The Concept of the Ergonomic Spectrum

doi:10.4236/ojf.2013.31002

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Open Journal of Forestry

2013. Vol.3, No.1, 8-11

Published Online January 2013 in SciRes (http://www.scirp.org/journal/ojf) http://dx.doi.org/10.4236/ojf.2013.31002

The Concept of the Ergonomic Spectrum

Yozo Yama da 1, Efi Yuliati Yovi2, Dianne Staal Wästerlund3, John J. Garland4, Janusz M. Sowa5

1Graduate School of Bio-Agricult ural Sciences, Nagoya University, Nagoya, Japan

2Faculty of Forestry, Bogor Agricultural University, Bogor, Indonesia

3Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden

4Garland & Associates, Waldport, USA

5Department of Forest and Wood Utilization, University of Agriculture in Krakow, Krakow, Poland

Email: [email protected]

Received November 14th, 2012; revised December 17th, 2012; accepted December 27th, 2012

Forestry conditions differ among regions and nations. Moreover, labor costs, forestry mechanization, and

environmental impacts are also different. These factors directly or indirectly influence the ergonomic state

of nations. The ergonomic state of a nation can be described in terms of ergonomic factors such as labor

productivity, work accidents, physiological burden, and stress. Labor productivity and work accidents can

be defined as income or condition factors, and physiological burden and stress as outcome or result fac-

tors. Thus, the value of outcome factors must be examined in relationship to income factors. On the ergo-

nomic spectrum, each factor can be conceived as a continuum from a negative to a positive ergonomic

status. All factors can be set in a line, and the present state of each nation is indicated by a profile formed

by the assembled factors. The locations of nations along the two-dimensional coordinates of the world

standard can be realized by an ergonomic spectrum. Moreover, future directions for improvement can be

obtained by reference to the three-dimensional coordinates, which include the axis of time.

Keywords: Ergonomic Spectrum; Economic Situation; Forestry Condition; Working Condition; Work

Accident

Introduction

Globally, forest engineering has been shifting from manual

to mechanized work. Consequently, ergonomic issues have

changed from physical or physiological burdens of forestry

workers to psycho-physiological stressors of machine operators.

However, many developing countries continue to rely on man-

ual work for most of their forestry operations. Manual work is a

classic ergonomic issue, and it remains significant in develop-

ing countries. Moreover, some countries, such as Japan, are

located midway between manual and mechanized forestry.

Forestry mechanization has spread in Japan except in the area

of felling operations due to the steep and complicated terrain.

This situation cannot be improved unless an innovative tech-

nique is developed to overcome the adverse natural conditions.

Manual felling operations with a chainsaw have been recog-

nized globally as one of the most dangerous jobs in forestry,

and many studies have been conducted from a safety perspec-

tive. For example, Hammond studied critical safety behaviors

of differently skilled workers using a helmet camera in the USA

(Hammond et al., 2011). Bentley noted the potential for injury

among inexperienced fellers in New Zealand and claimed that

felling safety is dependent upon an appropriate assessment of

hazards and good judgment with respect to decisions regarding

felling (Bentley et al., 2005). Felling operations in Japan have

been the most dangerous forestry work during this half century

(Oka et al., 2011), and many severe accidents have occurred

during manual felling operations in Sweden among private for-

est owners (Lindroos & Burstrom, 2010).

Wearing protective devices to reduce work accidents during

manual felling operations is one of the most effective direct

safety countermeasures. Kashima claimed that wearing protec-

tive trousers while operating a chainsaw results in a 60% de-

creases in lower body injuries (Kashima & Uemura, 2008).

However, many of the protective devices have been developed

in cool and dry climate countries and are not suitable for use in

tropical or wet temperate regions. Workers in those regions hate

to wear protective devices, even helmets and gloves, because

they are uncomfortable. Wästerlund researched heat stress in

forestry and argued for a standard research method to determine

protective clothing comfort (Wästerlund, 1998). Holland evalu-

ated the ventilation capacity of various helmets for forest har-

vesting (Holland et al., 2002).

Ergonomic issues vary in every nation, as each has different

forestry conditions. Although Feyer compared fatal occupa-

tional injuries among US, Australian, and New Zealand work-

ers (Feyer et al., 2001), very few cooperative studies have in-

volved multiple nations. Thus, it is difficult to describe the pre-

sent ergonomic state of each nation using a simple world stan-

dard.

This report offers the ergonomic spectrum as a new idea to

objectively identify current forestry ergonomic conditions in

each nation and to identify the actual and more preferred future

direction to improve each nation’s ergonomic conditions. At

first, we introduce the concept of ergonomic spectrum, and then

explain how to select indices for using the ergonomic spectrum,

and finally show two experimental examples.

Concept of Ergonomic Spectrum

Everyone wants to eliminate forestry accidents. If this occurs

thorough forestry mechanization, forestry work accidents will

decrease dramatically, including in felling operations. Unfortu-

nately, it is quite difficult to realize this scenario because of the

Y. YAMADA ET AL.

forestry conditions in each nation. Work accidents are influ-

enced significantly by forestry conditions, which are influenced

by national and regional indigenous characteristics such as geo-

graphy, topography, climate, vegetation, population, wood de-

mand, wood trade, and economic and social conditions. More-

over, labor costs, forestry mechanization, labor productivity,

and environmental impacts also differ among nations. Thus,

working conditions directly or indirectly influence the ergono-

mic state of each nation.

The ergonomic state of a nation can be estimated through

ergonomic factors such as work accidents, physiological burden,

and stress. These factors indicate the current ergonomic situa-

tion based on forestry activities in each nation, and improve-

ment in these factors would result in safer conditions, lighter

work and stress loads, and more comfortable working condi-

tions. If forestry and working conditions are defined as income

or conditions, then ergonomic factors can be defined as out-

come or results. The value of outcome factors must be exam-

ined relation to the income factors.

However, it is unrealistic to comparatively evaluate factors

that differ in substances, units, and scales. Thus, the spectrum

concept is used to allow a clear comparison among different

ergonomic situations in the world.

With respect to a spectrum, the emotional spectrum and the

recreational opportunity spectrum are well known to include

some vectors. The emotional spectrum (ES) can evaluate an

emotional state of human from the electroencephalogram, and

is composed of four element emotion vectors; anger, sadness,

joy, and relaxation. The recreation opportunity spectrum (ROS)

is an applied example. The ROS is a combination of physical,

biological, social, and managerial conditions that give recrea-

tional value to a place (Clark & Stankey, 1979).

The basic concept of the ergonomic spectrum is similar to

that of the ES and the ROS. Whereas the ROS separate s nations

into seven classes from the least to the most remote (British

Columbia Resources Inventory Committee, 1998), the ergo-

nomic spectrum is more complicated and not as easily divided

into patterns.

As shown in Figure 1, each factor is represented along a

continuum from a negative to a positive ergonomic state, with a

negative state shown in orange, and a positive one in green. All

factors are set in a line, and the present state of each nation is

indicated by a cross-section of the assembled factors. It appears

like a spectrum; thus, it is easy to recognize where a nation is

located compared to the world standard using the two-dimen-

sional coordinates. Moreover, the directions needed for impro-

vement can be shown in a three-dimensional coordinates that

include the axis of time.

Ergonom ic Spectrum

Fo r est ry C o n d itio n s

Wo r kin g C o n d itio n s

Work Accidents

P hy siological Burden

Str e ss

Influences

Econ om ical Situation

Income

Outcome

Figure 1.

Concept of the ergonomic spectrum .

Selection of Ergonomic Spectrum Indices

Indices for the ergonomic spectrum were defined as the eco-

nomic situation, forestry conditions, working conditions, and

work accidents. The first three factors are income factors, and

the last is an outcome factor. Physiological burden and stress

could not be included because these types of data are difficult

to gather from official reports. Although researchers sometimes

report these data, the studies are often case studies and usually

do not represent average burdens of all workers in a country.

Furthermore, other factors are applicable to the ergonomic

spectrum, but data on these could not be obtained for every

country; thus, they were eliminated from this study.

Economical Situation

National economic and social situations have great impact on

forestry as an industry. The economic situation of a nation can

be described by many factors such as nominal or real gross

domestic product (GDP), nominal or real gross domestic index,

the domestic population, consumer price index, and Engel’s co-

efficient. In this study, the nominal GDP per person, as an in-

dex of the national economic situation, and Engel’s Coeffi-

cient, as an index of rich and poor, were selected for use in the

ergonomic spectrum.

Forestry Conditions

Forestry conditions are characterized by climate zone, aver-

age slope gradient, forest coverage rate, artificial forest rate,

planted species, wood demand, wood self-support ratio, forest

road density, and forestry mechanization rate. Data on some of

these factors are difficult to obtain because no description is

available in official reports. In this study, the forest coverage

rate, as an index of potential wood resources, and the self-sup-

port ratio of timber, as an index of logging activities, were se-

lected.

Working Conditions

Working conditions can have a crucial impact on work acci-

dents, physiological burden, stress, and decision making during

forestry work. Working conditions include wage, number of

forestry workers, the age index, management area, and labor

productivity. In this study, the average wage, average manage-

ment area, and average productivity were selected as represent-

tative factors. The average management area per person was

calculated by dividing the forest area by the number of forestry

workers. Although the actual number of workers cannot be

compared against figures for other countries, management area

can be estimated by the number of workers. The average pro-

ductivity per year per person, which is calculated by dividing

felling volume by the number of forestry workers, also indi-

cates the degree of mechanization.

Work Accidents

Work accidents are external factors or objective variables

explained by the economic situation, forestry circumstances,

and working conditions. In this study, the work accident rate

and the fatal accident rate were selected as factors. These are

expressed as the rate of workers injured or killed per 1 million

felled trees. An effort must be made to decrease these objective

factors through every possible means. Unfortunately, Indonesia

Y. YAMADA ET AL.

has not surveyed the number of workers injured and killed in

their forestry operations.

Experimental Examples

Data of nine factors for the ergonomic spectrum were ob-

tained from official reports from five countries, Sweden, USA,

Poland, Indonesia, and Japan, to compare the ergonomic situa-

tions among them. Moreover, data were gathered at five differ-

ent times in Japan, namely 1970, 1980, 1990, 2000, and 2010,

to observe changes in the ergonomic situation.

Comparison of Ergonomic Spectra among the

Five Nation s

Figure 2 shows a comparison of the ergonomic situations

among the five countries. The right-hand side of the graph is

the desirable situation. Sweden’s profile shows values mostly

well to the right side, with little variation, whereas values for

the other countries range from values toward the left-hand side

to values approaching the right-hand side. The five countries

show quite different profiles. The USA maintains a positive

status in terms of economic situation, number of work accidents,

and management area but earns low or moderate scores for

forest coverage rate, the self-support ratio, wages, and produc-

tivity. Poland maintains low or medium status for the economic

situation, forestry conditions, and working conditions but scores

high for work accidents. Indonesia maintains low scores for

their economic situation and working conditions but gets the

highest marks for self-support ratio. Japan fluctuates wildly

among factors. Japan gets high marks for nominal GDP, forest

coverage rate, and wages. However, the high wages are due to

appreciation of the yen against the US dollar. In contrast, Japan

gets low scores for the self-support ratio, management area, and

productivity, which are significant problems in the Japanese

forestry industry. Moreover, the work and fatal accident rates

are worse than those in the other countries.

The forest coverage rate is fixed in each country, and the

nominal GDP and Engel’s coefficient cannot be improved by

the forestry sector. The self-support ratio and wage could be

changed if forestry realizes a revitalization. Management area

and productivity can be improved by multi-functional mecha-

nization, but it is not easy to promote multi-functional ma-

chines in Japan and Indonesia. Without high mechanization, the

accident rates can be reduced only by wearing protective de-

0%10% 20% 30% 40% 50% 60% 70% 80% 90%100%

Fatal Accident Rate

Work Accident Rate

Productivity

Management Area

Wage

Self-Support Ratio

Forest Coverage Rate

Engel's Coeffcient

Nominal GDP

JAPAN INDONESIA POLAND

USA SWEDEN

Figure 2.

Comparison of the ergonomic spectra among the five nations.

vices and safety training for forestry workers.

Changes in the Japanese Ergonomic Spectrum

Figure 3 shows the changes in the Japanese ergonomic spec-

trum over four decades. In 1970, values for all factors except

forest coverage rate were low. In 1980, nominal GDP, Engel’s

coefficient, and wage increased gradually. Notably, the fatal

accident rate decreased largely, but the work accident rate was

the worst. In 1990, the former three factors continued to in-

crease gradually, and the work accident rate improved dramati-

cally. Since 2000, the former three factors have continued to

increase, and the work accident rate has improved slightly. The

fatal accident rate has not changed since 1980.

Although wages increased dramatically due to the high yen,

the actual wage was not so high and has actually decreased

since 2000. The nominal GDP and Engel’s coefficient have

increased steadily, and productivity and management area have

increased slightly. Improving those factors in Japan will not

occur smoothly because of the difficulties of multi-functional

mechanization.

The work accident rate improved largely from 1980 to 1990.

However, improvement has slowed in the past two decades.

Moreover, the fatal accident rate has become slightly worse

since 2000. Manual felling remains common in Japanese for-

estry. The reduction in work injuries and fatal accidents is the

most significant and urgent issue. In the future, Japan should

struggle to improve work conditions, fatal accident rates, pro-

ductivity, and the self-support ratio.

Conclusion

We can appreciate the ergonomic situation of Japan in rela-

tion the world using the ergonomic spectrum. Moreover, we

can identify the direction for improvement in our forestry er-

gonomic situation based on the changes in the ergonomic situa-

tion through the past several decades. In other words, we can

understand easily where we are now and which directions we

should improve.

However, the following problems must be solved for the er-

gonomic spectrum to become a useful tool. The first problem is

factor selection. Which factors should we choose for the ergo-

nomic spectrum? We must discuss whether the factors are suf-

ficient to show the actual ergonomic situation. Moreover, we

must examine whether a factor can be corrected even if it is

0%10% 20% 30% 40% 50% 60% 70% 80% 90%100%

Fatal Accident Rate

Work Accident Rate

Productivity

Management Area

Wage

Self-Support Ratio

Forest Coverage Rate

Engel's Coeffcient

Nominal GDP

2010 2000 1990

1980 1970

Figure 3.

Changes in the Japanese ergonomic spectrum.

Y. YAMADA ET AL.

issues in ergonomics, they cannot be accomplished without the

help of management, local officials, owners, planners, supervi-

sors, and leaders. In this sense, improvements can be defined as

external and passive from the point of view of workers and

operators.

Control

Sensibilities

Consciousness

Management

Planners & Managers

Classical Cognitive

Physical Psycho- p hysiologic al

Physiological Stress

Manual Man-Machine

Workers Oper ato rs

Er gonomi c S pect r um

Passive

External

Active

Internal

We must think of extending future ergonomics to forest

management control spheres (Figure 4). Control ergonomics,

which is based on the ergonomic spectrum, aims to enhance the

sensibilities and consciousness of management and fosters in-

ternal change in each manager in working not only with staff

but also with workers and operators. It is also concerned with

classical ergonomics and cognitive ergonomics and considers

management philosophy, design, decision making, social re-

sponsibility, evaluation, improvement, and education and train-

ing for workers and operators. In this sense, control ergonomics

can be defined as active ergonomics.

Figure 4.

Ergonomic strategy based on the ergonomic sp ec trum.

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world. Surely, no one wants accidents in the work place. How-

ever, in each nation, some factors can be improved and others

are indigenous to the country and cannot be improved. For

example, Japan cannot reach the same ergonomic situation as

Sweden because its climate and terrain are different. Thus, we

must find another goal that is suitable and can be accomplished.

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The ergonomic spectrum is intended mainly for forestry

workers and operators to improve their working conditions.

Although improvements are traditionally basic and essential