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The Effect of Fallow Period Length on the Abundance and Diversity of Usable Plant Assemblages in Shifting Cultivation System (Swidden Agriculture) in Northern Laos

Delang C. O., Weiyi X., Brooke B., Chun K. P.

Polish Journal of Ecology

2016

Vol. 64, nr 3

350--356

Shifting cultivation, or swiddening, involves alternating cycles of cropping and fallow periods. Rather than being abandoned, the fallow swidden fields provide a source of important plant products for remote, forest-dwelling human communities. In northern Laos, the traditional length of fallow periods used to range between five and 11 years, depending on the availability of land and quality of the soil. Fallow periods are currently being shortened because of population pressures and government policies. To determine the potential impacts of shorter fallow periods, 128 swidden fallows of various ages (up to 20 years), located at altitudes between 400 and 800 m a.s.l. in northern Laos were sampled for usable plants. The impact of fallow length on plant abundance and species diversity was analysed. The number of usable plant species was found to increase with the fallow age until it was 11–12 years old, and then decline, while the abundance of usable plants increased beyond that period. We conclude that shorter fallows will result in a significantly smaller usable plant abundance and species diversity for the villagers. We propose that 11–12-year-long fallows should be considered in order to fully exploit the greater plant volume of older fallows as well as the compositional shift of species in fallows over time.

Ethnobotany of Natural Fibres - Bactris setosa (tucum) in a Traditional Rural Community

Sato Duarte A. Y., Santiago de Queiroz R., Sanches R. A., Garcia C. R., Dedini F. G.

Fibres & Textiles in Eastern Europe

2012

Vol. 20, no. 2 (91)

18-20

This work aimed to study the characteristics of the fibres of the species Bactris setosa ('tucum') used by close-knit social groups, located in Sorocaba - Săo Paulo - Brazil, in basketmaking techniques, for possible applications in textile activity. Optical microscopy (NBR 13 538:1995) and Tensile Properties (ASTM D 3 822-2001) were used to assess properties such as the fibre structre, linear density, breaking force, elongation at break and breaking tenacity of each species. Bactris setosa showed a longitudinal view similar to that of sisal; an average linear density of 41.2 tex, a tenacity average of 11.96 cN/tex, closer to fiberglass, and an elongation ranging between 1.35 and 3.87%.It is important to clarify the delicacy and detail of the tests, and from this we highlight the importance of carrying out these studies, based on which science and technology must be linked with socio-environmental aspects.

Artykuł poświęcony jest charakterystyce włókien palmy Bactris setosa stosowanych dotychczas przez lokalne grupy ludności w prowincji Sorocaba, Sao Paulo, Brazylia, mogących znaleźć zastosowanie w wyrobach włókienniczych. Badano strukturę włókien między innymi poprzez zdjęcia mikroskopowe oraz właściwości mechaniczne włókien takie jak masa liniowa, siła zrywająca, wytrzymałość właściwa na zrywanie i wydłużenie przy zerwaniu. Przekroje poprzeczne tych włókien wykazują podobieństwo do włókien sizalowych; przeciętna masa liniowa włókien wynosi 41,2 tex, wytrzymałość właściwa na zrywanie 11,96 cN/tex oraz wydłużenie przy zerwaniu w granicach 1,35 - 3,97%. Analiza właściwości włókien pozwala na prognozę ich zastosowania do celów tekstylnych i aktywizacje rejonów wiejskich.