Artificial regeneration in gaps and skidding trails after mechanised forest exploitation in Acre, Brazil

d’Oliveira, Marcus Vinício Neves

doi:10.1016/s0378-1127(99)00117-6

Cited by 70 publications

(40 citation statements)

References 5 publications

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“…Bertholletia excelsa is heliophytic (Salomão 1991;Scoles 2010) and depends on clearings for growth as well as the survival of seedlings and saplings (Mori and Prance 1990;Viana et al 1998;Myers et al 2000;Oliveira 2000). Plants appear in clearings as if they were pioneer species, but, unlike pioneers, they remain after the forest has grown into more advanced successional stages.…”

Section: The Speciesmentioning

confidence: 99%

Population Structure of Brazil Nut (Bertholletia excelsa, Lecythidaceae) Stands in Two Areas with Different Occupation Histories in the Brazilian Amazon

Scoles

Gribel

2011

Hum Ecol

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Here we hypothesize that the intensity of disturbances caused by human activities in Brazil nut stands (castanhais) is positively related with the regeneration of Brazil nut trees (Bertholletia excelsa H.B.K., Lecythidaceae) and consequently with a younger population structure of this species. In order to test this hypothesis we compared the population structure of Brazil nut trees in two areas of the Brazilian Amazon with different histories of land usage by humans. Archeological and historical data suggest that the region surrounding the Trombetas River was densely occupied in pre-Columbian times and experienced depopulation after European contact with Amerindian populations, especially in the 16 th century. The 25 Brazil nut stands sampled in this region were dominated by old B. excelsa trees and had scarce recruitment in the understory. These very mature stands likely owe their origins to the interval between the depopulation of the indigenous peoples in the 16 th -17 th centuries and the establishment of quilombos at the beginning of the 19 th century. The second study area was in the vicinity of the Madeira River (Capanã Grande Lake), where the castanhais were more accessible and disturbed. In this site, a younger population structure and abundant regeneration of B. excelsa were observed in the 10 sampled stands. Historical data from this region indicate that indigenous populations were replaced gradually beginning in the 18 th century, with no evidence of severe depopulation. We suggest that the different historical and contemporary land use patterns contributed to the current contrasting population structures of the castanhais at the two locations. The data also support the idea that the castanhais, even the ones considered to be pristine and "native" forests, result from anthropogenic influences. We found no evidence to support restrictions on seed harvesting as a means to improve regeneration rates of Brazil nut stands.

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Section: The Speciesmentioning

confidence: 99%

Population Structure of Brazil Nut (Bertholletia excelsa, Lecythidaceae) Stands in Two Areas with Different Occupation Histories in the Brazilian Amazon

Scoles

Gribel

2011

Hum Ecol

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“…Howe & Smallwood 1982, more cotyledon predation of recently emerged seedlings at high density or close to adult trees (as cotyledons become part of the stem, cotyledon predation kills the individual; cf. Howe & Smallwood 1982, Oliveira 2000, and spatial variation in light conditions. 'Dispersal' of Bertholletia seeds by Brazil-nut collectors may also have contributed to the observed difference in spatial distribution of fruits and seedlings.…”

Section: Regeneration In Exploited Populationsmentioning

confidence: 99%

Demography of the Brazil nut tree (Bertholletia excelsa) in the Bolivian Amazon: impact of seed extraction on recruitment and population dynamics

2002

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ABSTRACT. A demographic study was carried out on Bertholletia excelsa, the Brazil nut tree, in two primary forest sites in Northern Bolivia where Brazil nuts have been harvested for several decades. In spite of the large proportion (93%) of seeds that are harvested, reasonable densities of recently emerged seedlings were found. Seeds of Bertholletia are contained in woody fruits that are primarily opened by agoutis. Most fruits are left untouched on the forest floor for 1-2 y before they are opened, possibly due to high energetic costs of fruit opening just after fruit fall. However, the proportion of viable seeds is strongly reduced in older fruits.Growth in diameter at breast height (dbh) was low for pole-sized trees (< 15 cm dbh) and adult trees (> 100 cm dbh) and peaked for intermediate-sized trees (30-60 cm). These trees often attained a growth rate of > 1.5 cm y −1 , which is high compared with other non-pioneer tropical trees. This, and the strong growth response to increased light availability found for seedlings and saplings, suggest that Bertholletia excelsa can be classified as a gap-dependent species. Matrix population models were constructed for both study populations. Population growth rates (λ) were close to one, and were most sensitive to persistence in one size category. Age estimates revealed that age at first reproduction (at dbh > 60 cm) amounts to over 120 y, and age in the last category (dbh > 160 cm) to almost 300 y. Given the continuous rejuvenation of the population, the stable population size, the high age at maturity and the long reproductive period, it is concluded that current levels of Brazil nut extraction may be sustained at least for several decades and perhaps for even longer periods.

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“…Other studies have shown that disturbed soil results in an increase in the abundance and growth of tree seedlings (Dickensen et al, 2000;. Finally the absence of competitors has a positive effect on tree seedling and sapling growth (Kuusipalo et al, 1997;Quevedo and Fredericksen, 2000;Zagt, 1997;D'Oliviera, 2000;Rose, 2000).…”

Section: Introductionmentioning

confidence: 97%

Regeneration of timber trees in a logged tropical forest in North Bolivia

Rheenen

Boot

Werger

et al. 2004

Forest Ecology and Management

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Artificial regeneration in gaps and skidding trails after mechanised forest exploitation in Acre, Brazil

Cited by 70 publications

References 5 publications

Population Structure of Brazil Nut (Bertholletia excelsa, Lecythidaceae) Stands in Two Areas with Different Occupation Histories in the Brazilian Amazon

Population Structure of Brazil Nut (Bertholletia excelsa, Lecythidaceae) Stands in Two Areas with Different Occupation Histories in the Brazilian Amazon

Demography of the Brazil nut tree (Bertholletia excelsa) in the Bolivian Amazon: impact of seed extraction on recruitment and population dynamics

Regeneration of timber trees in a logged tropical forest in North Bolivia

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