Tree Density Research Articles

Tree-Climbing Behavior of a Forest-Dwelling Ungulate: The Formosan Serow.

Ungulates are terrestrial herbivores, basically adapted to running fast on the ground; tree-climbing behavior has been reported only in seven species, and five of them live in open habitats (Capra hircus, C. aegagrus, C. falconeri, C. cylindricornis, Oreotragus oreotragus). Tree-climbing behavior may also be evolved in ungulates inhabiting dense forests with abundant trees; however, this has rarely been reported in such species (Moschus leucogaster, M. moschiferus), probably due to the difficulty of observing in the wild. The numerous publicly available records in social networks hold potentially valuable information on the atypical behaviors of wild ungulates. Here, we explored the tree-climbing behavior of a forest-dwelling ungulate, the Formosan serow in Taiwan, a subtropical island, by extracting information from online social media platforms. We researched images and videos of Formosan serows through Facebook and YouTube and collected a total of 15 tree-climbing events. In these materials, Formosan serows climbed 10 tree species, including evergreen coniferous and broad-leaved trees, and a variety of parts, ranging in height from 0.6 to 4 m, and from branches of shrubs to trunks of tall trees. Tree-climbing behavior was recorded throughout Taiwan and from lowlands to subalpine zones, suggesting that tree climbing may be a common behavior in this species. Foraging while climbing trees was frequently observed (53.3%), suggesting that the purpose or benefit for climbing is to obtain additional food other than plants growing near the ground surface. In contrast to other tree-climbing ungulates, Formosan serows climbed trees not only in winter, but also in other seasons, when food is relatively abundant. This is the first scientific report of tree-climbing behavior in the Formosan serow that is typically a forest dweller.

Assessing Normalized Difference Vegetation Index as a proxy of urban greenspace exposure

The Normalized Difference Vegetation Index (NDVI) is a popular proxy of urban greenspace (UGS). However, it’s unclear how NDVI approximates physical characteristics of UGS in the context of urban health studies, causing ambiguities in translating research findings to UGS management. Therefore, we collected data from Landsat and MODIS satellites and Lidar 3D scans in New York City as of circa 2013, and we evaluated linear and non-linear relationships between NDVI and UGS characteristics. We found that: (1) % UGS was the best predicted UGS characteristic by NDVI (R2: 0.35–0.90, varies by data source and unit of analysis), whereas average tree height was the worst (R2: 0.09–0.46). The predictive power on % canopy cover, tree density, and crown volume density was in a similar range (R2: 0.10–0.67). Prediction improved with finer-resolution NDVI sources and larger units of analysis at the cost of losing useful variations; (2) There was a saturation effect where a linear relationship underestimated UGS characteristics in areas of high NDVI. These areas typically had NAIP-NDVI greater than the range of 0.08–0.25, Landsat-NDVI greater than the range of 0.42–0.65, and MODIS-NDVI greater than the range of 0.49–0.75; (3) Smaller absolute errors from a linear NDVI-UGS relationship were often found in more developed locations. We therefore recommend NDVI as a reliable predictor of UGS coverage and its use in longitudinal studies. Future studies should also consider fine resolution land cover maps and Lidar, which are increasingly available to derive detailed UGS characteristics.

Tree cavity density is a limiting factor for a secondary cavity nester in second-growth Andean temperate rainforests

Abstract Cavity-nesting bird populations are most frequently limited by the number of tree cavities available in second-growth forests. However, this possible limitation of a key resource is less clear in old-growth forests. We compared forest attributes (i.e., basal area, density of larger trees, density of dead trees, and tree cavity density) in second-growth and old-growth stands in Andean temperate rainforests in southern Chile. To examine the role of nest-site availability in limiting the populations of Aphrastura spinicauda (Thorn-Tailed Rayadito), a secondary cavity-nesting bird species, we conducted an experiment in which nest boxes were added and removed in old-growth and second-growth forests during a 5-yr period (2008–2013). In old-growth forests, as compared to second-growth forests, we found a more than double basal area (99.6 vs. 43.7 m2 ha–1), a three times higher density of larger trees (88.2 vs. 36.4 trees ha–1), and a 1.5 times higher number of small cavities (25.9 vs. 10.3 cavities ha–1). The density of cavities also strongly increased with tree diameter and basal area. In second-growth forests, A. spinicauda showed a strong response to the addition and removal of nest boxes, with population abundance increasing by 13% and then decreasing by 50%, respectively. In contrast, we found no impact in old-growth stands. Our experiment emphasizes the importance of maintaining large and dead trees in second-growth, disturbed, and managed forests. These trees provide suitable cavities for A. spinicauda, and likely many other secondary cavity nesters, increasing their abundances in a Globally significant Biodiversity Hotspot in southern South America.

The Essential of Trembesi in Djawatan: Identifikasi Persebaran Pohon Trembesi sebagai Penentu Biodiversitas di Kawasan Hutan Djawatan

Trembesi (Samanea saman) plays an important role in the Djawatan forest area. The presence of Djawatan forest in the city adds vital value to trembesi, such as maintaining ecosystem stability, soil stability, water supply stability, O2 supply, and CO2 absorption. This study aims to determine the density of trembesi trees in the Djawatan forest area. The presence of trembesi in the Djawatan forest is crucial for the numerous flora and fauna sheltered beneath it. Therefore, understanding the distribution pattern of trembesi in the Djawatan forest area is essential to ascertain environmental influences on the growth of trembesi. The research method used in this study was descriptive qualitative through observation and interviews. Trembesi distribution in this study was observed in four different zones: waterfront, rice field edge, central Djawatan forest, and settlement edge. Based on the research results, it is known that trembesi distribution is influenced by the surrounding environmental conditions. This is evidenced by data showing that the highest average density of trembesi is found in the central Djawatan forest area, which is 0.50%.

Morphotaxonomic Studies and Abundance of Simulium damnosumTheobald (Diptera: Simuliidae) Complex in Two Local Government Areas of Ogun State

The sibling species composition of Simulium damnosum sensulato and abundance of these sibling species in two communities (Opeji and Imala-Odo) of Ogun State south-western Nigeria was carried out in the wet months (May to October). Morphological identification of black flies using standard protocol was done from 07:00hr-18:00hr twice every two weeks. Climatic data like temperature, rainfall and relative humidity were documented for each month. A total of 1543 flies were dissected, 1228(79.6%) in Opeji and 315(20.4%) in Imala-Odo with a statistical significance (p<0.05). The result revealed an allopatric existence of forest dwelling flies. All the flies identified had dark fore coxa but there was variation in the colours of their wing tuft where wing tuft grade 05 was predominant and no fly had wing tuft grade 01 and there was significant difference (p<0.05) in the wing tuft colours observed among the flies. In Opeji, 477(38.8%) flies were parous while 155(49.2%) parous flies were recorded in Imala-Odo. However, no black fly was infected with the larva of Onchocerca volvulus. Relative diurnal distribution of flies caught revealed a bimodal peak between 10:00-11:00hr and 15:00-16:00hr in both communities. Monthly data on abundance also revealed a bimodal peak in the study sites in June and September with a significant difference (p<0.05) in the abundance across the months. Highest biting rate was recorded in June (Opeji=4492.5; Imala-Odo=780) while August recorded the lowest monthly biting rates (Opeji=284; Imala-Odo=62). The relationship between flies abundance and climatic data showed no significant relationship in both communities (p>0.05). This study revealed that there is high abundance of forest black flies during wet season which have epidemiological implication on humans living in these areas and efforts should be made towards constant monitoring of the siblings species

Dominance and rarity in tree communities across the globe: Patterns, predictors and threats

AbstractAimEcological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree communities? (2) Which ecological and anthropogenic factors predict these patterns? And (3) what is the extinction risk of locally dominant and rare tree species?LocationGlobal.Time period1990–2017.Major taxa studiedTrees.MethodsWe used 1.2 million forest plots and quantified local tree dominance as the relative plot basal area of the single most dominant species and local rarity as the percentage of species that contribute together to the least 10% of plot basal area. We mapped global community dominance and rarity using machine learning models and evaluated the ecological and anthropogenic predictors with linear models. Extinction risk, for example threatened status, of geographically widespread dominant and rare species was evaluated.ResultsCommunity dominance and rarity show contrasting latitudinal trends, with boreal forests having high levels of dominance and tropical forests having high levels of rarity. Increasing annual precipitation reduces community dominance, probably because precipitation is related to an increase in tree density and richness. Additionally, stand age is positively related to community dominance, due to stem diameter increase of the most dominant species. Surprisingly, we find that locally dominant and rare species, which are geographically widespread in our data, have an equally high rate of elevated extinction due to declining populations through large‐scale land degradation.Main conclusionsBy linking patterns and predictors of community dominance and rarity to extinction risk, our results suggest that also widespread species should be considered in large‐scale management and conservation practices.

Rationalization of post-harvesting unit operation of mahua flowers (Madhuca longifolia, Madhuca indiaca): Systematic interventions and benefits for tribals

<p>The most common method used for collection of mahua flowers by burning the undergrowth under mahua trees which often caused forest fire and loss or flora and fauna of nature. The comparative analysis of traditional flower collection vis-a-vis net collection was analyzed during the research. The most significant benefits were on prices, time reduction and quality of products. These benefits will encourage the adoption of this technique by forest dwelling communities for mahua collection. The net collected flowers sold at 110 to 120 ₹ compared with 25–30 ₹ with traditional collection (<em>p</em> < 5 ₹). The time and manpower reduced by 80% (<em>p</em> < 1%) in net collection. Total 87.95 K MT mahua exported from India with value of 70.01 million USD in FY 2022. India rank 7th in global export of Mahua in 2022. Nearly 75% of entire tribal household in the country are involved in the collection of mahua flower which will contributes up to 30% of their annual cash income. To handle mahua around 11 lakh peoples are directly involved and 20 to 25 lakh peoples indirectly involved. To produce liquid >90% mahua utilized in India. During this research post-harvest unit operations also standardized. New food product like syrup, cookies, jam, spread, jelly, gummies, energy drink, beverages, hard-boiled candies development were done, and stabilities were conducted with utilization of 10% to 60% mahua.</p>

Insights into the cashew production system in Guinea-Bissau: implications for agroecosystem sustainability

IntroductionWest Africa, particularly Guinea-Bissau, heavily relies on cashew nut (Anacardium occidentale L.) production, which significantly impacts the countries’ economies. Cashew exhibits remarkable adaptability to impoverished and arid soils. Understanding producers’ socio-economic characteristics is crucial due to their potential influence on crop productivity and household income.MethodsThis study aims to characterize the socio-economic, productive, and phytosanitary aspects of cashew production in Guinea-Bissau, through 151 interviews with producers across all administrative regions of the country.ResultsOur findings reveal that cashew producers are mainly males aged 40 to 60, they typically manage plantations under 5 ha, with the smaller plantation areas located in Gabú, Cacheu, and Bolama. The age of the older trees averaged 31 years, with the highest age found in Biombo. Tree density averaged 286 trees per hectare, with higher values in Cacheu, Bafatá, and Bolama. Cashew nut yield in 2020 averaged less than 0.5 tons per hectare, with farmer-set prices generally lower than government determined prices. Oio, Tombali, and Bolama were the regions most affected by pests, while Oio and Cacheu (North) were the most affected by diseases. Top pests included termites, branch girdler, weaver ants, African grasshopper, and stem borer; while top diseases comprised gummosis, anthracnose, and dieback.DiscussionCharacterization of cashew production system is crucial at both national and regional levels to identify region-specific limitations and strengths, aiding in the formulation of tailored strategies for sustainable production. Moreover, cashew production plays a crucial role in household incomes in Guinea-Bissau, underscoring the necessity of developing integrated management strategies.

Local extirpation of woody species in Colophospermum mopane woodland under chronic utilisation by elephants

AbstractThe hypothesis that certain woody species may be prone to local extirpation under chronic elephant utilisation was examined for Colophospermum mopane open woodland, for an area within the foraging range of elephants from permanent water. Elephant density increased from nearly absent in the 1970s to >3 elephants km−2, with 0.62 adult bulls km−2, by 2022. Study components of vegetation impact included a long‐term elephant exclosure, a fence‐line contrast with an adjacent communal area, comparison with an adjacent wildlife reserve carrying a fifth of the elephant density and the use of historical studies of the vegetation. A history of elephant utilisation resulted in woodland becoming hedged through pollarding of tree stems by elephants. Impacted woodland was characterised by a slightly lower tree density, reduced average height of trees, altered shrub composition and lower species richness. The dominant C. mopane and sub‐dominant species had persisted. However, about 14 species were potentially trending towards local extirpation on account of very high levels of adult mortality, but had persisted because of a low level of seedling recruitment. Fleshy fruits were a shared attribute among most extirpation‐trending species, which, together with a reduction in woody species richness that affects browsers, has ramifications for trophic flows.

The morphological diagnosis of 2 economically important subterranean termites in Western Indonesia, Coptotermes curvignathus and Coptotermes gestroi (Blattodea, Rhinotermitidae).

In Indonesia, the control of Coptotermes curvignathus populations as living tree termite pests has been carried out since the early 20th century. Recently, C. curvignathus has been considered the main termite pest and designated as the only species model for wood and wood products resistance tests against subterranean termite attack testing protocol in the Indonesian National Standard (SNI). However, the species distribution range of C. curvignathus has been long questioned as Coptotermes gestroi is commonly reported as a species found in urban areas of Southeast Asian region, particularly in Indonesia. One of the reasons for the species distribution discrepancies is the lack of morphological markers to distinguish both species in the field. Thus, limiting the field inspection effectiveness in termite pest management in Indonesia. This study reexamined and clarified the morphological differences between C. curvignathus and C. gestroi, based on soldier caste. The head shape, mandible shape, and distribution of genal setae on the ventro-anterior head part and pronotum marked the difference between the 2 species. These current results support previous findings of C. curvignathus as the forest dweller while clarifying C. gestroi as the common urban dweller in Indonesia. The putative benefit of morphological features related to the head, mandible, and setae distribution to the defensive adaptation in their common habitat was discussed. Ultimately, the inclusion of C. gestroi into the Indonesian National Standard (SNI) as an alternative species for efficacy tests against subterranean termites is highly recommended.

The effects of postfire regeneration patterns on soil microbial metabolic limitation based on eco-enzyme stoichiometry in the boreal forest of China

Postfire regeneration is essential for maintaining the stability and functionality of forest ecosystems following wildfires. However, it is unclear whether regeneration patterns affect carbon (C), nitrogen (N), or phosphorus (P) limitations on microbial metabolism in the soil. In this study, we investigated the soil extracellular enzyme activities (EEAs) in different forest types regenerated by five patterns (Dahurian larch monocultures, Dahurian larch and birch mixed plantations, Mongolian pine monocultures, Mongolian pine and birch mixed plantations, and naturally regenerated forests). Based on the principles of ecoenzymatic stoichiometry, we elucidated the spatiotemporal variation in energy (C) and nutrient (N or P) limitations on soil microbial metabolism by collecting a total of 135 composite soil samples across three seasons in the five regeneration patterns. The regeneration pattern had a significant effect on the activities of C-, N- and P-acquiring soil extracellular enzymes (P<0.05). The P-acquiring enzyme activity was 2.71 times greater than the C-acquiring enzyme activity and 3.44 times greater than the N-acquiring enzyme activity across all forest types and seasons. The activities of microbial metabolic C-, N-, and P-acquiring enzymes showed similar seasonal dynamic patterns, with the exception of L-leucine aminopeptidase. In all forest types, the activities of enzymes responsible for acquiring C, N, and P were linearly correlated with one another according to the findings from standard major axis regression analysis (P<0.001). The values of the enzymatic vectors were greater than 45°, indicating that P rather than N was the dominant constraint on soil microbial metabolism. Forests with mixed regeneration patterns had greater P limitations than did the corresponding monoculture forests. Soil temperature was the common soil variable affecting the activities of EEAs across seasons, while the contents of soil organic carbon, dissolved carbon, ammonium nitrogen, and nitrate nitrogen were the significant driving factors of EEAs in a single season. However, forest productivity, including tree density, stand basal area, and forest stand volume had a predominant influence on microbial metabolic P limitation. This study suggests a pronounced role of P in soil microbial metabolism within boreal forests regenerated after wildfires.

Environmental correlates of Whinchat Saxicola rubetra breeding territory retention in a declining upland population

ABSTRACT Capsule In a 461 km2 unenclosed upland landscape in south-west England, long-term breeding Whinchat Saxicola rubetra persistence is more likely in areas characterized by a mixture of Bracken Pteridium aquilinum, ericaceous vegetation, and very low tree densities, situated in steep-sided valleys at mid-altitudes, further from agriculturally improved grassland or arable. Aims To establish the correlates of Whinchat breeding territory retention between 1979 and 2015–2022 in a declining upland population. Methods Historical Whinchat territories (identified in 1979) were revisited to assess range occupancy, producing a lost (n = 104) and retained (n = 60) sample. Territory retention probability was modelled at local (100 × 100 m) and broad (500 × 500 m) scales against remotely sensed data and field habitat data measured in 2022. Results At the local scale, territory retention probability was greater in steeper valleys, further from arable or agriculturally improved grassland, peaked at five trees per ha in a quadratic response, and where Bracken cover was greater. Bracken cover effects were enhanced when ericaceous vegetation was also present. At the broad scale, retention probability was again greater in steeper valleys, with greater Bracken cover, and at very low tree densities in a quadratic response (but the latter was not important at the bottom of steep-sided valleys). Retention also peaked at around 350–400 m elevation in a quadratic response at the broad scale. Conclusions In this population in south-west England, steep-sided valleys at 350–400 m, with a light scattering of trees, situated further from intensive enclosed farmland are more likely to retain Whinchats long term. Within these areas, a mixed Bracken and ericaceous field-layer should be encouraged, and blanket afforestation avoided, although lower densities of native trees appear to be more tolerated.

Nest site preferences of the Eurasian Goshawk Accipiter gentilis, an indicator species of conservation concern, in hemiboreal mixed forests

The Goshawk has been recognized as an effective bioindicator sensitive to forest management. We used a comprehensive data set on 75 Goshawk nest sites from Estonia to explore the species’ preferences in relation with forest and landscape characteristics. Goshawk nest sites were regularly distributed with a mean nearest neighbour distance of 6.9 km. The hawks showed a preference for nesting in old (mean age 101 years) coniferous Oxalis-type stands with medium tree density, although the preferred nest tree species was deciduous birch. In surroundings of nest sites, there was a relatively high proportion of old-growth forest (64 %), and nests were closer to mires (1319 m) than expected, while being at a moderate distance from the forest edge (135 m). However, we did not detect any significant effect of the proximity of buildings and roads. Our results suggest that territoriality sets the upper limit to the nesting population, and the ultimate choice of nest location is constrained by the availability of suitable nest sites. We recommend that foresters planning timber harvesting near Goshawk nests avoid clear cutting and maintain sufficiently mature forest nearby. Furthermore, keeping suitable forest patches across forest land support a healthy Goshawk population.

Tree hollow decline in new forest reserves with a long history of logging

AbstractIn many parts of the world, achieving a target of 30% of land managed for conservation under the Kunming‐Montreal Global Biodiversity Framework will require the protection of land with a long history of management for production. In newly protected forests, past logging practices will have impacted key aspects of stand structure, including hollow‐bearing trees that provide critical habitat for vertebrate fauna. The impacts of past silvicultural practices on hollow density, distribution, type and longevity may necessitate targeted ameliorative actions. We investigated tree hollows in the largest river red gum (Eucalyptus camaldulensis Denh.) forest in the world, which had undergone logging‐induced woody thickening prior to being converted to a conservation reserve in 2010. We recorded stem diameters and hollows in living and dead trees in 66 two‐hectare plots. Our sites sampled two productivity states and a wide range of total tree densities. On all sites, we found that hollow‐bearing tree densities were lower than reference values for unlogged stands and average density had halved relative to reference values. We found no relationship between the density of hollow‐bearing trees and total tree density, but we did find a weak positive relationship with site productivity. Larger trees had more hollows, bigger hollows and a greater diversity of hollow sizes. However, of the 1254 hollow‐bearing trees recorded, 43% were dead, 48% of the dead trees had been ringbarked. The proportion of hollow‐bearing trees that were dead was positively correlated with tree size, with 60% of trees in the largest quartile (&gt;105 cm) recorded as dead. The prevalence of dead hollow‐bearing trees suggests that the density and diversity of hollows will continue to decline and ameliorative actions should be considered. These results highlight the need to consider the legacy of past silvicultural practices in the management of newly created conservation reserves.

Functional diversity of neighbours mediates sap flow density and radial growth of focal trees, but in different ways between evergreen and deciduous broadleaved species

Abstract The functioning of a tree is shaped by the neighbouring species through the interspecific interaction and local environments. The functional trait composition of the neighbourhood could provide mechanistic insights into the effects of neighbours on the resource strategies of focal trees. In this study, we deployed an automated high‐frequency measurement of the sap flow density (SFD) and the radial growth of 48 trees of 12 species at BEF‐China, a large‐scale forest biodiversity manipulation experiment, to investigate the consequences and underlying mechanisms of the functional trait composition of the neighbourhood on the sap flow and radial growth of focal trees. We found a positive relationship between SFD and growth, reflecting the important supportive role of sap flow in tree growth. High functional diversity (FD) of the neighbourhood depressed SFD but promoted growth when considering all species, and thus promoted water‐use efficiency. Acquisitiveness of neighbouring trees positively affected growth, suggesting interspecific facilitation. Furthermore, neighbourhood FD benefits evergreen focal trees by promoting growth. However, in deciduous focal trees, neighbourhood FD reduced SFD but had no significant effects on growth. Our findings suggest that considering the functional trait composition of neighbourhood communities will support effective afforestation and forest management. Read the free Plain Language Summary for this article on the Journal blog.

Forest floor environment overrules global change treatment effects on understorey communities in a mesocosm experiment.

Light availability profoundly influences plant communities, especially below dense tree canopies in forests. Canopy disturbances, altering forest floor light conditions, together with other environmental changes such as climate change, nitrogen deposition and legacy effects from previous land-use will simultaneously impact forest understorey communities. Yet, knowledge on the individual effects of these drivers and their potential interactions remains scarce. Here we performed a forest mesocosm experiment to assess the influence of warming, illumination (simulating canopy opening), nitrogen deposition and soil land-use history (comparing ancient and post-agricultural forest soil) on understorey community composition trajectories over a 7-year period. Strikingly, understorey communities primarily evolved in response to the deeply shaded ambient forest conditions, with experimental treatments exerting only secondary influences. The overruling trajectory steered all mesocosms towards slow-colonizing forest specialist communities dominated by spring geophytes with lower nutrient-demand. The illumination treatment and, to a lesser extent, warming and agricultural land-use legacy slowed down this trend by advancing fast-growing resource-acquisitive generalist species. Warm ambient temperatures induced thermophilization of plant communities in all treatments, including control plots, towards higher dominance of warm-adapted species. Nitrogen addition accelerated this thermophilization process and increased the community light-demand signature. Land-use legacy effects were limited in our study. Our findings underscore the essential role of limited light availability in preserving forest specialists in understorey communities and highlight the importance of maintaining a dense canopy cover to attenuate global change impacts. It is crucial to integrate this knowledge in forest management adaptation to global change, particularly in the face of increasing demands for wood and wood products and intensified natural canopy disturbances.

Ethno Medicinal, Phyto-Chemical and Physico-chemical Characterization of Selected Endangered Medicinal Plants of Indravati National Park, Bijapur, Chhattisgarh, India

Medicinal plants are beneficial for curing several ailments among traditional healers, indigenous people, local practitioners and forest dwellers. If harnessed, traditional knowledge of the ethnomedicinal plants can play a pivotal role in drug discovery and development. In many cases a single medicinal plant can be of multiple uses also, different plant parts of the same plant can be utilized for more than one disease condition. The Ethno-botanical, Phytochemical and physico-chemical characterization of five selected medicinal plants viz., Nyctanthes arbor – tristis, Andrographis paniculata, Cissus quadragularis, Plumbago zeylania and Costus specious is an essence and has been carried out to assess bioactive potential and to establish traditional belief in the light of scientific interpretation. Fresh leaves were collected from Indravati National Park, Bijapur, Chhattisgarh, India, dried and powdered for phytochemical and Proximate, ultimate, and compositional analysis. Study revealed that the highest concentration of Ash Content (18.513%), Moisture Content (8.56%), Carbon content (48.77%), Hydrogen Content (24.490%), Nitrogen Content (23.860%) was observed to occur in Plumbago zeylanica leaf than other experimental plants. In Cissus quadrangularis, the percentage composition of fat content (0.230%), extractive content (1.05%), Lignin Content (5.53%) was higher than others. Fat content (0.230%), Moisture Content (8.56%), Vit. C content (64.63%) and Oxygen contents (36.655 %) were observed to be higher in Nyctanthes arbor-tristis leaf than others. The concentrations of Crude Fibre (14.49 %), Moisture Content (8.56%), Protein content (12.16%), Carbon content (75.66 %), Cellulose content (47.63 %) were observed to be highest in Costus speciosus species than others. Carbon content (48.77%) and Hydrogen Content (24.490%) were higher in Andrographis paniculata than in others.

Quantifying the resistance of mixed-forests against natural hazards in the Pyrenees

Mountain protection forests can prevent natural hazards by reducing their onset and propagation probabilities. In fact, individual trees act as natural barriers against hydrogeomorphic events. However, assessing the structural strength of trees against these hazards is challenging, especially in a context of climate change due to the intensification of extreme events and changes in forest dynamics. Here, we focus on the mechanical analyses of two of the most common tree species across the Pyrenees (Abies alba Mill. and Fagus sylvatica L.) growing in two different areas (Spain and France), and affected by recurrent snow avalanche and rockfall events. We first performed 53 pulling test on mature trees, where the root-plate stiffness and the modulus of elasticity of the stems were evaluated. To further analyse the impact of forest management and climate on protective forests, we yielded information on tree growth using dendroecology techniques. Then, we assessed structure and neighbourhood characteristics for each target tree to account for the surrounding forest structure. Finally, using linear and structured equation models we tested if the mechanical capacity of the trees is determined either by functional traits (e.g. species, tree growth, diameter and height) or forest structural traits (e.g. tree density, tree structure and slenderness) or both. Our results suggest that the forest neighbourhood influences tree mechanical capacity through two pathways, including both functional and structural traits. The individual stiffness parameter of trees is influenced by their functional traits, while their structural traits are more closely related with changes in the modulus of elasticity. Both species exhibit varying levels of dominance in different locations, which is related to their resilience to the diverse natural hazards they confront. Our findings provide relevant insights to anticipating management strategies for forests that serve as a protective barrier against natural hazards in the context of a changing climate.

Restoring a dry tropical forest through assisted natural regeneration: enhancing tree diversity, structure, and carbon stock

Deforestation is a key factor in global climate change, severely impacting ecosystem services. Effective implementation of reducing emissions from deforestation and forest degradation (REDD+) initiatives is essential for mitigating this change. Reforestation is a sustainable way to mitigate deforestation effects. We studied the impact of assisted natural regeneration (ANR) on restoring dry forest land, increasing biodiversity, structure, and carbon stock. Reforestation units were established at a multiple row planting system in a dry tropic region. We selected 63 plots, each 20 m × 20 m, categorized into multiple row–mixed plantation (MRMP) and multiple row–unmixed plantation (MRUP). We measured tree height and diameter at breast height (DBH) and evaluated biodiversity indices, including the Shannon–Weiner Index (SWI), species richness, evenness, and Important Value Index (IVI). Carbon stock was estimated using allometric equations. We identified 931 individual trees representing 27 species, 24 genera, and 14 families. MRMP showed significantly higher biodiversity, species richness, and evenness than MRUP. Terminalia arjuna was the most dominant species (IVI=124.45), followed by Khaya senegalensis (53.84). Survival rates exceeded 90 % for T. arjuna, K. senegalensis, Madhuca longifolia, and Pongamia pinnata (p<0.001). No significant differences were observed in tree DBH, tree height, tree density, basal area, and carbon stock among the plantation categories. The species Albizia saman exhibited a high diameter increment rate (4.07 ± 1.55 cm/year), followed by K. senegalensis (3.83 ± 0.43 cm/year). A mean value of 5.63 ± 1.13 MgC/ha of carbon stock was stored, while 20.66 ± 4.13 Mg/ha of atmospheric CO2 was sequestered. The results highlight that promoting mixed tree species in multiple rows to enhance biodiversity and optimize carbon regulation. This technique should be popularized to restore the dry forest landscape across the region.

Diversity and Structure of Khaya Senegalensis (desr.) A.Juss Habitats Along Phytogeographical Zones in Chad (Central Africa)

In Chad, the species of Khaya senegalensis is commonly used by the local communities to treat several diseases such as malaria, fever and cough. However, the species is facing the greatest threat for the survival due to its exploitation as timber. The species is on the IUCN red list with endangered status locally. Thus, this study assessed the population structure and ecological indicators of vegetation in three climatic zones dominated by Khaya senegalensis in Chad as a basis for sustainable management and conservation strategies. A total of 88 plots (30 m x 30 m) were used in three phytogeographical zones for data collection. The structural parameters (tree density, basal area) and ecological indicators (specific richness, Shannon diversity index, Pielou’s evenness index, importance value index) were assessed for all tree species and for Khaya senegalensis following a climatic gradient. A number of 300 tree species belonging to 66 families, 11 life form and 14 chorological types were inventoried. K. senegaleensis had the highest significance value index across all three climate zones. In terms of vegetation characteristic, Sudano-Guinean and Sudanian zones were similar against Sudano-Sahelian zone which was different. These results should be fundamental for the conservation and sustainable management of K. senegalensis and its habitats specially in Chad. Likely, the findings contribute to knowledge addition for the species conservation. However, the methodological limitations related to sampling should not be obscured. Therefore, the species’ abundance areas were randomly identified while plots were placed stratified.