Dendrochronological growth characterization of timber species from moist to dry tropical forests in Bolivia

En la búsqueda de mayor información y entendimiento de las especies Machaerium scleroxylon, Amburana cearensis, Cedrela fissilis y Cedrela angustifolia, muy valiosas y comerciales en nuestro país pero cuyas poblaciones han estado considerablemente, hemos aplicado la dendrocronología como factor común en cada uno de los análisis, además de la relación del crecimiento y el clima. Las aplicaciones y casos variaron según la novedad del estudio, avances y vacíos de conocimiento. Capítulo II: Empezamos con el análisis del potencial dendrochronológico de una especies nueva y poco conocida, Macherium scleroxylon. Las características de la madera y fenología de esta especie presentan variaciones lo que ha dificultado el avance en las investigaciones, mayor conocimiento de la especie y consecuentemente deficiente manejo forestal. Las características anatómicas de la madera (false rings, lenses and wedging rings) requirieron mucho tiempo y paciencia para el reconocimiento e identificación de los anillos de crecimiento pero, una vez sobrellevado este contratiempo, se pudo estimar el MLD, cutting cycle and crecimiento medio además de analizar el crecimiento en relación al clima local (bosque tropical seco) y a atmospheric circulation patterns (El Niño-Southern Oscillation). Capítulo III: Para el caso del roble (Amburana cearensis), ya se contaba con información previa que determinaron la anualidad de la especie. El objetivo de la investigación fue el de ir paso más alla para conocer a la especie. Demostrando otra aplicación de la dendocronología en especies locales, reconstrucciones climáticas, además de su utilidad en proporcionarnos mayor información sobre el crecimiento y comportamiento de la especie en el bosque tropical seco. Capítulo IV: Finalmente y debido a la urgencia de conocer más sobre el crecimiento de Cedrela especies por su importancia en el CITES y normativas locales para regular el mercado internacional, se analizaron las diferencias de crecimiento de Cedrela fissilis y Cedrela angustifolia en 3 diferentes tipos de bosque: Bosque seco Chiquitano, Chiquitano transicional amazónico y montano Tucumano..

Chemical differentiation of Bolivian Cedrela species as a tool to trace illegal timber trade

Combating illegal timber trade requires the ability to identify species and verify geographic origin of timber. Forensic techniques that independently verify the declared species and geographic origin are needed, as current legality procedures are based on certificates and documents that can be falsified. Timber from the genus Cedrela is among the most economically valued tropical timbers worldwide. Three Cedrela species are included in the Appendix III of CITES: C. fissilis, C. odorata and C. angustifolia (listed as C. lilloi). Cedrela timber is currently traded with false origin declarations and under a different species name, but tools to verify this are lacking. We used Direct Analysis in Real Time Time-of-Flight Mass Spectrometry (DART-TOFMS) to chemically identify Cedrela species and sites of origin. Heartwood samples from six Cedrela species (the three CITES-listed species plus C. balansae, C. montana and C. saltensis) were collected at 11 sites throughout Bolivia. Mass spectra detected by DART-TOFMS comprised 1062 compounds; their relative intensities were analysed using Principal Component Analyses, Kernel Discriminant Analysis (KDA) and Random Forest analyses to check discrimination potential among species and sites. Species were identified with a mean discrimination error of 15–19 per cent, with substantial variation in discrimination accuracy among species. The lowest error was observed in C. fissilis (mean = 4.4 per cent). Site discrimination error was considerably higher: 43–54 per cent for C. fissilis and 42–48 per cent for C. odorata. These results provide good prospects to differentiate C. fissilis from other species, but at present there is no scope to do so for other tested species. Thus, discrimination is highly species specific. Our findings for tests of geographic origin suggest no potential to discriminate at the studied scale and for the studied species. Cross-checking results from different methods (KDA and Random Forest) reduced discrimination errors. In all, the DART-TOFMS technique allows independent verification of claimed identity of certain Cedrela species in timber trade

Tropical timber forensics : a multi-methods approach to tracing Bolivian Cedrela

Illegal logging is one of the main drivers of species degradation and contributors to global warming. This practice negatively impacts to forest stakeholders at international and local level. Effective control strategies are required to counteract illegal harvesting and trade of tropical timber. Stable isotopes, chemical properties, and DNA are non-manipulative tree characteristics and have the potential to be used for tracing geographical origin. The overall objective of my PhD thesis was to support the implementation of sustainable forest management in Bolivia through developing complementary methods to detect illegal logging. </p

Rainfall and temperature variability in Bolivia derived from the tree-ring width of Amburana cearensis (Fr. Allem.) A.C. Smith

Amburana cearensis is an important timber species in tropical lowland dry forests in Bolivia. We used dendrochronological methods to evaluate its climatic sensitivity and to identify its potential for the reconstruction of climate. For that, we collecte

Genetic differences among Cedrela odorata sites in Bolivia provide limited potential for fine-scale timber tracing

Illegal trade of tropical timber leads to biodiversity and economic losses worldwide. There is a need for forensic tools that allow tracing the origin of timber and verifying compliance with international and national regulations. We evaluated the potential for genetic tracing of Cedrela odorata, one of the most traded neotropical timbers, within Bolivia. Using a set of seven microsatellites (SSRs), we studied the spatial distribution and genetic diversity and tested whether populations show sufficient genetic discrimination for timber tracing at a national level. Cambium and leaves were sampled from 81 C. odorata trees from three sites, at 268–501-km distance. To explore genetic differentiation, Bayesian clustering and principal component analysis (PCA) were employed. To infer the origin of samples, we conducted kernel discriminant analysis (KDA) based on a PCA that included all alleles and a manual assessment of site-unique alleles. The PCA showed three distinct genetic clusters, but only one of them corresponded with one of the sampled sites. The KDA based on allele frequency had a 33.7% mean classification error, with a considerably lower error (8.2%) for the site which matched with one genetic cluster. The blind test on unique alleles led to a similar classification error (30%). The occurrence of multiple genetic clusters within sites suggests that Bolivian C. odorata populations contain several parental lines, resulting in limited potential for forensic tracing at a national level. Based on our findings, we recommend for additional sampling across the spatial range of C. odorata within the country to support the development of forensic techniques for this species.</p

Binary dataset of alleles from cambium and leaves of Cedrela odorata in Bolivia

Binary dataset of alleles from cambium and leaves of Cedrela odorata in Bolivi

Dendrochronological Advances in the Tropical and Subtropical Americas: Research Priorities and Future Directions

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Nuclear and plastid SNP markers for tracing Cedrela timber in the tropics

Illegal logging and trade of timber are major worldwide concerns, resulting in biodiversity and economic losses. Tropical tree species in the genus Cedrela, which have historically been heavily exploited, are still often illegally traded and there is an urgent need to develop tools to verify the origin of Cedrela products. A set of 351 SNP loci for Cedrela species from Bolivia, Brazil, Costa Rica, Cuba, Ecuador, French Guiana, Mexico, and Peru was developed using restriction associated DNA sequencing (RADSeq) and low coverage MiSeq genome sequencing, and adapted for MassARRAY genotyping. After screening of 94 individuals covering most of the distribution of Cedrela, a final set of 136 SNP loci which included 92 nuclear SNPs, 22 chloroplast markers (20 SNPs and 2 INDELs), and 22 mitochondrial markers (19 SNPs and 3 INDELs) was selected and tested for potential to verify Cedrela timber origin

Nuclear and plastidial SNP and INDEL markers for genetic tracking studies of Jacaranda copaia

Nuclear and plastidial single nucleotide polymorphism (SNP) and INDEL markers were developed using restriction associated DNA sequencing (RADSeq) and low coverage MiSeq genome sequencing for population genetics and timber tracking purposes in the Neotropical timber species Jacaranda copaia. We used 407 nuclear SNPs, 29 chloroplast, and 31 mitochondrial loci to genotype 92 individuals from Brazil, Bolivia, French Guiana, and Peru. Based on high amplification rates and genetic differentiation among populations, 113 nuclear SNPs, 11 chloroplast, and 4 mitochondrial loci were selected, and their use validated for genetic tracking of timber origin