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    ABSTRACT: The Brazilian wood industry is highly mobile. Over the past 20 years the eastern Amazon developed from a logging backwater to the principal hardwood processing center in Brazil. This occurred because of a decline in hardwood stocks in the south of Brazil coupled with the development of good transport, energy, and communications systems in eastern Amazonia.We studied the structure and economy of the wood industry along a 340 km stretch of the Bélem-Brasília Highway in eastern Amazonia. Of the 238 sawmills present in this study region in late 1989, 79% were installed in the 1980s. Ninety-seven percent of the mill owners came from outside Amazonia. Most (63%) of the mill establishments were vertically integrated, engaging in both forest mill processing and forest logging.Logging establishments realize substantial profits. A typical sawmill with one band saw produces, on average, 4300 m3 of sawnwood year−1 from 9200 m3 of roundwood. The value of this sawn production is estimated at $670 800 or $156 m−3. Production costs are $116 m−3 giving an annual mill profit of $170 000. For firms engaged in both logging and processing activities, annual profits were estimated at $217 000 (profit margin, 32%) or $900 ha−1 logged.An average of six trees were harvested per hectare in logging operations (n = 3 study areas) and the volume yield averaged 38 m3 ha−1. Damages to the forest during logging are significant. Twenty-seven trees greater than or equal to 10 cm dbh are severely damaged for each tree harvested. This damage occurs in the opening of approximately 40 m of logging road and 600 m2 of canopy per tree harvested. Vines are favored by these open conditions and forest fires are possible.Forest management is technically feasible but economically unattractive. Natural regeneration is abundant on logged sites: 4300 seedlings and saplings of economic species were registered per hectare. Stocking of larger trees of economic species with good form is also adequate: 16 trees ha−1 greater than or equal to 30 cm dbh. This residual stock could be favored by vine cutting and refinement thinnings at an estimated cost of $180 ha−1. Although these treatments result in increased growth rates, the projected return on management investments is low. Nonetheless, given the robust profits in the wood sector, profit margins would remain well above 20% if management were mandated by law.At present the biggest impediment to forest management in the eastern Amazon is the undervaluing of the timber resource. Ranchers, who own most forest land, sell harvest rights to loggers at low prices −$50–$150 ha−1. After the logging teams extract the timber, these same ranchers are left with badly damaged forest tracts. With careful extraction and management procedures, harvests could be accomplished on a 30- to 40-year rotation and forest integrity could be maintained. Ranchers, insofar as they control the forest resource, have the power to guarantee its wise use. They could do this by supervising harvest operations on their lands to reduce damage and by raising the price of their timber and using this additional revenue to finance simple silvicultural operations.
    Forest Ecology and Management. 01/1992;
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    ABSTRACT: Carbon stocks in vegetation replacing forest in Brazilian Amazonia affect net emissions of greenhouse gases from land-use change. A Markov matrix of annual transition probabilities was constructed to estimate landscape composition in 1990 and to project future changes, assuming behavior of farmers and ranchers remains unchanged. The estimated 1990 landscape was 5.4% farmland, 44.8% productive pasture, 2.2% degraded pasture, 2.1% ‘young’ (1970 or later) secondary forest derived from agriculture, 28.1% ‘young’ secondary forest derived from pasture, and 17.4% ‘old’ (pre-1970) secondary forest. The landscape would eventually approach an equilibrium of 4.0% farmland, 43.8% productive pasture, 5.2% degraded pasture, 2.0% secondary forest derived from agriculture, and 44.9% secondary forest derived from pasture. An insignificant amount is regenerated ‘forest’ (defined as secondary forest over 100 years old). Average total biomass (dry matter, including below-ground and dead components) was 43.5 t ha−1 in 1990 in the 410 × 103 km2 deforested by that year for uses other than hydroelectric dams. At equilibrium, average biomass would be 28.5 t ha−1 over all deforested areas (excluding dams). These biomass values are more than double those forming the basis of deforestation emission estimates currently used by the Intergovernmental Panel on Climate Change (IPCC). Although higher replacement landscape biomass decreases net emissions from deforestation, these estimates still imply large net releases.
    Forest Ecology and Management 01/1996; · 2.77 Impact Factor
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    ABSTRACT: Peach palm (Bactris gasipaes Kunth) is a relatively new food crop with great potential for the humid tropics. Native to tropical America, it is commercially grown to produce hearts-of-palm and, to a lesser extent, an edible fruit. Peach palm is well adapted to nutrient poor, acid soils, and is cultivated in Brazil and Costa Rica on highly weathered soils with low pH, high aluminum saturation and, often, low organic matter content. Fertilization trials on peach palm have shown significant responses to applied nitrogen while the response to other nutrients such as phosphorus has been less frequent. Additional research, however, is necessary to determine soil and foliar nutrient critical levels and to address questions concerning peach palm growth responses to nutrient additions varying in time and space. Recycled nutrients likely contribute significantly to peach palm nutrition because plant residues are produced in considerable amounts and can decompose rapidly in commercial peach palm plantation in humid environments where cut leaves and stems are left in the field following harvest. On the other hand, nutrient exports from the system are relatively small (e.g., 4.8–6.4 kg P ha-1yr-1, 28–32.3 kg N ha-1 yr-1, 31–45.2 kg K ha-1 yr-1). As for most perennial tree crops, diagnosis of nutrient deficiencies in peach palm is less clear than in annual crops because of factors such as nutrient cycling, internal retranslocation, stand age, foliage age and position within the crown, and seasonal and climatic variations. Some studies on peach palm have examined variation in nutrient content within leaves and plants, and among plants as well, but the sensitivity of different plant tissues to reflect changes in nutrient uptake and response to nutrient additions should be investigated in controlled field experiments.
    Nutrient Cycling in Agroecosystems 02/2000; 56(3):195-207. · 1.42 Impact Factor

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