Características ecofisiológicas e crescimento de Bertholletia excelsa Bonpl. em plantio florestal submetido ao desbaste
A better understanding of the effects of thinning on the ecophysiological aspects and the growth of Bertholletia excelsa, Amazon tree with high potential timber, can help to define the most appropriate management strategies plantations of this species. The objective of this study was to investigate...
| Autor principal: | Costa, Karen Cristina Pires da |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/5122 http://lattes.cnpq.br/8779471372627932 |
| Resumo: |
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A better understanding of the effects of thinning on the ecophysiological aspects and the growth of Bertholletia excelsa, Amazon tree with high potential timber, can help to define the most appropriate management strategies plantations of this species. The objective of this study was to investigate the effects of the application of silvicultural treatment of thinning on the ecophysiological characteristics and growth of B. excelsa in a dense planting. The study was conducted in a plantation belonging to the Agricultural Company Aruanã, Itacoatiara, AM. The method of thinning applied was selective, were removed 50% of the basal area of the planting. After thinning, we analyzed the percentage of canopy opening and were monitored chlorophyll a fluorescence, variables of the gas exchange, the contents of leaf nutrients, leaf water potential and diameter growth. The experimental design was a randomized complete block with two treatments (control and thinning) and eight repetitions. After applying the thinning was observed reduction in photochemical efficiency of photosystem II (TRO/ABS), with subsequent recovery to the levels of the trees of the control treatment. A week after applying the thinning was observed increase in photosynthetic rates (A), respiration (Rd), stomatal conductance (gs) and transpiration (E). Thinning did not affect the water potential of the trees, but the trees in this treatment showed efficiency in water use (WUE) 16% higher. The thinning resulted higher content of Na, Ka, Pa and MFA. At the end of the trial period, under the trees thinning treatment showed concentrations of Na, Pa, Ka and MFA about 27% higher than the trees of the control treatment. Thinning stimulated growth in diameter of B. excelsa, which was three times higher (1.12 cm yr-1) compared to control treatment of trees (0.39 cm yr-1). Thinning stimulated growth rates in diameter B. excelsa, in response to increased photosynthetic capacity due to increased stomatal conductance (gs), leaf mass per area (MFA) and leaf contents of Na and Pa. In addition, the rapid B. excelsa response to environmental changes caused by thinning, due in large part the ability of this species to acclimate to the new light conditions imposed by the application of silvicultural practice. |