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The forest canopy is home to a rich biota. One salient feature are the dynamics of the habitat‐building trees, which are growing and eventually vanishing. Tree species strongly differ in growth rates, final size and longevity. Nevertheless, these inherent dynamics have been a blind spot in studies on host specificity of vascular epiphytes (vascular plants dwelling on trees without parasitizing them)—not least because tree growth rates and longevity are usually unknown in highly diverse tropical forests. The present study aims at tackling this blind spot. We compared epiphyte abundances (>23,000 individuals) found on 285 individuals of four focal tree species in a lowland moist forest in Panama. Data on repeated dbh censuses from a permanent tree plot provided the unique opportunity to estimate the age of our sampled trees. We compared the relative importance of tree longevity for host biases with that of other host tree characteristics, namely microclimatic conditions and bark acidity, rugosity and stability. The studied tree species differ in host quality and epiphyte species partly differ in host preferences. The conclusions concerning relative host tree quality depend hugely on whether or not different tree growth rates are considered. Comparing these conclusions allows important insights into the role of tree longevity in shaping epiphyte communities. Relating tree trait differences to the observed distributions of epiphytes among the focal tree species shows how the simultaneous action of various tree characteristics causes host biases. Synthesis. This study highlights the substantial but, up to now, hidden role of different tree growth rates for host tree specificity of vascular epiphytes. Future investigations need to consider this possibly confounding factor adequately to avoid spurious conclusions. Differences in tree growth rates have been a blind spot in studies on host specificity of vascular epiphytes. We compared epiphyte abundances on four tree species in a lowland moist forest. Host quality ranking depends hugely on whether tree size or age is used as a covariate. Future investigations need to consider different tree growth rates to avoid spurious conclusions.

Large amount of wastes are burnt or left to decompose on site or at landfills where they cause air pollution and nutrient leaching to groundwater. Waste management strategies that return these food wastes to agricultural soils recover the carbon and nutrients that would otherwise have been lost, enrich soils and improve crop productivity. The incorporation of liming materials can neutralize the protons released, hence reducing soil acidity and its adverse impacts to the soil environment, food security, and human health. Biochar derived from organic residues is becoming a source of carbon input to soil and provides multifunctional values. Biochar can be alkaline in nature, with the level of alkalinity dependent upon the feedstock and processing conditions. This study conducted a characterization of biochar derived from the pyrolysis process of eggplant and Acacia nilotica bark at temperatures of 300 °C and 600 °C. An analysis was conducted on the biochar kinds to determine their pH, phosphorus (P), as well as other elemental composition. The proximate analysis was conducted by the ASTM standard 1762-84, while the surface morphological features were measured using a scanning electron microscope. The biochar derived from Acacia nilotica bark exhibited a greater yield and higher level of fixed carbon while possessing a lower content of ash and volatile components compared to biochar derived from eggplant. The eggplant biochar exhibits a higher liming ability at 600 °C compared to the acacia nilotica bark-derived biochar. The calcium carbonate equivalent, pH, potassium (K), and phosphorus (P) levels in eggplant biochars increased as the pyrolysis temperature increased. The results suggest that biochar derived from eggplant could be a beneficial resource for storing carbon in the soil, as well as for addressing soil acidity and enhancing nutrients availability, particularly potassium and phosphorus in acidic soils.

Phosphorus (P) is a vital soil macronutrient required by plants for optimum growth and development. However, its availability is limited because of fixation. The phosphorus fixation reaction is pH dependent. In acid soils, the predominance of aluminium (Al) and iron (Fe) oxides in both crystalline and amorphous forms reduces the solubility of soil inorganic P through fixation on positively charged surfaces and formation of insoluble Al and Fe precipitates. In alkaline soils, P readily reacts with calcium (Ca) to form sparingly soluble calcium phosphates. As a result, a large proportion of applied P may become chemically bound, whereas only a small fraction of soil P remains in the soil solution and available for plant uptake. To date, there is little information available on the use of charcoal with a highly negative charge and wood ash with high alkalinity to minimise P fixation in acid soils. Thus, this study examined the potential of the combined use of charcoal and wood ash to unlock P fixation in acid soils. Numerous studies have been conducted to identify effective approaches to improve P availability through the use of different types of soil amendments, regardless of whether P is organically or inorganically present. For example, to mitigate P fixation in acid soils, amendments such as compost and zeolite are used to reduce P sorption sites. These amendments have also been used to increase P uptake and crop productivity in P deficient acid soils by reducing soil acidity and the toxicity of Al and Fe. It is believed that long-term application of charcoal and sago bark ash can positively change the physical and chemical properties of soils. These improvements do not only reduce P fixation in acid soils, but they also promote an effective utilisation of nutrients through timely release of nutrients for maximum crop production.

Large amount of wastes are burnt or left to decompose on site or at landfills where they cause air pollution and nutrient leaching to groundwater. Waste management strategies that return these food wastes to agricultural soils recover the carbon and nutrients that would otherwise have been lost, enrich soils and improve crop productivity. This study characterised biochar produced by pyrolysis of potato peels (PP), cull potato (CP) and pine bark (PB) at 350 and 650°C. The biochar types were analysed for pH, phosphorus (P) and other elemental composition. Proximate analysis was done following ASTM standard 1762–84, while surface functional groups and external morphology characteristics were determined using FTIR and SEM; respectively. Pine bark biochar had higher yield and fixed carbon (FC), and lower ash content and volatile matter than biochar types from potato wastes. The liming potential of CP 650°C is greater than that of PB biochars. Biochar types from potato waste had more functional groups even at high pyrolysis temperature relative to pine bark. Potato waste biochars showed an increase in pH, calcium carbonate equivalent (CCE), K and P content with increasing pyrolysis temperature. These findings imply that biochar from potato waste may be valuable for soil C storage, remediating acidity and increasing availability of nutrients especially K and P in acidic soils.

Anthracnose of mango is one of the major postharvest diseases of mango fruit caused by members of the Colletotrichum gloeosporioides species complex such as Colletotrichum siamense. Crude extracts from dry trunk bark of four Cinnamomum species (C. burmanni, C. iners, C. loureiroi, and C. verum), a commercial cinnamon powder, cinnamaldehyde, eugenol, and cinnamon oil were assayed for their antifungal activity against Colletotrichum siamense. The crude extract of C. verum at 500 mg L−1 showed the highest inhibition of mycelial growth. At a concentration above 10 g L−1 cinnamaldehyde, eugenol, and cinnamon oil showed 100% mycelial inhibition. Using the microdilution assay, C. burmanni and C. verum crude extracts were effective against Colletotrichum siamense spore germination and showed a minimum inhibitory concentration (MIC) value of 625 mg L−1 while the MIC value of cinnamaldehyde was 50 mg L−1. The direct bioautography of the C. verum extract and the fractions obtained by column chromatography over silica gel against Cladosporium herbarum revealed clear inhibition zones on TLC plates. The treatment of Colletotrichum siamense spores with this active fraction led to severe membrane damage which was observed by scanning electron microscopy. Comparative HPLC analyses of the Cinnamomum extracts and the active fraction of C. verum, cinnamon power, and the cinnamaldehyde and eugenol as standards indicated cinnamaldehyde as the major compound. The C. verum fraction reduced disease severity and disease incidence on inoculated mango fruit. Moreover, uninoculated mango dipped into C. burmanni and C. verum extracts reduced the naturally occurring disease while total soluble solid, titratable acidity, and weight loss of dipped mango were insignificantly different from the untreated fruit control.

Herein, esterification of oleic acid (OA) over tosylic acid functionalized eucalyptus bark biochar (TsOH-MBC) to synthesize fatty acid methyl ester (FAME) was investigated. The TsOH-MBC catalyst was prepared via pyrolysis-activation-sulfonation process at various impregnation ratios and was characterized by SEM, FTIR, EDX, XRD, BET, TGA and acid site density techniques. The catalytic performance of the sulfonated biochar catalyst was described in terms of acidity and FAME yield. 6 g of sulfonic acid loaded on 10 g of MBC (6TsOH-MBC) appeared to be most appropriate combination to achieve a highly active catalyst for the esterification of OA with 96.28% conversion to FAME at 80 °C for 5 h with catalyst loading of 4.0 wt% and 8:1 methanol/OA molar ratio. The catalytic reaction kinetic data were very well described by the second-order model, with a rate coefficient of 0.223 mL mol −1  h −1 at 80 °C and activation energy of 81.77 kJ mol −1 . The thermodynamic parameters such as Δ H , Δ S and Δ G were determined to be 78.94 kJ mol −1 , 135.3 J mol −1  K −1 and 33.03 kJ mol −1 , respectively. This research provided an environmentally friendly procedure for FAME production that could be replicated on a commercial scale.

Source-sink relationships and the management of carbon partitioning among sinks in plants help us to understand crop physiology and yield limiting issues. The effect of variable leaf fruit ratio alone or in combination with girdling on the yield and fruit quality performance of nectarine peach cv. Silver King was analysed. With increasing leaf fruit ratio alone or in conjunction with girdling, the greatest leaf nutrients, such as N, P, K, Ca, and Mg, decreased. The fruit yield decreased linearly as the leaf fruit ratio increased and the lowest yield was reported with the leaf fruit ratio of 50:1 plus girdling half the bark. However, the fruit quality in terms of fruit size and weight were maximum when the leaf fruit ratio was 40:1 and half the bark was girdled. Other fruit quality indicators such as total soluble solids, total sugars, and sugar acid ratio were highest when the leaf fruit ratio was 50:1 coupled with girdling half the bark. The treatment with the lowest titratable acidity was leaf fruit ratio 40:1 + girdling half the bark, followed by leaf fruit ratio 40:1 + girdling half the bark. When compared to control, all of the leaf fruit ratio treatments alone or in combination with girdling half the bark advanced the harvest date by 1–4 days recording earliest harvest, with leaf fruit ratio 50:1 plus girdling half the bark. Overall, leaf fruit ratios of 40:1 combined with girdling half the bark and leaf fruit ratios of 50:1 combined with girdling half the bark were determined to be acceptable for producing high-quality Silver King nectarine.

Bark traits of trees often serve as a key factor determining the community structure of epiphytes. However, the extent to which barks modulate the relative importance of abiotic and biotic assembly processes of epiphytes is poorly understood. Here, using a community phylogenetic approach, we aimed to infer the assembly processes of epiphytic mosses and liverworts on tree species with varying bark traits in a temperate forest of central Japan. We observed a total of 56 moss and 35 liverwort species on 150 trees. Moss communities showed decreasing species richness and a tendency toward phylogenetic overdispersion, that is, higher phylogenetic diversity than expected by chance, in relation to increasing bark roughness and acidity. Along the same bark gradients, liverwort communities became phylogenetically clustered. Species richness of both mosses and liverworts increased with the nitrogen content of barks. The results indicate non-random assembly processes such as abiotic filtering associated with environmental harshness and microhabitat variety determined by barks. Our findings imply that bark traits modulate community assembly processes through which epiphyte diversity is maintained.

AbstractChanges in the acidity and cation exchange properties of soils in spruce ecosystems after the death of spruce as a result of an outbreak of the bark beetle (Ips typographus) in the coniferous-broadleaf forest zone (Moscow oblast) have been studied during long-term monitoring. The studies have been carried out in three types of forest ecosystems developed on eluvozems and soddy eluvozems on the two-layered parent material—mantle loam underlain by glaciofluvial sand—in 2008, 2019, and 2023, using uniform methods in accordance with the recommendations of the international monitoring program ICP Forests. Soil samples were collected in a stratified random manner in 30 × 40 m plots in organic layer and 0−5, 5−10, 10−20, 20−40 and 40−80 cm mineral layers. The soils have been characterized by a slightly acidic and acidic reaction, low cation exchange capacity and low base saturation. Over a 12-year period after the bark beetle attack, there were ambiguous changes in pH, an increase in exchange acidity and cation exchange capacity, enrichment of soils with exchangeable bases, and their redistribution in the soil layer. The organic layer and 80-cm mineral soil layer accumulated 560–1080 and 100–230 kg/ha of exchangeable calcium and magnesium and lost 140–370 kg/ha of exchangeable potassium with maximum changes in the soddy eluvozems of the most damaged complex spruce forest, which was replaced by a linden forest. The further dynamics of nutrients in soils and the need for forestry measures will be determined by the direction and rate of restoration of plant communities.

The recovery of critical and precious metals from waste electrical and electronic equipment (WEEE) is an environmental and economic imperative. Biosorption has been considered a key technology for the selective extraction of gold from hydrometallurgical liquors obtained in the chemical leaching of e-waste. In this work, the potential of tannin resins prepared from Pinus pinaster bark to sequester and recover gold(III) from hydrochloric acid and aqua regia solutions was assessed. Equilibrium isotherms were experimentally determined and maximum adsorption capacities of 343 ± 38 and 270 ± 19 mg g−1 were found for Au uptake from HCl and HCl/HNO3 (3:1 v/v) solutions containing 1.0 mol L−1 H+. Higher levels of acidity (and chloride ligands) significantly impaired the adsorption of gold from both kinds of leaching solutions, especially in the aqua regia system, in which the adsorbent underperformed. Pseudo-first and pseudo-second order models successfully described the kinetic data. The adsorbent presented high selectivity towards gold. Actually, in simulated aqua regia WEEE liquors, Au(III) was extensively adsorbed, compared to Cu(II), Fe(III), Ni(II), Pd(II), and Zn(II). In three adsorption–desorption cycles, the adsorption capacity of the regenerated adsorbent moderately decreased (19%), although the gold elution in acidic thiourea solution had been quite limited. Future research is needed to examine more closely the elution of gold from the exhausted adsorbents. The results obtained in this work show good perspectives as regards the application of pine bark tannin resins for the selective extraction of Au from electronic waste leach liquors.