Tree Volume Research Articles

High-Resolution Canopy Height Mapping: Integrating NASA’s Global Ecosystem Dynamics Investigation (GEDI) with Multi-Source Remote Sensing Data

Accurate structural information about forests, including canopy heights and diameters, is crucial for quantifying tree volume, biomass, and carbon stocks, enabling effective forest ecosystem management, particularly in response to changing environmental conditions. Since late 2018, NASA’s Global Ecosystem Dynamics Investigation (GEDI) mission has monitored global canopy structure using a satellite Light Detection and Ranging (LiDAR) instrument. While GEDI has collected billions of LiDAR shots across a near-global range (between 51.6°N and >51.6°S), their spatial distribution remains dispersed, posing challenges for achieving complete forest coverage. This study proposes and evaluates an approach that generates high-resolution canopy height maps by integrating GEDI data with Sentinel-1, Sentinel-2, and topographical ancillary data through three machine learning (ML) algorithms: random forests (RF), gradient tree boost (GB), and classification and regression trees (CART). To achieve this, the secondary aims included the following: (1) to assess the performance of three ML algorithms, RF, GB, and CART, in predicting canopy heights, (2) to evaluate the performance of our canopy height maps using reference canopy height from canopy height models (CHMs), and (3) to compare our canopy height maps with other two existing canopy height maps. RF and GB were the top-performing algorithms, achieving the best 13.32% and 16% root mean squared error for broadleaf and coniferous forests, respectively. Validation of the proposed approach revealed that the 100th and 98th percentile, followed by the average of the 75th, 90th, 95th, and 100th percentiles (AVG), were the most accurate GEDI metrics for predicting real canopy heights. Comparisons between predicted and reference CHMs demonstrated accurate predictions for coniferous stands (R-squared = 0.45, RMSE = 29.16%).

Assessing the Relationship between Tree Growth, Crown Size, and Neighboring Tree Species Diversity in Mixed Coniferous and Broad Forests Using Crown Size Competition Indices

Competition among trees for limited resources (e.g., sunlight, water, and nutrients) impacts their growth differently. Crown plays a crucial role in resource access for trees. However, uncertainties persist regarding crown size differences, tree growth, and tree competition levels between coniferous and broadleaf trees in mixed-age forests. We conducted a study on 3008 live trees across 28 plots in Hunan Province to measure individual crown size and tree growth increment. Introducing a new metric, the Crown Size Competition Index (CSCI), we assessed competition pressure among coniferous and broadleaf species in mixed-age forests. We examined the correlation between competition indices and tree growth increment while also investigating the influence of neighboring species diversity on tree competition. Our results revealed a significant negative correlation between the tree growth of Cunninghamia lanceolata (Lamb.) Hook.(CL) and Phoebe bournei (Hemsl.) Yang (PB) and the competition index. Increased competitive pressure on the focal tree corresponded to a decline in the growth of focal tree volume, with a more pronounced impact observed in PB compared to CL. The diversity of neighboring species contributed to variations in competition for the focal tree, with broadleaved species (PB) exerting a greater influence on the focal tree than coniferous species (CL). These findings underscore the competitive potential of PB in mature coniferous stands and advocate for the restoration of stratified mixes in CL broadleaf forests. Furthermore, our findings support the management strategies for the valuable tree species PB.

An Accuracy Assessment of Field and Airborne Laser Scanning–Derived Individual Tree Inventories using Felled Tree Measurements and Log Scaling Data in a Mixed Conifer Forest

Abstract On-the-ground sample-based forest inventory methods have been the standard practice for more than a century, however, remote sensing technologies such as airborne laser scanning (ALS) are providing wall-to-wall inventories based on individual tree measurements. In this study, we assess the accuracy of individual tree height, diameter, and volume derived from field-cruising measurements and three ALS data-derived methods in a 1.1 ha stand using direct measurements acquired on felled trees and log-scale volume measurements. Results show that although height derived from indirect conventional field measurements and ALS were statistically equivalent to felled tree height measurements, ALS measured heights had lower root mean square error (RMSE) and bias. Individual tree diameters modeled using a height-to-diameter-at-breast-height model derived from local forest inventory data and the software ForestView had moderate RMSE (8.3–8.5 cm) and bias (-3.0 – -0.3 cm). The ALS-based methods underdetected trees but accounted for 78%–91% of the field reference harvested merchantable volume and 71%–99% of the merchantable volume scaled at the mill. The results also illustrate challenges of using mill-scaled volume estimates as validation data and highlight the need for more research in this area. Overall, the results provide key insights to forest managers on accuracies associated with conventional field-derived and ALS-derived individual tree inventories. Study Implications: Forest inventory data provide critical information for operational decisions and forest product supply chain planning. Traditionally, forest inventories have used field sampling of stand conditions, which is time-intensive and cost-prohibitive to conduct at large spatial scales. Remote sensing technologies such as airborne laser scanning (ALS) provide wall-to-wall inventories based on individual tree measurements. This study advances our understanding of the accuracy of conventional field-derived and ALS-derived individual tree inventories by evaluating these inventories with felled tree and log scaling data. The results provide key insights to forest managers on errors associated with conventional field and ALS-derived individual tree measurements.

Moderate-severity silvicultural methods generate better forest reorganization than other silvicultural methods in temperate rainforests four decades after implementation

Silvicultural regeneration methods promote regeneration of new tree cohorts following the harvest of mature trees and include a gradient of options from cutting all (clearcuts) or some (selection cuts) trees resulting in even- or uneven-aged forests. For forest managers and landowners, it is essential to have the best possible information on how forests reorganize following these different methods. Forest development, composition and growth are dependent on site quality and harvest type. In this study we evaluated two even-aged (clearcut (CC), seed-tree cut (STC)), one two-aged cut (extended irregular shelterwood (ISC)), one uneven-aged (single-tree selection cut (SC)), and an unmanaged control (CON), four decades after harvest implementation in old-growth Evergreen temperate rainforests above 500 m a.s.l. in the Coastal Range of south-central Chile. These forests grow on poor-quality sites due to old and shallow soil conditions and were dominated by late-successional species and a thick understory with the bamboo Chusquea machrostachya at the time of harvest implementation. Compositional and structural conditions reflected the type of harvests, with even- and two-aged methods largely similar to one another and the SC and the OG having very similar characteristics, which is likely a consequence of the very light severity of the SC. Tree species composition in even-aged harvests was dominated by shade midtolerant species of high timber value, although short-lived pioneer species of the Proteaceae family were also abundant, especially in ISC. The ISC had the greatest homogeneity in all stand variables (tree density, basal area, volume, and quadratic stand diameter), and since it was a two-layered forest, had basal areas and volumes close to the SC and OG, and a rotated-sigmoid diameter distribution (different to all other treatments). Height of the new cohort in the ISC was significantly taller than in the CC and the STC for most species’ groups, suggesting that the cut plus the residual canopy of ISC diminished the initial cover of the bamboo C. macrostachya and competition for regeneration. Only diameter growth of trees of all shade tolerances was lower in ISC, but diameter growth patterns were similar to CC and STC, with increasing growth during the first two-three decades followed by a decline. Based on these findings, we conclude that silvicultural methods of intermediate harvesting severity, especially ISC, provide the best ecological and economic option in these poor-quality sites given rapid reorganization following their implementation, while maintaining a relatively complex vertical structure, high tree species diversity, and a growing stock dominated by tree species of high timber value.

Volume prediction of young improved Sitka spruce trees in Great Britain through Bayesian model averaging

Abstract More and earlier thinning operations are expected in Sitka spruce planted forests in Great Britain as a result of an increased demand for biomass and faster growth driven by breeding. It is however unknown whether the current models, which were designed to predict volume in adult trees, can provide unbiased volume predictions for the young individuals that are likely to be harvested in future thinning operations. The primary objective of this study was to answer this question. To do this, we used retrospective data from a destructive experiment originally aimed at assessing timber properties to reconstruct the taper and volume of 12 improved Sitka spruce trees at different ages. These volumes were then compared against the predictions from the current methods, which were found to be from moderately to strongly biased. The second objective was to provide proof of concept that a combination of existing volume models and other theoretical volume models could yield less biased predictions. We successfully addressed this objective through the Bayesian model averaging approach. The method, albeit tested with limited data, proved to be a promising alternative until new volume models are released. Further data from other available destructive experiments can be used to refine our calibration.

The Role of Wood Density Variation and Biomass Allocation in Accurate Forest Carbon Stock Estimation of European Beech (Fagus sylvatica L.) Mountain Forests

The European beech (Fagus sylvatica L.) is one of the most common tree species in Romania, with importance both economically and environmentally. Accurate methods of biomass assessment at the tree compartment level (i.e., stump, stem, branches, and leaves) are necessary for carbon stock estimation. Wood density (WD) is an important factor in determining biomass and, ultimately, the tree’s carbon content. The average tree density was found to be 578.6 kg/m3. For this study, WD was evaluated by the weighting method related to tree volume. Also, to investigate a practical approach to determining the weighted wood density (WWDst), models were run using density at the base of the tree (WDBase), density at breast height level using discs (WDDBH), the wood core density (WDic), and the diameter at breast height (DBH) as predictors. The biomass assessment was conducted using different model evaluations for WWDst as well as allometric equations using the destructive method. From the results, it was noted that using the WWDst, the total biomass was underestimated by −0.7% compared to the biomass measured in the field. For allometric equations that included DBH and tree height as independent variables, the explained variability was around 99.3% for total aboveground biomass (AGBtotal), while it was 97.9% for allometric function using just the DBH. Overall, the distribution of biomass across different compartments was as follows: 73.5% in stems, 23.8% in branches, 1.9% in stumps, and 1.3% in leaves. The study findings offer valuable insights into WD, biomass distribution among different components, and biomass allometric quantification in natural beech forest environments in mountainous areas.

First report of Truncatella angustata causing leaf blight on Thuja plicata Donn ex D. Don in Canada.

Western redcedar (Thuja plicata Donn ex D. Don) is one of the most important commercial tree species in British Columbia, generates more than $1 billion in economic activity annually and about 8-10 million trees are planted in reforestation efforts (Gregory et al. 2018). It has been selected as the provincial tree of British Columbia (BC) because of its tremendous economic, ecoogical and cultural value. However, foliar diseases such as leaf blights have serious impact on redcedar growth and may cause significant loss of tree volume (Russell, 2007). Our 2014 - 2015 surveys of western redcedar forests in coastal areas of BC indicated high incidence of a distinctive type of blight. We observed the incidence of this disease on more than 80% of western redcedar (approximately 493) trees from late May to early December. Early symptoms appeared as circular to oval, brownish to black spots (2-3 mm), 1-5 spots per branch tip, scattered at the tip margins. Sequentially, the spots enlarged and developed into necrotic lesions on both young and old leaves. More than 50 symptomatic leaves from 10 different trees were collected and rinsed in distilled water then surface-sterilized with three times washing in Tween 20 (%5 solution) for 2 minutes (each time) and %70 ethanol for 30 second (3 times repeat). Tissues from under lesions were placed on MEA (Malt Extract Agar; Phyto Tech® labs-Product ID: M498) and PDA (Potato Dextrose Agar; Phyto Tech® Labs-Product ID: P772). The plates were incubated at 21°C in the dark. They developed distinct dull white to brown, cottony colonies with each black acervuli approximately 450-500µm. The isolates produced fusiform conidia with four cells. They didn't have any distinct color. The conidiophore size was approximately 23-24 x 2-3 µm with mostly hyaline to light brown color, branched and conidiogenous was hyaline and not branched and simple. The spore size was approximately 15-20μm by 7-10μm with three transverse septa and endogenous papillae with hyaline apical appendages. Next, we collected spores and replated them on fresh MEA media culture and placed back in the incubator to produce pure cultures. We studied conidia from leaves of trees mentioned above using light and electron microscopy using Hitachi S-3500N Scanning Electron Microscope (Noshad et al. 2023). After morphological study, further identification to the species level conducted using Zambounis and Wenneker's approach (Zambounis 2019; Wenneker,2017). Genomic DNA from two single-spore isolates were isolated and sequenced. Sequences of ITS (Internal Transcribed Spacer) region amplified using primers ITS1/ITS4 and sequenced. Final sequences were deposited in Genbank and published (accession numbers OP086244 and OP086251). Blast analysis of these sequences showed 99% and 99% resemblances with T. angustata sequence (Sutton 1980). To verify its pathogenicity, we performed a comprehensive pathogenicity test to fulfill Koch's postulates. We collected their distinctive spores in an aseptic environment and standardized them (5000/ml) using a haemocytometer. Then we inoculated 100 western redcedar seedlings (three years old) by injecting standardized spore suspension solution (inoculum) using ultra-fine 0.3ml, 31G, 8mm syringes (approximately 0.1ml per inoculation site). Ten positive control seedlings were inoculated with distilled water and ten negative control seedlings were not inoculated at all. All inoculated (experimental) seedlings demonstrated same symptoms (black spots and characteristic spores) after eight weeks. None of the control seedlings showed any similar symptoms. In the next stage, we isolated and cultured spores from inoculated seedlings and studied them. The identity of reisolates confirmed using DNA sequencing. We used these spores for our next set of disease screening which was successful again. We identified Truncatella angustata (Pers.) Hughes as the causal agent for shoot-tip blight (STB) on western redcedar by examining morphological and molecular characteristics of the pathogen. This is the first report of T. angustata as a primary pathogen on western redcedar in British Columbia, Canada.

Estimating aboveground volume of diverse urban tree species: Developing allometric equations for higher taxonomic levels

Allometric equations are essential for quantifying carbon storage in trees; however, owing to the high species diversity in urban green spaces, the development of allometric equations for all urban tree species is not feasible. In this study, we estimated the aboveground volume of urban trees and determined the fitness of several allometric equations. We compared the equations for different taxonomic levels, i.e., division, family, and species. A field survey was conducted across three types of urban green spaces (street trees, parks, and residential gardens) in three cities (Seoul, Goyang, and Wonju) in South Korea. We estimated the aboveground volumes of 1080 trees from their diameter measurements using a laser dendrometer, carried out at successive points from the ground to the top of the trees. Various tree size metrics, such as the diameter at breast height (DBH), height, and/or crown diameter, were applied as independent variable(s) in the equations. For gymnosperm trees, the allometric equations for higher taxonomic levels (RMSE: 0.011 m3) yielded goodness-of-fits similar to those at the species level (RMSE: 0.009 m3). For angiosperm trees, the family-level allometric equations satisfactorily covered the inter-species heterogeneity of tree shape, whereas the division-level allometric equations did not. The scaling exponent coefficients of allometric equations for each family (b = 1.65−2.69) linearly increased with an increasing mean height-to-DBH ratio. Although the allometric equations based on crown diameter were more unstable than those based on the DBH, integrating the height variable into the equations could ensure the feasibility of the allometric equations based on crown diameter. Our study facilitates the development of nationally specific emission factors for settlement areas and suggests the applicability of generalized or crown-based allometric equations for urban trees.

Estimation of Additive and Dominance Effects in an Acacia crassicarpa Multi-Environment Progeny Trial Using Genomic Pedigree Reconstruction

Abstract Acacia crassicarpa is an important tree species in Southeast Asia, where hundreds of thousands of hectares of planted forests are supported by advancements in silviculture and genetic improvement. Although possible, controlled pollination is impractical for advancing breeding populations, requiring an unreasonable effort to produce more than a few crosses per year. For this reason, breeding populations often are bred by open pollination. This study used large-scale pedigree reconstruction in multi-environment trials to assess full-sib families to model the genetics of the quantitative traits survival, straightness, height, diameter at breast height, tree volume, mean annual increment (MAI), and basic density. The traits were predominantly controlled by additive effects, with heritabilities between 0.09 for survival and 0.45 for basic density. The genetic correlation across sites was high for all traits, showing the low impact of genotype-by-environment interaction. The trait-trait correlation showed that straightness was independent of any other traits, survival was only correlated with MAI, and growth traits were highly correlated among themselves. Basic density was positively correlated with growth traits and MAI. Study Implications: Parentage analysis using an informative single nucleotide polymorphism panel was used to reconstruct pedigree and allow a full-sib family model to estimate additive and dominance effects and genetic correlations across sites and among important traits in an open-pollinated population. The genetic control of all traits assessed in this study was mainly additive. In this scenario, the recommended breeding strategy is forward selection of outstanding progeny for advanced generation breeding and backward selection of outstanding parents to produce seed for deployment via family forestry. Full-sib families can be identified by pedigree reconstruction at a seedling stage, followed by tissue culture multiplication, rooted cutting propagation, and plantation establishment.

A new method for voxel‐based modelling of three‐dimensional forest scenes with integration of terrestrial and airborne LiDAR data

Abstract Simulating realistic three‐dimensional (3D) forest scenes is useful in understanding the links between forest structure and ecosystem functions (e.g. radiative transfer). Light detection and ranging (LiDAR) technology provides useful 3D data for forest reconstructions since it can characterise 3D structures of individual trees and canopies. High‐density terrestrial LiDAR (terrestrial laser scanning, TLS) is suitable for fine‐scale reconstructions but is limited to smaller forest plots; low‐density airborne LiDAR (airborne laser scanning, ALS) can cover larger areas but is only suitable for coarse‐scale reconstructions. How to take advantage of TLS and ALS to enable fine‐scale forest simulations in large areas needs to be studied. We propose a new voxel‐based method for forest simulations using the integration of TLS and ALS data. TLS data of representative reference trees are used to approximate the detailed architectures of the whole forest scene, with structural information on each individual tree extracted from ALS data. The high‐density point cloud data derived from TLS and ALS data are voxelised using high resolution solid voxels for scene representation. We tested the proposed method using two virtual forests (108 m × 108 m) and a real forest (300 m × 300 m) with conifer and broadleaf species. The physically based ray tracer (PBRT) was used to visualise the true virtual forest scenes, whereas voxel‐based radiative transfer (VBRT) was used to visualise the modelled forest scenes from LiDAR data. For the real forest scene, simulated and real ALS data were compared. Our results demonstrate that the images simulated by VBRT and PBRT are similar in the virtual forest scenes, with average radiance values of 1.02 and 1.72, respectively. In the real forest scene, the distributions of points and individual tree attributes (tree height, crown radius, and tree volume) derived from real and simulated ALS also match well, with Kullback–Leibler divergence ranging from 0.006 to 0.06. We conclude that the new method is capable of modelling fine‐scale 3D forests in large areas (over 1 ha) when TLS and ALS data are available, and it has good potential in studying the process of radiative transfer in conifer and broadleaf forests.

Enhancing Sustainability and Yield in Maritime Pine Forests: Evaluating Silvicultural Models for Natural Regeneration

The maritime pine (Pinus pinaster Ait.) forest is an essential element of the Portuguese forest landscape due to its social, economic, and environmental importance. The sustainability of these forests in the Mediterranean region faces challenges due to recurrent forest fires and the absence of or delayed management. The species has a high capacity for regeneration, but the perpetuation of pine forests in sustainable conditions depends on adequate management to achieve high biomass production and assure fire resilience. This study aimed to analyse four management scenarios (C1 to C4) for the natural regeneration of maritime pine in six areas with stand ages ranging from 6 to 16 years and densities varying from 15,000 to circa 93,000 trees per ha. The same four scenarios were implemented in each of the six areas. The scenarios considered the evolution of forest growth according to different management prescriptions and were simulated using Modispinaster and PiroPinus models. Scenario C1 considered no intervention, with only the final cut. Scenario C2 considered a thinning schedule to maintain the stand within the 50–60% range of the Stand Density Index (SDI). Scenario C3 followed the area’s Forest Management Plan (PGF), which typically includes two or three thinning operations throughout the cycle. Scenario C4 was adapted from the MS1 silvicultural model of the National Institute for Nature Conservation and Forests—ICNF, which involves opening strips at earlier ages (3 and 6 years), with the selection of trees to remain in the wooded area carried out between 4 and 10 years of age and performing thinning whenever the Wilson Spacing Factor (FW) reaches 0.21. The final cutting age was assumed to be 45 years but could be lowered to 35 years in Scenario 3 if defined in the plan. Based on the indicators generated by the simulators, the results showed variations in the total volume of timber produced at the time of harvest depending on the silvicultural guidelines. Scenario C4 was the most effective in generating the highest individual tree volume at the end of the cycle and the total volume of timber collected throughout the cycle. The ability of the forest to resist fire was evaluated before and after the first treatment for density reduction. The treatments performed did not decrease the resistance to fire control.

Individual Tree-Scale Aboveground Biomass Estimation of Woody Vegetation in a Semi-Arid Savanna Using 3D Data

Allometric equations are the most common way of assessing Aboveground biomass (AGB) but few exist for savanna ecosystems. The need for the accurate estimation of AGB has triggered an increase in the amount of research towards the 3D quantification of tree architecture through Terrestrial Laser Scanning (TLS). Quantitative Structure Models (QSMs) of trees have been described as the most accurate way. However, the accuracy of using QSMs has yet to be established for the savanna. We implemented a non-destructive method based on TLS and QSMs. Leaf-off multi scan TLS point clouds were acquired in 2015 in Kruger National Park, South Africa using a Riegl VZ1000. The 3D data covered 80.8 ha with an average point density of 315.3 points/m2. Individual tree segmentation was applied using the comparative shortest-path algorithm, resulting in 1000 trees. As 31 trees failed to be reconstructed, we reconstructed optimized QSMs for 969 trees and the computed tree volume was converted to AGB using a wood density of 0.9. The TLS-derived AGB was compared with AGB from three allometric equations. The best modelling results had an RMSE of 348.75 kg (mean = 416.4 kg) and a Concordance Correlation Coefficient (CCC) of 0.91. Optimized QSMs and model repetition gave robust estimates as given by the low coefficient of variation (CoV = 19.9% to 27.5%). The limitations of allometric equations can be addressed by the application of QSMs on high-density TLS data. Our study shows that the AGB of savanna vegetation can be modelled using QSMs and TLS point clouds. The results of this study are key in understanding savanna ecology, given its complex and dynamic nature.

Using Biodiversity Indices Effectively: Considerations for Forest Management

Since biodiversity is a multifaceted aspect of natural systems, several indices have been suggested to measure it. In this paper, we examined a number of well-known diversity indexes to see whether some performed better than others when applied to forest data. In order to reach this goal, we used data on basic forest variables (such as the diameters, heights, and volumes of trees) from forest plots to see if common diversity indices lead to the same conclusions about changes in biodiversity in a pairwise comparison (i.e., comparing the same region at two different times or two different regions at the same time). Out of a collection of 17 diversity indices, 8 of them exhibited robustness, indicating their constant ability to demonstrate either an increase or decrease in biodiversity over pairwise comparisons. However, it is important to note that the remaining seven diversity indices may yield inconsistent or inconclusive results, but only with regard to forest data, highlighting the complexity and nuances of measuring biodiversity with different sorts of data. In this review article, all 17 indices are presented, allowing the reader to choose which ones are most applicable to their particular dataset (genetic, econometric, sociometric, etc.).

Growth response to pre-commercial thinning of lodgepole pine is short-term but the effects on size distribution persist for decades

Pre-commercial thinning in Alberta is a potential option for increasing the growth rate and shortening the rotation age of regenerating forests. Previous studies have focused on the evaluation of either the immediate- or long-term response to thinning after many decades. Our current study compares the pre-commercial thinning response in lodgepole pine for a 10-year period immediately after thinning, and again 38-45 years after thinning, based on 22 paired plots of precommercially thinned trials in Alberta. The first group of plots was pre-commercially thinned in 1984, measured in 1985 and 1995 (short-term) and the second group was pre-commercially thinned between 1962 and 1969 and measured in 2007 and 2017 (long-term). In the short-term, individual tree DBH growth was 56% greater in pre-commercially thinned plots, while in the long-term plots, there were no measured growth differences between pre-commercially thinned and unthinned plots. Small- and medium-sized trees benefited more from pre-commercial thinning than larger trees. However, at the stand level, the number and volume of merchantable-sized trees (≥13.5 cm DBH) were higher in pre-commercially thinned plots than in unthinned plots in both the short- and long-term. Although the growth response of thinning appeared to be a short-term response (number and volume of larger trees), yield at the end of the long-term measurement period was still higher in pre-commercially thinned than in unthinned plots.

Intensity-modulated proton and carbon-ion radiotherapy using a fixed-beam system for locally advanced lung cancer: dosimetric comparison with x-ray radiotherapy and normal tissue complication probability (NTCP) evaluation

Objective. To assess the dosimetric consequences and the normal tissue complication probability (NTCP) for the organs at risk (OARs) in intensity-modulated particle radiotherapy of proton (IMPT) and carbon-ion (IMCT) using a fixed-beam delivery system when compared with intensity-modulated photon radiotherapy (IMRT) for locally advanced small-cell lung cancer. Approach. The plans were all designed under the same total relative biological effectiveness (RBE)-weighted prescription dose, in which the planning target volume (PTV) of the internal gross target volume(IGTV) and the PTV of the clinical target volume was irradiated with 69.3 Gy (RBE) and 63 Gy (RBE), respectively, using a simultaneously integrated boosting (SIB) technique. NTCPs were estimated for heart, lung, esophagus and spinal cord by Lyman–Kutcher–Burman (LKB) and logistic models. Dose escalation was simulated under the desired NTCP values (0.05, 0.10 and 0.50) of the three radiation techniques. Main results. Under the similar target coverage, almost all OARs were significantly better spared (p < 0.05) when using the particle radiotherapy except for D1cc (the dose to 1 cm3 of the volume) of the proximal bronchial tree (p > 0.05). At least 57.6% of mean heart dose, 28.8% of mean lung dose and 19.1% of mean esophageal dose were reduced compared with IMRT. The mean NTCP of radiation-induced pneumonitis (RP) in the ipsilateral lung was 0.39 ± 0.33 (0.39 ± 0.31) in IMPT plans and 0.36 ± 0.32 (0.35 ± 0.30) in IMCT plans compared with 0.66 ± 0.30 (0.64 ± 0.28) in IMRT plans by LKB (logistic) models. The target dose could be escalated to 78.3/76.9 Gy (RBE) in IMPT/IMCT plans compared with 61.7 Gy (RBE) in IMRT plans when 0.50 of NTCP in terms of RP in the ipsilateral lung was applied. Significance. This study presents the potential of better control of the side effects and improvement of local control originating from the dosimetric advantage with the application of IMPT and IMCT with the SIB technique for locally advanced lung cancer, even with limited beam directions.

Age trends of genetic variation and early selection for growth traits in Cunninghamia lanceolata open-pollinated families

Abstract The present study measured the growth traits of 98 open-pollinated half-sibling families from the second-generation clonal seed orchard of Chinese fir for 6 consecutive years from age 2 to 7, the change patterns of genetic variation in growth traits and genetic parameters were analyzed, and best linear unbiased prediction (BLUP) was used for early selection to determine the excellent families. The growth traits of Chinese fir revealed highly significant differences between families, indicating that there was significant genetic variation at the family level, which serves as the foundation for exceptional family selection. The heritabilities of family and individual for H (height) ranged from 0.61 to 0.65 and 0.41 to 0.46, respectively; for DGH (the diameter at ground height)/DBH (the diameter at breast height), they were 0.55 to 0.66 and 0.35 to 0.46, respectively; and for V (tree volume), they were 0.66 to 0.70 and 0.48 to 0.49, respectively. The growth traits of genetic control were at a greater level at age 5. The findings of the coefficient of variation analysis demonstrated that the phenotypic variation coefficient were larger than the genetic variation coefficient for three growth traits at various ages. The juvenile-mature genetic and phenotypic correlations revealed an increasing tendency with age, and mainly controlled by genetic factors. Compared to other age groups for growth traits, age 5 had greater phenotypic and genetic association coefficients, as well as greater efficiency of early selection. Based on the selection method of breeding value, nine families were selected with a 9.2 % selection rate.

Assessment of land use cover changes, carbon sequestration and carbon stock in dry temperate forests of Chilas watershed, Gilgit-Baltistan

Abstract Land use and land cover change are affecting the global environment and ecosystems of the different biospheres. Monitoring, reporting and verification (MRV) of these changes is of utmost importance as they often results in several global environmental consequences such as land degradation, mass erosion, habitat deterioration as well as micro and macro climate of the regions. The advance technologies like remote sensing (RS) and geographical information system (GIS) are helpful in determining/ identifying these changes. In the current study area, changes in carbon stocks, notably in forest areas, are resulting in considerable dynamics of carbon stocks as a result of climate change and carbon sequestration. This study was carried out in the Diamer district of the Gilgit Baltistan (GB) Pakistan to investigate the change in cover change/land use change (particularly Forest Land use) as well as carbon sequestration potential of the forests in the district during almost last 25years. The land cover, temporal Landsat data (level 1, LIT) were downloaded from the USGS EROS (2016), for 1979-1989, 1990-2000 and 2001-2012. Change in land uses, particularly forest cover was investigated using GIS techniques. Forest inventory was carried out using random sampling techniques. A standard plot of size 0.1 ha (n=80) was laid out to determine the tree density, volume, biomass and C stocks. Simulation of C stocks was accomplished by application of the CO2FIX model with the data input from inventory. Results showed a decrease in both forest and snow cover in the region from 1979-2012. Similarly decrease was seen in tree volume, tree Biomass, dynamics of C Stocks and decrease was in occur tree density respectively. It is recommended we need further more like project such as BTAP (Billion Tree Afforestation Project) and green Pakistan project to increase the forest cover, to control on land use change, protect forest ecosystem and to protect snow cover.

Individual tree inventory based on uncrewed aerial vehicle data: how to utilise stand-wise field measurements of diameter for calibration?

Uncrewed aerial vehicles (UAV) have great potential for use in forest inventories, but in practice they can be expensive for relatively small inventory areas as a large number of field measurements are needed for model construction. One proposed solution is to transfer previously constructed models to a new inventory area and to calibrate these with a small number of local field measurements. Our objective was to compare calibration of general models and the construction of new models to determine the best approach for UAV-based forest inventories. Our material included field measurements and UAV-based laser scanning data, from which individual trees were automatically identified. A general mixed-effects model for diameter at breast height (DBH) had been formulated earlier based on data from a geographically wider area. It was calibrated to the study area with field measurements from 2–10 randomly selected calibration trees. The calibrated diameters were used to calculate the diameter of a basal area median tree (DGM), tree volumes, and the volume of all trees at plot-level. Next, new DBH-models were formulated based on the 2–10 randomly selected trees and calibrated with plot-level random effects estimated during model construction. Finally, plot-specific height-diameter regression models were formulated by randomly selecting 10 trees from each plot. Calibration reduced the prediction errors of all variables. An increase in the number of calibration trees decreased error rates by 1–6% depending on the variable. Calibrated predictions from the general mixed-effects model were similar to the separately formulated mixed-effects models and plot-specific regression models.

Key traits influencing the resistance of Eucalyptus camaldulensis to wind damage in coastal areas of South China.

China is one of the countries in the world most seriously affected by typhoons, which pose a great threat to the eucalyptus plantation industry. However, few studies have comprehensively accounted for the impact of key traits on the wind damage/resistance of eucalyptus. To identify the key factors affecting the wind resistance of eucalyptus, 20 eucalyptus genotypes were selected; a total of 18 traits, including the wind damage index, growth traits, and wood traits, were measured, and the wind resistance was determined via the tree-pulling test. Correlation, principal component, canonical correlation, and path analyses were performed to evaluate these traits. Correlation analysis revealed that the wind resistance of eucalyptus plants was related to the tree height, volume, and duration of stress wave propagation. Principal components and tree-pulling variables were further used for correlation and path analyses. Canonical correlation analysis and the PA-OV model showed that holocellulose and lignin contents and fiber width, as well as growth traits, were important factors affecting the stability of standing trees under typhoon conditions. The key traits influencing the wind resistance of Eucalyptus camaldulensis, which may provide a reference for evaluating the wind resistance of Eucalyptus varieties for forest management, were identified. This study provides a knowledge base for forest management and planning in typhoon-prone coastal areas, and provides a theoretical basis for the breeding and genetically improving eucalyptus stocks based on wind resistance characteristics.

Developing stem taper of Shorea robusta in the far-western Terai of Nepal

Tree taper functions expressed in terms of height and diameter at breast height (BDH) can provide accurate and timely information on current growing stock. Taper equations are very important for calculation of growing stock in forest inventories, however, in the context of Nepal, these are still unavailable at the required level. The study aimed to develop taper equations, so that those can be used to predict the diameter anywhere along the stem, and estimate tree volumes at desired sections. The input data was a destructive sampling method of 81 sample trees of Shorea robusta distributed in ten locations of the far western Terai of Nepal (Kailali and Kanchanpur districts).&#x0D; Using two independent B-Spline and 5th-degree polynomial taper models, the upper stem diameters were imputed. Both models were applied on the whole dataset, irrespective of DBH size, to get common fitted taper models. Later, the same models were tested for three different DBH classes to compare and evaluate the best-fit model. &#x0D; Taper models, developed under the B-spline polynomial model of 3rd degree, were found to be highly dependent on the tree (DBH) sizes. Thus, better models could be developed by classifying the whole dataset based on different DBH classes. On the other hand, developed models under the 5th degree polynomial taper model did not exhibit their dependency on the tree (DBH) sizes and a better model was found for the unclassified datasets, i.e. for all DBH sizes.