Growth and yield studies in the Tapajós region, central brazilian Amazon
Growth and yield plots have been monitored in the Tapajós region, Pará State, Brazil, since 1981 in four research sites: unlogged primary forest, two research plots logged 7 and 13 years before the last assessment, and a secondary forest c. 50 years old. Diameter increment, mortality and volume increment in these sites are reported. Response of crown illumination and ecological guild of species on tree growth were investigated. Irrespectively of ecological guild, the amount of light received by the crowns determined significant differences on tree growth. A hierarchy of growth rates was observed: rates of dbh increment of intolerant species >tolerant canopy species> understorey tolerant species. Mortality rates were higher for weed species in all sites except in the secondary forest. In this site understorey tolerant species showed higher mortality rate, followed by weed species. Average annual volume increment ranged from 1.6 m3 ha-1 yr-1 in primary unlogged forest to 4.8 m3 ha-1 yr-1 in primary logged forest. Commercial species produced just over 1 m3 ha-1 yr-1 in the logged stands which is a very low productivity compared to plantations. Consequently, establishing cutting cycles in the Tapajós region and other similar sites must consider these low increment rates.
| Main Authors: | , , , , , |
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| Format: | biblioteca |
| Published: |
(Japon)
1994
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| Subjects: | CRECIMIENTO, RENDIMIENTO, DIAMETRO, MORTALIDAD, AMAZONIA, BRASIL, |
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| Summary: | Growth and yield plots have been monitored in the Tapajós region, Pará State, Brazil, since 1981 in four research sites: unlogged primary forest, two research plots logged 7 and 13 years before the last assessment, and a secondary forest c. 50 years old. Diameter increment, mortality and volume increment in these sites are reported. Response of crown illumination and ecological guild of species on tree growth were investigated. Irrespectively of ecological guild, the amount of light received by the crowns determined significant differences on tree growth. A hierarchy of growth rates was observed: rates of dbh increment of intolerant species >tolerant canopy species> understorey tolerant species. Mortality rates were higher for weed species in all sites except in the secondary forest. In this site understorey tolerant species showed higher mortality rate, followed by weed species. Average annual volume increment ranged from 1.6 m3 ha-1 yr-1 in primary unlogged forest to 4.8 m3 ha-1 yr-1 in primary logged forest. Commercial species produced just over 1 m3 ha-1 yr-1 in the logged stands which is a very low productivity compared to plantations. Consequently, establishing cutting cycles in the Tapajós region and other similar sites must consider these low increment rates. |
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