New information for managing Copaifera multijuga Hayne for oleoresin yield

Abstract

The harvesting of Copaifera oleoresin is an important source of income for traditional Amazonian peoples and natural product industries. However, many production processes-related aspects still require more concrete information if they are to be incorporated in effective forest management systems. The objective of this study was to evaluate the yield of Copaifera multijuga Hayne oleoresin harvesting over time, including those factors (diameter, heartwood percentage, harvesting season and age) that may influence its production and be linked to forest management practices. Research was carried out in a natural forest area in Adolph Ducke Forest Reserve, Manaus, Amazonas, Brazil (2°57′43″S and 59°55′38″W). The sixty C. multijuga trees selected included productive and non-productive individuals (with 7 and 32 years of fallow). Oleoresin production was monitored for a period of two years, and the following variables measured: trunk DBH, heartwood percentage, tree age, fallow interval and climatic seasonality. To analyze growth rings (demarcation, counting and width measurement), wood samples were collected from the trunk of productive and nonproductive trees. Tree ages were determined with growth ring counts. Tree ring widths were used to calculate radial growth. Accumulated radial increments were determined and growth curves constructed. Oleoresin production showed a stronger relationship with tree diameter and percentage of heartwood than with age. This shows that age is not the determining factor in the production, but rather the diameter and the percentage of heartwood. However, the greater amounts of oleoresin was harvesting in older trees. Trees initially not productive (1978) became productive 32 years later (2012). Radial trunk growth and consequent heartwood incorporation may have contributed to this. This explains why trees with small diameters do not produce oleoresin, since they have sapwood, but lack heartwood. On the other hand, some trees, whose production has declined, were beginning to show growth curve stabilization and likely the onset of senescence. The results also indicated that production is influenced directly by number of years between harvests. The best time to harvest oleoresin is at the end of the rainy season. Although oleoresin production declines naturally over the years, good management practices can be adopted to produce a lasting production system, maximizing the productive life of the trees, and linking economic and ecological viability. Key is the use of a minimum tree trunk diameter (DBH ≥ 45 cm) during initial oleoresin harvesting, and a resting period sufficient to allow adequate oleoresin synthesis by managed trees. © 2018 Elsevier B.V.