Tree Diameter Research Articles

Role of mangrove afforestation in the high saline zone of Bangladesh: Changes of carbon stock with stand age and species composition

The carbon storage in Bangladeshi mangrove plantations is influenced by site-specific variations and plantation management practices. This study was focused on evaluating the impact of stand age and above-ground factors on the carbon storage of the western-side high-saline mangrove plantations in Bangladesh. A comprehensive field study was conducted, encompassing mangrove plantations aged 3, 5, 7, 10, 12, 15, and 35 years, to assess their potential for ecosystem carbon storage. The biomass data was calculated by estimating the tree height and diameter at breast height (DBH) with common allometric equations and soil samples were collected from every plot for estimating the organic carbon in the soil of the mangrove plantations. Stand structure attributes showed significant differences among all age classes and Sonneratia apetala was found to be dominant among all other species (IV = 147.41). Biomass C storage upsurges with age, ranging from 51.5±3.2–259.9±103.5 Mg C ha−1, while soil C storage averages 33.1±3.1 Mg C ha−1, showing no significant variation on age. Ecosystem carbon storage increases significantly with age and 35-year-old mangrove plantations exhibit the highest storage potential (292.0±105.5 Mg C ha−1). An analysis of species composition highlighted that Sonneratia apetala accumulated 94.1±28.4 Mg C ha−1 of biomass carbon, a figure notably higher than other species. The comparison indicated that, while the ecosystem carbon storage in Bangladesh is higher in mature-aged mangrove plantations, it lags behind young-aged mangrove plantations in Myanmar. Bangladesh exhibits a higher biomass carbon accumulation rate than China and India but falls short by 56% when compared to Myanmar's biomass carbon accumulation. However, these insights from mangrove plantation studies can serve as valuable guidance for policymakers and researchers, aiding in the conservation and management of mangroves and developing a blue carbon framework to meet the required funding for sustainable development of mangrove plantations and local communities in Bangladesh.

Improving the Estimation of Structural Parameters of a Mixed Conifer–Broadleaf Forest Using Structural, Textural, and Spectral Metrics Derived from Unmanned Aerial Vehicle Red Green Blue (RGB) Imagery

Forest structural parameters are crucial for assessing ecological functions and forest quality. To improve the accuracy of estimating these parameters, various approaches based on remote sensing platforms have been employed. Although remote sensing yields high prediction accuracy in uniform, even-aged, simply structured forests, it struggles in complex structures, where accurately predicting forest structural parameters remains a significant challenge. Recent advancements in unmanned aerial vehicle (UAV) photogrammetry have opened new avenues for the accurate estimation of forest structural parameters. However, many studies have relied on a limited set of remote sensing metrics, despite the fact that selecting appropriate metrics as powerful explanatory variables and applying diverse models are essential for achieving high estimation accuracy. In this study, high-resolution RGB imagery from DJI Matrice 300 real-time kinematics was utilized to estimate forest structural parameters in a mixed conifer–broadleaf forest at the University of Tokyo Hokkaido Forest (Hokkaido, Japan). Structural and textual metrics were extracted from canopy height models, and spectral metrics were extracted from orthomosaics. Using random forest and multiple linear regression models, we achieved relatively high estimation accuracy for dominant tree height, mean tree diameter at breast height, basal area, mean stand volume, stem density, and broadleaf ratio. Including a large number of explanatory variables proved advantageous in this complex forest, as its structure is influenced by numerous factors. Our results will aid foresters in predicting forest structural parameters using UAV photogrammetry, thereby contributing to sustainable forest management.

Tracking the long‐term vegetation and soil characteristics of restored mangroves: a case study from Guyana's coast

The global urgency to halt and reverse mangrove loss has led to the implementation of numerous initiatives to protect and restore mangroves and recover critical ecological functions and services. Restoration success is assessed by estimating mangrove survival, while diversity, vegetation structure, and soil characteristics are often overlooked with no long‐term monitoring. Here, we investigated long‐term changes in vegetation and soil characteristics of Avicennia germinans‐dominated stands planted along Guyana's coast between 5 and 11 years old. A chronosequence approach was used to examine changes in vegetation and soil parameters in restored mangrove stands of different ages compared to natural stands of the same ages. Tree height, diameter, and aboveground biomass were inconsistent between restored and natural mangrove stands. Redundancy analysis (RDA) revealed that the soil properties were the important factors influencing both the restored and natural mangrove communities. There were no clear trajectories between the vegetation and soil characteristics with age, possibly due to site‐specific and hydrodynamic environmental factors, such as tidal dynamics, riverine inputs, and climatic variations. While there were some equivalent vegetation and soil characteristics at the end of the first decade after restoration, the restored mangroves may require a longer timespan (approximately 25 years) than the period overserved in our study to be entirely identical to the natural mangroves. This case study from Guyana provides valuable insights into the ecological processes driving mangrove recovery dynamics, growth patterns, and restoration effectiveness and offers reliable data needed to inform future restoration projects.

Soil and climate‐dependent ingrowth inference: broadleaves on their slow way to conquer Swiss forests

Forests provide essential ecosystem services that range from the production of timber to the mitigation of natural hazards. Rapid environmental changes, such as climate warming or the intensification of disturbance regimes, threaten forests and endanger forest ecosystem services. In light of these challenges, it is essential to understand forests' demographic processes of regeneration, growth, and mortality and their relationship with environmental conditions. Specifically, understanding the regeneration process in present‐day forests is crucial since it lays the foundation for the structure of future forests and their tree species composition. We used Swiss National Forest Inventory (NFI) data covering vast bio‐geographic gradients over four decades to achieve this understanding. Trees that reached a diameter at breast height of 12 cm between two consecutive NFI campaigns were used to determine regeneration and were referred to as ingrowth. Employing three independent statistical models, we investigated the number, species, and diameter of these ingrowth trees. The models were subsequently implemented into a forest simulator to project the development of Swiss forests until the mid‐21st century. The simulation results showed an ingrowth decrease and a shift in its species composition, marked by a significant reduction in Norway spruce Picea abies and concurrent increases in broadleaves. Nevertheless, the pace of this change towards climatically better adapted species composition is relatively slow and is likely to slow down even further as ingrowth declines in the future, in contrast to the fast‐changing climatic conditions. Hence, support through adaptive planting strategies should be tested in case ingrowth does not ensure the resilience of forests in the future. We conclude that since the regeneration of forests is becoming increasingly challenging, the current level at which ecosystem services are provided might not be ensured in the coming decades.

Characteristics of logs with signs of oviposition by the polyphagous xylophage Asian longhorned beetle (Coleoptera: Cerambycidae).

During the eradication program undertaken against Anoplophora glabripennis (Motschulsky) in the Greater Toronto Area, information was collected on the numerous signs of injury found on wounded trees. Herein, we used a portion of this information to assess the characteristics of logs with signs of oviposition (i.e., pits). Specifically, we related the basal diameter, type (log bole vs. log branch), height above ground, and branch hierarchy level of logs with pits to tree size (i.e., height and diameter at breast height) and level of infestation intensity. In general, pits were concentrated on logs from the bole and branches that were 8-14cm in diameter in the lower 8 m of the bole and in the first 2 levels of the branching hierarchy. Oviposition pit location was strongly influenced by tree size-both height and diameter at breast height, with more pits on the lower bole in small trees and then higher on the bole and into the branches as tree size increased. As tree-level infestation intensity increased, pits were found on both larger and smaller diameter portions of the trees, presumably as preferred oviposition sites became saturated. These findings can improve the efficacy of surveillance activities for A. glabripennis.

Assessment of Growth and Carbon Stock of 6-Year-Old Dryobalanops lanceolata

Dipterocarp species are the mainstay of forest products in the form of woodworking. Dryobalanops lanceolata is one of the dipterocarp species. The study aimed to analyze the effect of canopy cover on the growth and carbon storage of 6-year-old D. lanceolata. Data were collected by measuring diameter, height, canopy cover, soil samples, and carbon storage. The research method was carried out by regression between canopy cover and tree diameter and height growth, analyzing soil fertility and carbon content. The 6-year-old D. lanceolata has grown well with a canopy cover of less than 34% (canopy openness of more than 66%) and could grow on clay soil with acidic pH. D. lanceolata at the age of 6 years has been able to improve the nutrient content in the soil. Under 6-year-old D. lanceolata stands, it has provided significant changes to increase the availability of soil nutrients for C-organic, total N, and K-available content. Carbon storage in D. lanceolata has increased in 1 year by 41.91%. Keywords: biomass, canopy cover, carbon growth, Dryobalanops lanceolata

Carbon carrying capacity in primary forests shows potential for mitigation achieving the European Green Deal 2030 target

Carbon accounting in the land sector requires a reference level from which to calculate past losses of carbon and potential for gains using a stock-based target. Carbon carrying capacity represented by the carbon stock in primary forests is an ecologically-based reference level that allows estimation of the mitigation potential derived from protecting and restoring forests to increase their carbon stocks. Here we measured and collated tree inventory data at primary forest sites including from research studies, literature and forest inventories (7982 sites, 288,262 trees, 27 countries) across boreal, temperate, and subtropical Global Ecological Zones within Europe. We calculated total biomass carbon stock per hectare (above- and below-ground, dead biomass) and found it was 1.6 times larger on average than modelled global maps for primary forests and 2.3 times for all forests. Large trees (diameter greater than 60 cm) accounted for 50% of biomass and are important carbon reservoirs. Carbon stock foregone by harvesting of 12–52% demonstrated the mitigation potential. Estimated carbon gain by protecting, restoring and ongoing growth of existing forests equated to 309 megatons carbon dioxide equivalents per year, additional to, and higher than, the current forest sink, and comparable to the Green Deal 2030 target for carbon dioxide removals.

Native species diversity associated with Bosque Palmeras de Ocol in the Amazonas region, Peru

The objective was to evaluate the ecology and dynamics of the native species community in the Bosque Palmeras de Ocol in the district of Molinopampa, Amazonas, Peru. Six sampling points were established, in which 1,569 trees belonging to 47 species were found. Species such as Astrocaryum sp., with a relative density of 10.7 % and an importance value index (IVI) of 23.54 %, and Prunus sp., with a relative density of 8.9 % and an IVI of 22.23 %, stood out. Myrsine coriacea subsp. 2 was identified as key with a high relative frequency and an IVI of 16.21 %. Density per hectare revealed high values for Astrocaryum sp. (560 individuals/ha), Nectandra sp. (526 individuals/ha) and Prunus sp. 2 (470 individuals/ha). The distribution of tree height and diameter showed a predominance of smaller individuals, with most species presenting diameters less than 20 cm and heights between 3 and 4 m. The range/abundance curve highlighted Astrocaryum sp. as the most abundant species. The distribution models showed a good fit to the Null and Preemption distributions, with low values of Akaike's criterion (AIC) 111.56 and 114.60, respectively. These findings provide a detailed understanding of the species community in this forest, fundamental for its conservation and sustainable management.

Relationships between functional traits and survival mediated by tree size in subtropical forests

Abstract An important challenge in ecology is to link functional traits to plant survival for generalizable predictions of plant demographical dynamics. However, whether root and leaf traits are consistently associated with tree survival remains uncertain because of the limited representation of root traits. Moreover, the relationships between plant traits and survival are rarely linear and are likely to vary with tree size. We analyzed demographic data from 17 901 trees of 32 subtropical tree species under 3-year-old monocultures to test whether root and leaf traits have consistent relationships with tree survival and how the relationships between traits and tree survival vary with tree diameter. We discovered that leaf and root traits have inconsistent effects on tree survival. Specifically, while specific leaf area (SLA; an acquisition strategy) showed a marginally significant negative impact on survival, root diameter (RD; a conservative trait within the one-dimensional root economic spectrum) also demonstrated a significant negative effect on survival. Furthermore, we found size-dependent relationships between traits and tree survival. The effect of SLA, leaf phosphorus concentration and specific root length, on survival shifted from negative to positive with increasing tree size. However, species with high leaf thickness and RD were positively linked to survival only for small trees. The results highlight that to accurately predict the relationships between traits and tree survival, it is essential to consider both above- and belowground traits, as well as the size-dependent relationships between traits and tree survival.

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.

How do soil and topographic drivers determine tree diameter spatial distribution in even aged cork oak stands installed in average to high productivity areas

Local terrain or microsite conditions influence the development of trees, particularly at early ages. These conditions might be described by edaphic or topographic variables. We mapped soil and topographic variables from four even-aged and even-spaced cork oak plantations located in two climatically distinct Portuguese regions. The major goal of this research was to understand the relation between soil and topographic fine-scale conditions and tree growth expressed by diameter without cork annual growth (idu). The methodology consisted in (1) analysing the spatial variability and autocorrelation of idu; (2) modelling idu with ordinary least squares (OLS) regressions; (3) comparing with spatial modelling of idu, incorporating spatial autocorrelation. The driest stands A and B, exhibited weaker spatial autocorrelation, distributed in smaller clusters (R2 < 0.03, OLS models), while stands C (R2 = 0.18, OLS models) and D (R2 = 0.11, OLS models) showed higher predictive capacity. Spatial models increased R2 scores, keeping most variables from OLS models and accounting for spatial autocorrelation. A + B + C + D OLS model obtained an R2 = 0.34 and respective spatial model R2 = 0.58. Apparent electrical conductivity at 0.5 (ECa0.5) and 1 m of soil depth, slope, elevation and topography position index were included as predictors (OLS), but only ECa0.5, slope and elevation were selected in the spatial model. Models were fitted using average to high productivity stands and should be used cautiously outside this range. Local terrain conditions determine the growth of young cork oak trees. Mapping soil and topographic variables before establishing new plantations may identify limiting microsite conditions where using cork oak species is not suitable due to low growth rates expectations.

Light competition drives species replacement during secondary tropical forest succession

Light competition is thought to drive successional shifts in species dominance in closed vegetations, but few studies have assessed this for species-rich and vertically structured tropical forests. We analyzed how light competition drives species replacement during succession, and how cross-species variation in light competition strategies is determined by underlying species traits. To do so, we used chronosequence approach in which we compared 14 Mexican tropical secondary rainforest stands that differ in age (8–32 year-old). For each tree, height and stem diameter were monitored for 2 years to calculate relative biomass growth rate (RGR, the aboveground biomass gain per unit aboveground tree biomass per year). For each stand, 3D light profiles were measured to estimate individuals’ light interception to calculate light interception efficiency (LIE, intercepted light per unit biomass per year) and light use efficiency (LUE, biomass growth per intercepted light). Throughout succession, species with higher RGR attained higher changes in species dominance and thus increased their dominance over time. Both light competition strategies (LIE and LUE) increased RGR. In early succession, a high LIE and its associated traits (large crown leaf mass and low wood density) are more important for RGR. During succession, forest structure builds up, leading to lower understory light levels. In later succession, a high LUE and its associated traits (high wood density and leaf mass per area) become more important for RGR. Therefore, successional changes in relative importance of light competition strategies drive shifts in species dominance during tropical rainforest succession.

The importance of tree species identity and trait-based winter foraging ecology of bark-foraging bird species in a large Central European floodplain forest

Beyond preferences for particular species of tree, bark-foraging birds are associated with various tree characteristics such as decay stage, trunk diameter, or bark roughness. Our objectives were to study the winter foraging ecology of different bark-foraging bird species in the highly diverse floodplain forests of Donau-Auen National Park (Austria) by examining the importance of tree species and characteristics. We used 'first-foraging' observations on the great spotted woodpecker (Dendrocopos major), middle spotted woodpecker (Leiopicus medius), Eurasian nuthatch (Sitta europaea), treecreepers (Certhia spp.), great tit (Parus major), Eurasian blue tit (Cyanistes caeruleus), and marsh tit (Poecile palustris). We examined bird-tree relationships with a bird-plant network approach, where we compared traits of trees and their preferences among avian species. The five most important tree species relative to distance-weighted fragmentation were European white elm (Ulmus laevis), pedunculate oak (Quercus robur), common ash (Fraxinus excelsior), and white and black poplar (Populus alba, P. nigra). Avian taxa differed only in the use of tree condition, where woodpeckers used decayed and dead trees more than tits. Most species preferred trees of larger trunk diameter with rougher bark. We suspect that changes in these highly diverse floodplain forest stands will eventually lead to changes in bark-foraging bird assemblages. For the protection of such highly diverse floodplain forests, conservation-based water management practices will be crucial to maintaining a sufficient groundwater table. Our findings also suggest that forest management practices should focus on more diverse commercial forest stands with a critical amount of secondary tree species, a variety of size classes, varying tree conditions, and species with different bark roughness classes.

Structural and Successional Dynamics of Old-Growth Mixed Oak Forests in the West Qinling Mountains

Understanding the composition and structure of forest trees is crucial to comprehending the properties and functions of forests. It also helps in implementing effective management strategies for sustainable resource utilization. Our study analyzed the structural dynamics of the old-growth mixed oak forests in the Xiaolongshan Forest region, focusing on three long-term monitoring plots (A, B, C). We examined the tree species composition, diameter distribution, mortality, and recruitment dynamics of different successional species groups, as well as the spatial distribution patterns of living and dead trees, with surveys conducted every five years. The findings indicate: (1) Plot A experienced a decline in stand density and species diversity during the survey period, with the Importance Value Index (IVI) of pioneer successional species continually decreasing in plots B and C. (2) The tree diameter distribution structure in plot A significantly differed from other plots, showing notable change between 2007 and 2012. (3) All plots exhibited lower, well-balanced community-level demographic parameters based on stem number, but a higher recruitment rate for later successional species groups based on basal area. (4) Dead individuals in plot A had a slight clustering distribution, while the other plots showed a random distribution. We conclude that the individual growth rate significantly impacts the dynamics of the natural Quercus aliena var. acuteserrata forest, with pioneer species groups being gradually replaced by early or late-successional species groups in the succession process.

Modeling branch attributes and biomass for Catalpa bungei plantations under various fertilization regimes

The development and morphology of branches, a crucial step in producing high-quality large-diameter lumber, may be influenced by fertilization. The response of branch attributes to different fertilization regimes, however, is still poorly understood. The Catalpa bungei plantations, which had been growing for 6 years in northern China, were chosen to study how various fertilization measures affected branch attributes. The two fertilization techniques used were hole fertilization (HF) and water and fertilizer integration (WF), with no fertilization (CK) as a control. The quantity, density, morphology (e.g., diameter, length, and angle), and position (e.g., height and orientation) of branches, and organ biomass of 18 standard trees (total of 516 branches) were investigated. The results demonstrated a considerable increase in tree height, diameter at breast height (DBH), canopy ratio, branch quantity, and organ biomass following the addition of fertilizer. Both the maximum branch diameter and the number of branches rose with fertilization. Following fertilization, the number of branches rose by 16% (HF) and 28% (WF) compared to non-fertilized trees, while the maximum branch diameter increased by 3.5% (HF) and 17.3% (WF), respectively. WF led to an increase in the number of branches and largest branch diameter in comparison to CK and HF. The length, angle, and diameter of branches, however, were not affected significantly by different fertilization treatments. There were roughly equal amounts of branches in four orientations. The mixed-model analysis revealed that the number of branches was positively correlated with branch density and tree height. The branch diameter increased with the increase of branch length and angle. The branch length was negatively correlated with branch height and angle. The branch angle showed a larger angle at the bottom of the canopy. Tree height plus diameter at breast height combined, or just the diameter at breast height indicator alone, can both reliably predict the total biomass of trees. The branch models created in this research may offer some theoretical backing for understanding the crown dynamics of valuable tree species in northern China.

Topographical gradient of the structure and diversity of a woody plant community in a seasonally dry tropical forest in northwestern Madagascar

AbstractFew studies have evaluated the structure and dynamics of forests in Madagascar with high levels of endemism. Ankarafantsika National Park holds the largest of the remaining primary dry forests in northwestern Madagascar, where most of the forests have been lost or degraded by fire and other human activities. In this primary forest, we established a 15‐ha forest dynamics monitoring plot and mapped and identified all woody stems with a diameter at breast height (DBH) ≥5 cm. The forest stand was characterized by small‐sized individuals (75% of stems with DBH &lt;10 cm, with 99% of trees with height &lt;15 m), encompassing 35,758 tree and 513 liana individuals belonging to 160 species in 53 families (including 20 species of lianas accounting for 1.4% of the stems). Most species‐rich families were Rubiaceae, Fabaceae, Lamiaceae, and Malvaceae, which together encompassed 43 tree species and 23% of all tree individuals. The plot was located on a hill consisting of white sand at elevations from 150 to 200 m, with a gentle slope down from southwest to northeast. Over this elevation gradient, stem density and species diversity increased with elevation, while tree height and diameter decreased. The most abundant two species, Drypetes perrieri (Putranjivaceae) and Noronhia alleizettei (Oleaceae) are evergreen, suggesting the importance of a nutrient conservation strategy. These results provide the foundational knowledge necessary for the conservation and restoration of natural semi‐deciduous dry forests that used to cover large areas in northwestern Madagascar until recently.

Bayesian analysis of the growth of pears in the cultivate Shinseiki using non-linear models

The pear of the Pyrus genus is the third most consumed fruit in Brazil, however, internal production is low and most demand is obtained through imports. Brazil has favorable conditions for its cultivation and one of its main economic sectors is agriculture, being responsible for generating a large number of jobs and income for the country. In this sense, studies related to this fruit can provide information and encourage its production. Using non-linear models, it is possible to identify growth patterns such as fruit length and diameter, which can help determine the ideal harvest point. Therefore, the goal of this article was to compare the Logistic and Gompertz non-linear models in describing the growth curves in diameter and length of the Asian pear tree using the Bayesian approach. The results indicated the Logistic model as the best to describe these two variables and provided asymptotic averages of 70.0607 and 79.706 for length and diameter, respectively.

Effect of collection period on oleoresin yield of Pinus merkusii

Pinus merkusii is one of the most important timber species in Indonesia, the main product of which is its oleoresin. The objective of this study was to examine the effects of collection period (three periods, with 6-day observation each) on oleoresin yield in relation to two factors: growth sites of Pinus merkusii, which in the case of this study were East Banyumas, West Banyumas, and West Pekalongan Forest Management Units, and use of stimulants (sulfuric acid and ethephon mixtures, ETRAT, SR4, and no treatment). The average total oleoresin yield from a single tree or wound during the 18-day observation period was 110-185 g/tree for untreated trees and 159-442 g/tree for stimulant-treated trees. By analysis of variance, the interaction between each collection period (6-day observation period) and tree growing sites showed that the maximum average oleoresin yield for one hole was 109.32 g/tree measured in East Banyumas in the first collection period. Furthermore, the East Banyumas site consistently showed significantly the highest yield in each period. The interaction between the factors of stimulant and collection period (6-day observation) resulted in the highest average oleoresin yield (121.86 g/tree) measured for trees treated with sulfuric acid (20%) and Ethephon (2%) mixtures in aqueous solution (v/v) treatment in the first collecting period. In West Pekalongan, the resin yield from trees treated with different treatments tended to be positively related to tree diameter. In addition, a positive correlation was found between resin yield and tree height or crown closure, while a negative correlation was found between resin yield and site elevation in trees treated with certain stimulants.

A Critical Evaluation of the Carbon Sequestration Capacity of Trees in Specific Regions within Kaduna State Nigeria

This research evaluated the capacity of trees to store carbon in two specific locations, namely Gamji Park and Kaduna Polytechnic in Kaduna State. This was done by conducting field measurements, and observations. To facilitate measurement, the research area was partitioned into quadrants. A grand total of 1555 trees were quantified, with 775 trees found in Gamji Park and 780 trees at Kaduna Polytechnic. A non-destructive approach was used, whereby the measurement of tree height and diameter at breast height was conducted without the need for tree felling. The diameter at breast height (DBH) and height of trees with a diameter at breast height of at least 5cm were measured in each plot. The pantropical allometric equations were used to determine the carbon stock and the quantity of carbon dioxide sequestered by the plants. A total of 6875.4 Megatons/ha of carbon dioxide (CO2) was calculated to be sequestered by trees in the two research locations. The tree species Eucalyptus tereticornis and Magnifera indica had a much greater capacity for sequestration in comparison to the other trees that were examined. The Pearson correlation coefficient was employed to examine the association between tree parameters and carbon sequestration. The correlation coefficients for height and DBH were 0.934 and 0.979, respectively. These results suggest a positive relationship between tree parameters, specifically tree height and DBH, and carbon sequestration. Notably, DBH exhibited a stronger correlation compared to other parameters. A statistically significant difference in the tree parameters was observed, as shown by a p-value of less than 0.05.

Structure and Carbon Capture of a Temperate Mixed Forest across Altitudinal Gradients in Northern Mexico

Maximizing the ability of forests to capture carbon (C) from the atmosphere is critical to mitigate global warming. This is a daunting task as the warming climate is adversely affecting forests with increasing forest fires, pests, and a shift to tree species that can tolerate the newer climate conditions. A large (about 1 million hectares) mixed pine–oak forest in Chihuahua, Mexico, was characterized via 151 plots to determine its floristic diversity and biomass with respect to species, age (tree diameter), and at four altitudinal gradients equally distributed between 1850 and 2850 masl. Higher richness and diversity were found at the altitudinal gradient of 2101–2350 m with 36 species and a Shannon’s index (H’) of 2.95, and the lowest at 2601–2850 m with 17 species and H’ of 2.37. The Sorensen Index showed a high similarity in species composition, with the highest values (71% to 79%) obtained for the 2351–2600 gradient. C storage of the mixed forest increased with altitude from 7.85 Mg C ha−1 in the 1850–2100 m gradient to 14.82 Mg C ha−1 in the 2601–2850 m gradient. C storage in oak decreased with altitude while C storage of pine increased. Viable strategies to maximize C storage under changing climate conditions are discussed, including social safeguards and sale of carbon credits.