Characteristics Of Tree Structure Research Articles

Allometric relationships between stem diameter, height and crown area of associated trees of cocoa agroforests of Ghana

Allometric models which are used to describe the structure of trees in agroforestry systems are usually extrapolated from models developed for trees in forest ecosystems. This makes quantitative assessment of the functions of shade trees in agroforestry systems challenging since increased availability of light and space in these systems may induce structural differences from those growing under forest conditions. We addressed this issue by providing species-specific allometric information on the structural characteristics of associated shade trees on cocoa agroforestry systems and assessed if allometries conformed to theoretical predictions. At the plot level, stand and soil characteristics affecting tree structural characteristics were assessed. The study was conducted in cocoa agroforestry systems at Suhum, Ghana. The height-diameter at breast height (H-DBH) allometry had the best fits (R2 = 53–89%), followed by the crown area (CA)-DBH allometry (R2 = 27–87%) and then the CA-H allometry (R2 = 22–73%). In general, the scaling exponents of the CA-DBH, H-CA and H-DBH allometries conformed to the metabolic scaling theory (MST). However, both the CA-DBH and H-DBH allometries diverged from the geometric similarity model. Though forest tree species had similar crown areas as fruit trees, they were slenderer than fruit trees. Tree slenderness coefficients were positively correlated with soil P, Ca, Cu and the ratios (Ca + Mg):K, (Ca + Mg):(K + Na) and Ca:Mg, but not C:N while DBH and H were correlated with soil P and C:N ratio. Our results show that critical soil nutrients and their ratios affects shade tree structural attributes (e.g. slenderness and CA), which possibly restrict variations in species-specific allometries to a narrow range on cocoa systems. Furthermore, shade tree species richness and density are better predictors of relative canopy projection area (a proxy for shade intensity) than tree species diversity. In conclusion, the results have implications for shade tree species selection, monitoring of woody biomass and maintenance of biodiversity.

Factors Influencing Habitat Use by Owls in a Mosaic Landscape in the Garo Hills, Northeast India

Northeast India, located in a global biodiversity hotspot, faces several biodiversity issues. These include shorter fallow periods between ‘jhum’ (shifting cultivation) cycles which give less time for forests to recoup, along with encroachment, logging and other developmental activities. This is leading to widespread habitat loss and degradation. In such a scenario, Community Reserves that largely make up the Protected Area network in Northeast India could likely act as refugia for several species. Our study explored how owls use these Reserves in the Garo Hills in Meghalaya. We conducted three temporal replicates in thirty-three 500 × 500 m grids between January and March 2020. Ecologically relevant site and sampling covariates were quantified in each grid along with owl counts. Occupancy and N-mixture models revealed that wind speed, temperature, humidity and survey start time had the greatest effect on the detection probability of owls. On the other hand, occupancy and abundance were most influenced by slope, distance to water body, disturbance and tree structural characteristics (girth and tree height heterogeneity). With these findings, we highlight the importance of preserving water bodies and old-growth forests in Community Reserves of the Garo Hills landscape, which seem to be acting as refugia for the Brown Wood-owl Strix leptogrammica, an old-growth forest specialist thought to be currently in decline.

Street trees and crime: What characteristics of trees and streetscapes matter

The extent to which street trees affect crime is moderated by many characteristics of tree structure, streetscapes, and tree management. To effectively utilize urban greening interventions as crime preventing programs, it is necessary to distinguish tree-related characteristics that increase crime from those that cause crime to decline. This study derived a complete set of tree-related characteristics and crime attributes from a variety of sources. We then applied ordinary least squares and spatial Durbin regressions to reveal the associations between street trees and crime in New York City. Our results showed that street tree characteristics that were negatively associated with crime rates included tree canopy cover, species diversity, and streetscape greenery, while the opposite was observed for the proportion of small-sized trees. The characteristics of street trees that displayed a dual-feature with crime rates included tree health, proportion of harmful tree guards, and proportion of trees with trunk problems, while tree stewardship was not significantly associated with crime. In addition, our findings demonstrated that tree canopy cover and streetscape greenery were conducive to reduce crime severity. The mixed associations between street tree characteristics and crime could be potentially explained by the “broken window theory”, trees’ view-obstructing effect, the “eyes on the street”, and trees’ therapeutic effect. The revealed findings have important implications for the implementation of tree-planting programs in tackling the dual tasks of improving urban greening and reducing crime, and could help translate crime reduction into specific actions of streetscape design and tree management that can be taken by government and local stakeholders.

Local Drivers Associated to Temporal Spectral Response of Chlorophyll-a in Mangrove Leaves

The pigment content in leaves has commonly been used to characterize vegetation condition. However, few studies have assessed temporal changes of local biotic and abiotic factors on leaf pigments. Here, we evaluated the effect of local environmental variables and tree structural characteristics, in the chlorophyll-a leaf concentration (Chl-a) associated with temporal change in two mangrove species. Rhizophora mangle (R. mangle) and Avicennia germinans (A. germinans) trees of a fringe mangrove forest (FMF) and lower basin mangrove forest (BMF) were visited over a period of one year, to obtain radiometric readings at leaf level to estimate Chl-a. Measurements on tree characteristics included diameter at breast height (DBH), basal area (BA), and maximum height (H). Environmental variables included soil interstitial water temperature (Ti), salinity (Si), and dissolved oxygen (Oi), flood level (fL), ambient temperature (Tamb), and relative humidity (Hrel). Generalized linear models and covariance analysis showed that the variation of Chl-a is mainly influenced by the species, the interaction between species and mangrove forest type, DBH, seasonality and its influence on the species, soil conditions, and fL. Studies to assess spatial and temporal change on mangrove forests using the spectral characteristics of the trees should also consider the temporal variation of leave chlorophyll-a concentration.

Estimating Mangrove Tree Biomass and Carbon Content: A Comparison of Forest Inventory Techniques and Drone Imagery

Mangroves provide many ecosystem services including a considerable capacity to sequester and store large amounts of carbon, both in the sediment and in the above-ground biomass. Assessment of mangrove above-ground carbon stock relies on accurate measurement of tree biomass, which traditionally involves collecting direct measurements from trees and relating these to biomass using allometric relationships. We investigated the potential to predict tree biomass using measurements derived from unmanned aerial vehicle (UAV), or drone, imagery. This approach has the potential to dramatically reduce time-consuming fieldwork, providing greater spatial survey coverage and return for effort, and may enable data to be collected in otherwise hazardous or inaccessible areas. We imaged a mangrove stand using an RGB camera mounted on a UAV. The imaged trees were subsequently felled, enabling physical measurements to be taken for traditional biomass estimation techniques, as well as direct measurements of biomass and tissue carbon content. UAV image-based tree height measurements were highly accurate (R2 = 0.98). However, the variables that could be measured from the UAV imagery (tree height and canopy area) were poor predictors of tree biomass. Using the physical measurement data, we identified that trunk diameter is a key predictor of A. marina biomass. Unfortunately, trunk diameter cannot be directly measured from the UAV imagery, but it can be predicted (with some error) using models that incorporate other UAV image-based measurements, such as tree height and canopy area. However, reliance on second-order estimates of trunk diameter led to increased uncertainty in the subsequent predictions of A. marina biomass, compared to using physical measurements of trunk diameter taken directly from the trees. Our study demonstrates that there is potential to use UAV-based imagery to measure mangrove A. marina tree structural characteristics and biomass. However, further refinement of the relationship between UAV image-based measurements and tree diameter is needed to reduce error in biomass predictions. UAV image-based estimates can be made far more quickly and over extensive areas when compared to traditional data collection techniques and, with improved accuracy through further model-calibration, have the potential to be a powerful tool for mangrove biomass and carbon storage estimation.

Structural characteristics, above‐ground biomass and productivity of mangrove forest situated in areas with different levels of pollution in the Niger Delta, Nigeria

AbstractProductivity is a major driver of carbon sequestration in mangrove ecosystems worldwide. It is hypothesized that hydrocarbon pollution can accelerate litter fall and increase productivity through detoxification. We studied structural characteristics, above ground biomass (AGB) and productivity of mangroves in higher and lower polluted locations in the Niger River Delta, Nigeria. We established four 400 m2 plots in a random block design to test the effects of pollution on mangrove productivity. A total of 1,089 mangrove tree structural characteristics and importance values (IV) were estimated. For productivity, ten litter traps (0.1521 m2) were established within each plot, and emptied monthly for three years, June 2010 – June 2013. Total productivity was significantly different between treatments (F1, 1378 = 9.673, p < .001), with highly polluted having higher total productivity. Flowers (F1, 1378 = 9.673, p < .001) and fruits (F1, 1378 = 9.673, p < .001) productivity varied between treatments too, again with the highly polluted being significantly greater. Our results indicate that pollution increased litter fall, and thus altered productivity in the Niger Delta mangrove. To the best of our understanding, this is the first time productivity has been reported in the primary literature for the Niger Delta mangrove ecosystem.

Estimation of above‐ground biomass of large tropical trees with terrestrial LiDAR

Abstract Tropical forest biomass is a crucial component of global carbon emission estimations. However, calibration and validation of such estimates require accurate and effective methods to estimate in situ above‐ground biomass (AGB). Present methods rely on allometric models that are highly uncertain for large tropical trees. Terrestrial laser scanning (TLS) tree modelling has demonstrated to be more accurate than these models to infer forest AGB. Nevertheless, applying TLS methods on tropical large trees is still challenging. We propose a method to estimate AGB of large tropical trees by three‐dimensional (3D) tree modelling of TLS point clouds. Twenty‐nine plots were scanned with a TLS in three study sites (Peru, Indonesia and Guyana). We identified the largest tree per plot (mean diameter at breast height of 73.5 cm), extracted its point cloud and calculated its volume by 3D modelling its structure using quantitative structure models (QSM) and converted to AGB using species‐specific wood density. We also estimated AGB using pantropical and local allometric models. To assess the accuracy of our and allometric methods, we harvest the trees and took destructive measurements. AGB estimates by the TLS–QSM method showed the best agreement in comparison to destructive harvest measurements (28.37% coefficient of variation of root mean square error [CV‐RMSE] and concordance correlation coefficient [CCC] of 0.95), outperforming the pantropical allometric models tested (35.6%–54.95% CV‐RMSE and CCC of 0.89–0.73). TLS–QSM showed also the lowest bias (overall underestimation of 3.7%) and stability across tree size range, contrasting with the allometric models that showed a systematic bias (overall underestimation ranging 15.2%–35.7%) increasing linearly with tree size. The TLS–QSM method also provided accurate tree wood volume estimates (CV RMSE of 23.7%) with no systematic bias regardless the tree structural characteristics. Our TLS–QSM method accounts for individual tree biophysical structure more effectively than allometric models, providing more accurate and less biased AGB estimates for large tropical trees, independently of their morphology. This non‐destructive method can be further used for testing and calibrating new allometric models, reducing the current under‐representation of large trees in and enhancing present and past estimates of forest biomass and carbon emissions from tropical forests.

Research and Implementation of a New Retrieve for Auto Parts BOM

For wide varieties of auto parts and it is difficult to be managed, a new method was put forward. The methord is based on the conventional depth retrieve method and breadth retrieve method. It was raised for the data type of multilayer structure of auto parts. According to the tree structure characteristics of auto parts BOM, the method was introduced inheritance code and hierarchy field in the original BOM. The introduction of inheritance code allows a single part to inherit information from its parent part. Parts can be quickly located at which hierarchy in the BOM by the hierarchy field. For the introduction of them, the retrieve of the traditional tree structure model has changed from nonlinear relationship into a linear search, which improve search capacity and the efficiency of the retrieve system.

Structure Characteristics of Dead Tree in Dominant Species Populations in An Evergreen Broad-leaved Forest of Baishanzu

An experiment was conducted to study the dead tree structure characteristics of dominant species populations in an evergreen broad-leaved forest with the dead trees of ten years and living trees form ten dominant species in a 5 hm2 permanent plot in north slope of Baishanzu Mountain. In the age class of dead trees with inverted-J distribution,they were Cleyera pachyphylla,Sycopsis sinensis,Ilex editicostata,Cyclobalanopsis stewardiana and C. multinervis,Lithocarpus brevicaudatus and Fagus lucida,Schima superba. In the age class of dead trees with peak type distribution( with the peak in the second age class),they were Rhododendron latoucheae and Sorbus folgneri. The dead trees mainly concentrated in the top three age classes. The death ratio of every dominant species in the first age class was biggest,especially while the death ratio of Rhododendron latoucheae and Lithocarpus brevicaudatus in the first age class were relatively larger,being 47. 61% and50. 00%,respectively. The death ratio of dominant species decreased with the increasing of age class,and it changed after the fourth age class. The average death ratio of Sorbus folgneri was biggest( 30. 42%),and that of Fagus lucida was smallest( 13. 70%). The dead trees were denser in the habitats where the living trees were denser. The density of dead trees of Sycopsis sinensis was higher in gully,and that of Cyclobalanopsis multinervis had little difference among four kinds of habitats. The dead trees of the other eight dominant species populations were denser in ridge and sparser in gully. The death ratios of Sorbus folgneri in steep slope( 42. 86%) and Ilex editicostata in gully( 29. 78%) were higher,while that of Fagus lucida in ridge( 12. 40%) was lowest.

Socio-ecological dynamics and inequality in Bogotá, Colombia's public urban forests and their ecosystem services

Little is known about the distribution of urban forests of rapidly growing megacities in the developing world and what role they have on the well-being of citizens. Lack of information on their spatial distribution and ecosystem service (ESS) provision is especially pressing since megacities are often characterized by irregular land use patterns, social inequities, and socioeconomic instability. We explored spatial equity in key tree structural characteristics and ESS predictors from public urban forests in Bogotá, Colombia. We used one of the most comprehensive public urban tree inventories in Latin America, ESS indicators, and geospatial data to statistically and spatially analyze structural and diversity attributes and provision of ESS across Bogota's land uses and socioeconomic strata. We found that the poorest socioeconomic stratum had the lowest tree size and crown attributes while the wealthiest stratum had the largest trees attributes. Tree diversity was greatest in northern, affluent areas and total C stocks were greatest in residential areas. Potential particulate matter removal was notably proportional to socioeconomic strata with the wealthiest having the greatest potential while the poorest stratum had the lowest. Residential land-use property value premiums were weakly related to tree diameter and height, and locality and socioeconomic strata were the most significant predictors of property value in residential land-uses. We identified marked inequalities in ESS provision by urban trees in Bogotá, Colombia highlighting a need for urban forest ESS to be taken into account in city planning efforts to address environmental justice issues and improve citizen welfare.

Research on XML Data Structural-Integrity in XML Signature

With the extensive application of XML, especially in e-commerce field, XML data security has become the focus of people, which particularly shows in its structural attack specific to the location relation to elements in tree structure. Combined with the characteristics of tree structure of XML data as well as the basic features of traversing binary tree, the paper proposes a method to protect the structural-integrity of XML digital signature, so as to protect XML data element from structural attack through the basic features of traversing binary tree, and ensure the absolute location relationship among elements.

Structure characteristics of electrical treeing in XLPE insulation under high frequencies

Electrical tree structure is one of the most important influencing factors for electrical treeing characteristics in polymers. In this paper, we focused on the structure characteristics of electrical treeing in cross-linked polyethylene (XLPE) insulation under high-frequency voltages. The tree structure characteristics include structure distribution characteristics and structure conversion characteristics. The influences of voltage, frequency, and pin-plane spacing on tree structure characteristics were analyzed based on the experimental results. It can be concluded that tree structures regularly change with the local electric field and frequency. The electric field in a very small zone near the needle tip is an important influencing factor for the formation of bush-like trees, and the lowest frequencies for the observed pure-vine-like trees increased with voltage. For double-structure trees, the local electric field at the transition location of the two structures remained almost unchanged with voltage and pin-plane spacing, but obviously increased with frequency. In order to investigate the relations of the growth rate and fractal dimension with tree structure characteristics, a new parameter, the energy threshold W t , has been introduced and calculated for different tree structures.

Restoring natural characteristics in managed Norway spruce [Picea abies (L.) Karst.] stands with partial cutting, dead wood creation and fire: immediate treatment effects

This study investigated the immediate effects of restorative treatments on stand structure in mature managed Picea abies-dominated stands in southern Finland. The restorative treatments consisted of partial cuttings with three levels of coarse woody debris (CWD; 5, 30 and 60 m3 ha−1) with a constant volume of standing retention trees (50 m3 ha−1), and a burn/non-burn treatment. In addition, burned and unburned reference stands without cutting treatment were assessed. Each stand (n=24) included an upland and a paludified biotope; the paludified biotopes burned only partially. Detailed descriptions of stand structure were made for living and dead tree components before and after restorative treatments. Changes in tree diameter distribution and increases in standing dead tree volume were greatest in the combined burning and cutting treatments. The resulting standing dead wood volume varied greatly (1–52 m3 ha−1) between treatments, and was highest on burned paludified biotopes with 60 m3 ha−1 of CWD. The results indicate that creation of down wood was needed to achieve burning and that it is possible to regulate the severity of burnings through the amount of CWD, according to ecological restoration objectives. The study demonstrates that living and dead tree structural characteristics typical of natural postdisturbance early-successional forests can be rapidly restored to mature managed spruce stands, even when a significant portion of wood volume is harvested. These types of restorative cuttings provide one potential means of conserving biodiversity in managed forests.

Ultrasonic measurement of three‐dimensional structure of electrical trees using characteristics of tree structure

Ultrasonic measurement of three‐dimensional structure of electrical trees using characteristics of tree structure

Ultrasonic measurement of three-dimensional structure of electrical trees using characteristics of tree structure

In this paper we propose a method to distinguish noise-covered ultrasonic signals by making use of the distinguishing features of signals reflected from electrical trees extending toward the direction of depth within the specimen. This method utilizes the characteristics of signals due to the spatial continuity of a tree branch and also to the change of the delay time of the signal reflected from the electrical tree when the ultrasonic transducer is moved slightly near the target point. As a result, it is shown that the three-dimensional structure of the bush-type tree in polyethylene can be visualized in a nondestructive way. The resultant shapes of the trees agreed well with those obtained by actual sectioning of the specimen using a microtome. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(3): 7–13, 1997

トリー構造の特徴を利用した超音波による電気トリーの三次元構造計測

トリー構造の特徴を利用した超音波による電気トリーの三次元構造計測

Analysis and modelling of electrical tree growth in synthetic resins over a wide range of stressing voltage

A simple accumulated damage analysis method and an empirical field-driven tree growth model are proposed to characterize and describe the spatial and temporal development of electrical trees. Examples are presented for trees grown in CT200 and CY1311 epoxy resin pin-plane samples subjected to a wide range of 50 Hz alternating current electrical stress. It is shown that a material's resistance to treeing may be described quantitatively, allowing the relative performance of different synthetic resins to be easily compared. For CY1311 epoxy resin, tree structural characteristics change progressively from branch to bush structures as the stressing voltage is increased. It is shown that the time to failure is primarily influenced by the local electric field and the resultant tree geometry and fractal dimension of tree growth and is not simply dependent on the applied voltage.

Partitioning of rainfall in a eucalypt forest and pine plantation in southeastern australia: I throughfall measurement in a eucalypt forest: Effect of method and species composition

AbstractA seven year event‐based study partitioning of rainfall into throughfall, stemflow, and interception was conducted in a dry sclerophyll eucalypt forest and a Pinus radiata plantation. Resulting information will be of use for process modelling.Stemflow was influenced by event type, rain angle having a major effect; and the yields of the different species are compared. Tree characteristics that influenced stemflow yields are outlined and discussed.The canopy storage capacity of the eucalypt forest was determined and the influence of species composition is shown. The likely influence of climate variations is discussed. The canopy storage capacity is compared to the interception values estimated for continuous events of various sizes.The interception of the eucalypt forest and the pine plantation are compared on event basis for event size classes and on an annual basis. The comparative interceptions for continuous events are also discussed, while the effect of thinning the pine plantation on throughfall, stemflow, and interception is shown.The hydrological consequences of this study are: more informed judgment can be made about techniques for measurement of throughfall, tree structural characteristics (species related) can more adequately be considered when selecting trees for measurement of stemflow, and the stemflow yields can in some cases be better understood from the information about effect of event type.This paper deals with the influence of measurement method, species composition, and tree characteristics on the estimation of throughfall in the eucalypt forest. The site is near Canberra, lat. 35°S, 145°E, with annual rainfall about 650 mm.Two methods of measuring throughfall are compared: randomly placed, 200 mm cylindrical gauges (standard) and 50 mm square opening wedge type gauges (plastic), and randomly placed 5 × 0–22 m troughs. Despite the high placement density (150 to 225 ha−1), throughfall estimates from gauges has high variance and consistently underestimated those of the troughs, which had a total opening equivalent to 2325 raingauges (200 mm diameter) per hectare.Local concentration of stemflow into drip points provided by detaching bark pieces of one smooth barked species, Eucalyptus mannifera, is believed to be the principal cause of the lower collection and greater variance of the gauges. The low leaf area index (1–3) and large wood area of the forest together with a pendulous vertical habit of the leaves also contributed. The presence of E. mannifera is shown to substantially affect the relative values of throughfall as measured by troughs and gauges. The plastic receivers were found to underestimate rainfall or throughfall relative to the standard gauges, particularly for fine drop rainfall in multiperiod events.