Distribuição espacial de Aniba canelilla (H.B.K.) Mez. e sua produção de óleo essencial de galhos e folhas Na Amazônia Central

Abstract

The Aniba canelilla (H.B.K.) Mez. is an endogenous species in the Amazon and its essential oil is known for medicinal and perfumery uses. It is a rare species in the landscape and its spatial distribution may be related to environmental variables. Therefore, searching sites with high individual occurrence can help the management of the species for essential oil production. Several factors can interfere in its yield and composition. Productivity may be related to biomass production. Harvesting fine stems and leaves for essential oil production may provide a possible alternativo for trunk harvesting that still occurs íor Aniba rosaeodora. Therefore the aims of this study were: (1) to analyze the spatial distribution of adult individuais ofAniba canelilla whh a predictive topographic model and (2) to analyze the biomass and essential oil production (yield and chemical composition) before and after crown pruning. The study site belongs to the logging company Precious Woods Amazon (PWA), located in the municipality of Itacoatiara, Amazonas state, Brazil. To achieve the first aim two predictive variables height above nearest drainage and slope were used, both were extracted from Digital Elevation Models (DEM). The logistic model was used in training and validation area to predict the species probability of occurrence. To this, each pixel was categorized in 'presence' (individual geo-referenced points) or 'absence'. In the second aim, the fine stems and leaves from eleven trees were collected by pruning half the crown during rainy season. After nine months, the stems and leaves from resprouting and remaining crown after pruning were collected during dry season. The essential oil yield and chemical composition, along with the pruned and resprouted biomass were the dependent variables analyzed. The diameter breast height (DBH), the canopy openness and the herbivory were the independents variables measured. The results demonstrated that the spatial distribution ofAniba canelilla was related to height above nearest drainage. Nevertheless the probability of occurrence through predictive modeling showed limitations. With regards to rare species, the model has errors due to the surplus "absences". The logistic model applicability was limited because the probability of occurrence ofAniba canelilla is too small. The stems essential oil yield was greater in 1®' sprouting and during dry season while the leaves yield does not show any difference. The canopy openness was negatively related to resprouted biomass and positively to essential oil yield. Whilst the crown canopy openness had the opposite result. The herbivory and DBH influenced negatively leaves essential oil yield from remaining crown. The higher concentration of l-nitro-2-phenyletane compound was found in the stems while eugenol and metyleugenol compounds were higher in leaves. Concluding, the essential oil (yield and chemical composition) from leaves and stems showed differences in their production. The species Aniba canelilla showed good resprouting capacity after pruning and this resprouted biomass produces essential oil too. However, studies with longer cycles and different intensities of pruning are needed to complement this research.