Search

In this study, we investigated the effects of water-deficit stress on the leaf anatomical traits, physiological traits, and stem starch content in Quercus acutissima Carruth and Quercus serrata Murray by subjecting their seedlings to well-watered (WW) and water-deficit stress (WS) treatments. The water stress-induced changes in trichome density, trichome-to-stomata ratio, mesophyll thickness, vein density, vein distance, vein loopiness, vessel diameter, transpiration (E), stomatal conductance (gs), water use efficiency (WUE), and starch content were analyzed between two time points. While trichome density did not vary between treatments in Q. acutissima, it dramatically increased in Q. serrata (62.63–98.96 trichomes mm−2) at the final week. The WS-treated seedlings had a thicker palisade mesophyll (162.85–169.56 µm) than the WW-treated samples (118.56–132.25 µm) in both species. The vein density and loopiness increased significantly in the WS-treated Q. serrata seedlings. Small-sized vessels (10–50 µm) were more frequent in the WS than the WW in Q. serrata. The E, gs, WUE, and starch content declined significantly in the WS-treated seedlings compared with WW-treated samples in both species. Further, principal component analysis revealed significant relationships between anatomical and physiological traits, particularly in the WS-treated seedlings of Q. serrata. The coordinated changes in leaf anatomical traits, physiological traits, and stem starch content indicate an important role in the survival of Q. acutissima and Q. serrata seedlings in water-deficit stress environments, although Q. serrata may show higher survivability under prolonged water stress than Q. acutissima. [ABSTRACT FROM AUTHOR]

Wood ash generated as a by-product of biomass combustion can be a sustainable and reasonable approach to counteract acidification and correct nutrient deficiency in forest soils. We investigated the influence of wood ash (WA) and combined WA + N (nitrogen) on soil chemical properties, growth and foliar nutrients of Zelkova serrata and their potential as a soil amender across different soil types. We applied four levels of WA (0, 5, 10, and 20 Mg ha−1) and two levels of N fertilizer (0 and 150 kg ha−1) across three different soil types: landfill saline (LS) soil, forest infertile (FI) soil, and forest acidic (FA) soil. The WA generally improved soil pH, organic matter, available P, exchangeable cations (K+, Na+, Ca2+, and Mg2+), and EC of the three soils, but its ameliorating and neutralizing effects were predominant in FA soil. N fertilizer was more effective in improving plant growth, especially for biomass production in LS and FI soils. WA application significantly increased biomass production when it was applied over 5 Mg ha−1 in FA soil, but higher dose rate of WA (i.e. 20 Mg ha−1) seems to pose negative effects. Foliar P, K, and Ca concentrations also tended to increase with the increasing amount of WA. Therefore, lower dosage of WA without N can be applied as a soil amender to counteract forest soil acidity and improve plant growth and foliar nutrient concentration, whereas N fertilizer without WA can be added to correct nutrient soil deficiencies in landfill and infertile soils. This study should enhance our understanding of WA as a sustainable and reasonable approach to counteract acidification and correct nutrient deficiency in forest soils. [ABSTRACT FROM AUTHOR]

Current understanding of litterfall and fine root dynamics in temperate forests is limited, even though these are the major contributors to carbon and nutrient cycling in the ecosystems. In this study, we investigated litterfall and fine root biomass and production in five deciduous and four coniferous forests at the Gwangneung Experimental Forest in Korea. We used ingrowth cores to measure fine root production and root turnover rate. The litterfall was separated into leaves, twigs, and others, and then leaves were further separated according to species. Annual litterfall mass was not significantly different between the years, 360 to 651 g m-2 in 2011 and 300 to 656 g m-2 in 2012. Annual fine root (<5 mm) production was significantly higher in 2012 (421 to 1342 g m-2) than in 2011 (99 to 872 g m-2). Annual litterfall mass was significantly different among the stands, while fine root production did not statistically differ among the stands. The average fine root turnover rate, calculated by dividing the annual fine root production by the maximum standing fine root biomass, was 1.65 for deciduous forests and 1.97 for coniferous forests. Fine root production constituted 18–44% of NPP, where NPP was the sum of woody biomass production, litterfall production, and fine root production. Belowground production was a greater fraction of NPP in more productive forests suggesting their greater carbon allocation belowground. [ABSTRACT FROM AUTHOR]

Losses of soil base cations due to acid rain have been implicated in declines of red spruce and sugar maple in the northeastern USA. We studied fine root and aboveground biomass and production in five northern hardwood and three conifer stands differing in soil Ca status at Sleepers River, VT; Hubbard Brook, NH; and Cone Pond, NH. Neither aboveground biomass and production nor belowground biomass were related to soil Ca or Ca:Al ratios across this gradient. Hardwood stands had 37% higher aboveground biomass ( P = 0.03) and 44% higher leaf litter production ( P < 0.01) than the conifer stands, on average. Fine root biomass (<2 mm in diameter) in the upper 35 cm of the soil, including the forest floor, was very similar in hardwoods and conifers (5.92 and 5.93 Mg ha−1). The turnover coefficient (TC) of fine roots smaller than 1 mm ranged from 0.62 to 1.86 y−1 and increased significantly with soil exchangeable Ca ( P = 0.03). As a result, calculated fine root production was clearly higher in sites with higher soil Ca ( P = 0.02). Fine root production (biomass times turnover) ranged from 1.2 to 3.7 Mg ha−1 y−1 for hardwood stands and from 0.9 to 2.3 Mg ha−1 y−1 for conifer stands. The relationship we observed between soil Ca availability and root production suggests that cation depletion might lead to reduced carbon allocation to roots in these ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: Intensive management for biomass production results in high rates of nutrient removal by harvesting. We tested whether wood ash generated when burning wood for energy could be used to ameliorate negative soil effects of short-rotation harvesting practices. We measured the temporal and spatial dynamics of soil nutrient properties after wood ash applications in a willow plantation in central New York State and determined the influence of wood ash application on willow growth. Wood ash was applied annually for 3 years at the rates of 10 and 20Mgha−1 to coppiced willow, Salix purpurea, clone SP3. Wood ash application significantly increased soil pH in the 0–10cm soil layer from 6.1 in the control to 6.9 and 7.1 in the 10 and 20Mgha−1 treated plots. Wood ash application significantly increased soil extractable phosphorus, potassium, calcium, and magnesium concentrations. Potassium was the element most affected by wood ash treatment at all soil depths. Wood ash had no significant effect on nutrient concentrations of foliar, litter, and stem tissue. Wood ash did not affect either individual plant growth or plot biomass production, which declined over the course of the study; it did increase the size of stems, but this effect was balanced by a decrease in the number of stems. Applying nitrogen as well as wood ash might be required to maintain the productivity of this SRIC system. [Copyright &y& Elsevier]

Climate challenges impose the need for successful afforestation strategies which will increase the amount of carbon sequestered from the atmosphere. In practice, this means evaluation of suitable plant species and management practices for the long-term effects to prove beneficial. In the present study we employed a clasmometric approach to look into biomass partitioning in two tree species, Populus sibirica and Ulmus pumila, which have been included in the formation of the Green Belt project in Asia. Comparing the total biomass comprised of the above ground (AG) and below ground (BG) biomass of trees grown in different irrigation and fertilization regimes, we aim to better understand where the two species invest more biomass as a tool to deal with the environmental challenges. The results suggest that these two tree species prioritize different aspects of development when faced with various challenges. U. pumilia tends to be more resistant to drought making it favorable for the semi-arid and arid regions. P. sibirica is more sensitive to the lack of water but shows greater potential in terms of biomass production (especially AG biomass) and, therefore, overall higher C-sequestration. The fertilization treatments made no significant impact on tree development on Mongolian steppe soil. [ABSTRACT FROM AUTHOR]

Pyrogenic carbon capture and storage (PyCCS) based on biochar is considered a negative emission technology (NET) aimed at mitigating climate change, with the potential to reduce CO 2 by 0.3–2 gigaton/yr at the cost of $30–120/ton-CO 2. The annual biochar production needs a substantial scaling up of the current production rates (i.e., >150 million tons by 2050) to meet the above demand. However, current biochar production predominantly relies on a small-scale operation, which generally leads to high operational costs and limited control of the biochar properties. This work presents the operation of a state-of-the-art 1 ton/d pilot-scale Flexible Counter Flow Multi-Baffle (F-COMB) pyrolyzer designed for continuous biochar production, which is a prototype reactor for the scale-up. The F-COMB utilizes counter-flow and vortex mixing in a multi-baffle column structure to enable efficient contact of feedstock with hot gas. It boasts high energy efficiency and economic feasibility through a short residence time, reduced gas flow rate, and simple structure. It produces wood pellet biochar with accurate control of the reaction conditions such as temperature, retention time, hot gas flow rate, and feedstock loading. Moreover, continuous biochar production is done successfully with three flexible baffles configuration, demonstrating the significant potential for the scale-up. • Flexible Counter Flow Multi-Baffle (F-COMB) reactor is designed for pyrolysis. • F-COMB provides high energy efficiency via efficient contact of feedstock & hot gas. • Vortex mixing induced by multiple baffles gives the efficient contact. • Biochar production using a F-COMB was demonstrated at 1 ton/day scale successfully. • Continuous biochar production shows significant potential for the F-COMB scale-up. [ABSTRACT FROM AUTHOR]

The gradient in soil characteristics from the bulk soil to the root surface is important to roots and to the organisms that live in the rhizosphere. Our ability to measure ion concentrations at the root surface is extremely limited, and models are largely untested. We used data from a well studied Norway spruce stand in SW Sweden to compare the measured difference in nutrient concentrations between rhizosphere and bulk soil with the difference predicted by a steady-state simulation model based on ecosystem budgets of nutrient uptake. The simulation model predicted depletion of NH4, Ca, Mg, K in the rhizosphere, which shows that budgeted uptake rates were greater than the mass flow of bulk solution towards the root. In plots treated with ammonium sulphate, the model predicted an accumulation of S in the rhizosphere. In contrast, the observed rhizosphere concentrations were generally enriched in nutrients, relative to bulk soil. Collecting rhizosphere soil adhering to root surfaces may not be an appropriate method for describing the concentration gradient around the root. In addition, the simulation model omits some processes affecting conditions in the rhizosphere that are important to explaining nutrient uptake. [ABSTRACT FROM AUTHOR]

The environmental restoration of the semi-arid steppe of Mongolia is currently being addressed by creating new plantations able to protect the soil from the advancement of desertification and to improve the economy of the population living there. The success of these interventions relies on a high survival rate and good long-term growth performance of the transplanted trees. In the present work we analyzed stem height and root collar diameter (RCD) over 10 years for two native tree species (Populus sibirica and Ulmus pumila) grown with different water regimes and fertilizers. The investigated duration is sufficiently long to provide a reliable indication of the adaptation of these tree species to the steppe's harsh environmental conditions. Results suggest that both species could be used for environmental restoration projects, although P. sibirica requires the support of additional irrigation to achieve the best growth performance. U. pumila, on the other hand, shows good growth performance even with rainfall as the only water source. However, the higher water use by P. sibirica trees seems to be compensated by a more rapid ground cover compared to U. pumila. The addition of fertilizers to the soil before transplantation does not improve the growth performance of either species. [ABSTRACT FROM AUTHOR]

The study investigated the leaf architecture and petiole anatomy of eight Dipterocarpus (Dipterocarpaceae) species growing in Mount Makiling Forest Reserve (MMFR) in the Philippines to delineate the species, especially during their non-flowering phase. Leaf and petiole samples from MMFR were examined following the manual on leaf architecture studies. Freehand technique was used to examine the stomata and petiole characters. A UPGMA phenogram was then generated to determine the relationships among Dipterocarpus species using 26 leaf and petiole characters. The most useful characters to delineate Dipterocarpus species are the presence of trichomes, the arrangement of vascular bundles (medullary and outer vascular bundles), areolation, fimbrial vein, and leaf size. Other characters viz., the laminar ratio, blade class, laminar shape, base shape, margin type, and intersecondary, and layers and shape of parenchyma and collenchyma cells were useful as unifying characters. Therefore, certain characters of the leaf architecture and petiole anatomy may be used as taxonomic markers to delineate and correlate the Dipterocarpus species in the Philippines particularly during the nonflowering phase of the species. However, further investigations using samples from the wild populations of the species and molecular techniques may be done to elucidate the taxonomic use of the characters presented in this study. [ABSTRACT FROM AUTHOR]

• Floristic structure effects on litterfall are masked by local site and stand traits. • Broadleaf deciduous litter returns more macronutrients than coniferous evergreens. • Inter-stand variations in element flux indicate biomass allocation and nutrient use. • Nutrient cycling in secondary forests is determined by litter quantity. Determining litterfall and corresponding element fluxes is valuable in understanding productivity and biogeochemical cycling in floristically distinct secondary successional zones. Secondary-growth forests form a major portion of the cool-temperate forests of South Korea following decades of severe disturbance and intensive rehabilitation efforts. This study monitored the total and fraction-specific litterfall mass, element flux, and nutrient use efficiency patterns of a secondary-growth broadleaf deciduous forest (hereafter, BDF A) and compared these values in forests with contrasting sub-canopy compositions (BDF B) and with coniferous evergreen forests (CEF). Mean annual total litterfall mass was uniform across stands at a range of 871.5 g m−2 yr−1 to 990.2 g m−2 yr−1. Litterfall mass of seed, bark, and miscellaneous fractions varied per stand (p < 0.05 for seed; p < 0.01 for bark and miscellaneous). A pronounced unimodal litterfall peak was detected for all stands, with total litterfall responding positively to relative humidity but negatively to windspeed and solar radiation. Coniferous evergreen litter contained higher C but lower macronutrients relative to broadleaf deciduous litter. Macronutrient fluxes ranged from 156.2 to 183.9 kg ha−1 yr−1, with broadleaf stands having significantly higher K and Ca rates. Macronutrients were returned in all stands in the order of N > Ca > K > Mg > P, whereas NUE followed a reverse sequence. NUE in CEF was higher than BDF A and BDF B for all macronutrients, reflecting the distinct biomass allocation and nutrient utilization strategies between conifers and broadleaves. In temperate secondary-growth forests, nutrient cycling via litterfall is substantiated primarily by litterfall quantity and secondarily by litter element concentration. Our findings have important implications for elucidating forest litter ecology and improving sustainable management practices in secondary successional forests. [ABSTRACT FROM AUTHOR]

Roots are important to ecosystem nutrient pools and fluxes, but they are difficult to sample for tissue analysis, especially at depth. We analyzed patterns of nutrient concentrations in live roots up to 20 mm in diameter collected from quantitative soil pits in six northern hardwood sites at the Bartlett Experimental Forest, New Hampshire, USA. Root concentrations of nitrogen (N), phosphorus (P), calcium (Ca), and magnesium (Mg) were higher in the forest floor than in the mineral soil, by 23%-61% in fine roots (0-1 mm and 1-2 mm in diameter). Using only samples collected from the O horizon to characterize roots throughout the profile resulted in an average error across all elements of 16% in estimates of root nutrient contents. Within the mineral soil, there was little difference in root nutrient concentrations with depth. There were significant patterns with root diameter: N and Mg concentrations were highest in the finest roots, while Ca concentrations peaked in the 2-5 mm diameter class. One site (C8) differed from the others in having lower N but higher P, Ca, Mg, and potassium (K) concentrations in roots. In summary, analyzing roots by site and diameter class is more important to accurate nutrient accounting than is analyzing roots from depth in the mineral soil, but roots in the forest floor and the mineral soil differ dramatically for some elements. [ABSTRACT FROM AUTHOR]

Cornus officinalis Sieb. et Zucc. is one of the most important medicinal plants. The various medicinal properties include analgesic, diabetic, diuretic, and tonic properties. Several studies have focused on the characteristics of bioactive compounds. However, there is no information available on the bioactive compounds present in the different developmental stages of C. officinalis fruit. This study aims to provide a brief analysis of primary and secondary at the four different developmental stages of the Cornus officinalis fruit (green, light red, red, and red ripened fruit). According to this metabolome analysis, a total of 37 metabolites (1 amine, 2 sugar alcohols, 5 carbohydrates, 12 organic acids, and 17 amino acids) were detected in the fruit. The content of most sugars and sugar alcohols has been shown to increase during fruit ripening. Furthermore, increasing accumulation patterns of total anthocyanin and carotenoid contents and decreasing patterns of triterpenoid and phenolic contents were observed during fruit development. Most sugar levels were positively correlated with total anthocyanin and carotenoid contents. Additionally, the fruit have been found to have strong antibacterial activities that increased during ripening; the fruit also possessed strong antioxidant activities. Considerable variations in the primary and secondary metabolite contents during different fruit developmental stages of C. officinalis have been observed. This study used a biochemical approach to determine the primary and secondary metabolites present in C. officinalis during fruit development. [Display omitted] • Cornus officinalis fruits have a wide range of medicinal properties. • First report on the comparative metabolic analysis of C. officinalis fruits. • More than 56 primary and secondary metabolites were identified. • The fruit extracts exhibit strong antibacterial and antioxidant activities. [ABSTRACT FROM AUTHOR]

Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results. [ABSTRACT FROM AUTHOR]

Leaf litterfall represents an important nutrient flux in forests, but separating leaves by species and collecting fresh litter annually for nutrient analysis is time-consuming and expensive. To quantify the sources of variation in litterfall nutrient estimates and guide optimal allocation of research effort, we analyzed nutrient concentration (5 years) and mass (6 years) of leaf litter for nine tree species in 13 northern hardwood sites. Coefficients of variation (CVs) in nutrient concentration were higher across sites than over time within sites for most elements; phosphorus was especially variable across sites (56% CV). Thus, to estimate litterfall nutrient fluxes accurately in forests of this type, nutrient analyses should be site-specific as well as species-specific but may not need to be repeated annually (CVs over time averaged 17% for calcium, 21% for magnesium, 28% for potassium, and 32% for phosphorus concentration). Total leaf litterfall mass varied considerably from year to year, ranging from 234 to 370 g·m-2 averaged over 13 sites. We recommend that litter collectors be elevated above the ground to avoid oversampling during extreme wind events. Use of species-specific allometric equations, or even basal area, to estimate the species composition of total litter mass may obviate the need to sort litter by species. [ABSTRACT FROM AUTHOR]