DBH Classes Research Articles

Eco-Habitat Assessment of One of the Most Expensive Edible Mushrooms (Tricholoma matsutake) in Genekha, Thimphu, Bhutan

Tricholoma matsutake (S. Ito & Imai) Singer is most expensive edible mushroom, naturally grown dispersed in temperate oak pine forested areas in Bhutan. It is ectomycorrhizal fungi with high ecological and economic value requiring an important ecological niche and symbiotic tree associates. The present study is an attempt to give an account on floristic composition and vegetation structure of Tricholoma matsutake habitat in Genekha, Thimphu. A total of 10 plots were enumerated with plot size of 20m X 20m, 5m X 5m and 2m X 2m for trees, shrubs and herbs respectively. PAST (Paleontological Statistics) 4.10 software was used for diversity analysis. A total of 58 species under 44 genera belonging to 26 families were recorded in the natural habitat of matsutake. The study revealed that T. matsutake is associated with Quercus semecarpifolia Sm., Pinus wallichiana A.B. Jack., Rhododendron spp., and Pieris formosa (Wall.) D. Don. J-shaped distribution curve of DBH and height class with fair regeneration status is obtained for associated species in the habitat. The Menhinick’s species richness of (2.26, 2) for both North facing habitat (NFH) and South facing habitats (SFH) indicated high species richness. Moderate and low diversity is indicated with Simpsons index 0.94 (NFH) and 0.76 (SFH), Shannon index 3.06 (NFH) and 2.49 (SFH) with moderately even distribution 0.74(NFH) and 0.73 (SFH) of species in the habitats. Sorensens similarity index of 0.9 indicated highly similar species composition between two habitats. This research provides current floristic and vegetation structure of Tricholoma matsutake habitat, that will have high significance in habitat management and conservation.

Sustainable forest management for timber and non-timber resources in the Amazon forest under concession

The Amazon biome is one of the largest in terms of area and biodiversity. It provides impressive ecosystem services that are crucial to planetary functions, for example global precipitation patterns. Besides, it provides important timber and non-timber products that are crucial for local communities and even international markets. The aim of this study was to conduct a phytosociological analysis to select the species with important ecological functions and with commercial interest for timber and non-timber forest products (NTFP). Forest inventory data were collected were collected from 4 Annual Production Units (APUs) at the Paru State Forest. The 5 species with highest Importance Value Index (IVI) were: Chrysophyllum lucentifolium, Micropholis venulosa, Handroanthus serratifolius, Handroanthus impetiginosus and Manilkara huberi. These species presented commercial volume in the diameter classes of 40 to ≥ 170 cm. The species providing NTFP (Carapa guianensis, Bertholletia excelsa and Copaifera guianensis) presented IVI in the 1, 9, and 34 positions, respectively. The species Carapa guianensis presented more individuals in the 40 and 80 DBH classes. Bertholletia excelsa was the only one presenting individuals with DBHs exceeding 140 cm. Copaifera guianensis was the less common species. We concluded that all the 5 species producing timber are viable for sustainable forest management. Regarding the non-timber forest species, forest management need to be focused in Carapa guianensis and Bertholletia excelsa.

Population structure and regeneration of Tsuga dumosa and Abies spectabilis across altitudinal gradient in Rasuwa district, central Nepal

In Nepal, Tsuga dumosa thrives well between 2,100-3,600 m altitudes above the mean sea level, mostly in the temperate region while Abies spectabilis occurs between 3,000-4,200 m altitude above the mean sea level in the sub-alpine region. Research on mature T. dumosa-A. spectabilis forests in Nepal is limited. This study aimed to analyze the population structure and regeneration status of T. dumosa and A. spectabilis in the high-altitude mixed forests of Rasuwa, central Nepal. Conducted in 2023, a total of 61 concentric circular sample plots were laid out following a stratified systematic sampling method. The population-structure-curve displayed a consistent upward trend showing abnormality. The abnormal population structure with a lack of young trees and poor regeneration status in both species points towards potential threats like grazing and wildfires. The highest DBH class ranged from 90 cm to 120 cm DBH for T. dumosa while from 60 cm to 90 cm DBH for A. spectabilis. The study found that the seedling condition of T. dumosa species was ‘fair’ in the lower (2800-3100 m) and middle stratum (3100-3400 m), while it was ‘poor’ in the upper-elevation stratum (3400-3600 m). On the other hand, the seedling condition of A. spectabilis was found to be ‘poor’ in all the three elevation strata. Furthermore, the sapling condition of both the species were found to be ‘poor’. Therefore, the studied forest requires sustainable management along with a comprehensive strategy combining controlled grazing, zonation, monitoring, community engagement, regulation enforcement, restoration, ongoing research, and public awareness.

Composition and Structural Diversity of Woody Species in the Wof Ayzurish Forests, the Dry Afromontane Forest of the Northern EthiopiaI

Dry Afromontane Forest (DAF) is the largest Afromontane section and plays a fundamental role in preservation of species biodiversity. Despite its biodiversity, DAF is the most altered and threatened in the Ethiopian ecosystem. With the exception of a few isolated pockets left in some sacred places and protected areas of the country, most of forests are inaccessible. The scenario is not different for the present study forest. Therefore, the objective of the present study is to investigate woody species diversity, structure and regeneration status of Wof Ayzurish Forest, which is a dry Afromonatane in North Shewa of Ethiopia. A systematic method was employed whereby 67 quadrats set in 8 parallel lines transecting at 300-meter intervals and quadrats at 150-m distance. All trees and shrubs with diameters of breast height > 2.5 cm and height > 2 m were measured. The results revealed that Wof Ayzurish Forest harbors 76 species of woody plants that belong to 68 genera and 47 families, with Asteraceae, Fabaceae, and Solanaceae displaying the highest diversity. Shrubs had the highest composition than trees. The most abundant plants were Dodonaea viscosa subsp. angustifolia, Carissa spinarum, Juniperus procera, Olinia rochetiana and Olea europaea subsp. cuspidata. Dodonaea viscosa subsp. angustifolia was the most prominent plant, occurring in 98.5 % of all sample plots. The DBH and height classification pattern exhibited that the forest had a classic inverted J-shape, dominated by smaller trees and shrubs, indicating a secondary stage of regeneration. Total basal area (BA) for trees and shrubs DBH > 2.5 cm was 18.03 m2 ha−1. Remarkably, five species accounted for 57.45 % of the basal area, indicating that higher numbers of individuals concentrated in lower DBH classes. By using R software, agglomerative hierarchical cluster analysis and Canonical Correspondence Analysis (CCA) has done to identify plant community types and examine the relationship between plant community types and environmental variables, respectively. Three significantly different (p < 0.05) plant community types were identified. The CCA results showed that species diversity and community composition among community types were significantly influenced by altitude and human disturbance such as expansion of agriculture, cuttings, and grazing. Therefore, it is recommended that community-based methods and awareness creation should be devised in order to implement sustainable forest conservation.

Stand growth, Biomass and Carbon sequestration potentials of Parkia biglobosa (jacq.) Bench plantation in South-Western Nigeria

This study assessed tree growth variables, above (AGB), below ground biomass (BGB) and total carbon content (TC) sequestered by Parkia biglobosa (Jacq.) Bench. Plantation in Wasangare, Oyo State using non-destructive ground base survey. Tree growth data (Diameter at breast height, Dbh and Tree height, Th) were collected using lacer ace hypsometer and diameter girth tape from 20 temporary sampling plots of size 25 m X 25 m established through systematic transect lines. Diameter size classes (DSC) for the plantation was examined, carbon stock for each DSC was also determine while basal area (m2 ha-1), volume (m3 ha-1), Biomass (Mg ha-1) and Carbon (Mg ha-1) were also estimated. Results showed mean Dbh of 18.7 + 0.25 cm with 8.14 + 0.10 m, 0.033 + 0.00 m2 ha-1 and 0.320 + 0.01 m3 ha-1 for tree height, basal area and volume respectively. AGB and BGB were 10.877 + 0.39 Mgha-1 and 2.175 + 0.08 Mgha-1 respectively while TC was 6.527 + 0.24 Mgha-1. The percentage carbon stock proportion for each DSC revealed class size 25-29-9 cm (19.02%) as the highest while the least proportion was observed in less than 5 cm class with 0.04% of carbon. The DSC showed majority of the tree Dbh in lower Dbh classes with fewer trees in higher classes forming almost a normal bell shape. The study provides information that can help the management in planning silvicultural activities and selective removal from the stand (harvesting schedule). Tree Dbh, height, basal area, volume and biomass are the determinant characteristics for forest carbon assessment. In conclusion, the plantation actively sequesters carbon showing potentials for indigenous trees in climate change mitigation.

Understanding the influence of tree size distribution on the CTL harvesting productivity of two different size harvesting machines

Tree size is one of the major factors that determines harvester productivity and is heavily influenced by forest managerial activities. Stand silvicultural management can lead to managing tree size, the distribution of tree size, and tree height amongst others. Understanding the effect of tree size distribution on harvesting productivity is central for optimizing management of operations. To investigate the effects of tree size distribution on harvester productivity, productivity functions for a medium and larger-sized harvester were applied to harvester derived tree size distributions from 35 clearfelled pine stands. These functions were applied to a normal distribution of trees covering the same tree size ranges. Productivity differences were analysed on a stand-by-stand basis. Results showed that for the larger harvester, productivity rates remained constant (67.1 vs. 67.6 m3·PMH− 1) indicating relatively little sensitivity to variations in tree size distributions. Although the standard deviation (SD) halved from 11.6 to 5.6 in the case of the uniform tree distribution. The smaller harvester productivity decreased by 15% from 47.3 to 40.1 m3·PMH− 1 and the coefficient of variation (CV) by 6% in the same transition to a uniform distribution. Further investigation was done on more skewed tree size distributions, a family of nine Weibull distributions was generated, representing combinations of three mean DBH classes (25 cm, 30 cm, and 35 cm) and three levels of CV (15%, 20%, 25%), for each DBH class. Results clearly indicate that different distribution shapes have different effects on different machine sizes, and that a low CV correlates to a higher productivity in larger tree sizes. A more uniform tree size distribution also provides more predictable results (lower CV), which would promote machine scheduling and result in fewer discrepancies on production rates.

Structure and Composition of Woody Species in the Kpatawee Tropical Rainforest in Liberia

Studying ecosystem structure and species composition is pivotal, offering critical insights into environmental health and biodiversity. It facilitates the evaluation of environmental changes, like deforestation and climate shifts, and their influence on species dynamics within ecosystems. Our study aimed to assess the woody species composition and structure within Liberia's Kpatawee tropical rainforest. We conducted transect walks, crossing the forest south-north and east-west, establishing six 20 m x 20 m sampling plots. Using the PlantNet plant species identifier tool, we cataloged surviving trees with a DBH ≥ 5 cm, including their scientific names. Results unveiled 71 tree species across 42 families, with Leguminosae displaying the highest diversity. Prominent species included Quararibea asterolepis, Hasseltia floribunda, and Castilla elastica. An intriguing inverted J-shaped pattern in diameter distribution linked to stem-stand shrubs, small-sized trees, and young large trees characterized the first class. The tree layer, mainly species like Garcinia benthamiana, Iramyan therasagotiana, and Eschweilera decolarans, contributed significantly to the total DBH (65.45%). Total basal area (BA) for trees DBH ≥ 5 cm was 16.39 m² ha-1. Notably, eight species accounted for 93% of the basal area, reflecting a concentration of individuals in lower DBH classes in the first category. This trend suggests a gradual decline in numbers in higher DBH classes. Consequently, we recommend implementing sustainable forest management to mitigate the impacts of selective cutting on forest recruitment and regeneration processes. The inverted J-shaped pattern, indicating prolific regeneration but limited recruitment, possibly due to selective cutting, underscores the imperative for prudent forest management.

Floristic Composition, Diversity, and Regeneration of Woody Plant Species of Dabal Forest in Southeastern Ethiopia: Implication for Conservation.

Floristic composition, population structure, and regeneration status of woody species of Dabal forest found in East Hararghe zone of Oromia Regional State, Ethiopia, were studied. Vegetation data were obtained from 52 main plots of 20 × 20 m for mature woody species and 5 subplots of 5 × 5 m for seedlings and saplings. Density and dbh of each live woody plant species found in each sample plot were recorded. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were also computed. Totally 59 woody plant species distributed in 33 families were documented. Of these, 45.80, 44.10, and 5.08% were shrubs, trees, and lianas, respectively. Species diversity and evenness indices were 3.56 and 0.87, respectively. Stem count of all woody species was 3379 stems ha-1. Out of this, 44.6, 30.8, and 24.59% were seedlings (dbh <3.5 cm), saplings (dbh between 3.5 and 10 cm), and mature (dbh >10 cm) individuals, respectively. Total basal area of all individuals with dbh ≥3.5 cm was 29.88 m2 ha-1. Juniperus procera, Cupressus lusitanica, Eucalyptus globulus, Afrocarpus falcatus, Eucalyptus camaldulensis, Myrsine africana, Maytenus undata, Hagenia abyssinica, Ekebergia capensis, and Cordia africana were species with top ten IVI. Most of these species were top densest, dominant, and frequent. Analysis of population structure based on pooled densities of all species in each dbh class showed that density of seedling > sapling > mature individuals, signifying healthy population structure with good natural regeneration potential. On individual basis, however, 35.6 and 8.5% of species showed fair and poor regeneration statuses, respectively, that deserve attention for conservation.

Vegetation Structure and Regeneration Status of Woody Species in Gerba Dima Moist Afromontane Forest of Southwestern Ethiopia: Implications for Conservation

This study assessed vegetation structure and regeneration status of woody species in Gerba Dima forest, southwestern Ethiopia. Ninety sample plots measuring 25 m × 25 m were laid through a stratified random sampling procedure. The studied forest was stratified into three forest strata based on its altitudinal variation. Stratum I was found at an altitudinal range of 1500−1800 m, while strata II and III were located at altitudinal ranges of 1801−2000 m and 2001−2300 m, respectively. All woody plant species with a diameter at breast height (dbh) equal to or larger than 2.5 cm and a height of at least 1.5 m were recorded. Analysis of the structure of the vegetation was conducted using frequency distribution of dbh, height, and importance value (IV). The regeneration pattern of the study species was assessed by employing the total count of seedlings and saplings. The density of woody species in the study area was 1829 individuals ha−1. Basal area of the Gerba Dima forest was 65.05 m2ha−1. Total densities of seedlings, saplings, and trees/shrubs were 4558 ha−1, 2149 ha−1, and 1515 ha−1, respectively. Structural analysis and assessment of the regeneration status of woody species in the Gerba Dima forest showed that the overall ecological condition of the forest was healthy as indicated by inverse J‐curve dbh distribution, which showed a large number of individuals in lower dbh classes. Furthermore, a large number of seedlings and saplings were recorded for most species, in addition to the presence of a sufficient number of matured trees. However, some species exhibited abnormal population structure and abnormal patterns of regeneration characterized by fewer or no individuals in lower dbh, as well as in seedling and sapling stages. It was thus concluded that species with abnormal population structure and regeneration status (e.g., Sapium ellipticum and Trichilia dregeana) require urgent conservation attention.

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.

Population Structure and Regeneration Dynamics of Tree Species in Banj Oak Forests of Tehri Garhwal, Western Himalaya

Forest regeneration is a natural process of forest resource reclamation through production of young ones (saplings and seedlings). Tree species show variable regeneration potential in different associations and response to natural and man-made factors. Banj oak (Quercus leucotrichophora A. Camus), one of the important forest forming tree species in western montane Himalaya, is facing regeneration failure in different locations. The present study attempted to assess the population structure and regeneration of Q. leucotrichophora and associated tree species in five different stands (sites) of a less explored region (Tehri Garhwal, Uttarakhand, Western Himalaya). To investigate the phytosociological attributes, ten sampling quadrats (400 m2) were laid in random sampling manner in each forest stand for surveying tree layer, 2 sub-quadrats (25 m2) for saplings, and 5 sub-quadrats (1 m2) for seedlings in each sampling quadrat. Among the studied forest stands, tree species richness ranged 8 to 11 (8.8±1.3), total stem density (ind/ha) 750 to 950 (846±85.6), and total basal area (m2/ha) 18.68 to 29.18 (24.1±3.9). Based on abundance data the banj oak showed ‘good’ regeneration statuses (density of seedling &gt; saplings &gt; adult trees) in all forests. The distribution of adult tree individuals into different size classes (DBH classes) also indicate ‘good’ regeneration pattern (higher density in lower size classes and gradual decrease in density towards higher classes or forming a reverse J-shaped pattern). However, majority of the banj oak associated species (e.g. Prunus cerasoides, Pyrus pashia, Rhododendron arboreum, etc.) represented ‘fair’ regeneration statuses (seedlings &gt; or ≤ saplings ≤ adult trees). Overall, the results of this study shed light on the positive prospects for Q. leucotrichophora regeneration and the importance of sustainable coexistence between human communities and these vital forest ecosystems.

Fire-mediated biomass loss of woody species seedlings causing demographic bottleneck in the Terai Forests of Central Nepal

Forest fire produces varying ecological effects determining vegetation patterns in ecosystems. Plant community assemblages in forests are altered by fire influencing growth and development. Some plant communities are suppressed and some are encouraged to develop due to fire. Little empirical evidence exists revealing the condition of fire-mediated loss of small-sized individuals, and response of fire to demographic structure of woody plant species in Nepal. The aim of this research, therefore, is to quantify fire-mediated biomass loss of small-sized individuals of woody species (seedlings), and investigate the associated impacts on the demographic structure of plants in the Terai forests of central Nepal. Impacts on small-sized individuals of woody plant species were evaluated based on evidence from 25 sites with 50, 1 m × 1 m subplots for seedlings nested in 10 m × 10 m plots (n = 50) for saplings and adults. Of the 50 sampling plots, 25 represented fire-affected and the remaining 25 represented control plots. Mean density of resprouting and newly grown seedlings developed in one year after the surface fire was 46,800 ± 4071 inds. ha−1. Shorea robusta Gaertn. was the most abundant species regenerated with seedlings in the control forest sites. The estimated average yearly loss of above ground biomass (AGB) for woody plant seedlings in the forest due to surface fire was 1,651.5 ± 360.2 kg ha−1. Of the total fire-affected AGB of S. robusta, 700.0 kg ha−1 was the immediate burnt loss and 322.5 kg ha−1 was dead AGB left unburnt. Similarly, among the other most abundant species, higher proportion of immediate fresh AGB loss was observed for Mallotus philippensis (Lam.) Müll.-Arg. and Casearia graveolens Dalzell. compared to dead AGB left unburnt. The Weibull probability density function shows the existence of saplings recruitment bottleneck in the fire-prone forest sites, i.e., growth of seedlings to saplings was restricted. Surface fire impacted the development of DBH class > 0–5 cm saplings. Surface fires are one of the potential environmental filters of the plant species regeneration and composition in the forests of lowland Terai Nepal. These demographic variations and bottlenecks should be considered while formulating management actions to conserve vegetation assemblages in fire-mediated ecosystems.

Species diversity and vegetation structure of woody plants in regenerating Juniperus forest replacing Eucalyptus in the conservation area of Gullele Botanic Garden, Addis Ababa, Ethiopia

The Gullele Botanic Garden (GBG) adjoins the north-western limit of the city of Addis Ababa, capital of Ethiopia. The floristic composition, species diversity and vegetative structure of the woody plant species in the conservation area of the garden are presented from 81 plots (20 m x 20 m). A total of 104 woody plant species (90% indigenous, the rest planted or naturalised) of 83 genera and 47 families were recorded. The dominant families were Fabaceae and Asteraceae. The number of individuals of the most dominant species, Juniperus procera, decreases with increasing DBH and height class, which indicates a good and healthy reproduction potential of the species in the conservation area. No statistically meaningful plant communities could be identified in the conservation area. Many of the species present in the dry forests of the central Ethiopian plateau occur in GBG. The species richness appears to be relatively high in comparison with what other researchers have found in natural forests on the highland plateau; 87 native woody species (of which 11 are planted) in GBG, 57-97 (cumulatively 127) in Wof-Washa, 32-85 (cumulatively 113) in Menagesha and 41-77 (cumulatively 81) in Chilimo, 34-67 (cumulatively 69) in Entoto, though the definitions for woody species have varied between studies. Clustering on the floristic data gives four partly overlapping clusters with the lowest p-values for indicator species, but the distribution of the plots on clusters changes notably if information on Eucalyptus is in- or excluded. Ordination graphs with partly overlapping groups of species are presented. The findings in this paper can serve as a baseline to follow the regeneration of the conservation area towards natural forest. This is needed for future management and sustainable utilization of the forest species at local and national levels.

Woody species diversity and the carbon stock potentials of different land use types in agroecosystem of Jimma Ganati District, Western Ethiopia

We investigated the impact of land use types and topographical variables on the diversity of wood species and their carbon stocks in the studied agroecosystems. A generic allometric equation developed for woody plants in agricultural landscapes was used to estimate the carbon stock. We used a mixed-effects linear model using the lmer function in the lme4 package to test the effects of land use types and topographic variables on wood species diversity (Shannon diversity) and stem carbon stock potential. Our study result showed that there is significantly higher woody diversity (P < 0.05) in forests, home gardens and riverine than in grazing lands and croplands. Conversely, woody DBH (cm) and height (m) are relatively higher for croplands followed by grazing land, but lower for home garden and forest land use. There is a statistically significant difference between land use types in their carbon stock (χ² (4) = 18.164, p=0.0011), with forest having the highest total carbon stock, followed by home gardens, but grazing land having the relatively lower total carbon stock of woody species. The study finds that species diversity has a positive and significant (P<0.05) effect on both aboveground and belowground carbon stocks. However, its effect is modulated by land use types, where it is stronger in forest patches, but weaker in more disturbed land use types (e.g., grazing lands and cropland). The study also finds that topographical variables (elevation, slope, and aspects) have no significant (P>0.05) effect on aboveground and belowground carbon stock. The tree species' structural attributes such as height, DBH size, and basal area (BA) have a positive and statistically significant (P < 0.05) effect on carbon stock. The study also found that only a few high DBH class (old growth) tree individuals that are deliberately spared in cropland and grazing land matrix have a high carbon stock contribution. For example, seven species, Podocarpus falcatus, Ficus vasta, Prunus africana, Schefflera abyssinica, Ficus sur, Ekebergia capensis, and Apodytes dimidiate, contribute an estimated 70% of the estimated total carbon stock in the landscapes. These results indicate the need to protect such scattered old-trees in agricultural landscapes both for biodiversity conservation and carbon sequestration thereby integrating climate change adaptation and mitigation strategies into subsistence farming systems.

ARTICLE WOODY SPECIES STRUCTURE AND REGENERATION STATUS IN MEHAL WONZ - ZEGO FOREST, N/ SHEWA ZONE, AMHARA REGIONAL STATE, ETHIOPIA

This study was conducted on Mehalwonze- Zego forest in North Shewa zone, Amhara Regional State, Ethiopia, A Transect sampling method was used to collect vegetation data. Sixty seven(67) plots of 20m × 20m were laied each at 300m intervals and five subplots of 2m × 2m, one in the center and four in the corner of the main plots, were laid for seedling and sapling inventory. Vegetation parameters such as DBH &gt;2.5cm, H ≥2.5m of as well as seedling and sapling density with five sub plots of 2m × 2m. A total of 55 woody species belonging to 51 genera and 38 families were identified. The density of seedlings, saplings and matured woody plants in all of the plots were 1302, 1517 and 905 individuals, respectively. Importance Value Index (IVI) of each species were calculated, based on this value the conservation priority classes was done which indicated that there are woody species that require urgent conservation. The total basal area of the forest was 67.96 m2/ha. DBH and height class distribution of woody spcies confirms that the forest is under a secondary stage of development. Based on the results of regeneration assessment, conservation priority should be given for species with poor regeneration status.

Analysis of Selection-Cutting Silviculture with Thujopsis dolabrata—A Case Study from Japan Compared to German Plenter Forests

(1) Background: In Japan, single-tree selection-cutting silviculture with hiba (Thujopsis dolabrata var. hondai) is a traditional silvicultural system and is well documented. We evaluated an experimental forest regarding past structural dynamics and future development while comparing it to the German multilayer coniferous “Plenterwald/plenter forest”. (2) Methods: Classical growth and yield data were recorded since 1995 from two hiba-mixed species plots, one managed since Matsukawa’s (the founder) times in 1931 and the other unmanaged since 40–50 years before 1931. (3) Results: Clear structural differences appeared, with the managed plot having a reverse J-shaped DBH and tree height distribution curve, and a higher percentage of hiba, also typical for German plenter forests’ intensely multi-storied structure. The unmanaged plot was composed of trees with large stem diameters, even though they were more evenly distributed, together with less admixed species. In both plots, the growing stock increased in the past. While the managed plot’s growing stock in 2019 was 561 m3 ha−1, the unmanaged plot reached 982 m3 ha−1 with large portions accumulated in DBH classes &gt;60 cm. (4) Conclusions: When compared to today’s clearcutting system in Japan, selection silviculture shows advantages and may thus serve as a valuable inspiration for silviculture in Japan as it was with plenter forestry for Germany.

Woody Species Composition, Structure, and Regeneration Status of Gosh-Beret Dry Evergreen Forest Patch, South Gondar Zone, Northeast Ethiopia

Owing to its variable topographic features, Ethiopia is endowed with rich biological resources. However, nowadays, these vital resources, mainly forests, are declining alarmingly, largely, due to agricultural expansion and energy consumption. This study was conducted at Gosh-Beret forest with the objective of investigating the status of forest species. Fifty-one main plots, spaced at a 100 m interval, were laid on north-south oriented transects. Within the main plots, five subplots, at each corner and center, were set to collect data for juveniles. In each plot, individuals of each woody species were identified and recorded. Percent cover abundance of each woody species per plot was genuinely estimated, which was later converted into the modified Braun–Blanquet scale. For each mature woody species, diameters at breast height (DBH ≥ 2 cm) were measured. Hierarchical cluster analysis was performed to identify community types. The Shannon–Wiener diversity index and Sorensen’s similarity coefficient were used to compare the species diversity and composition among communities, respectively. The structure and regeneration status of the forest species were analyzed using structural parameters and size-class ratios, respectively. A total of 52 woody species distributed in 35 families were recorded. Fabaceae, Euphorbiaceae, and Asteraceae were the most dominant families with 4 species each. The overall species diversity of the forest was 2.6, and five community types were generated from cluster analysis. In the study forest, frequency and density of species decrease with increasing frequency and density classes. Likewise, density of individuals in each class decreases as DBH classes increase. The total basal area of the forest was 19.81 m2ha−1, and the forest was at fair regeneration status with species having small IVI values and few/no seedlings. Therefore, immediate conservation measures are required to save species with small IVI values and few/no seedlings.

Contribution of Tree Size and Species on Aboveground Biomass across Land Cover Types in the Taita Hills, Southern Kenya

Tropical landscapes comprise a variety of land cover (LC) types with characteristic canopy structure and tree species. Depending on the LC type, large-diameter trees and certain tree species can contribute disproportionately to aboveground biomass (AGB), and these patterns are not described at landscape-level in LC type specific studies. Therefore, we investigated the impact of large trees and tree species on AGB across a range of LC types in Taita Hills, Kenya. Data included 239 field plots from seven LC types: Montane forest, Plantation forest, Mixed forest, Riverine forest, Bushland, Grassland, and Cropland and homestead. Our results show that the contribution of large trees (DBH &gt; 60 cm) on AGB was greatest in Riverine forest, Montane forest and Mixed forest (34–87%). Large trees were also common in Plantation forests and Cropland and homestead. Small trees (DBH &lt; 20 cm) covered less than 10% of the total AGB in all forest types. In Grassland, and Cropland and homestead, smaller DBH classes made a greater contribution. Bushland differed from other classes as large trees were rare. Furthermore, the results show that each LC type had characteristic species with high AGB. In the Montane and Mixed forest, Albizia gummifera contributed 21.1% and 18.3% to AGB, respectively. Eucalyptus spp., exotic species planted in the area, were important in Mixed and Plantation forests. Newtonia hildebrandtii was the most important species in Riverine forests. In Bushland, Acacia mearnsii, species with invasive character, was abundant among trees with DBH &lt; 30 cm. Vachellia tortillis, a common species in savannahs of East Africa, made the largest contribution in Grassland. Finally, in Cropland and homestead, Grevillea robusta was the most important species (&gt;25% of AGB). Our results highlight the importance of conserving large trees and certain species to retain AGB stocks in the landscape. Furthermore, the results demonstrate that exotic tree species, even though invasive, can have large contribution to AGB.

Forest structures and carbon stocks of community forests with different forest management in Maha Sarakham Province, Thailand

Abstract. Wannasingha W, Gomontean B, Uttaruk Y. 2023. Forest structures and carbon stocks of community forests with different forest management in Maha Sarakham Province, Thailand. Biodiversitas 24: 799-809. Forest management comprises strategies and practices to regulate human activities and the utilization of forest products. Management and regulations have various effects on forest structure, tree diversity and carbon accumulation. This study was conducted in three community forests with different levels of rule regulations and managed duration in the northeast of Thailand. Thirty of 20×20 m plots were placed for recording all trees with diameter at breast height (dbh) ?4.5 cm and &gt;1.3 m height. One hundred and fifty plots of soil samples at 0-25 cm and 25-50 cm depths were also collected for organic carbon analysis. Forest carbon stocks were calculated from the sum of carbon in aboveground biomass (AGB) and soil organic carbon (SOC). The results showed that tree density, basal area, Shannon diversity index and evenness index of the best practices (BP) plots were higher than the plots in which moderate (MP) and slight practices (SP) were applied. Tree heights of the BP and MP forests were higher than the SP forest. The L-shape of dbh class distribution in all community forests means they were secondary forests; tree density was highest in the small dbh class and declined in the bigger size class. The bigger dbh class tree showed higher aboveground carbon (AGC) despite the lower tree density in all community forests. Most of the BP forest plots had the highest carbon stock (93.89, 80.52 and 54.96 Mg C ha-1) and CO2 absorption (344.25, 295.23 and 201.53 Mg CO2equiv.) compared with the others. Our results demonstrate the importance of forest management in affecting forest structures, carbon sequestration and carbon dioxide absorption from the atmosphere to reduce and mitigate climate change.

Form and Volume of the Stem of Tectona grandis L.f. in the Central-WESTERN Region of Brazil

The international market has recognized the high value of Tectona grandis L.f. plantations, requiring the development of reliable and accurate tools and techniques to quantify forest stocks accurately. In this study, we developed suitable equations to estimate the stem diameters and volume of Tectona grandis trees in the central-western region of Brazil, evaluating the stem form change points (FCPs) and testing the stratification of data as a measure to control their variation. The Schöepfer model was tested in the study of the FCPs of the stem, and single equation, segmented and variable-exponent taper functions were used to describe the stem profile. After the selection of the model for the taper, data stratification in the DBH classes, form parameter “r” and artificial form factor were proposed. The total volumes of each tree were calculated by integrating the Clark III et al. model. The FCPs of the Tectona grandis stems occurred at 28%, 57% and 73% of the total height, corresponding, on average, to the absolute positions of 6.4 m, 13.3 m and 16.5 m. The Clark III et al. equation, without stratification, was the most appropriate equation to estimate the diameters along the stem and the volume of Tectona grandis trees in the central-western region of Brazil.