Diameter Tape Research Articles

Evaluating airborne, mobile and terrestrial laser scanning for urban tree inventories: A case study in Ghent, Belgium

In urban tree inventories, structural measurements such as diameter at breast height (DBH), tree height (H), crown projection area (CPA) and crown volume (CV) are essential for diverse applications, including accurate ecosystem service estimation and management decisions. Traditionally, tree measurements are obtained using range finders and diameter tape. These measurements can be integrated into urban tree inventories through 3D laser scanning (also known as LiDAR). Multiple platforms for laser scanning exist, each with its own advantages and disadvantages, which have not yet been compared explicitly for urban tree inventories. We collected terrestrial laser scanning (TLS), mobile laser scanning (MLS) and airborne laser scanning (ALS) in leaf-on (TLS, MLS, ALS) and leaf-off conditions (TLS, MLS) in Ghent, Belgium. We evaluated the DBH, H, CPA and CV of 95 individual trees acquired from each acquisition platform, benchmarking against TLS. Our results show accurate DBH derivation from both TLS and MLS (bias < 2 cm, concordance correlation coefficient (CCC) ≈ 1). However, during leaf-on conditions, occlusion from shrubs and ivy is observed. For leaf-on MLS, point clouds of large trees exhibited occlusion in the top canopy, impacting crown volume (CV MLS leaf-on: bias = −116 m², CCC=0.85) and, to a lesser extent, tree height (H MLS leaf-on: bias = −0.38 m, CCC=0.99). Crown projected area was less affected (bias = 0.49 m², CCC=0.99), with differences more attributed to varying point precision among sensors. The difference between the metric and benchmark increased with tree size and the structural complexity of the surroundings (e.g. buildings), especially for MLS, for which limited GNSS coverage, traffic, and suboptimal walking patterns impeded ideal data collection. Our results will help city councils and tree managers choose the most optimal LiDAR platform for urban tree inventories, accounting for their purpose, site complexity and budget.

Measuring Tree Diameter Using LiDAR Equipped iPad: An Evaluation of ForestScanner and Arboreal Forest Applications

Abstract Forest owners need simple and efficient tools to capture and understand forest metrics. Additionally, they could benefit from emerging technologies in forest analysis. Light detection and ranging (LiDAR) sensors allow for precise measurements of different variables and can be used more easily in forestry settings thanks to their introduction into smartphones and tablets. ForestScanner and Arboreal Forest are two applications (apps) that allow for the measurement of tree diameter at breast height (DBH) on LiDAR-equipped devices. Our study sought to analyze and compare (1) the timing of traditional and LiDAR-based forest inventory methods and (2) the accuracy of traditional and LiDAR-based forest measurements. We established a series of plots to record and compare tree DBH and measurement time between a traditional diameter tape, ForestScanner, and Arboreal Forest. We found that DBH measurements from the apps were in good agreement with diameter tape measurements; however, both apps tended to underestimate DBH. Additionally, measurement time for both apps was found to be significantly shorter than traditional tape measurements. Further improvements in LiDAR apps can present a simple and efficient way for future forest analysis by seasoned foresters and private landowners. Study Implications: LiDAR smartphone applications represent a cost-effective and time-efficient method for wide-spread forest management, especially among landowners who have little access to forestry-specific equipment. As these technologies continue to advance, the incorporation of functions for plot establishment, height measurements, biomass estimations, and ecosystem dynamics could become valuable assets in the forest industry. We encourage individuals to further test LiDAR measurement applications themselves, as further training on these applications will help developers to improve application accuracy.

Woody Species Composition, Stand Structure and Regeneration Status of Londiani Forest in Kenya

Tropical forests provide habitats for diverse flora and fauna, in addition to playing a crucial role in climate regulation. They are being recognized for their roles as nature-based solutions to many sustainable development challenges, as shown by increased political commitment and global promises to reduce the rates of deforestation and boost the restoration of degraded forest ecosystems. Understanding tropical forest dynamics and their conservation status is therefore important. This study analysed the forest stand structure, the tree species composition and the regeneration status of Londiani Forest. In the three blocks of Londiani Forest, which are Kedowa, Chebewor and Londiani, belt transects that were 25 m wide and 1 km long were established. At every 200 m along the transects, 25 m × 25 m quadrats were set up in which an inventory of all the tree species was determined. Diameter tape was used to measure the diameter at breast height (DBH) 1.3 m above the ground. With the use of a Suunto angular clinometer, the tree height was measured. A nested 5 m × 5 m quadrat within the 25 m × 25 m quadrat was used to sample the saplings, while a 1m × 1 m quadrat was used to sample the seedlings. The quantities of seedlings and saplings were used to determine the state of regeneration. The data were entered into Microsoft Excel. The total stem density, species density, basal area, species basal area, relative density and species diversity were determined and extrapolated per hectare. A total of 1308 distinct trees from 34 different species and 24 families were counted. Kedowa recorded the highest (27) species richness, followed by Chebewor (19) and then Londiani (14). There was a statistically significant difference in the species richness among the three forest blocks (p &lt; 0.05). Within the three forest blocks, there were no statistically significant variations in the basal area distribution (p &gt; 0.005) or in the mean DBH (F = 0.560; p = 0.729) or height class distribution (F = 0.821; p = 0.558). There was a statistically significant difference in the stem density (F = 12.22; p = 0.005) and woody species diversity (F = 0.32; p = 0.001) within the three forests blocks. The similarity index ranged from 0.34–0.47. The presence of substantial numbers of seedlings and saplings in all forest blocks was an indication that there was regeneration.

Using homemade stainless steel dendrometer band for long term tree growth measurements

Dendrometer bands have been proposed as an accurate method for measuring tree growth. However, the constrained observation window and the material used in them hamper long-term tree growth monitoring. This study devised a dendrometer band made from stainless steel and primarily extended the extension length of the band spring to yield ample space to monitor diameter increments long-term. A total of more than 500 individual trees, including both coniferous and broadleaf trees, were examined. We compared the dendrometer band’s long-term performance with diameter tape for 5- and 10-year measurements. The results showed that the measurements of the two methods were highly correlated (R > 0.89) in both measuring periods. Differences between the two measurements for individual trees were typically less than 5 mm, and the mean differences at a stand level were less than 2 mm. These consistent observations suggested that the dendrometer band measurements were reliable for long-term measurement. Using the dendrometer bands, we further demonstrated the annual tree growths of diameter at breast height (DBH) and basal area (BA) for ten years of measurements. The size-dependent relationships between DBH/BA growth and initial DBH were also presented. Owing to their simple installation, low cost, and reliable measurement, these dendrometer bands would be helpful in forestry and forest ecology research.

ASSESSING THE RELATIONSHIP BETWEEN TREE DIMENSIONS IN AN URBAN ENVIRONMENT

Abstract. Urban forests can provide vital environmental and social functions if appropriately planned and managed. Tree inventory and tree dimensions are an important part of evaluating and monitoring the growth, size and health condition of urban trees. Accordingly, crown diameter (cd), height (h) and diameter at breast height (dbh) are significant biometric descriptors of tree size and bulk.When making decisions regarding urban environments it is important to be able to properly estimate these descriptors which are also needed to evaluate for example the so-called zones of upheaval (i.e., areas of interaction between roots and hard surfaces) and soil volume needs for planting trees in urban areas as well as for estimating their growth, control of diseases and preservation requirements.In line with the above, the scope of this contribution is that of assessing the relationship (via direct field measurements and regression analysis) that exists between the dbh of a given tree species relative to its h and cd. This information can be of assistance when substantiating tree measurements determined via existing mobile mapping technology systems.One hundred and three mature Norfolk Island pine trees (Araucaria heterophilla) located along a tourist shoreline of the Gold Coast (Queensland, Australia) were selected for this work. Their h, cd and dbh were individually measured, processed, and mapped in terms of their coordinate locations (i.e., latitude and longitude). Tree data was captured via field surveys using a diameter tape for dbh, and a laser range finder for measuring tree h and cd. A GNSS enabled digital camera was used to collect pictorial information and location description.For the case study investigated here, the regression models of h=F(dbh) and cd=F(dbh) reasonably validated (R2=0.928 and R2=0.899 respectively) the Australian standard estimates of h and cd of ornamental trees based on their dbh, thus making these estimates easier to determine via simplified mathematical functions. This is because the dbh is easier to be measured accurately in the field as compared to h and cd, and it can also provide information regarding the biomass, volume and carbon storage of trees.

Assessing the Best Fit Volume and Carbon Stock Equation of Pinus Roxburghii with Respect to Diameter at Breast Height Using Non-Destructive Method

Pinus roxburghii is dominant timber species in Nepal. However, there is not any model showing correlation of Diameter at breast height (DBH) with Volume and Carbon Stock. Therefore, this study was objectively conducted to show the correlation of diameter with volume and carbon stock. Gaumati community forest was selected as study site for this research. Total 214 sample trees were taken into account for the study. DBH classes were categorized into s 0-10, 11-20, 21-30, and 31-40, 41-50, and DBH &gt; 50 cm to represent the most of the diameter classes. Height and DBH were measured using Clinometer and Diameter tape. Four types of models were developed for volume and carbon stock with DBH viz. linear, logarithmic, power, and exponential. The models were tested, out of which the power equation was found to be the most accurate for both carbon and volume calculations. Power volume and carbon stock equations are y = 0.00004 x2.8404 (y=volume, x=DBH) and y = 0.0125x2.8404 (y=carbon stock, x=DBH) respectively. The estimated values of R2, MAD, MSE, RMSE and AIC were 0.9817, 0.178, 0.093, 0.305 and -41.58 respectively for power volume model and these values of R2, MAD, MSE, RMSE and AIC were 0.9817, 21.92, 1379.01, 37.13 and 1194.18 respectively for carbon stock calculation. Study shows that, there is a strong correlation between DBH vs. volume and DBH vs. carbon stock. Thus, the volume equation and carbon stock equation will be useful for forest science to calculate the volume and carbon stock of standing plants.

Development of Measuring Device for Diameter at Breast Height of Trees

Diameter at breast height (DBH) is the main metric for standing tree growth measurements. Developing fast and efficient measurement devices for measuring DBH is of great values in forest resource surveys. In this paper, we propose a new tree diameter measurement instrument developed using self-reset displacement sensor, which is equipped with a Personal Computer (PC) terminal to enable the measurement, transmission, storage, and analysis of tree diameters in one. The measurements showed an overall bias of 1.44% and an accuracy of 97.35% compared to the caliper, a conventional diameter measuring instrument. The overall bias was −0.52% compared to the diameter tape, and the measurement accuracy was 98.43%. Compared to the conventional devices, the proposed device is small and easy to carry, the measurement efficiency is significantly improved, and the measurement data can be directly derived for analysis. Compared with related electronic measuring instruments, this proposed device has the advantages of small volume, easy operation, large measurement range, and wider applicability.

Net benefits of silky oak (Grevillea robusta) for small farmers in Musanze District, Rwanda

This study was conducted in Musanze district, Rwanda, to evaluate the net benefits of silky oak (Grevillea robusta) production for small farmers. A semi-structured questionnaire was administered to 100 households distributed in four villages. The cost-benefit ratio was used as a decision-making tool. A diameter tape and a Haga altimeter were used to measure the DBH and height of grevillea and other dominant agroforestry tree species. Results indicate that 66 % of laborers were family members, gaining 625 Rwf per person day with grevillea production (US$ 0.61, with 4-8 hours of work per day. Also, results show that farmers earn 57,950 Rwandan Francs (Rwf) per hectare per year (US$ 57.48 from grevillea products (stakes, poles, charcoal, and timber), whereas the mean investment in grevillea production is 54,200 Rwf ha-1 year-1 (US$ 53.76. The net farm income is 3,225 Rwf (US$ 3.2 ha-1 year-1. The net benefit from grevillea product is affected by poor farmer data record as the majority of67% of respondents has not attended any formal education. However, farmers gain additional benefits of US$ 628, US$ 298, and US$ 224ha-1 year-1 from potatoes, maize, and bean, respectively, depending on their crop choice during intercropping with grevillea. The benefit-cost ratio is 1.06, which highlights the modest profitability of growing grevillea on the farm. In addition, soil erosion control, soil fertility increase, landslide prevention, shade provision, microclimate improvement, and biodiversity conservation were reported as ecosystem services of grevillea on the farm. Growth performance of grevillea (diameter at breast height, tree height, and volume) is analyzed in all four villages. The study shows that growing grevillea is profitable for smallholder farmers via tree products and farm benefits, including ecosystem services aspects.

Integrating Real Tree Skeleton Reconstruction Based on Partial Computational Virtual Measurement (CVM) with Actual Forest Scenario Rendering: A Solid Step Forward for the Realization of the Digital Twins of Trees and Forests

Digital twins of forests (trees) are computational virtual recreations of forests (trees) in which the entity distributions and physical processes in real-world forests (trees) are duplicated. It is expected that conventional forest science and management can be undertaken in a digital twin of forests (trees) if the recreation of a real-world forest (tree) has accurate and comprehensive enough information. However, due to the various differences between the current tree model and the real tree, these envisioned digital twins of the forests (trees) stay a theoretical concept. In this study, we developed a processing strategy that partially integrated computational virtual measurement (CVM) process into the tree modeling workflow. Owing to the feature of CVM, partial tree skeleton reconstruction procedures were considered to have higher mechanical objectivity compared to conventional mathematical modeling methods. The reason was that we developed a novel method called virtual diameter tape (VDT), which could provide a certain percentage of modeling elements using CVM. Technically, VDT was able to virtually measure diameters and spatial distribution of cross-sectional area of trees, including the basal area, from point clouds. VDT simulated the physical scenario of diameter tapes, observing point clouds of trees. Diameter and the cross-sectional area of stem and branches were obtained by two consecutive physical measurement processes, one in the forest sample site and another in the virtual space. At the same time, VDT obtained better or a similar accuracy compared to the mathematical methods, i.e., Hough transform-based methods, using the same data sets. The root-mean-square deviation (RMSE) of retrieval of diameter at breast height (DBH) using VDT was 1.02 cm, while DBH obtained from three conventional methods varied from 1.29 cm to 1.73 cm. Based on VDT measurement results, tree skeleton reconstruction and actual forest scenario rendering of our sample plots were further implemented. Beyond the visual consistency, we believe that our work might be a small and solid step in the technological evolution from tree models to the digital twin of forests (trees).

Influence of Gap Size on Regeneration, Structure and Species Diversity of Woody Vegetation in a Secondary Montane Forest Reserve, Kenya

South-Western (SW) Mau forest reserve has been experiencing anthropogenic and natural disturbances creating canopy openings in the forest. The objective of this study was to determine how these canopy openings influence regeneration, forest structure and species diversity. The study employed nested sampling design in disturbed sites of the forest reserve. Plots of 500 by 500 m were laid once at 100 m inwards from the forest edge in the three blocks of SW Mau; Ndoinet, Maramara and Itare. Gaps were randomly identified in the plots and gap area calculated using Ellipse Method (EM). Gap sizes were categorized based on area (m2). Woody species surrounding the gaps were identified and names inventoried. To determine regeneration, two quadrats of 5 by 5 m and 1 by 1 m were randomly delineated in every gap size four times and eight times for saplings (1-3 m high) and seedlings (&lt;1 m high), respectively. Tree heights surrounding the gaps were measured using suunto clinometer. Diameter at breast height (dbh) was measured using diameter caliper (65 cm for small trees) and diameter tape for large trees (dbh&gt; 65 cm). A total of 41 gaps were identified with small gap sizes dominating (23). Kruskal-Wallis rank sum test indicated non-significant differences in regeneration, forest structure and species diversity in the three gap sizes.&#x0D; This was attributed to Piper capensis which invaded medium and large gap sizes creating a closed canopy. It was, therefore, concluded that canopy cover from the invasive species influenced woody vegetation parameters in the gap sizes. It is, therefore, recommended to clear the dense ground cover to allow better natural regeneration and also enrichment planting in the gaps.

Individual Tree Parameters Models for Melia Azedarach (Chinaberry) Tree Grown in Erbil

The crown width of a tree is very important parameter. It is responsible for tree survival and for producing the food for the whole tree. They produce oxygen, filter out dust and other airborne pollutants from the air, purification of the water, generate shadow and determine the scenic beauty of trees and forests. The tree crowns have a significant effect on the microclimate. But measuring of the crown width is a difficult task that needs much money, time and effort. Thus this study aimed at developing of mathematical relationship between the crown width and breast height diameter for Chinaberry trees grown in Sami Abdulrahman Park in Erbil, Iraq. Both crown width and breast height diameters are the most important parameters of a tree. The breast height diameter of a tree can be measured very easily using diameter tape or caliper, unlike measuring of the crown width which is more cumbersome. Therefore, it is accustomed to regress it with breast height diameter in mathematical equations.to be used for prediction of crown width instead of measuring it whenever it is needed. Such regression models were undergone many measures of precision in order to select the most appropriate one that best fits the collected dataset. In this study 50 regression models were developed, of which 25 included the y- intercept and the other 25 regression models was without Y-intercept. The first group of regression models were excluded from the competition list because of having low values of the coefficient of determination. The second group of equations were subjected to many criteria for the purpose of selecting the best one and at last the equation: was finally selected for its high prediction ability and simplicity in application. According to this equation the crown width of for Chinaberry trees grown in (Sami Abdulrahman Park in Erbil) increases with 1.50168m for each unit increase in .

The species composition, diversity and regeneration status of Alamata woodlands, Tigray Regional State Northern Ethiopia–a descriptive analysis

Woody species composition, diversity and regeneration of Alamata woodland forest were evaluated and sampled using systematic random sampling techniques. Fifteen temporary sample plots of 20m x 20m (400 m2) each were established in the sampled woodland forest along altitudinal gradients 100m along plots. Three subplots, 5m x 5m were situated diagonally inside the 20m*20m one in the centre and edges for saplings, shrubs and seedlings data collection. Diameter at breast height (DBH) (cm) and height (m) were measured using a diameter tape and Haglöf Vertex IV Hypsometer. Woody species diversity, structure, important value index (IVI) and regeneration analyzed using appropriate formulas. Four tree species were found in the studied woodland forest. Most abundant tree species were Acacia seyal, Acacia etabaica and Balanites aegyptica, while the least abundant tree species was: - Acacia tortilis. The basal area (m2 ha-1) per plot basis (20m*20m) was ranged from 1.38 to 13.62, while the basal area for the sampled trees was ranged from 2.41 to 9.25. The volume for the sampled plots and trees were ranged from 5.91 to 46.11 and 10.58 to 41.25 m3 ha-1. The highest number of stems was recorded for Acacia seyal followed by Acacia etbaica. The lowest number of stems 43 N ha-1 were recorded for Acacia tortilis followed by Balanites aegyptica. The overall population distribution pattern of the targeted forest exhibited an inverted J - shaped distribution. Among the four sampled woody species in Alamata dry woodland forest regeneration was recorded for only two species Acacia etbaica and Balanites aegyptiaca, while others had no regeneration potential of seedlings and saplings. Better attention of development practitioners, policy makers and church communities may help to improve the woody species composition of this woodland forest and conservation role of Ethiopian dry woodland for carbon sequestration.

Carbon Stock Estimation of Selected Subtropical Broad-Leaved Evergreen Scrub Forest

This research estimates the carbon stock of the subtropical broad-leaved evergreen scrub forest of Lehtrar, a revenue estate of Kotli Sattian, Rawalpindi, Punjab, Pakistan. A total of six nested co-centric plots of 17.84 m2 each were laid out in the forest, having two sub-plots of 5.64 m2 and 1 m2 each, for shrubs and litter, respectively. Stem density, tree height, diameter at breast height (DBH), total tree biomass, and total carbon stock were calculated. In each plot, parameters like latitude, longitude, aspect, slope, elevation, tree count, etc., were catalogued. The carbon value was calculated in pools such as aboveground biomass (AGB), belowground biomass (BGB), litter, shrubs, etc. The tree height was measured using Abney’s level and the diameter at breast height (DBH) with diameter tape, while factors such as volume, shrub mass, litter mass, total tree biomass, and total carbon stock were calculated by using standard formulas. Results showed Olea ferrugineae to be the most abundant tree species in the study area, followed by Acacia modesta. The total average DBH and height were calculated as 17.03 and 16.79, respectively, with the species Dalbergia sissoo having the greatest DBH value. The mean carbon stock came out to be 47.75 tons/ha, with plot number 3 having the highest value of carbon stock, owing to the greatest stem count. The results of the study were significant and reflected a rich stem density, rich biomass, and an adequate carbon stocking capacity. The scrub forests of the study area, being important carbon sinks, are prone to deforestation and forest degradation activities that need to be controlled by using proper forest management practices to keep their carbon sequestration ability intact, as suggested under various reducing emissions from deforestation and forest degradation (REDD initiatives of UNFCCC.

ForestScanner: A mobile application for measuring and mapping trees with LiDAR‐equipped iPhone and iPad

Abstract Ground‐based light detection and ranging (LiDAR) is becoming increasingly popular as an alternative means to conventional forest inventory methods. By gauging the distances to multiple points on the surrounding object surfaces, LiDAR acquires 3D point clouds from which tree sizes and spatial distributions can be rapidly estimated. However, the high cost and specialized skills associated with LiDAR technologies have put them out of reach for many potential users. We here introduce ForestScanner, a free, mobile application that allows LiDAR‐based forest inventories by means of iPhone or iPad with a built‐in LiDAR sensor. ForestScanner does not require any manual analysis of 3D point clouds. As the user scans trees with an iPhone/iPad, ForestScanner estimates the stem diameters and spatial coordinates based on real‐time instance segmentation and circle fitting. The users can visualize, check and share the scanning results in situ. By using ForestScanner, we measured the stem diameters and spatial coordinates of 672 trees within a 1 ha plot in 1 hr 39 min with an iPhone and in 1 hr 38 min with an iPad (diameter ≥ 5 cm; detection rate = 100%). The diameters measured by ForestScanner and a diameter tape were in good agreement; R2 = 0.963 for iPhone and R2 = 0.961 for iPad. ForestScanner and a conventional surveying system showed almost identical results for tree mapping (assessed by the spatial distances among trees within 0.04 ha subplots); Mantel R2 = 0.999 for both iPhone and iPad. ForestScanner reduced the person‐hours required for measuring diameters to 25.7%, mapping trees to 9.3%, and doing both to 6.8% of the person‐hours taken using a dimeter tape and the conventional surveying system. Our results indicate that ForestScanner enables cost‐, labour‐ and time‐efficient forest inventories. The application can increase the accessibility to LiDAR for non‐experts (e.g. students, citizen scientists) and enhance resource assessments and biodiversity monitoring in forests world‐wide.

COMPARISON OF VARIED FOREST INVENTORY METHODS AND OPERATING PROCEDURES FOR ESTIMATING ABOVE-GROUND BIOMASS IN MALAWI’S MIOMBO WOODLANDS

This study assessed forest inventory methods and standard operating procedures (SOPs) for estimating above-ground biomass (AGB) and carbon, as employed in the key REDD+ Miombo Forest Reserves of Malawi. Analysis of Variance statistical technique was applied to investigate the following methods and SOPs: (i) allometry, (ii) sample plot configuration, and (iii) dendrometric measurements. Results indicate that the allometric equations parameter significantly (P&lt;0.001) affected the AGB estimations and was the highest contributor (97.95%) of the total variation. Malawi’s specific allometry provided the highest AGB estimate (113.08±1.56 t/ha). In contrast, the Pan-Tropical/generalized allometric models substantially underestimated AGB within the range of 16.7-67.9%. Furthermore, the findings demonstrate that the use of varied sampling plot sizes significantly (P&lt;0.001) affected the estimates of AGB. However, the plot size parameter contributed only 1.65% to the total variation. The 20m radius plot size registered the highest AGB (75.31±0.77 t/ha) compared to the 17.84m radius plot (66.12±1.61 t/ha). This signifies that the plot size of 17.84m radius underestimated the AGB by 12.2%. However, results on dendrometric measurements showed no significant (P&gt;0.05) differences in the AGB estimates between the use of diameter tape (D-tape) and calliper in measuring dbh of individual trees despite the former yielding higher estimates of AGB (74.65±0.93 t/ha) than the latter (72.53±0.98 t/ha). This demonstrates that the use of calliper in measuring dbh underestimated AGB t/ha by only 2.8% compared to the use of D-tape. Therefore, the study recommends; employment of local allometry, adoption of a circular sampling design of 20m radius, and consistent use of D-tape in measuring dbh for AGB in Malawi’s Miombo Woodlands. In conclusion, incorporation of these changes is envisaged to facilitate quick realisation of Malawi’s REDD+ carbon payments, smooth running of the National Forest Inventory system, robust implementation and global recognition of the REDD+ efforts.

Tree Measurements in the Urban Environment: Insights from Traditional and Digital Field Instruments to Smartphone Applications

Urban forests can provide essential environmental and social functions if properly planned and managed. Tree inventories and measurements are a critical part of assessing and monitoring the size, growth, and health condition of urban trees. In this context, the parameters usually collected are diameter at breast height (DBH) and total height, but additional data about crown dimensions (width, length, and crown projection) are required for a comprehensive tree assessment. These data are generally collected by urban foresters through field surveys using tree calipers or diameter tape for DBH and the electronic ipsometer/clinometer to measure tree height and crown size. Greater detail could be achieved using a digital instrument such as Field-Map, a portable computer station, to quickly realize dimensional and topographic surveys of trees and forest stands. Additionally, the incorporation of a LIDAR scanner into a smartphone such as the iPhone 12 Pro has made this device able to measure tree attributes as well as additional spatial data in the field. In this study, we tested these 3 different measurement systems in a field sampling of an urban forest and compared them in terms of measurable parameters, accuracy, cost, and time efficiency. Furthermore, we discussed the pros and cons of each measurement approach and how the resulted data can be used to evaluate ecosystem services of trees and provide guidance on tree management in order to reduce potential risks or disservices.

Carbon Stock in above and below Ground Biomass of Three Age Series of Pinus carribaea and Nauclea diderrichii Plantations; Omo Forest, Area J4 Ogun State, Nigeria

Forest carbon is identified in three major pools that is, above and below ground living vegetation, dead organic matter and soil organic carbon whose quantities have been identified for few forest types. The study investigated the carbon stock in above and below ground biomass in three age series of Pinus (1991, 1992 and 1996) and Nauclea (1974, 1975 and 1976) plantations at area J4, Ogun state Nigeria. Five plots of 20m x 20m dimension were randomly laid making a total of 30 plots. Diameter at breast height and height were measured using diameter tape and Spiegel Relaskop respectively. Soil samples were collected in each plantation at 0–15cm and 15–30cm depth with the aid of soil auger and laboratory analysis carried out. Data were analyzed using the General Linear Model of SAS software. Analysis of Variance (ANOVA) and Duncan Multiple Range Test was used to separate means and correlation analysis was carried out. Above ground was estimated using Brown et al. (1989) equation {Y= 34.4703- 8.0671 (DBH) + 0.6589(DBH2)} and below ground biomass was also estimated as 20% of above ground biomass. Result showed that Organic carbon stored up in the soil was highest (3.05±0.52g/kg) in Nauclea plantation (1975). Pinus plantation (1996) had a higher total carbon stock (1166.35ton/ha) than Nauclea plantation (1976) with (380.41ton/ha). Pinus plantation (1996) had the highest above ground biomass, below ground biomass and carbon dioxide concentration (728966.19, 160372.56 and 4198845.28/ha) lowest (227644.66, 50081.83 and 1311233.26/ha), Pinus plantation (1992) respectively. Variation in the above ground carbon stock among these plantations could be result of tree stand density, hence, higher number of trees in a plantation will eventually result to high above ground carbon stock of that plantation.

Assessment of Wood Production and Structural Composition of Domboma Community Based Forest in Dasse Chiedom, Moyamba District, Sierra Leone

This research was carried out in August and September 2020 in the Domboma community-Based forest of Domboma community in Dasse chiefdom, Moyamba district, southern Sierra Leone. The objective of the study was to assess wood production and structural composition of Domboma community Based-forest in Dasse Chiefdom, Moyamba District. The systematic sampling design was adopted and data were collected in 12 circular sample plots with a radius of 10 m and an area of 0.031 ha. The stand was divided into four transects that were 50 m apart and the interval between sample plots in any transect was 10 m. In total, 12 plots covering a sampling area of 0.38 ha were laid out. In each plot all trees ? 10 cm diameter at breast height (DBH, 1.3 m above ground level) were measured for both DBH and total height, using diameter tape and suunto hypsometer, respectively. The species was identified for every measured tree either directly by botanical name or by local names. The total individual trees enumerated were 147. These individual trees were distributed into four diameter classes as follows; 76 trees in diameter class 1, 33 trees in diameter class 2, 4 trees in diameter class 3 and 34 trees in diameter class 4. The Shannon-wiener index of diversity calculated was 3.38 using natural logarithm for the four diameter classes. The index of dominance was 0.76 and the index of dispersion estimated was 16.0 for all diameter classes respectively. The average (DBH) and height of trees were 51.17cm and 27.06m respectively. The basal area and wood volume were 241.35m2/ha and 31227.62m3/ha respectively and the stocking was 390 stems ha-1. The 26-tree species found in all the 12 plots were listed in IUCN redlist categories as follows; 19.2% as data deficient (DD), 57.7% as least concerned (LC), 3.8% as nearly threatened (NT), 11.5% as vulnerable (VU), 7.7% as endangered (EN) and none of the species was classified as critically endangered.

MORPHOLOGICAL PROPERTIES OF HURA CREPITANS L. (EUPHORBIACEAE) AS PROSPECTIVE RESOURCE FOR PULP AND PAPERMAKING

Hura crepitans L. (Euphorbiaceae) is a tropic tree species that was investigated for pulp and paper characteristics in this study. The diameters of five (5) different stands of Hura crepitans trees were first determined using diameter tape. Wood slivers were obtained from sapwood of the trees parallel to grain and at three (3) different positions along the axis, at the base (5%), middle (50%) and top (90%). The wood slivers were macerated in a mixture of equal volumes of glacial acetic acid and hydrogen peroxide at between 80 -100 degrees Celsius for 2 hours. Macerated fibres were washed and used to prepare microscopic slides where 15 fibres were measured per slide. Data recorded was subjected to One-way Analysis of Variance (ANOVA) based on Completely Randomized Design (CRD). Results show that both the primary fibre characteristics and derived characteristics were significantly different at p&lt;0.05? The mean fibre characteristics ranged as follows, Fibre lengths (0.87-1.16 mm), Fibre diameter (18.84 - 24.44 µm), Lumen width (9.92-16.89 µm) and Cell wall thickness (3.93-4.60 µm). The derived mean fibre characteristics ranged as follows; Runkel ratio (0.36-0.78), Elasticity coefficient (44.20-67.91%), Rigidity coefficient (15.98-27.82 %) and Slenderness ratio (0.44-0.80). This result implies that Hura crepitans has short fibres with high flexibility, which can collapse easily and form a fully bonded paper and is therefore recommended for pulp and paper production

Comparison of Numerical Calculation Methods for Stem Diameter Retrieval Using Terrestrial Laser Data

Terrestrial laser scanning (TLS) can be used as a millimeter-level measurement tool for forest inventories. However, the stem diameter retrieval accuracy in sample plot scanning is not yet convincing. The errors in each step of stem diameter retrieval algorithms must be evaluated. In this study, six numerical calculation methods for the numerical calculation step, i.e., cylinder fitting (CYF), circle fitting (CF), convex hull line fitting (CLF), the proposed caliper simulation method (CSM), closure B-spline curve fitting (SP) and closure Bézier curve fitting with global convexity (SPC), were applied to stem diameter retrieval, and the similarities and differences were evaluated. The ovality, completeness and roughness were used to evaluate the stem slice point cloud quality. A total of 165 stem slice point clouds at breast height collected from three Larix kaempferi plots were used. Compared with the field-measured stem diameters at breast height (DBHs), the root mean square errors (RMSEs) of the CYF, CF, CLF, CSM, SP and SPC methods were 0.30 cm, 0.30 cm, 0.51 cm, 0.51 cm, 0.56 cm and 0.54 cm, respectively. Compared with the SPC method results, the RMSE of the CSM results was 0.05 cm. The results illustrated that the CYF and CF methods performed the same, as did the CLF and CSM methods. Most DBHs retrieved by the CYF and CF methods were smaller than the field-measured DBHs, and most DBHs retrieved by the CLF, CSM, SP and SPC methods were larger than the field-measured DBHs. This study demonstrated that the CYF and CF methods perform the best and are the most robust, and the measurements by a diameter tape and a caliper are similar enough for forestry inventories. Evaluating and preprocessing stem slice point clouds is a potential way to improve stem diameter retrieval accuracy.