Nagoya University Global COE Program: From Earth System Science to Basic and Clinical Environmental Studies

BCES

GCOE Fellows/PD

Isao HIROTA

Name Isao HIROTA Isao HIROTA
Position, Department COE Postdoctoral Fellow (PD), Graduate School of Environmental Studies
Office Room 101, Environmental Studies Hall
E-mail
Research Keywords Slash-and-burn, Laos, Utilization of natural resources, Bamboo

Message

I have conducted a significant amount of field research, up until now, in northern Laos. Northern Laos is distinctive by its mountainous regions, and traditionally mountain slopes have been used for upland rice cultivation through slash-and-burn systems, with paddy fields in intermountain basin areas used for paddy rice cultivation. In slash-and-burn areas, mixed crops other than upland rice cultivation have been cultivated; equally, wild animals and non-timber forest products have been sourced from fallowed forests. At the same time, paddies have been a source of more than just rice; lowland weeds, fish and insects have all been used by local people as products for which there is distinct demand. The agro-ecosystem of Laos, then, has traditionally provided diverse production spaces.

In recent years, however, mountain slopes are being increasingly used for rubber trees and cultivation of cash crops; paddies are also becoming increasingly affected by cash crop demand. The way in which land is used, therefore, is changing rapidly. Faced with these new land use trends, my research will examine how traditional land use is likely to change, and how traditional land use practice and inherited knowledge on the utilization of natural resources can be adapted to new trends in land use.

Research Themes

Knowledge and Skills from Traditional Land Use amongst Laotian Mountain Communities

My principle area of research has been northern Laos, where particular research interests have included the vegetation dynamics and functions of fallowed forests in the slash-and-burn agricultural system.

As I mentioned in my message, slash-and-burn comprises a system wherein a disturbed environment, caused by slash-and-burn practices, is used overall. The knowledge and skills about the utilization of natural resources that the local people have are rich to the extent that they have allowed communities to utilize all systems of the region's ecological environment. For example, animals are trapped according to a calendar unique to the local community and to a calendar adapted to lunar months; these determine when traps are to be laid, and when parties are to set out hunting. These calendars also determine the dates and locations of slash-and-burn and fallow land. Equally, the location of traps is determined according to strong community knowledge about where certain types of animals can be found, and at what levels. This is the case for plants and mushrooms also, where empirical knowledge is able to dictate which environments are best suited to cultivation, distinctive growth characteristics, the distribution of resources and cultivation levels, and so on.

In other words, communities have strong, comprehensive knowledge of the dynamics of their local ecosystems, and use their knowledge of the distribution, life cycle, and growth and development characteristics of animals and vegetation, together with traditional and empirical knowledge, to determine their daily actions. Going forward, I would like to build upon the knowledge of these practices that I have gained thus far to further clarify the overall picture and significance of this local, traditional knowledge, and investigate the links between ecosystem dynamics and this knowledge.

Ecological Dynamics and Cultural Role of Bamboo

Bamboo is widely used throughout Asia, and there are 90 reported species of this important vegetation resource in Laos alone, almost all of which are used by humans, be they wild or cultivated varieties.

Bamboo also grows in Japan, often near to human communities, but in northern Laos it mainly grows in the fallowed forests that result from the slash-and-burn system. In recent years, the shortening of the fallow period has been increasingly seen as problematic, with many pointing to such shortening as being the principle factor behind the reduction of forested areas and the qualitative deterioration of forest land. Most of the theories positing such a correlation are based upon presumptions of the consecutive transition of burnt and fallow fields; however, research in northern Laos has shown that discontinuous events, such as the general flowering of bamboo, have a significant influence on local vegetation. With regard to the general flowering of bamboo in Laos, it should be noted that bamboo, when restricted to a single variety, normally has a cycle of once every several decades. In Laos, however, multiple varieties of bamboo are present, so an average cycle would be one variety flowering once every five years. The general flowering of bamboo is a significant natural event; even more so when it occurs in addition to the large-scale social change and the changes in land use seen in recent years. My research will focus on answering questions on the extent of the impact of general flowering on natural vegetation, and the impact on human society as users of bamboo.

↓ Click to enlarge


Image 1. Bamboo forest extending across a burnt crop field and fallowed forest

Image 2. Trap known as a ka thip set up on a burnt field

Biography

Mar 2002 BSc, Faculty of Agriculture, Kyoto University
Mar 2009 Ph.D., Graduate School of Agriculture, Kyoto University
Apr 2009 Researcher, Graduate School of Agriculture
May 2009 Researcher, National Agriculture and Forestry Research Institute, Laos
Oct 2009 Took up current post

Papers & Publications

  • Hirota I, Nakanishi A. 2007. "Bamboo Forests" in Akimichi, T (ed.) An Illustrated History of the Mekong River Basin. Koubundou Publishers Inc.: Tokyo, pp22-23 (in Japanese)
  • Yokoyama S, Ochiai Y, Hirota I, Sakurai K. 2008. "Chapter 5: Ecological Value of Slash-and-Burn Fields" in Kono Y (ed.) An Ecohistory of Monsoon Asia, vol.1, Production. Koubundou Publishers Inc.: Tokyo, pp.85-100 (in Japanese)
  • Hirota I, Nakanishi A, Nawata E, Kono Y. 2008. "Chapter 8: Changes in Slash-and-Burn Fields and Rural Communities in the Southeast Asia Continent" in Daniels, Christian (ed.) An Ecohistory of Monsoon Asia, vol.2, Regions. Koubundou Publishers Inc.: Tokyo, pp165-180 (in Japanese)
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