Cedrela Odorata Research Articles

Soil bioindicators associated to different management regimes of Cedrela odorata plantations

A good bioindicator of soil health is one that perceives minor changes due to changes in soil management and leads to changes in the processes of the soil ecosystem. The aim was to evaluate the use of soil bioindicators in the determination of the utility of two different Cedrela odorata forestry management systems. The litter and soil samples were collected from the rhizosphere of a monoculture (with no fertilization nor irrigation), and a co-culture (with fertilization and irrigation) stand with Citrus latifolia. The soil and litter bioindicators measured were the activity of acetylesterase (FDA), acid phosphatase (AcPh), alkaline phosphatase (AlkPh), laccase, and the estimation of the potential net rate of carbon mineralization (PNRCM). The results indicated that soil enzyme activities (FDA and phosphatases) in the litter were sensitive to the different management system treatments. Enzymatic activity, per unit dry weight, was higher in litter of co-culture (FDA = 1.05 nkat g-1 AcPh = 1.33 nkat g-1; AlkPh = 03.0 nkat g-1) than in litter of monoculture (FDA = 0.617nkat g-1; AcPh = 0.40 nkat g-1; AlkPh = 0. 983 nkat g-1). Differences in soil total nitrogen content, organic matter (OM) content, and micronutrients were found. In general, the co-culture stand (with fertilization and irrigation) with C. latifolia showed the best results.

English

Water stress, caused by excess or lower of water, can negatively affect leaf metabolism and seedling growth and prevent it from developing its maximum genetic potential. In this sense, it is necessary to use as that can mitigate these deleterious effects on plants at their initial phase of growth. The aim of this work was to evaluate the effect of hydrogel in the mitigation of water stress (deficit and flooding) on photosynthetic metabolism and growth characteristics of C. odorata seedlings, and also evaluate their recovery potential after the resumption of irrigation. The characteristics of photosynthetic metabolism, growth and quality of C. odorata seedlings showed a reduction caused by water fluctuations, indicating sensitivity to these conditions, although photosynthesis photochemistry was affected to a lower extent. The addition of the hydro-retainer polymer contributed little to the biochemical and photochemical indicators of photosynthesis and seedling quality, a fact that directs us to reject our hypothesis that its use promotes mitigation of damage to the photosynthetic apparatus and to the growth. Cedrela odorata is sensitive to water variations in the soil, but recovers the photosynthetic metabolism and quality of the seedlings once the stressful water condition is suspended. The application of the hydro-retainer polymer mitigated, but the seedlings recovered regardless of their presence. © 2021 Friends Science Publishers

Kinetic analysis of thermal degradation of Cedrela odorata, Marmaroxylon racemosum and Tectona grandis from timber industry

Thermal analysis is a powerful tool to predict the composition and thermal stability of different materials. In this work, thermogravimetric analysis of Cedrela odorata, Marmaroxylon racemosum and Tectona grandis was carried out at four different heating rates (5 °C·min-1, 10 °C·min-1, 20 °C·min-1 and 40 °C·min-1) in a non-isothermal condition. The degradation kinetics was evaluated based on Flynn-Wall-Ozawa and Criado methods. The half-life time of wood degradation reaction was also studied. The wood thermal degradation process in an oxidizing atmosphere can be divided in dehydration, devolatilization, and combustion. The kinetic results revels apparent activation energy values of 130-240 kJ·mol-1 for Tectona grandis, 150-191 kJ·mol-1 for Marmaroxylon racemosum and 188-205 kJ·mol-1 for Cedrela odorata, when conversion values ranged from 0,1-0,5. The most probable degradation mechanism for wood species studied is a diffusion model based on a three-dimensional diffusion. Cedrela odorata presented the lowest reaction half-life time while Marmaroxylon racemosum showed the highest. On the basis of these results, it can be concluded that Flynn-Wall-Ozawa and Criado methods associated with half-life time of reaction may contribute to better understand the wood degradation before use it in polymer composites

Hepatoprotective effect of kaempferol glycosides isolated from Cedrela odorata L. leaves in albino mice: involvement of Raf/MAPK pathway.

Background and purpose:Paracetamol is the most implicated xenobiotic in inducing hepatotoxicity. Our study aimed to determine the impact of some kaempferol glycosides isolated from the leaves of Cedrela odorata L. on paracetamol hepatotoxicity.Experimental approach:The methanolic extract of dried leaves of C. odorata L. was subjected to the combination of spectroscopic methods (1H and 13CNMR). Six kaempferol glycosides were isolated: kaempferol-3-O-β-D-glycopyranoside (astragalin), kaempferol-3-O-β-L-rhamnopyranoside, kaempferol-3-O-β-D-rutinoside, kaempferide-3-O-β-D-rutinoside, kaempferide-3-O-β-Drutinosyl-7-O-β-D-rhamnopyranoside, and kaempferol-3-O-β-D- rutinosyl-7-O-a-D-arabinopyranoside. Fifty-four female Swiss Albino mice were divided randomly into 9 groups including (1) control negative (1 mL/kg saline; IP), (2) control positive (paracetamol 300 mg/kg; IP), (3) silymarin 50 mg/kg (IP). Animals of groups 4-9 were injected with 6 different samples of isolated compounds at 100 mg/kg (IP). One h later, groups 3-9 were injected with paracetamol (300 mg/kg IP). Two h later, tissue samples were taken from all animals to assess nitrotyrosine, c-Jun N-terminal protein kinase (c-JNK), Raf -1kinase, and oxidative stress biomarkers viz. reduced glutathione (GSH) and malondialdehyde (MDA).Findings/Results:Isolated glycosides had a prominent anti-apoptotic effect via inhibition of c-JNK and Raf-1 kinase. They also exerted a powerful antioxidant effect by modulating the oxidative stress induced by paracetamol via increasing GSH, reducing MDA and nitrotyrosine concentrations compared to positive control. The glycoside (1) showed a better effect than silymarin (standard) in ameliorating the formation of nitrotyrosine, Raf-1 kinase, c-JNK, and GSH.Conclusion and implication:Kaempferol glycosides isolated for the first time from C. odorata L. leaves exerted antioxidant and antiapoptotic effects via amelioration of oxidative stress and inhibition of Raf/MAPK pathway.

The Potential of Traditional Knowledge to Develop Effective Medicines for the Treatment of Leishmaniasis

Leishmaniasis is a neglected tropical disease that affects people living in tropical and subtropical areas of the world. There are few therapeutic options for treating this infectious disease, and available drugs induce severe side effects in patients. Different communities have limited access to hospital facilities, as well as classical treatment of leishmaniasis; therefore, they use local natural products as alternative medicines to treat this infectious disease. The present work performed a bibliographic survey worldwide to record plants used by traditional communities to treat leishmaniasis, as well as the uses and peculiarities associated with each plant, which can guide future studies regarding the characterization of new drugs to treat leishmaniasis. A bibliographic survey performed in the PubMed and Scopus databases retrieved 294 articles related to traditional knowledge, medicinal plants and leishmaniasis; however, only 20 were selected based on the traditional use of plants to treat leishmaniasis. Considering such studies, 378 quotes referring to 292 plants (216 species and 76 genera) that have been used to treat leishmaniasis were recorded, which could be grouped into 89 different families. A broad discussion has been presented regarding the most frequent families, including Fabaceae (27 quotes), Araceae (23), Solanaceae and Asteraceae (22 each). Among the available data in the 378 quotes, it was observed that the parts of the plants most frequently used in local medicine were leaves (42.3% of recipes), applied topically (74.6%) and fresh poultices (17.2%). The contribution of Latin America to studies enrolling ethnopharmacological indications to treat leishmaniasis was evident. Of the 292 plants registered, 79 were tested against Leishmania sp. Future studies on leishmanicidal activity could be guided by the 292 plants presented in this study, mainly the five species Carica papaya L. (Caricaceae), Cedrela odorata L. (Meliaceae), Copaifera paupera (Herzog) Dwyer (Fabaceae), Musa × paradisiaca L. (Musaceae), and Nicotiana tabacum L. (Solanaceae), since they are the most frequently cited in articles and by traditional communities.

Vermicompost and Mycorrhizae Use on Cedrela odorata L. Growth in Nursery Conditions

Objective: To evaluate the effect of mycorrhizal inoculation and the use ofvermicompost on the growth of red cedar (Cedrela odorata L.) seedlings under nurseryconditions.Materials and Methods: The treatments were with and without a Glomus intraradicesinoculum, combined with different amounts of vermicompost in the growth substrate (0,10, 20 and 30 %), in a completely randomized block design. The variables evaluatedwere plant height (PH), stem diameter (SD), number of leaves (NL), dry weight (DW),mycorrhizal colonization (MC) and number of spores (NS).Results: The addition of vermicompost to the growth substrate improved the growth ofC. odorata seedlings, the best treatment being 30% of vermicompost withoutmycorrhizae. The percentage of mycorrhizal colonization and number of spores per 100g of soil decreased when increasing the amount of vermicompost in the substrate.Study Limitations/Implications: None. Findings/Conclusions: Vermicompost was the leading promoter of C. odorata plantgrowth under nursery conditions.

Preparation and characterization of biochar derived from the fruit seed of Cedrela odorata L and evaluation of its adsorption capacity with methylene blue

Biochar has proven to be an effective tool in several aspects of environmental management; as well as many other applications. Herein we report biochar derived from the capsule-like interior of the seeds of Cedrela odorata L, prepared via pyrolysis at 400 °C. The biochar was characterized using: Elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA) and Raman Spectroscopy. Results demonstrate that a biochar of high thermal stability and porosity was obtained, with surface functional groups that enhance the adsorption process. Equilibrium adsorption data were consistent with the Langmuir isotherm model, indicating surface homogeneity, with maximum adsorption capacity of 158.8 mg/g. These results demonstrate that the biochar is an efficient adsorbent for the removal of MB dye from aqueous solution; and suggests its utility for further exploration in removing heavy metals from water as well as its use as a solid support in catalysis.

Alimentación, comportamiento de oviposición, ciclo de vida y enemigos naturales de Hamadryas feronia (Nymphalidae) en la Amazonía del Perú

Introduction: Hamadryas feronia feronia, which mimics the bark of trees and often makes attention-grabbing sounds when flying, has good potential for bio-business (export, handicrafts and tourist breeding centers). However, its biological aspects are still unknown, which hinder its captive breeding. Objectives: To determine the biological aspects of feeding, oviposition behavior, life cycle and natural enemies of Hamadryas feronia feronia L. in San Rafael-Indiana, Loreto, Peru. Methods: Sampling was conducted from January 2018 to December 2019 in the community of San Rafael, Amazon River. Adults were observed during the day, their food plants, oviposition behavior, biological cycle and natural enemies were recorded. The life cycle was evaluated in the laboratory, using 20 eggs recently deposited on the leaves of their host plant. Results: The larvae of H. feronia feronia feed on the leaves of Dalechampia juruana and the adults feed on the bark sap of Cedrela odorata, Spondias mombin, Uncaria guianensis and the fermented fruits of Syzygium malaccense and Pouteria caimito. Adults fly on sunny days, males emit a loud sound when flying. Females prior to oviposition flit irregularly around their host plant between 8.00 and 14.00 h and deposit their eggs on the upper and underside of leaves in isolation, most frequently on the underside. The duration of the cycle from egg to adult was 28.24 days. The average egg period was 3.75 ± 0.40 days. The larvae passed through five larval instars: the first instar 3.21 ± 1.03 days, the second 2.78 ± 0.73 days, the third 2.67 ± 0.77 days, the fourth 3.22 ± 0.81 days, and the fifth 4.61 ± 0.70 days. The prepupal period lasted 1.33 ± 0.49 days and the pupal period 6.67 ± 0.80 days; the adults hatched between 10:00 to 11:00 h. Adult males lived on average 31.80 ± 3.29 days, the female 42.00 ± 2.14 days and their eggs were parasitized by a microhymenopteran (Scelionidae). Conclusions: This study allowed to know the biological aspects of H. feronia feronia identifying its food plants of both larvae and adults, its oviposition behavior, as well as it has been determined that it has a relatively short biological cycle with a period of less than one month and its eggs are consumed by a small Hymenoptera that can hinder its production. This work provides necessary information to develop the breeding of H. feronia feronia, oriented to its conservation, environmental education and biotrade (tourism and handicrafts) in the Peruvian Amazon.

Limonoids from Guarea guidonia and Cedrela odorata: Heat Shock Protein 90 (Hsp90) Modulator Properties of Chisomicine D.

Nine new limonoids (1–9) were isolated from the stem bark of Guarea guidonia (1–4) and Cedrela odorata (5–9). Their structures were elucidated using 1D and 2D NMR and MS data and chemical methods as three A2,B,D-seco-type limonoids (1–3), a mexicanolide (4), three nomilin-type (5–7) limonoids, and two limonol derivatives (8 and 9). A DFT/NMR procedure was used to define the relative configurations of 1 and 3. A surface plasmon resonance approach was used to screen the Hsp90 binding capability of the limonoids, and the A2,B,D-seco-type limonoid 8-hydro-(8S*,9S*)-dihydroxy-14,15-en-chisomicine A, named chisomicine D (1), demonstrated the highest affinity. By means of mass spectrometry data, biochemical and cellular assays, and molecular docking, 1 was found as a type of client-selective Hsp90 inhibitor binding to the C-terminus domain of the chaperone.

Identification of mahogany sliced veneer using handheld near-infrared spectroscopy device and multivariate data analysis

Abstract The illegal logging of valuable tree species is mainly motivated by a global market that consumes logs, lumber, veneers, and furniture. The use of objective techniques to identify species and the effects of international initiatives such as CITES rules contributes to controlling trade, exploitation, and smuggling of these products. The anatomical identification of wood veneers is limited due to the loss of several anatomical characters in the production process of the veneers. For this reason, we propose the Near-Infrared Spectroscopy technique associated with chemometric tools for the discrimination of wood veneer of woods with similar general characters: Swietenia macrophylla King (mahogany), Carapa guianensis Aubl. (andiroba), Cedrela odorata L. (cedro), Micropholis venulosa Pierre (curupixá), and Hymenaea coubaril L. (jatobá) using a portable spectrometer.The development of the discrimination models was performed using the PLS-DA (Partial Least Squares for Discriminant Analysis) algorithm. The detection and subsequent exclusion of outliers were performed based on Hotelling T2, Q residuals, and errors in estimating class values. The PLS-DA models showed an efficiency between 96.5% and 100% in the samples’ discrimination among the five forest species. In conclusion, the portable NIRS technology and the PLS-DA models were suitable for the rapid identification and discrimination of the wood veneers.

Furfurylation of tropical wood species with and without silver nanoparticles: Part I: Analysis with confocal laser scanning microscopy and FTIR spectroscopy

ABSTRACT This work focused on the upgrading of non-durable tropical wood species originating from fast-growing plantations of Costa Rica. Modification of such tropical woods with furfuryl alcohol, although has not been broadly studied up to date, offers a potential way to increase their low durability. The purpose of this research was to investigate the modification effects on cell wall, vessels wall, radial and axial parenchyma using confocal laser scanning microscopy (CLSM) as well as the changes in the bands of chemical composition using Fourier-transform infrared spectroscopy (FTIR). In fact, nine tropical wood species such as Cedrela odorata, Cordia alliodora, Enterolobium cyclocarpum, Gmelina arborea, Hieronyma alchorneoides, Samanea saman, Tectona grandis, Vochysia ferruginea and Vochysia guatemalensis were treated with plain furfuryl alcohol (FA), and furfuryl alcohol combined with silver nanoparticles (FA-NPsAg). Furfurylation effects were also assessed by the weight percentage gain (WPG) of wood. Results showed that WPG varied from 14.4% to 44.3% with the FA treatment, and from 12.9% to 44.5% with the FA-NPsAg treatment. In the species which exhibited a WPG over 25% with the FA treatment, fluorescence at 600 nm band occurred mostly in the cell walls of fibres, while the furfurylation degree in radial and axial parenchyma was limited. Moreover, furfurylation occurred in lesser extent in wood species with high abundance of axial parenchyma as revealed by fluorescence. Wood species such as Vochysia ferruginea, Vochysia guatemalensis, Cedrela odorata, Samanea saman, Enterolobium cyclocarpum, which showed WPGs>25%, evidenced considerable changes in the lignin structure as observed in the FTIR spectra. In particular, with the FA treatment, the changes were observed in the bands of 1711, 1652, 1561, 889, 796 and 733 cm–1, whereas, with the FA-NPsAg treatment, the changes occurred in the bands of 1711, 1505, 1426, 1370, 1224 and 1016 cm–1. Overall, no significant difference was found in FTIR spectra and anatomical fluorescence between the FA and FA-NPsAg treatment, probably because the NPsAg concentration was insufficient for a change to occur in the bonds.

Wood profiling by non-targeted high-resolution mass spectrometry: Part 1, Metabolite profiling in Cedrela wood for the determination of the geographical origin

The determination of the geographical origin of wood can be highly relevant for several reasons: On the one hand, it can help to prevent illegal logging and timber trade, on the other hand, it is of special interest for archaeological artefacts made of wood, as well as for a variety of biological questions. For this reason, different extraction methods were first tested for the analysis of polar and non-polar metabolites using liquid chromatography coupled electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). A two-phase extraction with chloroform, methanol and water proved to be particularly successful. Subsequently, cedrela (Cedrela odorata) samples from South America were measured to distinguish geographic origin. Using multivariate data analysis, numerous origin-dependent differences could be extracted. The identification of the marker substances indicated that several metabolic pathways were affected by the geographical influences, some of them probably indicating pest infections.

Enhancing the Viability of the Modified Taungya System through Bee Keeping

ABSTRACT Beekeeping as a Non-Timber Forest Product (NTFP) under the Modified Taungya System (MTS) is under exploited. Information on the types of tree plantation and wood hives suitable for its productivity is scarce. This study addressed this knowledge gap by setting up different bee wood hives under three monoculture plantation stands of Tectona grandis Linn, Cedrela odorata L. and Terminalia superba Engl. in the Tano Offin Forest Reserve of Ghana. The experiment was laid using factorial in Randomized Complete Block Design (RCBD) and replicated 3 times. The study revealed that plantations of Tectona grandis, Cedrela odorata and Terminalia superba were all suitable for honey production even though Cedrela odorata produced the lowest honey yield. The most significant factor that affected honey production was the type of wood used to construct the bee hive. Cedrela odorata wood hives were not suitable for beekeeping since none was colonized. However, Tectona grandis wood hives yielded the highest honey, bee wax and propolis of 57.81 kg/harvest, 6.44 kg/harvest, 2.30 kg/harvest respectively. Also, Tectona grandis wood hives generated a profit of US$ 443.48/harvest compared to US$ 201.17/harvest for Terminalia superba wood hives. Tree plantations under MTS can be added value through bee keeping. Incorporating beekeeping in plantations could bring other unintended benefits such as farmer's preparedness to protect the plantations from fires which is a major threat to plantation establishment.

Amazon false cedar: a substitute for medium-density timbers from vulnerable species

Some Amazon timber species, such as Cedrela odorata and Swietenia macrophylla, are considered vulnerable due to overexploitation. Cedrelinga cateniformis, known as false cedar, has a medium-density wood that may replace species under great commercial pressure. We have assessed some physical (basic and apparent density; tangential, radial, and volumetric shrinkage) and mechanical properties (resistance to parallel compression, shear, static bending, and static bending stiffness), as well as the shear strength in the bonding surface. With an average apparent density of 0.721 g/cm³, the C. cateniformis wood presented density and shrinkage classified as medium and anisotropy coefficient of 1,654. The mechanical properties were similar or superior to higher density woods. C. cateniformis fits the C20 resistance class, with the potential to substitute species such as Couratari oblongifolia, Vochysia maxima, Cedrela odorata, and Swietenia macrophylla. The shear strength in the bonding surface was lower than that of solid wood and the wood failure percentage was below the recommended. However, the results indicate that it is possible to find an efficient bond when evaluating different bond pressures. C. cateniformis have also a high potential for timber plantations, due to its ecological characteristics, for instance, resistance against the Meliacea shoot borer and association with mycorrhiza.

Productive Potential of Precious Wood Species in the State of Chiapas, Mexico

In order to promote forest plantations in Mexico, the federal government has implemented, since 1977, programs such as the Commercial Forest Plantations Development Program (PRODEPLAN) and in 2000 launched the Strategic Forest Program for Mexico 2025. In spite of these initiatives, nowadays there are new programs (The Sembrando Vida Program) recording a critical deforestation rate of 115 thousand hectares per year and a population decrease of forest species which are endemics for Mexico and Central America. The main focus of the Sembrando Vida Program is the rescue of four timber species, although red cedar (Cedrela odorata L) and mahogany (Swietenia macrophylla King) are the two main ones. Both species are being produced under nurseries conditions, for future commercial plantations, in the state of Chiapas Mexico but there is a lack of information about the best agroecological conditions to be planted. The objective of this work was to determine the productive potential areas for cedar and mahogany under rainfed conditions in the state of Chiapas. The Arc/View version 3.3 software, which is a Geographic Information System developed by the American company ESRI was used to process and analyze the information. The results indicate that under rainfed conditions there are 81,116 hectares of high potential for cedar and 91,939 for mahogany, and 428,465 hectares of medium potential for cedar and 629,000 for mahogany.

Forest Resources Depletion: An Ecological Model for Biodiversity Preservation and Conservation in Cote D’Ivoire

The biodiversity-rich primary forest of Cote d’Ivoire has been substantially converted into a mosaic of secondary forests, cash and lumber plantations, food crops, and timber plantations, food crops, and wasteland. Deforestation started even before independence but has increased dramatically in the last three decades, resulting in the loss of most of the country’s biodiversity. It is essential to have information about the condition of the country’s natural resources following many human pressures. This research aimed to examine the Cote d’Ivoire Phytogeographical zones to understand the state of the wood’s ad wildlife in 2020 about the anthropic pressure on the whole Ivorian land. The Land-Use Planner approach has been used as a tool for creating a model for preserving biodiversity. There are 15 endangered tree species recognized, five each phytogeographical zone. Buffaloes are seen and distributed in the West and north of Cote d’Ivoire, duikers are observed in nearly all phytogeographical zones, elephants are observed in the West and North. At the same time, harnessed guibs are observed and dispersed across the nation, according to the findings. In terms of endangered tree species, the most frequent endangered trees species in the country’s south are Strombosia pustulata (6.2%), Diospyros mannii (5.1%), Protomegabaria stapfiana (3.7%), Musanga cecropiodes (3.6%), and Xylopia quintasii (3.2%). In the Middle Tectona grandis accounts for (11.8%), Nesogordonia papaverifera accounts for (4.2%), Cedrela odorata accounts for (3.7%), and Gmelia Arborea accounts for (2.8%). In the North, Isoberlinia doka accounts for (10.3%), Upaca togoenisis accounts for 8.9%, Anogeisssus leicarpa accounts for (5.1%), Pterocarpus erinaceus accounts for (4.6%), and Pericopsis laxiflora accounts for (3.9%). In reforested woods, the volume of merchantable wood timber of the P1, P2, and P3 categories per hectare is more significant than in wild forests. We find that biodiversity is severely endangered. Endemic species have decreased due to human activities like agriculture and logging, which are the root causes of deforestation and animal and plant biodiversity loss.

Chemical composition of the wood of Cedrela odorataL. andits relationship with the chemical properties of the soil of the Zumba parish province of Zamora Chinchipe, Ecuador

The research had the objective of determining the chemical composition of the wood o f Cedrela odorataL. and its relationship with the chemical properties of the soil in a forest ecosystem; for this purpose, five trees were taken as samples, from which a branch of one meter long of 10 to 20 centimeters in diameter was obtained and the analyses of ash, extracts, lignin and holocellulose of each sample were carrie d o ut; th e analysis of the level of pH, phosphorus and nitrogen of the soil was made. For statistical analysis, the non-parametric Kruskal-Wallis test was used with the Dunn test, and a bivariate correlation of Spearman was applied. In general, it was obtained that the holocellulose (62,97 %), is the most abundant component, followed by lignin (30,15 %) and with a lower percentage the content of extractable (5,64) and Ashes (1,24 % ). Th e soil where the individuals grew is very acidic (pH of4,70) with a medium p h os p ho rus level (33,74 ppm), and a high level of nitrogen (165,24 ppm). The relationship betw ee n the chemical properties of the wood and each of the chemical properties of the soil resulted in four relationships, two positive (phosphorus -lignin with a s ign if ic a n c e o f 0.1 and nitrogen -holocellulose with a significance = 0,01) and two negative (p H -a s h with a significance of 0,01 and nitrogen -lignin with a significance value of 0,04). Key words: Chemical composition, wood, Cedrela odorata

Causes and consequences of Cedrela odorata invasion in West African semi-deciduous tropical forests

Most of the West African forests have disappeared or have been deeply fragmented. This deforestation dynamic is still ongoing under a strong demographic pressure, forests being mostly replaced by agricultural lands. On the other hand, some reforestation projects are also undertaken, in particular by planting non-native species like Cedrela odorata. To our knowledge, this study is the first to investigate the causes and consequences of Cedrela odorata spread in West African natural forests. We studied a 400ha area of natural forest where 100ha of permanent plots have been affected by a major fire in 1983. Within these permanent plots, 21,444 trees were mapped, botanically determined and their diameters at breast height were measured in 2018. Using a bayesian hierarchical framework, we modelled the causes of the spread of Cedrela odorata in the studied plots, and its consequences on aboveground biomass and tree community diversity. Regarding the causes, the occurrence of Cedrela odorata is significantly linked to the fire occurence 25 years ago, to the proximity of the forest edge and to the presence of hydromorphic soils. Regarding the consequences, Cedrela odorata invasion doesn’t have any significant impact on the above-ground biomass but has a strong negative effect on the tree community diversity, as far as decreasing Simpson diversity in Hill numbers from 27 equivalent species in slightly invaded plots to 2 equivalent species in largely invaded plots. Our results highlight the long-lasting impacts of human disturbance (fire, Cedrela odorata introduction) on forest ecosystems and the need to use local species for ongoing reforestation plans in West African semi-deciduous forests.

Survival of Coptotermes testaceus (Isoptera: Rhinotermitidae) to Environmental Conditions (Relative Humidity and Temperature) and Preference to Different Substrates

Coptotermes testaceus (L.) (Rhinotermitidae) is a subterranean termite species that causes damage in urban and agricultural areas in the neotropics. Despite its economic importance, there are no studies on its basic biological aspects for laboratory management and the development of strategies for its control. The objective of the present study was to evaluate the relative humidity, temperature, substrate moisture and preference to different wood substrates for the best C. testaceus survival under laboratory conditions. For this, a range of eight relative humidity (from 9 to 100%), three temperatures (20, 25 and 30 °C), six substrates (Pinus sp, Cedrela odorata (L.), Cocos nucifera (L.), Eucalyptus urophylla (S. T. Blake), Haematoxylum campechianum (L.) and Tabebuia rosea [Bertol.] DC) and four substrate moistures, (0 to 60%) were tested. The results of this study indicated a significant effect of all factors on termite survival or termite preference. When tested independently, the highest survival percentage of C.testaceus was obtained with humidity of 100%, temperature of 20 °C, substrate moisture of 60% and the Eucalyptus urophylla substrate, reaching 83.33% survival at 21 days of observation. With these preliminary assays on small termite groups, it is concluded that with the appropriate percentages of humidity, temperature and substrate and the interaction of these three factors, further research can be conducted using larger termite groups in biologically relevant conditions, in order to study various aspects of C. testaceus biology.

Shade tree species affect gas exchange and hydraulic conductivity of cacao cultivars in an agroforestry system.

Shade tolerance is a widespread strategy of rainforest understory plants. Many understory species have green young stems that may assimilate CO2 and contribute to whole-plant carbon balance. Cacao commonly grows in the shaded understory and recent emphasis has been placed on diversifying the types of trees used to shade cacao plants to achieve additional ecosystem services. We studied three agricultural cacao cultivars growing in the shade of four timber species (Cedrela odorata L., Cordia thaisiana Agostini, Swietenia macrophylla King and Tabebuia rosea (Bertol) A.D.C.) in an agroforestry system to (i) evaluate the timber species for their effect on the physiological performance of three cacao cultivars; (ii) assess the role of green stems on the carbon economy of cacao; and (iii) examine coordination between stem hydraulic conductivity and stem photosynthesis in cacao. Green young stem photosynthetic CO2 assimilation rate was positive and double leaf CO2 assimilation rate, indicating a positive contribution of green stems to the carbon economy of cacao; however, green stem area is smaller than leaf area and its relative contribution is low. Timber species showed a significant effect on leaf gas exchange traits and on stomatal conductance of cacao, and stem water-use efficiency varied among cultivars. There were no significant differences in leaf-specific hydraulic conductivity among cacao cultivars, but sapwood-specific hydraulic conductivity varied significantly among cultivars and there was an interactive effect of cacao cultivar × timber species. Hydraulic efficiency was coordinated with stem-stomatal conductance, but not with leaf-stomatal conductance or any measure of photosynthesis. We conclude that different shade regimes determined by timber species and the interaction with cacao cultivar had an important effect on most of the physiological traits and growth variables of three cacao cultivars growing in an agroforestry system. Results suggested that C. odorata is the best timber species to provide partial shade for cacao cultivars in the Barlovento region in Venezuela, regardless of cultivar origin.