Distinct Tree Species Research Articles

Urban Trees and Elderly Well-Being: Species-Specific Strategies for Thermal Comfort in Heat-Stressed Cities

The dual challenges of global aging and intensifying urban heat demand innovative, evidence-based strategies to foster thermally and psychologically comfortable environments for vulnerable populations, particularly the elderly. Despite the documented benefits of urban greenery, the species-specific impacts of urban trees on thermal comfort and well-being remain underexplored. This study investigates how distinct tree species—Camphora officinarum (camphor), Platanus acerifolia (London plane), and Ginkgo biloba (ginkgo)—regulate urban microclimates and support elderly well-being during hot summer days. Conducted at five sites in Shanghai, including a control site and four vegetated plots, this study engaged 210 elderly participants. Microclimatic variables were measured using the physiological equivalent temperature (PET) alongside air temperature, humidity, and wind speed. Physiological responses, assessed through heart rate variability (HRV), and psychological outcomes, evaluated via validated self-report scales, were analyzed. The results revealed that dense-canopy trees significantly reduced PET, enhanced thermal comfort, and improved ROS and SVS scores, while lower LF/HF ratios indicated reduced physiological stress. Correlation analyses underscored the pivotal role of canopy density (SVF) in fostering psychological and physiological well-being. Camphor and London plane trees consistently provided the greatest benefits, emphasizing the importance of species selection in urban greening strategies. These findings underscore the critical role of species selection in urban forestry to mitigate heat stress and foster age-friendly resilience. Practical implications emphasize integrating dense-canopy species into urban landscapes to enhance microclimate regulation and public health.

Vertical variations in enzymatic activity and C:N:P stoichiometry in forest soils under the influence of different tree species

Abstract Tree species play a crucial role in shaping soil properties, significantly influencing nutrient cycling and ecological dynamics within forest ecosystems. In this comprehensive study, we examined the influence of tree species on soil chemistry especially on C/N/P stoichiometry and enzymatic activities across soil profiles. We analyzed soil samples beneath eight distinct tree species at three vertical horizons of soil: organic (O), humus mineral (A), and mineral enrichment (B) horizons. Our study involved detailed assessment of soil carbon, nitrogen, and phosphorus contents, along with the activities of key enzymes: β-glucosidase, N-acetyl-β-glucosaminidase, and phosphatase. The study revealed pronounced vertical stratification in soil properties, significantly influenced by the tree species. General linear models (GLMs) highlighted differences in C: N:P stoichiometry and enzymatic activity across different soil horizons and among tree species. Enzymatic activity was strongly correlated with C, N and P content. The conducted research confirms the distinctiveness of coniferous and deciduous species in terms of C, N and P stoichiometry and the activity of the tested enzymes involved in the C, N and P circulation. These variations are indicative of the intricate interactions between tree species and soil processes. Our findings underscore the role of diversity of trees in modulating soil nutrient dynamics and enzyme-driven processes, which are crucial for understanding soil ecosystem functions and nutrient cycling. This study provides new insights into the role of tree species in shaping the soil environment, offering implications for forest management and conservation strategies. Taking into account the impact of individual tree species covered by the research on the soil, it is worth considering the cultivation of mixed stands.

Mapping forest tree species and its biodiversity using EnMAP hyperspectral data along with Sentinel-2 temporal data: An approach of tree species classification and diversity indices

Forests play a crucial role in maintaining ecological balance and biodiversity, making the accurate mapping of tree species and assessment of biodiversity indices essential for informed management decisions. This study introduces an innovative methodology that integrates EnMAP (Environmental Mapping and Analysis Program) hyperspectral data with Sentinel-2 multitemporal data to classify tree species in the biodiverse landscapes of Kampinos National Park and its surrounding regions in Poland.We extract essential vegetation indices such as NDVI, NDMI, SAVI, and EVI from Sentinel-2 data to assess forest health and dynamics. The Sentinel-2 data is upscaled from 10 m to 30 m to align with EnMAP’s spatial resolution, followed by precise co-registration of the images using QGIS. Utilizing a rich dataset from the National Forest Inventory, we extract spectral signatures of nine distinct tree species from both data sources. We employ five machine learning algorithms—Support Vector Machines (SVM), Random Forest (RF), CatBoost (CAT), Gradient Boosting Classifier (GBC), and XGBoost (XGB)—to enhance classification accuracy.Through iterative experimentation with data reduction techniques and algorithm tuning, we achieve optimal performance across needle-leaved and broad-leaved species. The resulting tree species maps are validated through quantitative accuracy assessments against mixed-species polygons from the National Forest Inventory and ground truthing in the Kampinos National Park. Achieving an overall accuracy of 85% to 93%, our study demonstrates the efficacy of this integrated approach in tree species mapping. Furthermore, the tree species maps serve as a foundation for deriving key biodiversity indices—species richness, Shannon-Wiener Diversity Index, Simpson’s Diversity Index, and a composite Biodiversity Index—providing insights into spatial biodiversity patterns and informing targeted conservation strategies. This study exemplifies the potential of combining advanced remote sensing techniques with field validation to enhance our understanding of forest ecosystems and guide sustainable management practices.

New Understanding of Meta-Topolin Riboside Metabolism in Micropropagated Woody Plants.

Topolin cytokinins have emerged as valuable tools in micropropagation. This study investigates the metabolism of meta-topolin riboside (mTR) in three distinct tree species: Handroanthus guayacan and Tabebuia rosea (Bignoniaceae), and Tectona grandis (Lamiaceae). Employing labeled N15 mTR, we unraveled the complex mechanisms underlying cytokinin homeostasis, identifying N9-glucosylation as the principal deactivation pathway. Our findings demonstrate a capacity in T. rosea and H. guayacan to reposition the hydroxyl group on the cytokinin molecule, a previously unexplored metabolic pathway. Notably, this study reveals remarkable interfamilial and interspecies differences in mTR metabolism, challenging established perspectives on the role of callus tissue in cytokinin storage. These insights not only illuminate the metabolic intricacies of mTR, a cytokinin with interesting applications in plant tissue culture, but also enhances our understanding of cytokinin dynamics in plant systems, thereby enriching the scientific discourse on plant physiology and cytokinin biology.

Soil fungal composition under decomposing deadwood is largely affected by tree bark density rather than soil properties

Deadwood is an important structural and biological component of forest ecosystems habitating for a variety of soil fungal communities. However, it is unknown how decomposition of deadwood impacts fungal communities in the soil underneath functionally different tree species in forests. This study compared the effects of the barks of seven tree species, differing in physicochemical characteristics, on soil fungal communities during the early stages of deadwood decomposition in a subtropical forest. A field experiment consisting of 3 evergreen broadleaf, 3 deciduous broadleaf and 1 coniferous tree species, was conducted for 18 months to examine the impact of deadwood decomposition on soil fungal community using real-time PCR and high-throughput sequencing. Our results demonstrated that wood decomposition led to significant declines in soil pH. Functionally distinct tree species significantly shaped the distinct soil fungal composition and abundances underneath the deadwood of both broadleaf and coniferous trees after 18 months of decomposition. The fungal ecological guilds underneath the deadwood were altered, with symbiotrophs being more prominent, and a higher proportion of pathogens were observed under certain broadleaf tree species. Out of the soil fungal ASVs detected, only 51 (3 %) were generalists, while 1053 ASVs (52 %) exhibited traits indicating potential fungal specialists. There were stronger coniferous tree species preferences in soil fungal composition, compared to broadleaf trees. The initial bark density from broadleaf and coniferous species illustrated the most obvious difference. Interestingly, tree bark density, rather than soil chemistry, was the key driver causing the fluctuations in fungal composition during deadwood decomposition. Tree species traits notably affected soil fungal community during early wood decomposition. These findings highlight the importance of considering the bark traits in understanding the dynamics of soil fungal communities and its implications for forest health and ecosystem management.

Facilitation: Isotopic evidence that wood-boring beetles drive the trophic diversity of secondary decomposers

Deadwood heterogeneity is regarded as a primary causal driver of deadwood-associated soil biodiversity, but the underlying mechanisms remain elusive. This is partly due to the technical difficulties in disentangling and quantifying different components (e.g., deadwood is both habitat and food) of heterogeneity to which soil organisms may have context-dependent responses. Furthermore, non-trophic interactions, e.g., facilitation, also add complexity to deadwood heterogeneity-biodiversity relationships, yet their influences are unaccounted for in most deadwood biodiversity studies. To address these research gaps, we sampled isopod communities from 40 logs of two isotopically distinct tree species, which had been cut and incubated reciprocally for eight years in each of two environmentally contrasting sites (e.g., differences in background isotopic signatures and litter turnover rates). We then assessed the extent to which the variation in the biodiversity of isopod communities is explained by deadwood heterogeneity induced by wood-boring beetles. Stable isotope ratios (i.e., δ13C and δ15N) were employed to examine the response of trophic diversity of isopod communities to the rarely tested food facet of deadwood heterogeneity. We hypothesized the deadwood heterogeneity is boosted by wood-boring beetles and thereby positively affects the abundance, taxonomic diversity and trophic diversity of isopod communities. Our results supported this hypothesis: the abundance and Shannon and Simpson diversity as well as trophic diversity of isopods were positively correlated to wood-boring beetle tunnel densities in both sites and across the two tree species. We observed significant tree species and reciprocal treatment effects on the δ15N values of isopods in one of the two sites. This result suggested that the use of deadwood as food sources versus habitats by isopods is environmentally dependent. This study demonstrates that there is substantial heterogeneity within deadwood that promotes the diversity and trophic diversity of macroinvertebrates. This relationship is mediated by saproxylic beetle facilitation, with implications for the roles of saproxylic beetles and within-deadwood heterogeneity in determining microbial wood decomposition in temperate forests.

Effects of afforestation on soil fungi in rocky mountain areas of North China

AbstractAfforestation has a substantial influence on soil fungal communities by introducing ecological variations within forest ecosystems via the inclusion of distinct tree species (coniferous and broadleaf) and afforestation patterns (pure forests and mixed forests). However, the specific effects of these variations on soil fungal communities require further investigation. Soil samples from birch (B: Betula platyphylla Suk.), larch (L: Larix gmelinii (Rupr.) Kuzen.), and mixed birch and larch (B–L) forests were used in this study, and a shrub–grassland field (S–G) was used as a reference. The abundance, diversity, and community composition of fungi in the soil of the monoculture forest (B and L), mixed forest (B–L), and S–G were studied by high‐throughput sequencing. The results showed that Basidiomycota was the dominant fungus in B and B–L, and the dominant genera were Inocybe and Amanita, respectively. Ascomycota was the dominant fungus in L and S–G, and the dominant genus was Mortierella. Afforestation reduced the richness and diversity of soil fungi. Larch forests were richer in soil fungi than B and B–L forests. Soil organic carbon was the main soil factor affecting the soil fungal community structure. Soil fungal community network changed less after planting L than after planting B and B–L, and the soil fungal community structure was more complex and stable in L than in B and B–L. For soil fungal community composition and function, mixed forests did not show outstanding advantages. Planting monoculture forests may be a more effective afforestation strategy in the rocky mountain areas of North China.

The Sensitivity Feature Analysis for Tree Species Based on Image Statistical Properties

While the statistical properties of images are vital in forestry engineering, the usefulness of these properties in various forestry tasks may vary, and certain image properties might not be enough to adequately describe a particular tree species. To address this problem, we propose a novel method to comprehensively analyze the relationship between various image statistical properties and images of different tree species, and to determine the subset of features that best describe each individual tree species. In this study, we employed various image statistical properties to quantify images of five distinct tree species from diverse places. Multiple feature-filtering methods were used to find the feature subset with the greatest correlation with the tree species category variable. Support Vector Machines (SVM) were employed to determine the number of features with the greatest correlation with the tree species, and a grid search was used to optimize the model. For each type of tree species image, we obtained the important ranking of all features in this type of tree species, and the sensitive feature subset of various tree species according to the order of features was determined by adding them to the Deep Support Vector Data Description (Deep SVDD). Finally, the feasibility of using a sensitive subset of the tree species was confirmed. The experimental results revealed that by utilizing the filtering method in conjunction with SVM, a total of eight feature subsets with the highest correlation with tree species categories were identified. Additionally, the sensitive feature subsets of different tree species exhibited significant differences. Remarkably, employing the sensitive feature subset of each tree species resulted in F1-score higher than 0.7 for all tree species. These experimental results demonstrate that the sensitive feature subset of tree species based on image statistical properties can serve as a potential representation of a specific tree species, while features that are less strongly associated with tree species may be significant in related areas, such as forestry protection and other related fields.

Airborne Dust and Associated Metals: A Link between its impact and sink rate within different roadside plants

<p>Transportation driven by fossil fuels increases air pollution induced by urbanisation. Heavy metals such as Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), and Zinc (Zn) are life-threatening elements and their concentration is increasing alarmingly in soil in various countries. Air pollution and associated metals contaminate the environment and affect nature's abiotic and biotic components. The significance of tree species originates from their connection to the effects of pollution and the solution approach to their biological cycle. Nineteen distinct tree species dominate the region, with heavy metals sinking in the range of Cd<0.4, Cr<1, Cu<15, Fe<2, Pb<5, and Zn<2 mg/kg or parts per million. According to the findings of this study, tree species can sink heavy metals. The different trees have distinct metals-sink ratios. The competence results showed the order of heavy metal sink as Delonix Regia-red (4) > Delonix Regia-yellow (4) > Syzygium Cumini (3) > Muntingic Calabura (3) of the trees with the highest sink rates and nine species had absorbed lead metal. The nine tree species were unsuitable for heavy metal absorption or deposition. There, Albizia Lebbeck (T02), Biancaca Decapetela (T05), Brucea Javanica (T06), Ficus Elastica (T09), Ficus Religiosa (T10), Pithecellobium Dulce (T13), Tamarind (T17), Terminalia Catappa (T18), and Thespesia Populnea (T19) were very low, less than 10% of other dominant tree species. Syzygium cumini (T16) is a high-yielding tree species that absorb significant quantities of Lead (Pb) and Copper (Cu). These studies confirm that, tree species can capture several heavy metals simultaneously from the polluted environment.</p>

Global bioregionalization of warm drylands based on tree assemblages mined from occurrence big data

Drylands represent about 41% of Earth’s land area, host more than 1,500 tree species and support more than 20% of the world’s human population. Trees are key to the functioning of numerous dryland ecosystems and contribute to goods and services for many local human communities, but many are threatened by global changes. From this perspective, mapping tree species assemblages of drylands can provide valuable information for conservation. To our knowledge, warm drylands, including hot deserts, have never been subject to a comprehensive tree biodiversity analysis independent of administrative boundaries or pre-defined regions. Our study aimed to address this gap by redefining warm drylands based on climate data and delineating bioregions using tree species assemblages at the global scale. We based the analyses on aridity and temperature data and a co-occurrence network approach using more than 1,000 tree species. Our data are mined from the Desert Trees of the World database, the Global Biodiversity Information Facility database, and the African Plant Database. This new delimitation of warm drylands reveals eight bioregions, covering about 19% of Earth’s land area across all continents. These are: North America, two bioregions in South America, the southern Mediterranean Basin and Macaronesian islands, the Saharo-Sindian region and the Horn of Africa, Southern Africa, the Socotra archipelago, and Australia. These bioregions have very distinct tree species assemblages, as well as high rates of endemism. This original diversity is found under a wide range of aridity conditions both within and between bioregions, offering the opportunity to anticipate different responses of tree assemblages face to future climate change among the world’s warm drylands. It will aid in conservation, restoration, and rehabilitation strategies involving the use of native trees among the most threatened regions worldwide.

Land use effects on tree species diversity and soil properties of the Awudua Forest, Ghana

Rubber plantation establishment is a common land use that can profoundly impact plant diversity and soil properties in tropical forest ecosystems, although empirical data on such effects are scarce in tropical Africa. In this study, we examined the effects of this land use on tree species diversity and soil physicochemical properties of the Awudua Forest in Ghana. We surveyed 60 25 m × 25 m plots, 20 in each of three land uses (i.e., primary forest, secondary forest and rubber plantation) of the study area. Within each plot, we identified and enumerated all trees (≥ 10 cm diameter at breast height, dbh at 1.3 m) and collected soil samples at three depths (i.e., 0–10 cm, 10–20 cm and 20–30 cm) for the determination of soil physicochemical properties (bulk density, particle size distribution, pH, OC, TN, AP, K, Mg, Ca). Soil physicochemical properties; sand, OC, AP, K, Mg, Ca in the rubber plantation decreased by 4.4%, 24.9%, 40.0%, 16.7%, 50.0% and 20.2% respectively, whereas the primary forest recorded decreases in OC (42.2%), TN (25%), AP (71.1%), K (69%), Mg (59.6%), Ca (27%) from the surface to the sub layers. Results showed significantly lower tree species richness ( S , 12), diversity ( H', 0.37), evenness ( E , 0.43), and basal area (BA, 2.86 m 2 /ha) in the rubber plantation compared to those of the secondary forest (36, 1.10, 0.85 and 0.93 m 2 ha -1 , respectively) and the primary forest (46, 2.28, 0.97, and 3.32 m 2 ha -1 , respectively). Non-metric multidimensional scaling ordination also revealed distinct tree species composition among the land uses. Terminalia ivorensis (IVI = 7.1%), Musanga cecropoides (28.91%) and Hevea brasiliensis (72.03%) were the most dominant species in the primary forest, secondary forest and plantation respectively. Soil OC, TN, K, AP, Mg and bulk density differed among the land uses, but no differences were observed in pH and Ca. The findings confirmed the strong negative impacts of rubber plantation land use on plant diversity and soil properties, suggesting the need for mitigation measures such as afforestation and offsetting to ensure sustainable utilization and conservation of biodiversity in the reserve. • Three land uses—rubber plantation, primary forest and secondary forest—were analyzed. • Rubber plantation impacted floristic attributes more than the other land uses. • Conversion of forest to other land uses also affected soil physicochemical properties negatively.

Functionally distinct tree species support long-term productivity in extreme environments.

Despite evidence of a positive effect of functional diversity on ecosystem productivity, the importance of functionally distinct species (i.e. species that display an original combination of traits) is poorly understood. To investigate how distinct species affect ecosystem productivity, we used a forest-gap model to simulate realistic temperate forest successions along an environmental gradient and measured ecosystem productivity at the end of the successional trajectories. We performed 10 560 simulations with different sets and numbers of species, bearing either distinct or indistinct functional traits, and compared them to random assemblages, to mimic the consequences of a regional loss of species. Long-term ecosystem productivity dropped when distinct species were lost first from the regional pool of species, under the harshest environmental conditions. On the contrary, productivity was more dependent on ordinary species in milder environments. Our findings show that species functional distinctiveness, integrating multiple trait dimensions, can capture species-specific effects on ecosystem productivity. In a context of an environmentally changing world, they highlight the need to investigate the role of distinct species in sustaining ecosystem processes, particularly in extreme environmental conditions.

The model of trees for the restoration of historical manor parks in Estonia

The aim of this article is to work out the methodological basis for the restoration of historical manor parks according to the requirements of the Florence Charter. This is why the park is not studied as an object of biodiversity but as a built monument and an architectural piece, whose composition is mainly created by woody plants particularly trees. The purpose of the current research was to clarify the proportion of examples of distinct tree species in manor parks today and to determine the main tree and shrub species originally used in manor parks. Working out the model for the composition of stands of trees in a historic park. The model for the composition of stands of trees in a historic park was developed. The article summarizes the results of a survey what is a part larger study that explores and understand the key characteristics of Estonian Manor Ensembles and parks.

The distinct roles of water table depth and soil properties in controlling alternative woodland-grassland states in the Cerrado.

Open grassy vegetation and forests share riparian zones across the Neotropical savannas, characterizing alternative stable states. However, factors determining the occurrence and maintenance of each vegetation type are yet to be elucidated. To disentangle the role of environmental factors (soil properties and groundwater depth) constraining tree colonization of wet grasslands in the Cerrado, we assessed tree establishment during the early seedling and sapling stages and the influence of these factors on leaf gas exchange and leaf water potential of tree saplings. Three functionally distinct tree species were studied: (1) flood-tolerant species characteristic of gallery forests, (2) flood-intolerant species characteristic of seasonally dry savannas, and (3) generalist species found in both gallery forests and seasonally dry savannas. Savanna species was constrained by waterlogging, especially at the sapling stage, with restricted stomatal conductance and leaf water potential, resulting in low carbon assimilation, decreased plant size, and high mortality (above 80%). The gallery forest and the generalist species, however, were able to colonize the wet grasslands and survive, despite the low seedling emergence (below 30%) and sapling growth constrained by low gas exchange rates. Soil waterlogging is, therefore, an effective environmental filter that prevents savanna trees from expanding over wet grasslands. However, colonization by trees adapted to a shallow water table cannot be constrained by this or other soil properties, turning the wet grasslands dependent on natural disturbances to persist as an alternative state, sharing the waterlogged environments with the gallery forests in the Cerrado region.

Elevation and latitude drives structure and tree species composition in Andean forests: Results from a large-scale plot network.

Our knowledge about the structure and function of Andean forests at regional scales remains limited. Current initiatives to study forests over continental or global scales still have important geographical gaps, particularly in regions such as the tropical and subtropical Andes. In this study, we assessed patterns of structure and tree species diversity along ~ 4000 km of latitude and ~ 4000 m of elevation range in Andean forests. We used the Andean Forest Network (Red de Bosques Andinos, https://redbosques.condesan.org/) database which, at present, includes 491 forest plots (totaling 156.3 ha, ranging from 0.01 to 6 ha) representing a total of 86,964 identified tree stems ≥ 10 cm diameter at breast height belonging to 2341 identified species, 584 genera and 133 botanical families. Tree stem density and basal area increases with elevation while species richness decreases. Stem density and species richness both decrease with latitude. Subtropical forests have distinct tree species composition compared to those in the tropical region. In addition, floristic similarity of subtropical plots is between 13 to 16% while similarity between tropical forest plots is between 3% to 9%. Overall, plots ~ 0.5-ha or larger may be preferred for describing patterns at regional scales in order to avoid plot size effects. We highlight the need to promote collaboration and capacity building among researchers in the Andean region (i.e., South-South cooperation) in order to generate and synthesize information at regional scale.

Banco de sementes do solo em áreas restauradas no sul do estado de Mato Grosso do Sul – MS

O objetivo foi avaliar o banco de sementes de três diferentes áreas em processo de restauração após 12, 13 e 16 anos de implantação, localizadas no estado de Mato Grosso do Sul. Foram coletadas 20 amostras (20 x 20 cm) no interior de cada floresta restaurada em pontos distribuídos ao acaso, a uma profundidade de 0 a 5 cm, considerando-se a serapilheira. Após serem dispostas em bandejas plásticas, as amostras foram irrigadas e monitoradas diariamente por um período de aproximadamente três meses (90 dias). As espécies também foram avaliadas conforme sua síndrome de dispersão, adotando os critérios morfológicos dos frutos como anemocóricas, zoocóricas, e autocóricas, além de serem classificadas quanto à forma de vida e a origem. A diversidade do banco de sementes foi estimada através do índice de diversidade de Shannon (H’) e a Equabilidade de Pielou (J’). Essas análises foram realizadas no programa Fitopac 2.0. Verificou-se, que a composição da comunidade herbácea variou com os locais, sendo a maior densidade de sementes viáveis para esta classe observadas em Ivinhema, onde o banco de sementes foi composto principalmente por ervas espontâneas oriundas de áreas antropizadas do entorno e grande densidade de plântulas da família Poaceae, contando com quatro espécies distintas. Já a área de Jateí apresentou uma alta densidade de plântulas de Cecropia pachystachya Trécul., além de quatro outras espécies arbóreas distintas. A área restaurada de Caarapó apresentou diferentes classes de vegetação e a presença de componentes importantes para sucessão tais como árvores e lianas. Nos três bancos de sementes avaliados houve a presença de espécies arbóreas representando um avanço no processo sucessional de cada área.

No Ontogenetic Shifts in C-, N- and P-Allocation for Two Distinct Tree Species along Elevational Gradients in the Swiss Alps

Most of our knowledge about forest responses to global environmental changes is based on experiments with seedlings/saplings grown in artificially controlled conditions. We do not know whether this knowledge will allow us to upscale to larger and mature trees growing in situ. In the present study, we used elevation as a proxy of various environmental factors, to examine whether there are ontogenetic differences in carbon and nutrient allocation of two major treeline species (Pinus cembra L. and Larix decidua Mill.) along elevational gradients (i.e., environmental gradient) in the Swiss alpine treeline ecotone (~300 m interval). Young and adult trees grown at the same elevation had similar levels of non-structural carbohydrates (NSCs), total nitrogen (TN), and phosphorus (TP), except for August leaf sugars and August leaf TP in P. cembra at the treeline. We did not detect any interaction between tree age and elevation on tissue concentration of NSCs, TN, and TP across leaf, shoot, and root tissues for both species, indicating that saplings and mature trees did not differ in their carbon and nutrient responses to elevation (i.e., no ontogenetic differences). With respect to carbon and nutrient allocation strategies, our results show that young and adult trees of both deciduous and evergreen tree species respond similarly to environmental changes, suggesting that knowledge gained from controlled experiments with saplings can be upscaled to adult trees, at least if the light is not limited. This finding advances our understanding of plants’ adaptation strategies and has considerable implications for future model-developments.

Modeling net primary productivity of tropical deciduous forests in North India using bio-geochemical model

The present work investigates the applicability of a widespread bio-geochemical model (Biome BGC) to simulate monthly net primary productivity (NPP) and leaf area index (LAI) of Indian tropical deciduous forests. We simulated the monthly NPP and LAI of three plant functional types (PFTs) [dry mixed (DM), sal mixed (SM) and teak plantation (TP)] having distinct tree species compositions, canopy structure, different carbon assimilation rates and microclimate within a broad tropical deciduous forest during 2011–2012. The parameterization of 11 major eco-physiological parameters of Biome BGC was performed from in-situ physiological measurements gathered from 9 long-term ecological research plots in above three PFTs and PFT specific indices were developed. Bimodal trends, with highest peak in September during autumn and second peak in January during winter were observed for simulated monthly NPP in all three PFTs. Simulated NPP (gC/m2/year) values were 408.8 and 414.6; 376.8 and 392.9; and 327.5 and 338.2 during 2011 and 2012 in DM, SM and TP PFTs respectively. Observed NPP (gC/m2/year) values ranged between 463.4 and 493.1; 498.0 and 529.5; and 542.1 and 677.9 in 2012 in DM, SM and TP PFTs respectively. Biome BGC simulated NPP were in positive agreement with observed NPP in all PFTs (R2 = 0.92, 0.83 and 0.72 in DM, SM and TP respectively). In all PFTs Biome BGC led to an underestimation of LAI. The current investigation evaluated the operational application of Biome BGC in Indian tropical deciduous forest and opens scope for further improvement for LAI algorithms for better in-situ LAI simulation.

Litter conversion into detritivore faeces reshuffles the quality control over C and N dynamics during decomposition

Abstract In many terrestrial ecosystems, detritivorous soil organisms ingest large amounts of leaf litter returning most of it to the soil as faeces. Such conversion of leaf litter into faeces may stimulate decomposition by increasing the surface area available for microbial colonisation. Yet, experimental support for either the outcome or the mechanism of these conversion effects is lacking. Based on the hypothesis that the identity of plant species from which leaf litter is transformed into faeces has a critical role in how faeces decomposition proceeds, we collected faeces of the widely abundant millipede Glomeris marginata fed with leaf litter from seven distinct tree species. We compared the physical and chemical characteristics and the rates of carbon (C) and nitrogen (N) loss between litter and faeces. We found that after 100 days of exposure under controlled conditions, C loss was on average higher in faeces (40.0%) than that in litter (26.6%), with a significant increase for six of the seven species. Concurrently, N dynamics switched from a net immobilisation (7.7%) in litter to a net release (14.6%) in faeces, with a significant increase for five of the seven species. Litter conversion into faeces generally homogenised differences in physical and chemical characteristics among species. Despite such homogenisation, variability in rates of faeces C and N loss among species was similar compared to leaf litter, but correlated with a different set of traits. Specifically, faecal pellet C loss was positively related to compaction (decreased specific area and increased density of faecal pellets), and both C and N loss from faecal pellets were positively related to fragmentation (increased specific area and perimeter of particles within faecal pellets). We conclude that litter fragmentation and compaction into detritivore faecal pellets lead to substantially enhanced decomposition, with a particularly strong impact on N dynamics that changed from immobilisation to net release depending on litter species. Moreover, litter quality control on decomposition is reshuffled by litter conversion into faeces. In ecosystems with high detritivore abundance, this so far largely overlooked pathway of organic matter turnover may strongly affect ecosystem C and N cycling. A plain language summary is available for this article.

A simplified model of biosonar echoes from foliage and the properties of natural foliages.

Foliage echoes could play an important role in the sensory ecology of echolocating bats, but many aspects of their sensory information content remain to be explored. A realistic numerical model for these echoes could support the development of hypotheses for the relationship between foliage properties and echo parameters. In prior work by the authors, a simple foliage model based on circular disks distributed uniformly in space has been developed. In the current work, three key simplifications used in this model have been examined: (i) representing leaves as circular disks, (ii) neglecting shading effects between leaves, and (iii) the uniform spatial distribution of the leaves. The target strengths of individual leaves and shading between them have been examined in physical experiments, whereas the impact of the spatial leaf distribution has been studied by modifying the numerical model to include leaf distributions according to a biomimetic model for natural branching patterns (L-systems). Leaf samples from a single species (leatherleaf arrowwood) were found to match the relationship between size and target strength of the disk model fairly well, albeit with a large variability part of which could be due to unaccounted geometrical features of the leaves. Shading between leaf-sized disks did occur for distances below 50 cm and could hence impact the echoes. Echoes generated with L-system models in two distinct tree species (ginkgo and pine) showed consistently more temporal inhomogeneity in the envelope amplitudes than a reference with uniform distribution. However, these differences were small compared to effects found in response to changes in the relative orientation of simulated sonar beam and foliage. These findings support the utility of the uniform leaf distribution model and suggest that bats could use temporal inhomogeneities in the echoes to make inferences regarding the relative positioning of their sonar and a foliage.