after the start of felling

3

1


Utilisable volume

85.44 m

101.90 m

Volume per tree

2.14 m

2.32 m

* Plot/01: Wind-blown tree

Plot/02: Tree knocked down by felling of neighbouring tree

Note: In this study, workplace time excludes meal time because of its high variability.

Table 7. Time study results for tree felling under conventional logging and planned harvesting.

Work elements (classification)

Conventional logging, Plot/01

(without tree location map)

Planned harvesting, Plot/02

(with tree location map)

 

[min]

%

[min]

%

           

Locating tree

(CW)

1.50

17.27

1.34

16.94

Preparing for felling

(CW)

1.07

12.30

1.33

16.76

Felling

(MW)

1.86

21.61

1.45

18.25

Bucking and delimbing

(MW)

1.84

21.22

1.76

22.28

           

Productive work time

(PW)

6.27

72.40

5.88

74.23

           

Searching for tree

(PL)

0.84

9.65

 

-

Evaluating tree

(OP)

0.05

0.60

0.08

0.97

Repairing equipment

(RT)

 

-

 

-

Maintaining equipment

(MT)

0.71

8.15

1.20

15.22

Refuelling chainsaw

(RF)

0.25

2.89

0.36

4.50

Clearing the site

(AW)

0.30

3.42

0.40

5.08

Cutting chainsaw free

(AW)

0.11

1.30

 

-

Other

(AW)

0.14

1.59

 

-

           

Supportive work time

(SW)

2.40

27.60

2.04

25.77

Time required to fell a single tree

8.67

100.00

7.92

100.00

The work element "searching for tree" refers to the time spent by the chainsaw operator searching for harvestable trees in the area. In accordance with the forest work study nomenclature (IUFRO 1995), this is considered supportive work since it does not directly contribute to the work progress on an individual work object and is to be distinguished from the work element "locating tree". The latter is part of the productive work time and of each individual cutting cycle where the operator moves to the next tree together with the chainsaw.

The productive time spent in felling a single tree on both plots is quite similar as expected due to similar stand conditions and the same felling crew involved. The major difference is that under conventional logging the chainsaw operator must spend an average of 0.84 minutes per tree searching for the next tree to be felled. When this non-productive time is included, the time required to fell a single tree then amounts to 7.11 minutes in conventional logging versus 5.88 minutes in planned harvesting.

A comparison of the time distribution of work elements that occurred in felling a single tree under the two logging systems reveals the following: