FORM FACTORS AND VOLUME MODELS FOR ESTIMATING TREE BOLE VOLUME OF MAHOGANY AT COMMUNITY FORESTS IN CENTRAL JAVA

Form factors and volume models are often be used in the estimation of tree volumes. However, a few studies have developed and evaluated the accuracy of form factors and volume models for estimating tree volumes of community forests. This study aimed to formulate form factors and volume models and assess their prediction accuracy for estimating tree bole volumes of mahogany at community forests in Central Java. This study used 120 sample trees with diameters of 6–38 cm to formulate artificial and absolute form factors and to develop tree bole volume models. These form factors coupled with bole height and total height were used in simple volume equations. Regression analyses were used to develop volume models using the diameter and total height as predictors. The simple volume equations and volume models' prediction accuracy was evaluated using a cross-validation dataset and independent dataset (30 sample trees). The artificial form factor (0.68 ± 0.11) of mahogany, which was higher than the absolute form factor (0.46 ± 0.09), provided accurate estimates of tree bole volumes when it was used with the bole height instead of the total height. The volume model that uses diameter and total height produced the most accurate estimates, while the volume model that uses diameter alone provided the most practical yet reliable tool for estimating tree bole volumes of mahogany. The results of this study are useful for improving community forest management.

Growth of Acacia mangium at Different Stand Ages and Soil Physicochemical Properties in Sarawak, Malaysia

The information on soil physicochemical properties is vital for the optimum wood biomass production in forest plantation management. The objective of this study was to determine the topsoil physicochemical properties under different Acacia mangium stand ages and their effect on the growth parameters. Five plots were established randomly within each five different stand ages. In all sample plots, the diameter at breast height (DBH) and the total height of standing trees were measured. Soil samples were collected at a depth of 0 to 20 cm at three random points in each plot, then mixed to get a composite before determining physical and chemical properties. DBH mean and the total height of A. mangium increased as stand age increased. The mean annual volume increment maximised at the 8.5 years old stand with 27.9 m3 ha-1 yr-1. Survival rate and stem density decreased as stand age increased. Principal component analysis (PCA) results showed that the most important soil physical properties were soil organic matter, silt and sand contents, bulk density, and moisture content. For soil chemical parameters, exchangeable magnesium (Mg), cation exchange capacity (CEC), total carbon (TC), total nitrogen (TN), and carbon-to-nitrogen (C/N) ratio were the influential soil variables. Soil pH, available phosphorus (P), and clay content were negatively correlated with the growth development of A. mangium trees. Observations suggest that multiple soil variables are essential for the success of the A. mangium plantation.

Land use impacts on Boswellia dalzielii Hutch. an African frankincense tree in Burkina Faso

Boswellia dalzielii Hutch., an African frankincense tree, is a socio-economically important aromatic and medicinal tree. It is currently threatened by uncontrolled exploitation, and therefore requires action to ensure its sustainable management. This study assessed the population structure and regeneration of its natural stands across three land use types in Burkina Faso: woodlands, fallows and farmlands. Sixty, fifty and fifty 50 m × 20 m plots were established respectively in woodlands, fallows and farmlands. All the plots were surveyed for adult tree (dbh ≥ 5 cm) density, dbh, total height and health conditions. Data on regeneration density (dbh < 5 cm), source (generative, stem shoots, suckers), total height and collar diameter were also collected. The results show similar total tree heights (7.0 m-9.0 m) but significantly (p < 0.05) smaller tree dbh in woodlands (mean ± SD: 20.5 ± 0.49 cm) and fallows (29.3 ± 0.64 cm) than in farmlands (32.8 ± 0.15 cm). Adult tree density (trees/ha) was 1.3 and 2.7 times higher in woodlands (82.37 ± 6.57) than in fallows (62.00 ± 3.98) and farmlands (30.02 ± 1.63), respectively. The density of regeneration in woodlands was 28 and 6 times higher than in fallows and farmlands, respectively. The majority (> 50%) of regenerating plants were suckers and no seedling regeneration was found in farmlands. The distribution of trees in diameter classes was J-shaped in woodlands, bell-shaped in farmlands and positive asymmetric in fallows, indicating recruitment bottlenecks. We found that 80.18% of individuals encountered were unhealthy. Intensive debarking and cutting were the main threats to the species and no conservation strategy was in place in the study region. We suggest measures to reduce intensive debarking and cutting, which should contribute to better management of the species.

Effects of provenance, pre-treatment and seeds’ mass on germinability and seedling growth of socio-economically important Balanites aegyptiaca (L.) Delile and Ricinodendron heudelotii (Bail.) Pierre in Benin (West Africa)

Balanites aegyptiaca (L.) Delile and Ricinodendron heudelotii (Bail.) Pierre are socioeconomically important but endemic species to sub-Saharan Africa. This study was conducted to assess the germination capacity of their seeds and seedling growth according to seed provenance, seed mass and pre-treatment techniques as a contribution to the development of strategies for their conservation and domestication in Benin. The seeds were randomly collected in the species occurrence phytodistricts. A split-split plot design with three replicates was used. The survival analysis and generalized linear mixed effects models were implemented on the data. Findings were that the heaviest seeds ( B. aegyptiaca seed mass ≥ 3 g and R. heudelotii ≥ 1.50 g) , provided the highest germination rates (73.60 ± 5.19% and 62.50 ± 5.71%) with seeds scarified with a hammer first emerging at day-8 and day-10 for B. aegyptiaca and R. heudelotii respectively. For B. aegyptiaca seedlings, the seeds from North Borgou phytodistrict scarified with a hammer and the heaviest seeds showed the highest total height (36.43 ± 1.03 cm), basal diameter (2.84 ± 0.03 mm), the greatest number of leaves (32) and ramifications (1). The heaviest seeds of R. heudelotii showed also the highest total height from the day-28 after sowing (26.73 ± 13.56 cm) until the day-105 (151.97 ± 6.37 cm) and those from Pobe phytodistrict showed the highest basal diameter (12.53 ± 1.47 mm) and the greatest number of leaves (14), with almost no ramification during the trial period. These findings constitute a step towards upscaling the reproducibility of these species for better contribution to economies while serving for restoration plans.

Height Allometry of Pinus nigra Arn. in Troodos National Forest Park, Cyprus

Total height is one of the basic morphometric tree variables included in all forest management inventories, because it is connected with several forest processes and functions related to the estimation of the woody tree volume and sustainable forest yield. The current research, based on a total sample of 1059 measured Black pine (Pinus nigra Arn.) trees from Cyprus, is an attempt to explore the biological processes related to the tree height allometry of this species and develop a generalized mixed-effects model for tree height prediction. The proposed model, with three additional basic covariates and two random parameters, explained almost 96% of the height variance. The model results showed that although competition and site-connected variables affected the total height, it was the crown base height that explained, to a large degree, the height expression. Through the mixed-effects modeling approach it was possible to explore the complex biological processes related to the tree allometry of Black pine and depict those within a mathematical formulation. The proposed generalized model decreased the error significantly, and therefore it can be used for operational forest management purposes. However, for marginal predictions, use of only the fixed part of the basic model could suffice, since this also provided unbiased parameter estimates.

Predicting Eucalyptus Diameter at Breast Height and Total Height with UAV-Based Spectral Indices and Machine Learning

Machine learning techniques (ML) have gained attention in precision agriculture practices since they efficiently address multiple applications, like estimating the growth and yield of trees in forest plantations. The combination between ML algorithms and spectral vegetation indices (VIs) from high-spatial-resolution line measurement, segment: 0.079024 m multispectral imagery, could optimize the prediction of these biometric variables. In this paper, we investigate the performance of ML techniques and VIs acquired with an unnamed aerial vehicle (UAV) to predict the diameter at breast height (DBH) and total height (Ht) of eucalyptus trees. An experimental site with six eucalyptus species was selected, and the Parrot Sequoia sensor was used. Several ML techniques were evaluated, like random forest (RF), REPTree (DT), alternating model tree (AT,) k-nearest neighbor (KNN), support vector machine (SVM), artificial neural network (ANN), linear regression (LR), and radial basis function (RBF). Each algorithm performance was verified using the correlation coefficient (r) and the mean absolute error (MAE). We used, as input, 34 VIs as numeric variables to predict DHB and Ht. We also added to the model a categorical variable as input identifying the different eucalyptus trees species. The RF technique obtained an overall superior estimation for all the tested configurations. Still, the RBF also showed a higher performance for predicting DHB, numerically surpassing the RF both in r and MAE, in some cases. For Ht variable, the technique that obtained the smallest MAE was SVM, though in a particular test. In this regard, we conclude that a combination of ML and VIs extracted from UAV-based imagery is suitable to estimate DBH and Ht in eucalyptus species. The approach presented constitutes an interesting contribution to the inventory and management of planted forests.

Desain Pintu Air Sekunder Berbantu Komputer Untuk Daerah Irigasi Cinangka Kabupaten Bogor

The most problem that occurs in Cinangka Irrigation Area is the not function of sluice and not used to properly regulate water of it. If the discharge regulator is not operated properly, the provision of irrigation water has the potential to be wasteful or lacking. The purpose of this study is to determine the discharge requirements for secondary irrigation water in Cinangka, produce a design of sluice in the channel and an estimated cost of manufacture. The study was conducted in the Cinangka Irrigation Area, Cibitung Tengah Village, Tenjolaya District, Bogor Regency. The study began from April - June 2020. The results obtained were known to be evapotranspiration, effective rainfall, and irrigation needs in the secondary channel of DI Cinangka per period of irrigation for one year. The largest Eto value occurred in September of 5.8 mm / day, the largest Cheff value occurred in November of 8.4 mm / day and the largest debit of needs occurred in March of 0.6 m3 / sec. Secondary sluice designed manifold steel sluice with high specification and door width 1x 1 m, total height 2 m door, handlebar diameter 45 cm. Dratstick used is 1.5 inches. Estimated cost for making doors is IDR 7,085,000. These costs can increase depending on the manufacture location and manufacture services.

Modeling of aboveground tree stand-level biomass in Erukot Forest of Oban Division, Cross River National Park, Nigeria

This research estimated aboveground tree stand level Biomass in Erukot Forest of Oban Division, Cross River National Park. A total of 872 individual trees were identified and measured for diameter at breast height and total height (dbh ≥ 5cm). The 872 individual trees spread across 51 species belonging to 25 different tree families. Simple random sampling was used with sampling intensity of 0.3% to lay 15 nested plots (7m x 7m, 25m x 25m and 35m x 35m). Diameter at breast height, total height and specific density of each wood species were used to determine aboveground biomass for each tree. Conversion factors were applied to estimate stand level green and dry biomass, sequestered carbon and carbon dioxide (CO2) emission in the study area. Simple linear regression models were fitted into the stand level growth data for the forest (basal area and volume). The mean diameter at breast height and mean total height were 38.5cm and 18.5m respectively. Mean basal area of 39.8 m2 ha-1 was obtained with a mean volume of 177.3 m3 ha-1 . Average green biomass, dry biomass, carbon stock and carbon-dioxide emission of 521.8113 ton ha-1 , 341.5880 ton ha-1 , 183.196 ton ha-1 and 694.2067 ton ha-1 respectively were obtained in the study area. Stand level biomass model developed for the forest showed that common logarithm of volume per hectare is significantly related to common logarithm of stand biomass (R2 = 58%). The actual and predicted biomasses were not significantly different (Paired T-test at p ˂ 0.05). Estimated bias of 0.10% for the stand biomass model means that the developed model can be used to predict the aboveground biomass of the study area without any adjustment. The research has provided easy to use regression model for determining aboveground biomass at stand level. This is very useful for carbon trade and assessment of carbon-dioxide emissions through deforestation in the study area. The model is also a tool for assessing the wood productivity of the study area and for better management of the park. Keyword: Sequestered carbon, aboveground biomass, dry biomass, conversion factor

Wood Loss Assessment in Forest of Sal (Shorea robusta) by Heart Rot of Central Terai of Nepal

A significant volume of wood was lost due to wood defects; however, few studies were done to quantify wood loss by wood defects. This study was focused on quantifying wood loss by heart rot, especially hollowness in Shorea robusta. The study was conducted in Tileswornath community forest of Rautahat district. The data were collected from the felling site of the regeneration felling block of Tileswornath community forest. 44 trees were selected randomly, and tree diameter, total height, and volume were measured. The destructive method was followed as heart rot cannot be visible from the surface. Felled trees were sanctioned into 285 logs and separated based on the hollowness. Hollow diameters at both thin end and mid and thick end, as well as length, were measured on the hollow log, and Smalian’s formula was used to calculate the volume of hollowed portion, and volume calculation formula for the cylinder was used to calculate total volume. For the solid logs, mid diameter and length of the log were measured and volume calculation formula for the cylinder was used to calculate total volume. Logistic regression was performed to identify the relation of total height and diameter with the probability of hollowness presence. The study showed that 59% of sampled trees and 34.39% of logs were found to be hollowed due to heart rot. 41.79% volume was occupied by hollow on the hollowed log. Logistic regression discards the relation of height to the hollowness but signified the relation of diameter to the probability of hollowness presence. Before implementation of scientific forest management modality, the timber retained in stump per tree was found as 0.18 cubic feet.

Mimosa scabrella Benth. planted for forest restoration in southern Brazil

Tropical trees planting resurgent in a global warming scenario, and this activity relies on information about forest species ecology and its different functional traits. we evaluated the initial performance of Mimosa scabrella using the Generalized Linear Models (GLM) technique to fit mathematical models for collar diameter growth x height, and for crown projection area x collar diameter in a forest restoration planting. The following variables were obtained in the first four years after planting: collar diameter (mm), total height (m), crown projection area (m²) and crown volume (m³). The models fitting was performed by GLM on Gamma, Normal and Poisson distribution, identity and logarithmical join function, and they were analyzed based on Akaike and Bayesian Information Criteria, standard deviation of the estimate and determination coefficient. M. scabrella showed an excelled performance on the 48 months of age, with average increment of 200.28 mm in collar diameter, 6.88 m in total height, 2.95 m² in crown projection area and 83.41 m³ in crown volume. Its growth reduced only on periods of frost occurrence, but it restarted after these climatic events. The species growth, as well as its high survival rates and resprouting, allow its recommendation as a shady species of fast canopy fulfillment in forest restoration projects.