Botanical Literature Details

• Author(s)

  Scoles, R., Gribel, Rogério, Klein, G. N.

• Article or Chapter Title

  Crescimento e sobrevivência de castanheira (Bertholletia excelsa Bonpl.) em diferentes condições ambientais na região do rio Trombetas, Oriximiná, Pará

• Year

  2011

• Journal or Book

  Boletim do Museu Paraense Emílio Goeldi, Ciências Naturais. 6(3): 273-293

• Notes

  Resumo:
  
  Este estudo analisa o crescimento e a sobrevivência da castanheira (Bertholletia excelsa, Lecythidaceae) em diferentes condições ambientais a partir de plantios experimentais na região do rio Trombetas. Foram plantadas 144 mudas num delineamento experimental com quatro repetições e três tratamentos ambientais de exposição à luz: roçados de mandioca (100% de abertura de dossel), capoeiras jovens (20-80%) e sub-bosque de castanhais (menos que 10%). Durante dois anos, a cada dois meses, mediram-se a altura e o diâmetro do colo de todas as plantas e anotaram-se as incidências de mortalidade e rebrota. Diferenças significativas no desempenho das mudas de castanheira foram observadas entre os três tratamentos, especialmente favorável ao de maior luminosidade. As mudas de roçado cresceram em altura 13 vezes mais do que as de capoeira e quase 30 vezes mais que as do castanhal. O crescimento em diâmetro das plantas no roçado foi 4,4 vezes maior do que na capoeira e 7,7 vezes maior do que no castanhal. Independente das condições luminosas, a castanheira mostrou alto índice de sobrevivência e capacidade de rebrota. Conclui-se que a castanheira se desenvolve melhor em condições de plena luminosidade, como áreas de roçado ou grandes clareiras florestais. Nas experiências de enriquecimento ou reflorestamento, deve-se limpar periodicamente ao redor das mudas, evitando sombreamentos da parte aérea, garantindo, assim, altas taxas de crescimento para as mesmas.
  
  PALAVRAS-CHAVE = Bertholletia excelsa, castanheira, sobrevivência, crescimento de árvores, plantios de enriquecimento, abertura de dossel.
  
  Abstract:
  
  This study examines the growth and survival of Brazil nut trees (Bertholletia excelsa, Lecythidaceae) in different environmental conditions within experimental plantations in the Trombetas River Valley. One hundred and forty four saplings were planted in a random block design, with three natural light treatments: manioc field (100% canopy removal), young secondary forest (20-80% canopy cover), and the understory of a Brazil nut plantation (less than 10% canopy opening). Every two months for a period of two years plant height and stem diameter were measured, and mortality and regrowth were noted. There were significant differences in the performance of Brazil nut saplings among treatments different light exposure, with the most marked differences being at the highest level of luminosity (manioc field). The open field saplings grew in height 13 times more than those planted in secondary forest, and nearly 30 times more those in the understory of the plantation area. The open field saplings exhibited a growth in diameter 4.4 times greater than saplings planted in secondary forest and 7.7 times greater than saplings planted in the understory. Regardless of the light treatment, the Brazil nut saplings had high survival rate and exhibited strong regrowth following stem damage. Overall we report that Brazil nut saplings perform better in full daylight conditions such as abandoned crop fields and forest gap. In enrichment or reforestation plantings, vegetation around Brazil nut plants should be cleaned frequently to avoid over-shading the crown and to guarantee high growth rates.
  
  Keywords: Bertholletia excelsa, Brazil nut, ecology, gaps, tree growth, tree mortality.
  
  Additional notes by S. A. Mori (21 Feb 2012)
  
  Introduction. The Brazil nut is distributed unequally thoughout the entire Amazon Basin, being common in some places and rare or absent in other places. It is one of the principal sources of revenue, especially during the rainy parts of the year. It is the second most important non-timber forest crop in the Amazon. The açaí fruits and palm hearts of açaí trees are the most important. Toward the end of the 1990s, Bolivia became the biggest producer of Brazil nuts where it is now the number one non-timber forest product.
  
  Discussion. Brazil nut seedling have great capacity for sprouting after they have been damaged, e.g., by a fallen limb or by an animal destroying the terminal bud. Survival after damage was greatest in capoeira (80%), less so in castanhais (70%), and the least in roçados (55%). Capoeira is secondary growth, castanhal is the name for a Brazil nut grove, and roçado is the name for an agricultural field such as those dedicated to the cultivaton of manihot. Growth in seedlings is greatest in those that are exposed to the most light. The second year after planting seedlings was when the greatest growth in height took place. Other studies have shown that the growth in young capoiera was highest whereas in this study it was under the conditions found in roçados. This study concludes that saplings without remnant hypocotyls have the greatest chance of survival.and that saplings of the Brazil nut have a very high recovery rate after injury.
  
  Note that this paper calls the tissue that nourishes the seedling and young sapling endsperm; it is, however, the hypocotyl, of the embryo. It is from the embryo where the epicotyl and hypocotyl beginn growth and its remnant is marked by a swollen part on the stem. The endosperm of Lecythidaceae has been absorbed long before the sending germinates.