Sampling methods for titica vine (Heteropsis spp.) inventory in a tropical forest

International audienceAbstractKey messageTitica vine provides useful raw fiber material. Using sampling schemes that reduce sampling error can provide direction for sustainable forest management of this vine. Sampling systematically with rectangular plots (10 × 25 m) promoted lower error and greater accuracy in the inventory of titica vines in tropical rainforestContextThe titica vine (Heteropsis spp.) is an important raw material for native communities located in the Amazon tropical rainforest. However, variability and spatial distribution of this species are some factors that hinder the assessment of accurate productivity prediction, and thus, inventory methods for management plan must be defined.AimsThe aim of this study was to develop and compare accuracy of different sampling approaches for the inventory of titica vines (roots ha−1) using simulations based on field data.MethodsEighty-eight treatments were defined by the combination of the process (random or systematic), sampling intensity (5, 10, 15, and 20 % of 18 ha), plot size (250 to 3000 m2) and shapes (square, rectangle, and transect). Production estimate, sampling error, and relative efficiency were used to compare treatments with each other and with the reference inventory.ResultsThe mean production estimates for the random and systematic processes were 570 and 597 vine roots ha−1, while the reference estimate was 500 vine roots ha−1. Among of the treatments evaluated, only 5.8 % of them provided a sampling error less than 15 %.ConclusionThe sampling procedure that combines systematic or random process, plots sizes of 250 or 300 m2 and sampling intensity greater than 15 % was the most efficient for inventory of titica vine in tropical forests

Interspecific differences in the oleoresin production of Copaifera L. (Fabaceae) in the Amazon rainforest

Context Copaifera species produce an oleoresin of commercial importance that is widely extracted in Amazon communities. Aims This paper addresses two questions. (1) What are the morphological characteristics of Copaifera species that influence oleoresin production? (2) How do different Copaifera species respond to repeated harvests? Methods We performed a large-scale experiment in the Brazilian Amazon. We tapped 110 Copaifera trees belonging to four species, and several morphological tree characteristics were measured to determine their effect on oleoresin production. Results The proportion of Copaifera reticulata and Copaifera paupera trees that yielded more than 1 ml oleoresin was higher than the other species. The oleoresin volumes from yielding Copaifera pubiflora trees were significantly higher than those from C. reticulata and C. paupera, with Copaifera multijuga yielding intermediate values. Interestingly, none of the studied morphological tree characteristics had a significant effect on the proportion of yielding trees. Hollowed trees yielded significantly smaller volumes than non-hollowed trees. Both the proportion of yielding trees and oleoresin volumes decreased from the first to the second harvests for C. reticulata and C. paupera; however, the opposite pattern was observed for C. pubiflora. Conclusions Oleoresin production capacity varies by species, and management protocols should account for these differences

Análise econômica de sistemas agroflorestais na Amazônia ocidental, Machadinho d'Oeste- RO Economic analysis of agroforestry systems in eastern Amazonia, Machadinho d'Oeste- RO, Brazil

O objetivo deste estudo foi realizar a análise financeira e a simulação de risco de investimento em sistemas agroflorestais (SAFs) implantados em 1987, no Campo Experimental da Embrapa Rondônia, localizado no município de Machadinho d'Oeste, RO. A análise financeira foi realizada mediante os métodos de avaliação de projetos florestais, e para a análise de risco utilizou-se a técnica de simulação de Monte Carlo, mediante o programa @RISK. Entre os arranjos testados, o SAF T1 Castanha-do-brasil-banana-pimenta-do-reino-cupuaçu apresentou o melhor desempenho financeiro em relação aos SAFs T2 Freijó-banana-pimenta-do-reino-cupuaçu e T3 Pupunha-banana-pimenta-do-reino-cupuaçu . Os custos com tratos culturais e colheita representaram mais de 70% da composição dos custos totais, e a participação da mão-de-obra foi superior a 50% nas fases de preparo da área e de manutenção (tratos culturais) dos SAFs. A simulação da análise de risco indicou que as variáveis que afetaram o Valor Presente Líquido no Horizonte Infinito (VPL*), de acordo com a ordem de importância (R), foram: taxa de desconto, preço do fruto de cupuaçu (Theobroma grandiflorum), custo de colheita, preço da madeira de castanha-do-brasil (Bertholletia excelsa) e o custo de tratos culturais. Apesar do alto custo de implantação e manutenção, o SAF T1 apresentou uma probabilidade de 15% de os valores do Valor Presente Líquido (VPL) se concentrarem em torno de R$35.000 ha-1.ano-1.<br>The objective of this study was to carry out the financial analysis and the risk of investment simulation in agroforestry systems (AFSs) established in 1987 in the Experimental Field of Embrapa Rondônia, located in the County of Machadinho d'Oeste, RO. Financial analysis was made through the evaluation of results from the forestry enterprise evaluation methods, and the risk analysis was carried out through the Monte Carlo simulation technique by @RISK software. Among the arrangements tested, T1 Brazil nut-Banana-Black pepper-Cupuaçu was the agroforestry system (AFS) with the best financial results, comparing to T2 Frreijó wood- banana-black pepper-cupuaçu and T3 Pupunha palm- banana-black pepper-cupuaçu. The management and harvesting costs represented more than 70$ 35.000 ha-1 year-1