Mahogany Research Articles

Soybean morphology and physiology in mahogany agroforestry system with organic fertilizer application

Land conversion causes a decrease in the area of agricultural land, so that agricultural cultivation efforts through agroforestry systems are needed, such as planting between mahogany trees. The aim of the study was to examine the morphological and physiological responses of soybeans to organic fertilizers in mahogany-based agroforestry systems. The study consisted of a single factor, namely the type of organic fertilizer using a completely randomized block design. Treatment of types of fertilizers with four levels, namely: chemical fertilizer, chicken, goats and cow manure. The results showed that the type of organic fertilizer affected soybean morphology, namely plant height 3 and 4 WAP, leaf number 4 WAP, and soybean physiology, namely total chlorophyll. The plant height and the number of leaves were highest in the cow manure fertilizer. Chicken manure produced the highest total chlorophyll, which was 0.0743 mg/g. Total chlorophyll count was positively correlated with the amount of chlorophyll a and b. In addition, plant fresh weight was positively correlated with plant biomass. Soybean has the potential to be cultivated in agroforestry systems and the addition of nutrients with organic fertilizers.

Production of mahogany particleboards using branches and wood residues

Abstract Mahogany (Swietenia macrophylla King) is one of the most valuable wood species found in the American Continent. This study is an evaluation of the production of particleboards using wood residues from the branches and trunk of a mahogany tree. It was designed to test the feasibility of production and the mechanical and physical characteristics of the finished particleboards, as well as to compare the results with similar studies and the requirements of normative documents. The particles were generated from the trunk and branches of a mahogany tree separately and mixed in different proportions to test their influence on the final product. They were bonded using 12% polyurethane resin from renewable resources and pressed under 90º C and 3.5 MPa for 10 minutes. The specimens were prepared and tested according to the guidelines established by the NBR 14810 regarding the static bending, internal bond, stiffness and thickness swelling (24h) tests. The results indicated that there is no significant correlation between the trunk-branches proportion and the Modulus of Elasticity/Rupture values. The production of the particleboards using the residues is feasible and the results of most of the tests fitted the normative requirements, which means that with the refinement of the production process it is possible to have a good product that fully complies with the technical standards.

Enhancement growth of Swietenia Mahogany seedlings under different irrigation intervals by foliar application of basil leaves extract

Drought is a global problem that many countries suffer from, as a result of climate change. Swietenia mahogany tree is grown as an ornamental and timber tree and its wood is used in shipbuilding and furniture manufacturing. Therefore, the goal is to use this type of plant for its multiple uses, while reducing the quantities of water consumed for its growth to cope with the drought conditions by using basil leaves extract as natural extract and eco-friendly, it is noticed that all vegetative growth parameters and photosynthetic pigments decreased by increasing irrigation intervals, the rest chemical constituents were increased by increasing irrigation intervals except total sugar content which showed the highest value at irrigation every 7 days. Treating the seedlings with BLE at 10% enhanced all vegetative growth parameters and photosynthetic pigments and reduce all oxidative markers and so antioxidant compounds, it was concluded that BLE at 10% enhanced the tolerance of S. mahogany seedlings under all irrigation levels. The irrigation every 5 days showed preferable results followed by irrigation every 7 days.

The Development of Supplement Book of Mycorrhizal Spore Based on Science Literacy at The Campus Forest in State University of Medan

This study aims to determine the feasibility and effectiveness of the supplement book of mycorrhizal spore based on science literacy at the campus forest in State University of Medan that has been developed. The subjects of this research are material experts, learning experts, design experts, and students who take the Lower Level Organism Taxonomy course in the Department of Biology, State University of Medan. Research and development (R and D) with the Thiagarajan (4D) model, namely: (1) Define data taken from the results of student needs analysis and get a score of 69% Students to need mycorrhizal spore supplement books based on scientific literacy, (2) Design the outline of the supplement book produces four chapters that will be discussed, namely, introduction, the development of mycorrhizae in the tropics, methods of observing mycorrhizal and mycorrhizal fungi on mahogany trees in the Unimed campus forest, (3) Development of field research that has been carried out to obtain results. the results of three genera of mycorrhizal spores found under the tree Swietenia mahogany L, namely Glomus sp. with 28 types of spores, Gigaspora sp. with 4 types of spores, and Acaulospora sp. with 3 types of spores. After the observation results are obtained, it is developed into a supplement book that will be tested for feasibility. The results of the material expert assessment obtained a score of 81% in the very worthy category and 95% for the assessment of scientific literacy aspects in the very worthy category, and the results of the learning expert assessment obtained a score of 85.5% in the very worthy category and the results of the design expert assessment obtained a score of 86.6% in the very worthy category. After the book is declared worthy, the fourth stage is carried out. Dissemination (dissemination) is carried out by individual product trials obtaining a score of 87% in the very worthy category, the small group test obtaining a very worthy score of 89%, and the limited group test obtaining a score of 87% in the very worthy category. To prove whether the developed supplement book is effective for use in the Lower Level Organism Taxonomy course, the N-Gain test obtained a score of 63% in the category of quite effective.

Study on the Potential of Historical Mahogany Trees in Improving Urban Air Quality

Metro City is one of the cities in Lampung Province, Indonesia, which has experienced various infrastructure development which contributed to the decrease of the air quality. Urbanization also causes constant decrease in term of the number of green open spaces.Yet green open space plays an important role in maintaining urban air quality. Vegetation (i.e., tree) as the main component of green open space has the ability to absorb and store carbon emission. In Metro city, there is a major green open space that includes numerous large-sized Mahogany trees lining along A.H. Nasution Road. The purpose of this study was to estimate the level of air pollution from emissions of the passing-by motorized vehicles, calculate the capacity of carbon sequestration by the Mahogany trees, and determine the potential of the Mahogany trees in improving air quality. Authors collected primary data on the diameter of the tree trunks and the number of passing-by vehicles to estimate the carbon-storing capacity and carbon emission by utilizing allometric equation and emission load analysis. This study concluded that the Mahogany trees could play an important role on storing 74% of expected annual CO2 emission in Metro City. This could be linked to the achievement of the SDGs especially Target 11.6.

Molecular characterization of mahogany tree (Swietenia macrophylla King, Meliaceae) in the remnant natural forest of Ecuador

ABSTRACT The Swietenia macrophylla King (Meliaceae) mahogany tree is widely spread in the neotropics. In Ecuador, it has a wide distribution range from the coastal zone to the Amazon. The mahogany tree is an endangered species due the overexploitation of the high commercial value of its wood. This study is aimed to characterize the Simple Sequence Repeat (SSR) variability of 123 trees selected from six provinces of Ecuador. The results showed that the natural mahogany population had a low level of genetic diversity (A = 6.9; Ho = 0.39; He = 0.43) and a significant heterozygous deficit inbreeding coefficient (F = 0.16). The probability of identity (PI) of the 12 microsatellite markers was low 4.3 × 10−9 and the cumulative exclusion probability of 99.99%. Additionally, the relatedness coefficient among individuals was −0.010 (se = 0.004). The genetic diversity among populations was moderate (ΦST = 8%). In addition, the structure analysis showed two genetic groups; however, it was possible to distinguish admixture within the entire range evaluated. These results show the need to establish strategies that allow the recovery and increase of the genetic diversity in natural populations, especially with the selection of trees to harvest seeds, as well as crossing the tree genetic pool to recombine their diversity.

Assessing the Spectral Information of Sentinel-1 and Sentinel-2 Satellites for Above-Ground Biomass Retrieval of a Tropical Forest

Earth Observation (EO) spectral indices have been an important tool for quantifying and monitoring forest biomass. Nevertheless, the selection of the bands and their combination is often realized based on preceding studies or generic assumptions. The current study investigates the relationship between satellite spectral information and the Above Ground Biomass (AGB) of a major private forest on the island of Java, Indonesia. Biomass-related traits from a total of 1517 trees were sampled in situ and their AGB were estimated from species-specific allometric models. In parallel, the exhaustive band combinations of the Ratio Spectral Index (RSI) were derived from near-concurrently acquired Sentinel-1 and Sentinel-2 images. By applying scenarios based on the entire dataset, the prevalence and monodominance of acacia, mahogany, and teak tree species were investigated. The best-performing index for the entire dataset yielded R2 = 0.70 (R2 = 0.78 when considering only monodominant plots). An application of eight traditional vegetation indices provided, at best, R2 = 0.65 for EVI, which is considerably lower compared to the RSI best combination. We suggest that an investigation of the complete band combinations as a proxy of retrieving biophysical parameters may provide more accurate results than the blind application of popular spectral indices and that this would take advantage of the amplified information obtained from modern satellite systems.

Rhipsalis baccifera (J.S.Muell) Stearn, an Epiphytic Cactus of Bandung City, Indonesia: the Field Examination on the Biological Features and Host Distribution

This study is the first report on the distribution of Rhipsalis baccifera (J.S.Muell) Stearn in Bandung, West Java, Indonesia. R. baccifera is an epiphyte cactus that generally grows on the vertical substrate of tree barks. The distribution of R. baccifera was examined by tagging the tree hosts using a global positioning system (GPS). Additionally, the organs and growth stages of the cactus, as well as the interactions of the cactus with the host plants, were photographed. The results show that R. baccifera is distributed unevenly in Bandung, as the population density is higher in the northern area of the city than in the south. This uneven distribution suggests that frugivorous birds and human activities in the area play an important role in the distribution of R. baccifera. The cactus has spines during its early stage, which is greatly reduced upon reaching its mature stage. However, within the same region, the cactus appears to selectively grow on specific hosts, mainly on trees with rough barks or grown by moss. In Bandung, the cactus is mostly found growing on mahogany trees (Swietenia macrophylla King). Not all trees adjacent to the host trees have the cactus growing on them, which further suggests the cactus’ preference for specific host trees.

The role of the mahogany tree (Swietenia macrophylla King) on quantity and quality of water that fall below the canopy

Mahogany trees (Swietenia macrophylla) are often planted in urban forests area. This shady-crowned tree has a role in controlling the quantity and quality of rainwater that falls to the ground. Mahogany trees also affect the quality of rainwater through interception, fall, and stemflow. The purpose of this research was to determine the impact of the interception process, such as throughfall and stemflow, on changes in rainwater quality of the mahogany tree. The Data that needed to be measured were tree dimension, rainfall interception, and rainwater quality. Interception measurement was performed by calculating the number of throughfall and stemflow in one month-measurement. While the measurement of rainwater quality was measured once in the laboratory. These water quality measurements include Electrical Conductivity (EC), hardness, the content of Elements Ca, Mg, Na and K, and pH concentrations. The results based on the total area of the crown showed that mahogany had an interception value of 18.088%. In the throughfall measurement, the mahogany has a throughfall of 81.799%, while the amount of the stemflow is only 0.113%. The correlation of interception values, throughfall, and stemflow with rainfall are in general positively correlated. That means the higher rainfall water will increase the number of interception, throughfall, and stemflow. The results on water quality measurement explain that Ec value in rainwater interception was increased compared to water produced from rainfall in mahogany trees. It also has the same condition in hardness measurement. In pH measurements, the interception of rainwater has less pH when compared to direct rainfall water. In addition, the content of Elements Ca, Mg, K, and Na in Stemflow and Throughfall water have more numbers than rainfall itself.

Argyrotoxins A-C, a trisubstituted dihydroisobenzofuranone, a tetrasubstituted 2-hydroxyethylbenzamide and a tetrasubstitutedphenyl trisubstitutedbutyl ether produced by Alternaria argyroxiphii, the causal agent of leaf spot on African mahogany trees (Khaya senegalensis)

Three previously undescribed metabolites named argyrotoxins A-C, were isolated, together with the well known porritoxinol, its closely related phthalide, a phthalide derivative, zinniol, alternariol and its 4-methyl ether from Alternaria argyroxiphii E.G. Simmons & Aragaki, the causal agent of leaf spot on African mahogany trees, Khaya senegalensis A. Juss. (Meliaceae). The known compounds were identified comparing their physical and spectroscopic properties to those previously reported in literature. Argyrotoxins A-C were characterized essentially by NMR (1H, 13C, COSY, HSQC, HMBC and NOESY NMR spectra) and HRESIMS spectra as 4-(7-methoxy-6-methyl-3-oxo-1,3-dihydro-isobenzofuran-5-yloxy)-2-methyl-butyric acid, 5-but-2-enyloxy-N-(2-hydroxyethyl)-2-hydroxymethyl-3-methoxy-4-methyl-benzamide and 1-(5-(hydroxymethyl)-3-methoxy-4-(methoxymethyl)-2-methylphenoxy)-3-methylbutane-2,3-diol, respectively. The absolute configuration of argyrotoxin A was determined through electronic circular dichroism, by applying the biphenyl chiroptical probe approach. The phytoxicity of all metabolites isolated was evaluated by leaf puncture assay at concentration of 1 mg/mL. Zinniol proved to be the most active compound causing necrotic lesions on young leaves of Hedera elix L., Phaseolus vulgaris L. and Quercus ilex L. Argirotoxins A and B were found active, to a minor extent, on Phaseolus vulgaris L. leaves, while porritoxinol exhibited activity on holm oak leaves. The other secondary metabolites herein reported for A. argyroxiphii were inactive.

Quantification of biomass and litter in agroforestry system with sour orange cultivation in the Brazilian Amazon

The knowledge of the quantity and composition of the deposited biomass is useful to plan the nutrient management of cultivations in agroforestry systems. The objective of this work was to evaluate the production of biomass and litter in two agroforestry systems with organic and conventional cultivations of sour orange. The areas use models of orange production by monoculture and under agroforestry systems: the first agroforestry system is composed of rows of brazilian mahogany (Swietenia macrophylla K.) accompanied by double rows of orange trees (Citrus aurantium L.); the second system is composed of rows of ingá (Ingá edulis Mart.) accompanied by double rows of orange trees. A completely randomized design was used in a 10x2 factorial scheme, with 4 replications. The locations within the management systems were organized as follows: agroforestry system composed of mahogany trees; Ingá trees agroforestry system; conventional sour orange monoculture system. The areas that the biomass and litter were collected in the locations in the systems were: between plants in the row for cultivation of forest species that make up the system; between rows of the forest species row and orange cultivation row; between plants in the orange cultivation row; between rows of the double row of orange cultivation. Two periods were analyzed in the experiment: the months of lowest and highest rainfall. Agroforestry systems promoted greater biomass and litter to the soil compared to monoculture. In this way, they were configured as a beneficial practice for the soil in sour orange crops in the Brazilian Amazon.

Studies on Some Mechanical Properties of PVC-Wood Fiber Composite

In this study some mechanical properties of PVC-Wood fibre composite were investigated. The wood fibre was gotten from a mahogany tree. The sample was moulded and shaped at a temperature of 150oC using a hadraulic hot press and pressure of 3bar for 5mins and the mechanical properties were studied base on varying the wood fibre contents from 0% to 50%. The hardness test carried out using the durometer hardness tester show a decrease in the hardness of the composite as the wood fibre is varied from 0%, 10%, 20%, 30% 40% and 50% and the impact strength of the composite decreases as well in that order. The tensile strength conducted using the Mensato Tensometer show a decrease at 10% wood fibre, while an increase in the wood fibre to 20% show an increase in the tensile strength on further addition of the wood fibre a decrease is noticed. This decrease in tensile strength decreases the strain of the PVC-wood fibre composite and hence increasing the modulus of elasticity of the PVC-wood fibre composite as the wood fibre is been added.

Shading effect of multipurpose trees on growth and yield of Boro rice cv. BRRI dhan29

A field experiment was conducted during Rabi season (December-May) to compare the vegetative growth and yield of Boro rice cv. BRRI dhan29 under tree shade and ambient (shade free) condition in Boira village at Sadar upazila of Mymensingh district. In this study, twelve years old Mango (Mangifera indica), eight years old Mahogany (Swietenia macrophylla) and ten years old Sissoo (Dalbergia sissoo) trees were selected as treatment and each of the tree had six replications. The experiment was laid out in a two factorial Randomized Complete Block Design (RCBD). To achieve the objective, the parameters reflect on growth, yield and yield contributing characters were recorded at different stages of rice plants under both tree shade and ambient condition. The result showed that different treatments significantly influenced on the growth and yield contributing components viz. plant height, effective tillers hill-1, leaf number hill-1, leaf area hill-1, panicle length, filled spikelet’s panicle-1 and grain yield. The maximum (5.20 tha-1, 7.65 tha-1 and 13.20 tha-1) grain yield, straw yield and biological yield of rice was produced in the Mango ambient condition and the minimum (1.68 tha-1 ) grain yield in the Mango tree shade and straw yield and biological yield (3.64 tha-1 and 5.93 tha-1) was produced in the Mahogany tree shade area. The highest (43.87%) harvest index of rice was recorded in Mahogany tree ambient area and the lowest (24.94%) in Mango tree shade area. From the above results, it was found that maximum (68%) reduction of rice grain yield was recorded under Mango tree shade, moderate (28%) under the shade of Mahogany tree where as no rice grain yield reduction was occurred in Sissoo tree shade and ambient condition. Therefore, it can be concluded that in consideration of shade casted by different trees, Sissoo-Boro rice and Mahogany-Boro rice based agroforestry systems is suitable in second case although there was some yield loss (28%) compare to Mango-Boro rice agroforestry system.

Control techniques and evaluation of pathogen influence on African mahogany (Khaya grandifoliola C. Dc.) infected by Lasiodiplodia theobromae Pat.

The constant demand by society for quality timber associated with reduced exploitation of native forests has promoted the use of alternative species such as the African Mahogany (Khaya grandifoliola C. Dc.). The production cycle of this species began with the introduction of seeds in the 1970s and good silvicultural performance of the first planted matrix trees, then spreading throughout several Brazilian regions and resulting in increased occurrence of pest insects and diseases, such as African mahogany canker (Lasiodiplodia theobromae Pat.). In this context, this work aimed to identify control methods and to analyze the damage caused by canker in symptomatic African mahogany trees. Scraping and chemical treatments were carried out in different concentrations to analyze the best method to prevent an increase of lesions caused by the pathogen. The anatomical characteristics and basic density of wood with and without canker were evaluated. It was observed that scraping until reaching the healthy tissue is an effective method of control which stimulates the healing process after a certain period. For the chemical treatment without scraping, Nativo® fungicide is efficient through direct application. The presence of canker promoted an increase in wood density and changes in anatomical characteristics.

Bark-stripping of African mahogany trees (Khaya spp.) by cattle in silvopastoral systems in Brazil

African mahogany (Khaya spp.) produces high-value wood, and its cultivation is expanding in tropical regions. The silvopastoral system is an alternative method for growing timber trees, but may involve cattle stripping bark from trees, which limits its usefulness. We evaluated cattle bark-stripping rates in two African mahogany species, K. grandifoliola and K. senegalensis, in a silvopastoral system with Guinea grass, Panicum maximum, in South-eastern Brazil. Cattle had free access to plantations of both tree species for 2 weeks in May 2018 and July 2019, when trees were 5 and 6 years old, respectively. In 2018, we found bark-stripping only in K. grandifoliola, but in 2019 both species were bark-stripped. The proportion of bark-stripped trees was higher for K. grandifoliola than for K. senegalensis. Considering both years, 29/155 (18.7%) K. senegalensis trees and 106/153 (69.3%) K. grandifoliola trees had some of their bark-stripped by cattle. Bark-stripped trees had lower trunk diameter growth than unaffected trees, and their growth was affected by the degree of bark-stripping. Some trees were girdled by bark-stripping. These trees dried up, and some of them fell down 1 year after girdling. In 2019, despite the high herbage mass, levels of crude protein in the pasture were very low, which may have stimulated bark-stripping. Although we could not identify the reasons for bark-stripping, we recommend avoiding the use of silvopastoral systems with cattle and African mahogany in times of the year when pasture has a low quality.

Genetic diversity of Fusarium pseudocircinatum in the central western region of Mexico: the case of big-leaf mahogany malformation disease

Fusarium pseudocircinatum is the main causal agent of big-leaf mahogany malformation disease (BLMMD) of mahogany (Swietenia macrophylla) in Mexico. Although, BLMMD is the most important disease for this high-value timber species, there is a lack of information on the genetic variation present in geographically diverse isolates of F. pseudocircinatum. The objective of this study was to determine the genetic diversity of populations of F. pseudocircinatum causing BLMMD in the central western region of Mexico. A total of 611 big-leaf mahogany trees were inspected at eight sites in four states (Colima, Guerrero, Jalisco and Michoacán); of these, 42.7% showed malformation symptoms similar to those of BLMMD. Of 374 Fusarium isolates that were recovered, 277 were identified as F. pseudocircinatum, 56 were F. mexicanum, and 41 were Fusarium spp. An ISSR analysis of the F. pseudocircinatum isolates generated 51 bands of which 38 were polymorphic (76.8%) with a mean of 17 bands per primer. A total of 87 multilocus genotypes (MLGs) were identified. Nei's genetic diversity analysis showed that the isolates had a high genetic diversity average (0.147), with values ranging from 0.070 to 0.365 depending of the geographical location. An analysis of molecular variance revealed that the variation within the populations was low (27.36%), while the variation within MLGs was significant (72.64%), indicating genetic flow. Overall, the genetic variability of F. pseudocircinatum populations was high and the MLGs from Colima (Colima) and Gabriel Zamora (Michoacán) were placed centrally, which possibly is evidence of ancestry and indicates its dispersion routes in the central western region of Mexico.

Leaf nutrient status as a predictor for Mahogany (Swietenia sp.) fruit productivity

Soil fertility is one of the limiting factors for tree productivity. Trees as seed sources that have grown in low-fertility soil would not have sufficient edaphic supports for its physiological- and morphological- development, including fruit production. As the ambient environmental conditions are manifested in tree physiology, leaf nutrition status can be used for diagnosing soil fertility. This study aimed to test the possibility of leaf nutrient status as a predictor for Mahogany seed source productivity. The study examined six locations of mahogany fruit productions in West Java from February until December 2018. Soil and leaves samples were collected from fruiting and un-fruiting Mahogany trees, which have similar levels of generative and vegetative phases. Sampling was conducted two months after the fruiting season. Results showed that the fruiting phenomenon was highly correlated with Nitrogen (N) concentration in leaves after the fruiting phase of the tree. The N-total concentration of mahogany leaves obtained from six stands in Bogor and Cianjur were ranged from 1.76% to 3.66%, with an average of 2.33%. Trees that have N concentration above the average indicated a propensity of unproductive (not fruiting) in that year.

Accumulation of Lead (Pb) in the Lichen Thallus of Mahogany Trees in Medan City Road

Rapid growth of vehicles in Medan, Indonesia, is one of the causes in the increasing of air pollution, in which approximately 85% is contributed merely by vehicles. On the other hand, the use of lead-based fuel in motor vehicle increases the air contamination in Medan. This study aimed to obtain an accumulation of lead (Pb) in the thallus of lichens in mahogany trees in four different locations in Medan, Sumatera Utara, Indonesia, in which the lichens act as a bioindicator of air contamination as well as measuring the lichen’s lead correlation and traffic densities. Purposive sampling location was determined based on the traffic density level with different air pollutions; the location which was far from traffic circulation was used as the control. The analysis of Pb was conducted using atomic absorption spectrophotometry (AAS). The data were analyzed descriptively to discover and compare Pb accumulation between each location with different traffic density levels. The result showed that there were 11 species of 7 genera and 7 families with two types of the thallus (foliose and crustose) in mahogany trees. The traffic density level influenced the diversity of lichens as the traffic density was quite significant with the number of lichen types. The levels of Pb and traffic density correlated very significantly at the level of α = 0.01 for Parmelia saxatilis, Lepraria incana, and Pertusaria amara type, while Opegrapha atra had a significant correlation. The accumulation of Pb in the thallus of Pertusaria amara ranged from 5.23 to 15.07 μg/g, whereas medium in Lepraria incana ranged from 1.19 to 4.88 μg/g. Thus, Pertusaria amara which had greater Pb level than Lepraria incana had the potential as a resistant bioindicator. The correlation analysis of Pb levels and traffic density showed that Pertusaria amara had a significantly high correlation compared with Parmelia plumbea, Parmelia glabratula, and Graphis scripta. Furthermore, Lecanora conizaeoides was a tolerant bioindicator of air pollution whereas Parmelia saxatilis had the potential to be a tolerant bioindicator.

Significant emissions of dimethyl sulfide and monoterpenes by big-leaf mahogany trees: discovery of a missing dimethyl sulfide source to the atmospheric environment

Abstract. Biogenic volatile organic compounds exert a strong influence on regional air quality and climate through their roles in the chemical formation of ozone and fine-mode aerosol. Dimethyl sulfide (DMS), in particular, can also impact cloud formation and the radiative budget as it produces sulfate aerosols upon atmospheric oxidation. Recent studies have reported DMS emissions from terrestrial sources; however, their magnitudes have been too low to account for the observed ecosystem-scale DMS emission fluxes. Big-leaf mahogany (Swietenia macrophylla King) is an agroforestry and natural forest tree known for its high-quality timber and listed under the Convention on International Trade in Endangered Species (CITES). It is widely grown in the American and Asian environments (>2.4 million km2 collectively). Here, we investigated emissions of monoterpenes, isoprene and DMS as well as seasonal carbon assimilation from four big-leaf mahogany trees in their natural outdoor environment using a dynamic branch cuvette system, high-sensitivity proton transfer reaction mass spectrometer and cavity ring-down spectrometer. The emissions were characterized in terms of environmental response functions such as temperature, radiation and physiological growth phases including leaf area over the course of four seasons (summer, monsoon, post-monsoon, winter) in 2018–2019. We discovered remarkably high emissions of DMS (average in post-monsoon: ∼19 ng g−1 leaf dry weight h−1) relative to previous known tree DMS emissions, high monoterpenes (average in monsoon: ∼15 µg g−1 leaf dry weight h−1, which is comparable to oak trees) and low emissions of isoprene. Distinct linear relationships existed in the emissions of all three BVOCs with higher emissions during the reproductive phase (monsoon and post-monsoon seasons) and lower emissions in the vegetative phase (summer and winter seasons) for the same amount of cumulative assimilated carbon. Temperature and PAR dependency of the BVOC emissions enabled formulation of a new parameterization for use in global BVOC emission models. Using the measured seasonal emission fluxes, we provide the first estimates for the global emissions from mahogany trees which amount to circa 210–320 Gg yr−1 for monoterpenes, 370–550 Mg yr−1 for DMS and 1700–2600 Mg yr−1 for isoprene. Finally, through the results obtained in this study, we have been able to discover and identify mahogany as one of the missing natural sources of ambient DMS over the Amazon rainforest as well. These new emission findings, indication of seasonal patterns and estimates will be useful for initiating new studies to further improve the global BVOC terrestrial budget.

Chlorine Sky by Mahogany L. Browne

Chlorine Sky by Mahogany L. Browne