Forest Structure Research Papers - Academia.edu (original) (raw)

2025, Acta Botanica Brasilica

This work assessed data from 32 forest sites in Rio de Janeiro and São Paulo, Brazil, using multivariate analysis to answer the question: Are there floristic patterns of the Atlantic Forest tree-shrub layer related to the Serra do Mar and the width of coastal plains in the states of Rio de Janeiro and São Paulo? Three multivariate analyses were performed to investigate the relationship between the tree-shrub flora and environmental variation in these 32 study areas. Our analyses demonstrated the influence of geo-climatic variation on floristic differentiation of tree and shrub species in Atlantic Forest regions generating groups of areas based on similar biotic and abiotic characteristics. These groups support the existence of floristic patterns within the states of São Paulo and Rio de Janeiro and reflect tree-shrub species substitution between the study areas as a consequence of annual rainfall, altitude, and mean annual temperature variation linked to a change in the position of ...

2025, Current forestry reports

Purpose of the Review Many LiDAR remote sensing studies over the past decade promised data fusion as a potential avenue to increase accuracy, spatial-temporal resolution, and information extraction in the final data products. Here, we performed a structured literature review to analyze relevant studies on these topics published in the last decade and the main motivations and applications for fusion, and the methods used. We discuss the findings with a panel of experts and report important lessons, main challenges, and future directions. Recent Findings LiDAR fusion with other datasets, including multispectral, hyperspectral, and radar, is found to be useful for a variety of applications in the literature, both at individual tree level and at area level, for tree/crown segmentation, aboveground biomass assessments, canopy height, tree species identification, structural parameters, and fuel load assessments etc. In most cases, gains are achieved in improving the accuracy (e.g. better tree species classifications), and spatial-temporal resolution (e.g. for canopy height). However, questions remain regarding whether the marginal improvements reported in a range of studies are worth the extra investment, specifically from an operational point of view. We also provide a clear definition of "data fusion" to inform the scientific community on data fusion, combination, and integration. Summary This review provides a positive outlook for LiDAR fusion applications in the decade to come, while raising questions about the trade-off between benefits versus the time and effort needed for collecting and combining multiple datasets.

2025

Forests are of great economic and ecological benefit because they function as timber source and provide avariety of vital ecosystem services. To maintain the functioning of forest ecosystems and the provision of these diverse services, regular acquisitions of the forest conditions, including timber stock estimations, are required. Forest inventories (FI) which have evolved from economic demands provide such information and allow to optimize management strategies. FIs also form the basis to monitor abundance, health and changes of forest ecosystems. FIs traditionally rely on field measurements that include anumber of forest parameters within plots. With the increasing availability of airborne laser scanning (ALS) systems, such local plot level inventories can be upscaled to larger areas in aconvenient, robust and reproducible way. However,current FI acquisition methods suffer from anumber of deficiencies. Firstly, FIs still rely on measurements in the field which are labor-intensive to acquire and partially subjective (e.g. the determination of crown closure). Secondly,allometric functions, which are deduced from field inventories and applied to ALS or auxiliary remote sensing data to predict FI parameters (e.g. growing stock) over larger areas, do not necessarily reflect site-specific characteristics. This leads to errors in the predicted parameters. Locally adjusted allometric functions, however,a re cumbersome and expensive to achieve through field inventories. Therefore, such functions often do not exist. Thirdly,today's forest stands, to which the respective allometric functions are applied, are derived from manual delineations based on ortho-images. Stand delineation, however,isacomplex task, and resulting stands do not necessarily represent homogeneous compartments. Available forest stand boundaries are often originating from historical forest management units that have changed over time. The aim of this thesis is to investigate possibilities to improve current FI acquisition strategies through the integration of the various laser scanning systems we have at hand today. The miniaturization of laser scanning sensors and positioning systems allows the systems to be operated on light weight unmanned aerial vehicle-platforms (UAVborne laser scanning, ULS) or placed on the ground (terrestrial laser scanning, TLS). There is ag ap, however,b etween ALS and these close-range systems. Firstly,t he systems deliver completely different point cloud qualities in terms of the resolution of the resulting point clouds. Secondly,the viewing direction and geometry differ vii fundamentally,particularly between TLS, which records the canopy from the bottom, and ALS, which can hardly acquire forest areas close to the ground. Ye t, FIs could be improved through the combination of the different laser scanning systems. Closerange systems with the high level of detail allow for af ast, accurate and costefficient acquisition of field reference data, from which site-specific allometries can be deduced. Improved allometries can subsequently be applied to ALS data acquired from large areas with low point densities. Thus, the combination of the different systems allows to accomplish the scale transition from plot to landscape scales. Locally detailed single tree information could be brought to wide areas, allowing for landscape-wide FI parameter estimations. Ye t, open aspects remain for such aproceeding, which are addressed in this thesis. In afi rst study,t he point cloud quality requirements are investigated in order to allow acomplete and accurate scene reconstruction from ULS data. The results show thatthe pointdensity is crucial for thestem detection,whereas the accuracy of the stem reconstruction mainly depends on the accuracy of the sensor.Asecond study analyses differences in the waysALS andULS systems capture the foreststructure. ULS systems acquire the forest structure more completey.I ncombination with the high level of detail, this allows to directly measure single tree components within the point cloud, apart from the computation of classical ALS metrics. In contrast, derived structure metrics differ between ALS and ULS, depending on the way the point cloud information is used for the metrics computation. In at hird study,a n approach is proposed to delineate homogeneous forest compartments with asimilar forest structure from ALS point clouds. Homogeneous forest compartments can be used to upscale locally measured FIparameters from close-range laser scanning to larger areas by applying locally adjusted statistical models to ALS point cloud metrics. Afinal study deals with the temporal aspect of the inventories and investigates the potential to update ALS forest structure information with Sentinel-1 (S-1) C-band time series. Since the general height and stand density structures, respectively,are well reproduced, S-1 data facilitates to fill gaps between ALS acquisitions. The insights gained in the four studies will help making optimal use of the information content each system provides. Thus, the integration of the different laser scanning devices into the scale transition contributes to improving FI acquisition strategies. With such aprocedure, landscape-wide accurate spatial forest information could be acquired in arobust, fast and cost-efficient way.T his opens up new possibilities to integrate remote sensing in operational forest management activities, for instance for the selection of tree species, for shading studies, or for the modelling of forest fires, the sun irradiance or the water cycle. Ultimately,the integration of data from different systems will improve our ability to monitor the condition and development of forests. Wälder sind für uns von grossem ökonomischem und ökologischem Nutzen. Wälder liefern einerseits Holzressourcen, anderseits erbringen sie eine Vielzahl an lebensnotwendigen Ökosystemdienstleistungen. Um die Funktionsfähigkeit der Waldökosysteme zu gewährleisten und um sicherzustellen, dass Wälder weiterhin diese Ökosystemdienstleistungen bieten, sind regelmässige Erhebungen über den Zustand des Waldes wichtig. Dies schliesst auch Abschätzungen des Holzvorrates mit ein. Diese Informationen werden in Waldinventuren (FI, von engl. forest inventories) erhoben. FIs ermöglichen die Optimierung der Waldbewirtschaftung und entstammen ursprünglich ökonomischen Erfordernissen. Die Information, welche in FIs bereit gestellt wird, liefert aber genauso die Grundlage für die Überwachung des Zustandes und der Gesundheit der Wälder und zeigt deren Veränderungen. FIs werden klassischerweise durch Messungen im Feld erhoben. Diese Messungen schliessen eine Vielzahl an Waldparametern mit ein, die innerhalb einer Parzelle erfasst werden. Mit der zunehmenden Verfügbarkeit von flugzeuggestützten Laserscanning-Systemen (ALS, von engl. airborne laser scanning) können solche lokal erhobenen Inventuren in einfacher,zuverlässiger und reproduzierbarer Weise auf grössere Flächen hochskaliert werden. Die derzeitigen Ansätze zur Erhebung und Hochskalierung von FIs weisen allerdings eine Reihe von Defiziten auf.E rstens basieren FIs auf Messungen im Feld. Solche Messungen sind arbeitsaufwändig und zudem teilweise subjektiv,z .B. die Abschätzung des Kronenschlussgrades. Zweitens werden FI-Parameter,b eispielsweise der Holzvorrat, grossflächig über allometrische Funktionen geschätzt. Diese allometrischen Funktionen werden aus den Felderhebungen abgeleitet und dann auf ALS-oder andere Fernerkundungsdaten angewendet. Allerdings geben die allometrischen Funktionen nicht notwendigerweise die gebietsspezifischen Charakteristiken wieder,was zu Fehlern in den geschätzten Parametern führt. Die Erhebung lokal angepasster allometrischer Funktionen mittels Felderhebungen hingegen ist aufwändig und teuer,weshalb oft keine entsprechenden Funktionen existieren. Drittens werden die Waldbestände, auf welche die allometrischen Funktionen angewendet werden, manuell auf der Basis von Orthophotos abgegrenzt. Die Abgrenzung von Waldbeständen ist jedoch eine komplexe Aufgabe, was dazu führt, dass die resultierenden Bestände nicht notwendigerweise homogene Einheiten darstellen. Die verfügbaren Bestandesgrenzen basieren zudem oft auf historischen Waldbewirtschaftungseinheiten, welche sich über die Zeit verändert haben können. Das Ziel dieser Thesis ist es nun, zu untersuchen, wie die heutigen Ansätze zur Erhebung von FIs durch die Integration der unterschiedlichen Laserscanning-Systeme, die uns heute zur Verfügung stehen, verbessert werden könnten. ix Die Miniaturisierung der Laserscanning-Sensoren und der Positionssysteme erlaubt es, diese Systeme von leichten, unbemannten Drohnen (UAV-gestütztes Laserscanning, ULS) oder vom Boden aus (terrestrisches Laserscanning, TLS) einzusetzen. Allerdings besteht eine Lücke zwischen ALS und solchen Nahbereichs-Systemen. Erstens liefern die verschiedenen Systeme sehr unterschiedliche Punktwolken-Qualitäten in Bezug auf die Auflösung der Punktwolke. Zweitens unterscheiden sich die Blickrichtung und die Aufnahmegeometrie der Systeme fundamental, insbesondere zwischen TLS, womit die Kronenschicht von unten betrachtet wird, und ALS-Systemen, welche die bodennahen Waldbereiche kaum zu erfassen vermögen. FIs könnten nun durch die Kombination der unterschiedlichen Laserscanning-Systeme verbessert werden. Nahbereichs-Systeme mit ihrem hohen Detaillierungsgrad erlauben die schnelle, genaue und kosteneffiziente Erhebung von Feldreferenzdaten, aus welchen gebietsspezifische Allometrien abgeleitet werden können. Diese verbesserten Allometrien können anschliessend auf ALS-Daten angewendet werden, welche eine tiefere Punktdichte aufweisen, jedoch grosse Gebiete abdecken. Eine derartige Kombination der unterschiedlichen Systeme ermöglicht den Skalenübergang von der Parzelle auf ganze Landschaften. Die lokal sehr detaillierte Information auf Einzelbaumebene lässt sich damit auf weite Fläche übertragen, was die...

2025, Remote Sensing

We propose a flexible framework for automated forest patch delineations that exploits a set of canopy structure features computed from airborne laser scanning (ALS) point clouds. The approach is based on an iterative subdivision of the point cloud using k-means clustering followed by an iterative merging step to tackle oversegmentation. The framework can be adapted for different applications by selecting relevant input features that best measure the intended homogeneity. In our study, the performance of the segmentation framework was tested for the delineation of forest patches with a homogeneous canopy height structure on the one hand and with similar water cycle conditions on the other. For the latter delineation, canopy components that impact interception and evapotranspiration were used, and the delineation was mainly driven by leaf area, tree functional type, and foliage density. The framework was further tested on two scenes covering a variety of forest conditions and topograp...

2025, Remote Sensing of Environment

Space-borne LiDAR systems can potentially assist large-area assessments of forest resources, in particular when a subset of the acquired LiDAR footprints is combined with field surveys of forest stand characteristics at footprint location. When combined, space-borne LiDAR geolocation error and the footprint size may however have considerable effects on the estimation accuracy of forest stand variables, such as aboveground biomass (AGB). The aim of this study was to draw recommendations for future space-borne LiDAR systems, which should deliver data for unbiased AGB assessments. The recommendations were drawn from AGB estimations based on space-borne LiDAR waveforms simulated over a 1300 ha large study site in southern Sweden. Large-footprint, nadir-looking satellite waveforms were simulated by stacking individual small-footprint, airborne LiDAR waveforms observed near a predefined sampling pattern. The stacked waveforms, represented by their metrics, were used as input for a two-phase systematic sampling in combination with model-assisted estimation or hybrid inference for estimating AGB and its variance. The second-phase sample included 264 inventory plots, whereas the first-phase sample included 1010 sample locations, where satellite waveforms were simulated. After simulating satellite waveforms with different footprint sizes and analyzing the AGB variance, the recommendation is to have a footprint size that is similar to the size of the field plots used for collecting reference data, i.e. 20 m diameter in our case. For the optimal footprint size, AGB was estimated with a precision of 2.9 Mg per hectare (2.9 % of the average). The results also showed that variance estimates increased constantly with increasing geolocation error. For a geolocation error of 14 m, variance estimates increased by 17%, which justifies investing additional efforts in minimizing it.

2025

As an active remote sensing technique airborne laser scanning (ALS) is able to capture the topography with high precision even for densely forested areas. Due to the high pulse repetition frequency of up to 400 kHz a high sampling rate on the ground can be achieved, which allows the description of the terrain surface in decimeter scale. In this contribution two approaches to characterize terrain roughness are described. In the first approach the standard deviation of detrended terrain points is calculated. To achieve a high spatial resolution of the derived roughness layer a high terrain point density is essential, which requires especially in dense forested areas a very high sampling rate. In addition to the 3D position of backscattering objects, full-waveform ALS systems provide the width of each detectable echo, which provides information on the range distribution of scatterers within the laser footprint that contribute to one echo. It is therefore, an indicator for surface roughness and the slope of the target. In comparison to the roughness layer derived from the first approach using high point densities, the derived echo width image shows similar spatial patterns of terrain roughness even for moderate point densities. The results show that both the echo widths and the vertical distribution of terrain echoes are useful to derive reliable geometric terrain roughness layers of large areas.

2025, Journal of Geophysical Research

Forest disturbances greatly alter the carbon cycle at various spatial and temporal scales. It is critical to understand disturbance regimes and their impacts to better quantify regional and global carbon dynamics. This review of the status and major challenges in representing the impacts of disturbances in modeling the carbon dynamics across North America revealed some major advances and challenges. First, significant advances have been made in representation, scaling, and characterization of disturbances that should be included in regional modeling efforts. Second, there is a need to develop effective and comprehensive process-based procedures and algorithms to quantify the immediate and long-term impacts of disturbances on ecosystem succession, soils, microclimate, and cycles of carbon, water, and nutrients. Third, our capability to simulate the occurrences and severity of disturbances is very limited. Fourth, scaling issues have rarely been addressed in continental scale model applications. It is not fully understood which finer scale processes and properties need to be scaled to coarser spatial and temporal scales. Fifth, there are inadequate databases on disturbances at the continental scale to support the quantification of their effects on the carbon balance in North America. Finally, procedures are needed to quantify the uncertainty of model inputs, model parameters, and model structures, and thus to estimate their impacts on overall model uncertainty. Working together, the scientific community interested in disturbance and its impacts can identify the most uncertain issues surrounding the role of disturbance in the North American carbon budget and develop working hypotheses to reduce the uncertainty.

2025, Agroforestry Systems

Nothofagus antarctica forests at the Chilean Patagonia are valued for both their ecological and livestock production value. Despite their importance, there is not enough information about the understory associated to these forests. Previous studies have reported the dependence of the understory on the light intensity reaching the sward. Thus, our objective was to study the effect of the tree canopy cover on the plant community composition and productivity of the forests understory. We established four experimental sites along a 100-km transect covering an area of 700 km 2 in Southern Chilean Patagonia. 73 1-m 2 metal exclusion cages (quadrats) were randomly distributed along tree cover gradients on the sites. Bare soil, litter and understory cover were registered. Plant botanical composition was also recorded. At the end of the growing season plant biomass was harvested to estimate yield. Species frequency and abundance were analyzed. Species richness and biodiversity were determined. We found 37 species distributed in 20 families. Woody species represented 13.5%, grasses 24.3% and forbs 62.2% of the total. Species richness was higher in grasslands than forests. There was a trend in decreasing biodiversity when increasing tree canopy cover. Differences in yield between grasslands and open forests were not significant. High forage value species presented higher abundance in open forests than grasslands. We conclude that open forests of N. antarctica have higher grazing potential than their associated grasslands. These findings support the facilitation effect of trees over understory species reported previously.

2025, IEEE Transactions on Geoscience and Remote Sensing

A microwave scattering formulation is presented for grassland and other short vegetation canopies. The fact that the constituent elements of these targets can be as large as the vegetation layer make this formulation problematic. For example, a grass element may extend from the soil surface to the top of the canopy, and thus the upper portion of the element can be illuminated with far greater energy than the bottom. By modeling the long, thin elements of this type of vegetation as line dipole elements, this nonuniform illumination can be accounted for. Additionally, the stature and structure of grass plants can result in situations where the average inner-product or coherent terms are significant at lower frequencies. As a result, the backscattering coefficient cannot be modeled simply as the incoherent addition of the power from each element and scattering mechanism. To determine these coherent terms, a coherent model that considers scattered fields, and not power, is provided. This formulation is then used to provide a solution to the multiple coherent scattering terms, terms which include the correlation of the scattering between both dissimilar constituent elements and dissimilar scattering mechanisms. Finally, a major component of the grass family are cultural grasses, such as wheat and barley. This vegetation is often planted in row structures, a periodic organization that can likewise result in significant coherent scattering effects, depending on the frequency and illumination pattern. Therefore, a formulation is also provided that accounts for the unique scattering of these structures.

2025, Forest Ecology and Management

An individual-tree growth modelling methodology capable of explicitly modelling observed spatial dependence was sought using growth data for even-aged Eucalyptus pilularis (Smith.) in New South Wales, Australia. Candidate methodologies included the moving average autoregression, the directly specified Gaussian covariance function, and the Papadakis method. The directly specified Gaussian covariance function and the Papadakis method adequately modelled positive spatial dependence attributable to micro-site influences, but failed to model the negative spatial dependence attributable to competitive influences. The moving average autoregression was the only model which facilitated the simultaneous modelling of spatial dependence attributable to confounded competitive and micro-site influences. Consequently, the moving average autoregression was identified as the best methodology for explicitly modelling the spatial dependence prevalent among the individual trees of forests. Benefits from this new methodology for estimating individual-tree growth models include valid parameter estimates and inferences, improved estimation efficiency and a strengthened theoretical basis for the model. Furthermore, the moving average autoregression provides a definition of the dispersion matrix which can be used to generate more realistic stochastic predictions of individual-tree growth. The results detailed here apply to an even-aged eucalypt stand, and their generality need to be explored further in different forest structures, particularly irregular natural forests. Practical application of the methodology is discussed.

2025, Movimenti, acque, soliloqui: Poesia bengalese moderna, Officina Libraria: Roma. ISBN: 978-88-3367-291-5

Traduzione italiana di tre poesie di Buddhadeva Bose (Iliś, Kalkātā, Rāt tinṭer soneṭ 1), con testo a fronte in lingua bengali

2025, Giuseppe Flora e Alessandro Anil (eds.), Movimenti, acque, soliloqui: Poesia bengalese moderna, Officina Libraria: Roma. ISBN: 978-88-3367-291-5

Il saggio introduce al pubblico italiano lo scrittore, traduttore e critico letterario bengalese Buddhadeb Basu, figura di spicco del modernismo indiano di metà Novecento. Si analizzano alcune tendenze linguistiche, estetiche e politiche riconoscibili nell’opera dell’autore bengalese, ponendo l’accento sul suo impegno nel campo della traduzione, pratica di un internazionalismo sia politico che letterario, oltre che cifra caratterizzante del modernismo indiano.

2025, Ecosphere

Amazonia contains a vast expanse of contiguous tropical forest and is influential in global carbon and hydrological cycles. Whether ancient Amazonia was highly disturbed or modestly impacted, and how ancient disturbances have shaped current forest ecosystem processes, is still under debate. Amazonian Dark Earths (ADEs), which are anthropic soil types with enriched nutrient levels, are one of the primary lines of evidence for ancient human presence and landscape modifications in settings that mostly lack stone structures and which are today covered by vegetation. We assessed the potential of using moderate spatial resolution optical satellite imagery to predictADEs across the Amazon Basin. Maximum entropy modeling was used to develop a predictive model using locations ofADEs across the basin and satellite‐derived remotely sensed indices. Amazonian Dark Earth sites were predicted to be primarily along the main rivers and in eastern Amazonia. Amazonian Dark Earth sites, when compared w...

2025, Ornithological Applications

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), we monitored their populations in both forest types during a 5-year period (2008-2013), while we conducted an experiment in which nest boxes were added and then, after two years, removed by blocking cavity entrances. 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 3 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 later to the removal of nest boxes, with population abundance increasing by 13% and then decreasing by 50%, respectively. In contrast, we found no impact on 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 abundance in a Globally significant Biodiversity Hotspot in southern South America.

2025, Arthshastra Indian Journal of Economics & Research

The present study was based on information collected from 50 chilli growers, 12 retailers, and eight wholesalers from the
Mokokchung district of Nagaland in the crop year 2012-13 through a pre-tested well designed questionnaire. Purposively, the
paper intended to discover the surplus, cost, margin, and price spread of chilli production and marketing in Longsa village.
The study revealed that after holding 9.5% for domestic purpose, producers were left with 90.5% as marketable surplus of
which the actual marketed surplus was 86.33% due to 4.17% loss in spoilage and wastage. Regression coefficient with and
without the dummy factor showed that area and production were two major determinants having a positive impact on
marketed surplus at the 1% probability level of significance. Furthermore, it was observed that a majority of the farmerproducers
(52.3%) sold their produce to retailers, that is, channel – II, indicating the most prominent channel. The net price
received by producers in consumer's rupee in channel – I was 97.63%, channel – II: 82.43%, and channel – III: 61.9%, signifying
that the producer-consumer channel was the highest marketing efficiency channel according to Shepherd's and Acharya-
Agarwal's methods. It further concluded that 93% of chilli was traded in the market by way of retailers and wholesalers, and
only 7% within the village.
Keywords : production, marketed surplus, cost, margin, price spread, efficiency, constraints

2025, Arthshastra Indian Journal of Economics & Research

The study highlighted the trends in area, production, and productivity of rice cultivation in India and the North East Region and
tried to investigate the major issues and challenges of rice cultivation. The data from the years 1997 - 98 to 2015 - 16 were
collected from sources such as Handbook of Statistics, Directorate of Economics & Statistics, Ministry of Agriculture, Govt. of
India and The North Eastern Development Finance Corporation Ltd. (NEDFi) databank. The study revealed that the area,
production, and productivity in India witnessed an increasing trend at a lower rate of about 0.99%, 1.24%, and 5.94%,
respectively. However, in case of the North East Region, there was an increasing trend in area and productivity by about 0.18%
and 1.07%, which was much lower than the national average, while production was 2.05%. The study showed that there was a
fluctuating trend in area, production, and productivity in India and the North East Region over this period. Lack of advanced
machinery, floods, infestation by weeds and pests, non - availability of HYV seeds, discouraging price conditions are some
limiting factors for the rice growers, weaning them away from rice cultivation in India in general and the North East Region in
particular.
Keywords : rice, land, production, productivity trends and determinants, North East Region

2025, Arthshastra Indian Journal of Economics & Research

Cultivation of flowers in Nagaland has been in practice since time immemorial, and production and marketing of cut flowers
was confined to a small area. However, since 2004-05, under the active support of Horticulture Mission for North-Eastern and
Himalayan states (HMNEH), more area was brought under floriculture for commercial purposes. Increase in the domestic
demand for fresh-cut flowers and support from the state government is encouraging more women to take up flower cultivation
on a commercial basis. The district of Kohima was selected for the present study. This study was done on primary data
collected from 100 flower growers interviewed using a pre-tested questionnaire. Simple tabulation and regression model was
used to analyze the data collected. With the commercialization of floriculture products, the floriculture sector has now
become one of the fastest growing segments of horticulture, opening ways for Naga women and unemployed female youths
to earn a living by engaging themselves in activities which were earlier a mere hobby for them, pushing the economy towards
development. The flower industry in Nagaland, being a fresh industry, is facing many challenges and shortcomings. Thus,
efforts have been made to study the extent of women empowerment through floriculture, employment opportunities, income
generation, and challenges associated with it.
Keywords : floriculture, employment, and women empowerment

2025, Journal of Applied Ecology

1. Until very recently there have been no digital data from satellites for studying events that occur at scales of 10-1000 m 2 over large areas (100-100 000 ha). Many phenomena of interest to ecologists, such as impacts of selective logging on forest processes, occur over large extents but at local scales. Here we report results from a pilot project to evaluate through visual interpretation the potential of newly available 1-m panchromatic and 4-m multi-spectral data from the IKONOS satellite, for studying forest structure, dynamics and logging impacts in logged and old-growth tropical moist forest. 2. The study area, the Mil Madeireira Itacoatiara Ltda site of Precious Woods Amazon, near Itacoatiara, Amazonas, Brazil, is managed using reduced-impact logging practices to minimize environmental impacts, and thus represents a lower bound for logging impacts in tropical rain forests. 3. The IKONOS image was georeferenced using uncorrected global positioning system (GPS) locations for 10 control trees whose crowns were clearly visible in the image. The root mean square error (RMSE) of the geometric transformation was 4 m, while the mean crown diameter of 50 randomly chosen trees in old-growth forest was 9•4 m. The fact that the RMSE was less than half the average crown diameter implies that it will usually be possible to locate from the ground crowns that are distinct on the image, given sufficiently accurate GPS locations. 4. IKONOS data are well suited for evaluating and monitoring logging impacts. Many impacts of logging were clearly observable in the image, including major and some minor roads, logging patios and larger logging gaps. Smaller extraction roads and logging gaps were not observable. 5. Many individual trees were distinct on the IKONOS image, indicating that it is now feasible to conduct demographic studies of tropical rain forest canopy trees based on repeated satellite observations. Linking these remotely sensed data to ground data will require improved GPS positions, because it is currently difficult to obtain accurate GPS readings in tropical rain forest understoreys. 6. Synthesis and applications. IKONOS 1-m and 4-m data were found to be useful for identifying individual trees as well as some logging management features in a tropical moist forest in central Amazonia. These data will have many applications for research and management of intervened and old-growth tropical forests, including planning and assessment of logging activities, as well as monitoring adherence to certification criteria such as those of the Forest Stewardship Council.

2025, Remote Sensing

The tree crown, with its functionality of assimilation, respiration, and transpiration, is a key forest ecosystem structure, resulting in high demand for characterizing tree crown structure and growth on a spatiotemporal scale. Airborne laser scanning (ALS) was found to be useful in measuring the structural properties associated with individual tree crowns. However, established ALS-assisted monitoring frameworks are still limited. The main objective of this study was to investigate the feasibility of detecting species-specific individual tree crown growth by means of airborne laser scanning (ALS) measurements in 2009 (T1) and 2014 (T2). Our study was conducted in southern Finland over 91 sample plots with a size of 32 × 32 m. The ALS crown metrics of width (WD), projection area (A 2D), volume (V), and surface area (A3D) were derived for species-specific, individually matched trees in T1 and T2. The Scots pine (Pinus sylvestris), Norway spruce (Picea abies (L.) H. Karst), and birch (Betula sp.) were the three species groups that were studied. We found a high capability of bi-temporal ALS measurements in the detection of species-specific crown growth (∆), especially for the 3D crown metrics of V and A3D, with Cohen's D values of 1.09-1.46 (p-value < 0.0001). Scots pine was observed to have the highest relative crown growth (r∆) and showed statistically significant differences with Norway spruce and birch in terms of r∆WD, r∆A 2D, r∆V, and r∆A 3D at a 95% confidence interval. Meanwhile, birch and Norway spruce had no statistically significant differences in r∆WD, r∆V, and r∆A 3D (p-value < 0.0001). However, the amount of r∆ variability that could be explained by the species was only 2-5%. This revealed the complex nature of growth controlled by many biotic and abiotic factors other than species. Our results address the great potential of ALS data in crown growth detection that can be used for growth studies at large scales.

2025, Ecological Applications

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

2025

Forest stand structure is the basis for forest planning in Croatia. Most of the stand structure data are obtained by sample plot measurements. For every dominant tree species number of trees per diameter class is calculated as a number of trees per hectare both on the single plot or the stand level. Number of trees per diameter classes is displayed as whole (rounded) number in Management plans. When calculating total stand volume, two approaches are used. Most of the forest planners used raw (not rounded) data in calculation, while displaying rounded number of trees per hectare and only some of them used rounded number of trees for calculation as it is written in Management plans. This paper presents the effect of rounding the tree number (whole number, one decimal and two decimal places) on total volume calculation in two different Management units: ''Opeke'' and ''Sungerski lug''. Total volume in Management unit “Opeke” (even-aged stands) is higher ...

2025, African Journal of Ecology

Tropical montane forests can store and sequester substantial amounts of carbon in above‐ground biomass (AGB), but variations in this storage related to location or degradation have not been quantified in the Cameroon Highlands. We established 25 permanent plots (20 m × 40 m) and sampled all trees ≥10 cm diameter following standard RAINFOR protocols. We estimated AGB and investigated variations related to taxonomic and structural forest attributes, including the height–diameter allometry in five forest types (four old‐growth dominated by different species and one secondary forest). Secondary forests had significantly lower AGB than old‐growth forests (49.4 ± 2.5 vs. >476.3 ± 168.7 Mg/ha, respectively), mostly related to lower basal area and tree height. Significant differences in species composition but not in forest structure or AGB were found between the four types of old‐growth forests studied, located at different altitudes and mountains. We discuss the importance of these mon...

2025

The forest near the Hostería Selva Virgen, located in Pichincha, northwestern Andean Chocó area, is one of the biodiversity hotspots in the world, reason that determined the analysis of the vascular flora in the zone. For this study we did a temporary transects of 50 x 4 and 50 x 2 m covering an area of 0.1 hectares. We calculated Sorensen, Simpson and Shannon indexes, using the Past software, obtaining the following results: 159 species (spp.) registered corresponding to 121 genera and 54 families. Families with more species were: 15 spp Moraceae, Rubiaceae 10 spp, Arecaceae 9 spp, Fabaceae 9 spp, Melastomataceae 8 spp and Meliaceae 8 spp. The diversity obtained has a value of 0.95. It is interpreted in the Simpson index as a high diversity. Richness was 0.33, interpreted as an average richness. Sorensen index identifies areas that share more species. Endemism is low: 6.25%. The high biodiversity found in the studied forest shows an important biological richness; therefore more stu...

2025, Forest Ecology and Management

We investigated stand development along a chronosequence on organic, clay and sand sites in black spruce boreal forest in northwestern Quebec, Canada. Our objectives were: (1) to describe trends and stages of structural development following fire; (2) to compare trends and stages of development both in isolation from and in conjunction with species replacement. We tested the hypothesis that although trends in structural development are similar among site types, productivity and composition affect the timing of developmental stages. Data on live trees, snags and logs were collected at 91 sites. Trends with time since fire were analyzed using segmented piecewise linear regression. On organic sites, tree basal area and density increased continuously with time since fire, while deadwood abundance decreased and then increased. Live tree basal area, tree density and deadwood abundance generally followed expected S-, N-and U-shaped trends, respectively, on clay sites, but often with decreases in later stages due to paludification. Fewer trends were significant on sand sites, although tree basal area decreased likely due to a change in species composition. Older forests on all site types were more structurally diverse. To estimate the timing of the stages of structural development, we introduce a new analysis technique which uses the breakpoints of the piecewise regressions. On organic sites, only three stages of stand development were evident, whereas a four-stage stand development model was appropriate for both clay and sand sites. We found that local conditions affected not only the timing of developmental stages, but also the number of stages and the trends themselves. We attributed these differences to changes in species composition and productivity. We refine the theory of structural development by representing patterns in both live and deadwood as two-stage trends with two possible outcomes for each stage. Our new method of determining the timing of the developmental stages using empirical data can be used to develop management practices that emulate structural development in order to conserve biodiversity on a landscape scale.

2025, International Symposium on Imprecise Probabilities and Their Applications

The Bayesian Dirichlet equivalent uniform (BDeu) function is a popular score to evaluate the goodness of a Bayesian network structure given complete categorical data. Despite its interesting properties, such as likelihood equivalence, it does require a prior expressed via a user-defined parameter known as Equivalent Sample Size (ESS), which significantly affects the final structure. We study conditions to obtain prior independence in BDeu-based structure learning. We show in experiments that the amount of data needed to render the learning robust to different ESS values is prohibitively large, even in big data times.

2025

2012 Stakeholders ’ Vision on the Socio-Ecological System (SES) situation in Mexico. A Case Study 2

2025

Urban impacts tree growth and mortality in complex ways. Increased CO2 and temperature may enhance tree growth, 5 but ozone and other air pollutants may decrease tree growth and lead to mortality. 5 year remeasurement data provides first napshot into productivity and mortality in Forest Park Plots.Tree boles account for 40-70% of forest carbon in mature Douglas fir stands 12 . • Net Primary Productivity of Boles (NPPB) = [Δ Biomass (living) + Biomass (dead)] Methods: Remeasured tree diameter in 4 of 6 LTER plots. Related DBH to biomass and carbon store using standard allometric equations.Noted Tree mortality, and whether cause was densitydependant (i.e., suppression) or density-independent (e.g. windthrow). Also noted if dead bole remained as snag or contributed to CWD pool.

2025, Artvin Çoruh Üniversitesi Orman Fakültesi Dergisi

Artvin'in Ardanuç ilçesi Aydın Köyü yakınlarında yürütülmüş olan bu araştırmada, orman üstü doğal mera alanlarında botanik kompozisyon, kuru ve yaş ot verimi, otlatma kapasiteleri ile bazı toprak parametrelerinin kısa mesafeli yükselti artışlarına bağlı olarak değişimleri irdelenmiştir. Bu amaçla; 1900, 2000 ve 2200 metre yükseltilerde tel kafesler yardımı ile her biri 1 m 2 olan toplam 36 adet deneme parseli kurulmuştur. Kafeslerle ayrılan bu parsellerden alınan bitki örnekleri teşhis edildikten sonra botanik kompozisyonlarına ayrılarak yaş ve kuru ot verimleri ile otlatma kapasiteleri hesaplanmıştır. Ayrıca, 0-20 cm derinlikten alınan bozulmuş ve bozulmamış toplam 72 adet toprak örneği üzerinde geçirgenlik, hacim ağırlığı, iskelet içeriği, ince kısım ve kök miktarı, tekstür, tane yoğunluğu, gözenek hacmi, organik madde (OM), toprak reaksiyonu (pH) analizleri yapılmıştır. Yapılan hesaplama sonuçlarına göre meraların ortalama yaş ot verimi 647.22 kg/da, kuru ot verimi 196,67 kg/da olarak tespit edilmiştir. Botanik kompozisyonun ise %46.19 ile buğdaygillerden, %14.36 ile baklagillerden ve %39.45 ile diğer familyalardan oluştuğu belirlenmiş ve yükselti kademelerine göre bazı istatistiksel farklılıklar göstermiştir. Ayrıca, meraların toprak özellikleri içerisinde OM, hacim ağırlığı, ince kısım, iskelet içeriği ile gözenek hacmi değerlerinin yükselti kademeleri arasında önemli seviyede farklılıklar gösterdiği anlaşılmıştır. Son olarak, yapılan korelasyon analiz sonuçları, meralardaki botanik kompozisyonun şekillenmesi üzerinde bazı toprak özelliklerinin istatistiksel önem derecelerinde rol oynadığını ortaya çıkarmıştır.

2025

Due to its ecological importance, the monitoring of the vertical structure of forests is continuously raising the interest of the synthetic aperture radar (SAR) scientific community. SAR tomography allows reconstructing the 3-D distribution of the radar power backscattered by a volume by combining more than two SAR acquisitions with baseline diversity. Beyond specific estimation algorithms, the link between the estimated tomograms (depending in general on frequency, polarization and acquisition geometry) and physical forest structure is essential for establishing potential applications. In this work, we contribute to this topic by presenting first investigations aimed to characterize the changes on forest tomograms due to weather and seasonal effects, with the perspective of analysing potentials for monitoring forest ecosystem changes and discuss guidelines for an effective implementation of spaceborne forest structure sensing.

2025, Journal of Tropical Ecology

Climate is one of the most important factors determining variation in forest structure, but whether soils have independent effects is less clear. We evaluate how climate and soil independently affect forest structure, using 89 200 stems ≥ 10 cm dbh from 220 1-ha permanent plots distributed along environmental gradients in lowland Bolivia. Fifteen forest structural variables, related to vertical structure (forest height and layering), horizontal structure (basal area, median and the 99th percentile of the stem diameter and size-class distribution) and density of life forms (tree, palm and liana), were evaluated. Environmental variables were summarized in four multivariate axes, related to rainfall, temperature, soil fertility and soil texture. Multiple regression indicates that all structural variables were affected by one or more of the environmental axes, but the explained variation was generally low (median R 2 = 0.15). Rainfall and soil texture affected most forest structural variables (respectively 87% and 80%) and had qualitatively similar effects. This suggests that plant water availability, as determined by rainfall and soil water retention capacity, is the strongest driver of forest structure, whereas soil fertility was a weaker driver of forest structure, affecting 53% of the variables. Maximum forest height, palm density, total basal area and liana infestation showed the strongest responses to environmental variation (with R 2 ranging from 0.31-0.82). Forest height, palm density and total basal area increased with plant water availability, while liana infestation decreased with plant water availability. Therefore, multiple rather than single environmental factors must be used to explain the structure of tropical forests.

2025, Ethiopian journal of health sciences

2025, Forest Ecology and Management

 Cultivation of coffee alters composition and structure of Ethiopian rainforest.  Coffee yield is primarily determined by coffee shrub characteristics and density.  Coffee yield is negatively related to the degree of canopy closure. ... more

2025, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

NASA's Global Ecosystem Dynamic Investigation (GEDI) mission has been designed to measure forest structure using lidar waveforms sampled as it orbits the Earth while aboard the International Space Station. In this paper, we report the results of a study using airborne measurements of large-footprint (LF) lidar to simulate GEDI observations and to verify its capability its to retrieve ground elevation, vegetation height and aboveground biomass (AGB) by comparing to airborne small-footprint (SF) lidar measurements. The study focused on tropical forests and used data collected during the NASA and ESA AfriSAR ground and airborne campaigns in the Lope National Park in Central Gabon. The measurements covered a gradient of successional stages of forest development with different height, canopy density and topography. The comparison of the two sensors shows that LF lidar waveforms and simulated waveforms from SF lidar are equivalent in their ability to estimate ground elevation (RMSE=0.5 m, bias=0.29 m) and maximum forest height (RMSE=2.99 m; bias=0.24 m) over the study area. The difference in the AGB estimated from both lidar instruments at the 1-ha spatial scale is small over the entire study area (RMSE=6.34 Mg  ha -1 , bias=11.27 Mg  ha -1 ) and the bias is attributed to the impact of ground slopes greater than 10-20 degrees on the LF lidar measurements of forest height. Ourresults verify the ability of GEDI LF lidar to measure the complex structure of humid tropical forests and to provide estimates of AGB comparable to SF.

2025, Biogeosciences

Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. standlevel basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (P V ), dry season length (S D ), and mean annual air temperature (T A ) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within a median -2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H , especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account. Africa, Asia, Australia, and South America, with Shiela Lloyd also providing invaluable assistance with manuscript preperation.

2025, Jungle Trees of Central India: A Field Guide for Tree-Spotters

Pradip Krishen's Introduction to his Field Guide to the Jungle Trees of Central India

2025

The Anap Muput Forest Management Unit (AMFMU) located in Bintulu, Sarawak, Malaysia is a production forest. It have undergone at least one or two cycle of selective logging where valuable timber species are depleting. Therefore the structure, composition and productivity of the re growth forests are quite different from the virgin stands. Measuring the diversity is one of the ways to access the soundness of ecological ecosystems. This study aim to collect information on tree diversity, forest structure and species composition. A total of 61 circular plots of 25-m radius were established covering a total area of 7.67 hectares. Trees with diameter at breast height (DBH) of 10 cm and above were recorded. Species composition, diversity, relative density (RD), relative basal area (RBA) and relative frequency (RF) and important value index (IVI) were calculated. A total of 5,871 trees comprised of 66 families, 208 genera and 827 species were recorded. Dipterocarpaceae was the most dominan...

2025, Annals of the Association of American Geographers

2025

2025, Global Ecology and Biogeography

AimLarge tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and field inventories. To close this gap, we propose a new pan‐tropical model to predict plot‐level forest structure properties and biomass from only the largest trees.LocationPan‐tropical.Time periodEarly 21st century.Major taxa studiedWoody plants.MethodsUsing a dataset of 867 plots distributed among 118 sites across the tropics, we tested the prediction of the quadratic mean diameter, basal area, Lorey's height, community wood density and aboveground biomass (AGB) from the ith largest trees.ResultsMeasuring the largest trees in tropical forests enables unbiased predictions of plot‐ and site‐level forest structure. The 20 largest trees per h...

2025, Biotropica

ABSTRACTWe studied the spatial heterogeneity of tree diversity, and of forest structure and productivity in a highly diverse tropical mountain area in southern Ecuador with the aim of understanding the causes of the large variation in these parameters. Two major environmental gradients, elevation and topography, representing a broad range of climatic and edaphic site conditions, were analyzed. We found the highest species richness of trees in valleys <2100 m. Valleys showed highest values of basal area, leaf area index and tree basal area increment as well. Tree diversity also increased from ridges to valleys, while canopy openness decreased. Significant relationships existed between tree diversity and soil parameters (pH, total contents of Mg, K, Ca, N and P), and between diversity and the spatial variability of pH and Ca and Mg contents suggesting a dependence of tree diversity on both absolute levels and on the small‐scale heterogeneity of soil nutrient availability. Tree dive...

2025, Natural Hazards Review

In fire-prone areas of the western United States, mechanical thinning is often seen as a way to achieve two outcomes: Wildfire mitigation and restoration of historical forest structure. In this study, a spatial modeling approach is used to ͑1͒ find which forests are likely to be thinned under different criteria; ͑2͒ for these forests, evaluate whether wildfire mitigation and restoration of historical forest structure are potentially needed; and ͑3͒ determine whether these results change under alternative assumptions related to weather and fire history. Effectively, the spatial models in this study allow us to "test" thinning criteria to see if they lead to the selection of land where the stated management goals are needed in the study area of the montane zone of Boulder County, Colo. The spatial modeling results indicate that common management practices-such as thinning dense stands on Forest Service land near communities-may be inappropriate if the desired outcome is both wildfire mitigation and restoration of historical forest structure. Instead, modeling results suggest that lower elevation forests in the study area should receive priority. Though specific to the montane zone of Boulder County, the results of this study support wider criticisms of national fire policy.

2025, Journal of Biogeography

In the Southwestern United States of America, the structure and composition of ponderosa pine (Pinus ponderosa P. and C. Lawson) forests are thought to have been altered by fire exclusion, leading to increases in tree density and a host of associated ecological changes . A formalized restoration model (Friederici, 2003) suggests that restoration of pre-fire exclusion forest conditions and a lowseverity fire regime is also consistent with a reduction in the risk of crown fires in ponderosa pine ecosystems. Thus, this low-severity model has contributed to the widespread assumption that ecological restoration and fire hazard mitigation can be simultaneously achieved in most lowelevation, dry forest ecosystems of the western United States (e.g. , which is a major driving force behind

2025, Ecosystems

A key issue in ecosystem management in the western U.S. is the determination of the historic range of variability of fire and its ecological significance prior to major land-use changes associated with Euro-American settlement. The present study relates spatial variation in historical fire occurrence to variation in abiotic and biotic predictors of fire frequency and severity across the elevational range of ponderosa pine in northern Colorado. Logistic regression was used to relate fire frequency to environmental predictors and to derive a probability surface for mapping purposes. These results indicate that less than 20% of the ponderosa pine zone had an historic fire regime (pre-1915) of relatively frequent fires (mean fire intervals, MFI, <30 years). More than 80% is reconstructed to have had a lower frequency (MFI ‡ 30 years), more variable severity fire regime. High fire fre-quency is clearly associated with low elevations. Lower and more variable fire frequencies, associated with high and moderate severities, occur across a broad range of elevation and are related to variations in other environmental variables. Only a small part of the ponderosa pine zone fits the widespread view that the historic fire regime was characterized mainly by frequent, low-severity that maintained open conditions. Management attempts to restore historic forest structures and/or fire conditions must recognize that infrequent severe fires were an important component of the historic fire regime in this cover type in northern Colorado.

2025, Annals of the Association of American Geographers

2025, Ecological Research

Lianas play a key role in forest structure, species diversity, as well as functional aspects of tropical forests. Although the study of lianas in the tropics has increased dramatically in recent years, basic information on liana communities for the Brazilian Atlantic Forest is still scarce. To understand general patterns of liana abundance and biomass along an elevational gradient (0–1,100 m asl) of coastal Atlantic Forest, we carried out a standard census for lianas ≥1 cm in five 1‐ha plots distributed across different forest sites. On average, we found a twofold variation in liana abundance and biomass between lowland and other forest types. Large lianas (≥10 cm) accounted for 26–35% of total liana biomass at lower elevations, but they were not recorded in montane forests. Although the abundance of lianas displayed strong spatial structure at short distances, the present local forest structure played a minor role structuring liana communities at the scale of 0.01 ha. Compared to s...

2025

The paper explores the possibilities of assessing five stand parameters (tree number, volume, stocking, basal area and stand age) with the application of a multi-layer perceptron artificial neural network. An IKONOS satellite image (PAN 1 m x 1 m) was used to asses parts of stands in the sixth (121-140 yrs) and seventh (141-160 yrs) age class of pedunculate oak management class in the »Slavir« Management Unit of Otok Forest Office. Six features extracted from the first order histogram and five texture features extracted from the second order histogram were used as input data for neural network training. Data from the Management Plan were used as outputs of the neural network. An early stopping method and scaled conjugate gradient algorithm with error back propagation were used to improve generalization property of the neural network. Two neural network models were applied to assess the required stand parameters. The first model has one neuron in the output layer, where separate neuron network training was conducted for each stand parameter. The second model has five neurons in the output layer related to five assessed stand parameters. Both networks were trained and tested simultaneously. The conducted research showed that both of these neuron network models have good generalization properties. However, further analysis gave precedence to the second neural network model. Assessment of five quantitative stand parameters did not show any statistically significant differences between the Management Plan data and the neuron network model in terms of tree number, volume, stocking, basal area and stand age analysis.

2025

A comparative Ethnohistory and Anthropology of a Chinantec and a Huave Community in their regional contexts from the Conquest to 1990.

2025, Environment, Earth and Ecology

The study aimed to investigate effectiveness of forest management zoning in conserving biodiversity of Mabira forest reserve. The study sites buffer, production, and strict nature reserve management zones were purposively selected. This was undertaken through investigating woody species diversity, composition and structure. A total of 60 sampling plots with a size of 20 m x10 m were used to collect vegetation data. Variables such as woody plant species identification and counts as well as diameter at breast height (DBH) of trees were done. The result depicted a total of 65 woody species; 39 in buffer, 19 in productions and 37 in strict nature reserve. Of these, only 9 trees species were found common to all zones and their Sorensen similarity coefficient was 0.2213. The population structure of the buffer and strict nature reserve zones was found to be a J -shape pattern, whereas the production zone shown an inverted J-shape pattern. Higher woody species diversity was depicted in the buffer and strict nature zones with (H'=2. 73512) and (H'=2. 68412) respectively, and lower in a production zone (H'=1. 63628). The evenness index value of a buffer zone was (J =0. 746574), strict nature (J= 0.743335) and production (J=0. 555719). The production zone had shown higher IVI values followed by buffer and strict nature reserve zone. The most important woody species identified based on their IVI value were Broussonetia papyrifera (Production), Acalypha neptunica (Buffer), Funtumia Elastica (strict nature reserve). The existing forest management is effective in conserving the biodiversity of the forest reserve. Nevertheless, the production zone was still suffering from exploitation of the surrounding community, hence serve for protecting the remaining management zones from further human interference. Further investigation is also required on the adjacent community perceptions of the forest management zoning.