scholarly journals Natural regeneration in logging gaps of different sizes in Subri River Forest Reserve (Ghana)

Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný ◽  
Simon Abugre ◽  
Augustine Gyedu

AbstractSubri River Forest Reserve (SR) is the most extensive forest area in Ghana with an accompanying rich floral species. Over the years, logging from both legally prescribed and illegal operations remain the predominant forest disturbance in SR. Gap creation following logging is crucial in determining tree species composition and diversity. Hence, the study evaluated the composition and diversity of naturally regenerated tree species in logging gaps of different sizes and, again examined the roles of these tree species in fulfilling the economic and ecological agenda of sustainable forest management after logging in SR. Twelve gaps were randomly selected: 4 each were grouped into small size (≤ 200 m2), medium size (201–300 m2), and large size (≥ 300 m2). Data were gathered from 1 m2 circular area at gap centres and repeatedly inside 1 m width strip along 20 m individual N-S-E-W transects. Species diversity differed significantly between gap sizes. Higher diversity indices were measured in large size gaps. Gap sizes shared similar species. There were significant differences among various height groupings of tree species across all three gap sizes. Pioneers preferred medium to large size gaps, while shade-tolerant tree species preferred small size gaps for their abundance. Vulnerable and Lower Risk Near Threatened tree species under Conservation Status and, Premium and Commercial tree species under Utilisation Status preferred small size gaps for their proliferation and conservation. Therefore, we recommend the single tree-based selective logging for ensuring creations of small to medium size (200–300 m2) gaps through adjustments to the logging permit process, revision of Allocation Quota Permit, strict adherence to the 40-year polycyclic selection system, along with more dedicated enforcement and monitoring. Changes along these protocols would tremendously facilitate natural regeneration of different suites of timber species resulting in the improvement of the overall biodiversity conservation associated with the forest, more sustainable forest harvests and more income to those who receive permits.

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1059
Author(s):  
Marlene Soriano ◽  
Pieter A. Zuidema ◽  
Cristina Barber ◽  
Frits Mohren ◽  
Nataly Ascarrunz ◽  
...  

A typical case of multiple-use forest management (MFM) in Southwestern Amazon is the commercial harvesting of Amazon or Brazil nut (Bertholletia excelsa) seeds and of timber of other tree species. Although the Amazon nut is the most important non-timber forest product (NTFP) in the Amazon basin, the species is under serious threat due to deforestation and may also be affected by overharvesting. However, selective logging of other tree species coexisting with Bertholletia may positively affect Bertholletia populations, thus enabling a special case for MFM. For this research, we investigated the impact of the intensity of Amazon nut harvesting and timber logging on Bertholletia populations in the Bolivian Amazon. We used demographic data from 72 two-hectare transects located within 24 community-based household forests varying in the intensity of nut collection (0–100%) and timber logging (0–15% of logging-disturbed forest area). Simulated Bertholletia population size increased with logging intensity but decreased with Amazon nut harvesting intensity. Bertholletia populations were projected to grow at the average MFM harvesting scenario tested: 57.4% of nut harvesting, 5.3% of logging-disturbed area (λ100 = 1.011). Our simulations also revealed that up to 89% of Amazon nut seeds can be harvested while sustaining Bertholletia populations, under 15% of logging-disturbed area, and applying liana cutting. Modest levels of timber logging and application of liana cutting may compensate for the negative effect of Amazon nut collection on Bertholletia populations for the next century. Our study demonstrates that Amazon nut and timber production could be combined in a sustainable MFM scheme, thus increasing the economic value of managed tropical forests and its promotion to reduce the increasing pressure by deforestation.


2019 ◽  
Vol 25 (3) ◽  
Author(s):  
Magdaleno Mendoza-Hernández ◽  
Patricia Gerez-Fernández ◽  
Silvia Purata-Velarde ◽  
Tarin Toledo-Aceves

Tropical montane cloud forests (TMCF) are under severe threat from deforestation, fragmentation and degradation. Several tree species are harvested and commercialized by local communities through unplanned selective logging. Lack of information regarding the growth rates of the most economically valuable timber species hampers the design of effective sustainable management schemes for TMCF. The objective of this study was to determine the diameter growth rates and evaluate the influence of tree size, crown class and neighbouring tree basal area on the growth of common and valuable TMCF timber species. Annual diameter growth was measured during two years in 60 trees (10 to 45 cm in diameter at breast height; dbh) each of Alnus acuminata, Liquidambar styraciflua and Quercus xalapensis, located in two unmanaged secondary TMCF sites in Veracruz, Mexico. High diameter growth rates (centimeter per year [cm yr-1]; mean ± SE) were recorded in the three species; the highest was recorded in A. acuminata (1.62 cm yr-1 ± 0.08 cm yr-1), followed by Q. xalapensis (0.91 cm yr-1 ± 0.07 cm yr-1) and L. styraciflua (0.71 cm yr-1 ± 0.08 cm yr-1). Diameter growth rate was inversely related to the basal area of the neighbouring trees, indicating a negative effect of competition in the three species. Dominant trees had higher growth rates than supressed trees in the three species. The high growth rates recorded in forests with no previous management and the negative effect of basal area of neighbouring trees support the potential for silvicultural management in secondary TMCF.


Author(s):  
D. McC. Newbery ◽  
J. S. Gartlan

SynopsisDiameter frequency distributions (dfds) of 197 tree species in Korup National Park and 118 tree species in Douala–Edea Forest Reserve (based onc.41 000 and 25 000 trees ≥ 30 cm gbh in 135 and 104 plots along four transects at each site, respectively) were individually classified into four groups of species according to their maximum diameters (≥99% trees <50, <70 and <90cm dbh, and > 1% ≥90cm dbh), and separated into two abundance classes (n≥50 andn= 20–49 (or 15–49). A fifth group, from those species in 3 and 4, was defined by a relative lack of small stems and given detailed attention. Dfds were evaluated for all species together on a transect and site basis, and compared for individual species across transects, and between sites for those group 5 species in common.Analysis focussed on three large ectomycorrhizal species in groups 3 and 4,Microberlinia bisulcata, Tetraberlinia bifoliolataandT. moreliana(Caesalpiniaceae), which were restricted to, and dominated, the forest on the nutrient-poor soils of transect P at Korup.M. bisulcata, the most abundant, was markedly group 5 in character, with very few small trees, whilst theTetraberliniaspecies had strong replacement potential. Although there were 27 species (42% of groups 3 & 4) at Korup and 19 (48%) at Douala–Edea in group 5,M. bisulcatawas unique in its combination of large size, dfd, mycorrhizal habit, spatial distribution and soil association. The potential replacement of this species was contrasted also with a non-ectomycorrhizal caesalp with similar dfd that occurred on nutrient-richer soils,Erythrophleum ivorense.Knowledge of the Caesalpiniaceae-richla forêt biafriéeneof Letouzey (which includes Korup and Douala–Edea) is reviewed, and the distribution, ecology and regeneration of the caesalps discussed. Structure and inferred dynamics of the forest at Korup are discussed with special regard to the ectomycorrhizal species.


2021 ◽  
Author(s):  
Martin Cheek ◽  
Jean Michel Onana ◽  
Sebastian Hatt

We revise and update the records of strict and near endemic species of the Bali Ngemba Forest Reserve, the largest known surviving patch (c. 8 km2 in area) of submontane or cloud forest in the Bamenda Highlands, Cameroon which have lost >96 % of their original forest due to human activities. Nine strict endemics, and 11 near endemics are now documented, a drop from the number recorded after the first survey in 2004, since when five of the provisionally named species have been formally published. We test the hypothesis that a further one of the provisionally named putative Bali Ngemba new species, Vepris sp. A, an 8 - 20 m tall tree from cloud forest in the 1310 - 1600 m altitudinal band, is indeed new to science. We compare it morphologically with other multicarpellate, apocarpous, trifoliolate Cameroon tree species formerly placed in the genus Oricia Pierre until they were subsumed into Vepris by Mziray (1992). These are Vepris trifoliolata (Engl.) Mziray and V. gabonensis (Pierre) Mziray. We conclude that Vepris sp. A is a new undescribed species here named as Vepris onanae. The new species is illustrated, mapped and its conservation status assessed as Endangered using the 2012 IUCN standard due to the threats of habitat clearance from agricultural pressures at its three locations all of which remain formally unprotected. Vepris onanae appears unique among the Guineo-Congolian African oricioid species of Vepris in occurring in cloud forest, the other species, apart from V. renierii of the Albertine Rift, occurring in lowland forest. It also differs in the very broad, (7.8 - ) 11.3 - 18 cm wide leaflets of the flowering stems which have a 6-18(-30) mm long, narrowly triangular acumen (vs leaflets <12 cm wide, acumen absent or short) and in having both subsessile and pedicellate (pedicels 0.25 - 0.3 mm long and 1( - 2) mm long) male flowers (vs male flower pedicels all sessile, or all c. 3 mm long). We report for the first time on stage-dependent leaf heteromorphy in Vepris and characterise a level of sexual dimorphism more advanced than usual in the genus.


Interação ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 413-428
Author(s):  
Nisângela Severino Lopes Costa ◽  
Fernando Cristovam da Silva Jardim ◽  
Raphael Lobato Prado Neves ◽  
Gustavo Schwartz ◽  
Luiz Fernandes Silva Dionisio

The natural regeneration dynamics of Theobroma subincanum Mart. (Malvaceae) around canopy gaps created by tree felling due to selective logging was assessed. For that, an experiment located in the Experimental Field of Embrapa Eastern Amazon in Moju municipality, PA, Brazil was carried out. Nine logging gaps were selected, and four strips of 10 m x 50 m were installed in each of these gaps following the cardinal directions. These plots were split in five 10 m x 10 m plots numbered from 1 to 5 from the gap’s border toward the forest. In plots 1, 3, and 5 and in the gap’s center 2 m x 2 m plots were installed to monitor individuals ≥ 10 cm in height and < 5 cm in DBH. In most of the variation factors analized, Theobroma subincanum presented higher recruitment rate in period 1 (1998-2000), since the competition for light were less intense. In period 2 (2000-2010), under a possible lower luminosity and higher competition, RR was lower for all factors analyzed. In relation to gap size, T. subincanum presented the best results in RR around medium size gaps. The distance of 20 m in relation to the gap center, with intermediary sunlight condititions, T. subincanum presented higher RR. The population of T. subincanum had better performance under intermediate light conditions.


2019 ◽  
Vol 48 (3) ◽  
pp. 417-425
Author(s):  
Md Khayrul Alam Bhuiyan ◽  
Md Akhter Hossain ◽  
Abdul Kadir Ibne Kamal ◽  
Mohammed Kamal Hossain ◽  
Mohammed Jashimuddin ◽  
...  

A study was conducted by using 5m × 5m sized 179 quadrates following multistage random sampling method for comparative regenerating tree species, quantitative structure, diversity, similarity and climate resilience in the degraded natural forests and plantations of Cox's Bazar North and South Forest Divisions. A total of 70 regenerating tree species were recorded representing maximum (47 species) from degraded natural forests followed by 43 species from 0.5 year 39 species from 1.5 year and 29 species from 2.5 year old plantations. Quantitative structure relating to ecological dominance indicated dominance of Acacia auriculiformis, Grewia nervosa and Lithocarpus elegans seedlings in the plantations whereas seedlings of Aporosa wallichii, Suregada multiflora and Grewia nervosa in degraded natural forests. The degraded natural forests possess higher natural regeneration potential as showed by different diversity indices. The dominance-based cluster analysis showed 2 major cluster of species under one of which multiple sub-clusters of species exists. Poor plant diversity and presence of regenerating exotic species in the plantations indicated poor climate resilience of forest ecosystem in terms of natural regeneration.


Alloy Digest ◽  
1982 ◽  
Vol 31 (12) ◽  

Abstract AISI Type S2 is a water-hardening tool steel with extreme toughness and resistance to shock loading. Even at a hardness of Rockwell C 59-60, it will bend before it breaks. When hardened in medium-size and large-size pieces, it acquires a hard case and a tough core. Sizes under 3/4-inch (19mm) diameter will water harden to the center. The extreme toughness of Type S2 makes it suitable for use in many applications where no other tool steel will hold up. Its many uses include chisels, rivet busters, spike mauls, screw drivers, punches and sledges. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: TS-408. Producer or source: Tool steel mills.


Author(s):  
Georgios Ermidis ◽  
Rasmus C. Ellegard ◽  
Vincenzo Rago ◽  
Morten B. Randers ◽  
Peter Krustrup ◽  
...  

The purpose of this study was to quantify the exercise intensity and technical involvement of U9 boys’ and girls’ team handball during different game formats, and the differences between genders. Locomotor activity (total distance, distance in speed zones, accelerations, and decelerations), heart rate (HR), and technical involvement (shots, goals, and duels) metrics were collected during various 15 min game formats from a total of 57 Danish U9 players (37 boys and 20 girls). Game formats were a small size pitch (20 × 13 m) with 3 vs 3 players and offensive goalkeepers (S3 + 1) and 4 vs 4 players (S4), a medium size pitch (25.8 × 20 m) with 4 vs 4 (M4) and 5 vs 5 (M5) players, and a large size pitch (40 × 20 m) with 5 vs 5 (L5) players. Boys and girls covered a higher total distance (TD) of high-speed running (HSR) and sprinting during L5 games compared to all other game formats (p < 0.05; ES = (−0.9 to −2.1), (−1.4 to −2.8), and (−0.9 to −1.3) respectively). Players covered the highest amount of sprinting distance in L5 games compared to all other game formats (p < 0.01; ES = 0.8 to 1.4). In all the game formats, players spent from 3.04 to 5.96 min in 180–200 bpm and 0.03 min to 0.85 min in >200 bpm of the total 15 min. In addition, both genders had more shots in S3 + 1 than M5 (p < 0.01; ES = 1.0 (0.4;1.7)) and L5 (p < 0.01; ES = 1.1 (0.6;2.2)). Team handball matches have high heart rates, total distances covered, and high-intensity running distances for U9 boys and girls irrespective of the game format. Locomotor demands appeared to be even higher when playing on larger pitches, whereas the smaller pitch size and fewer players led to elevated technical involvement.


Author(s):  
Maame Esi Hammond ◽  
Radek Pokorný ◽  
Daniel Okae-Anti ◽  
Augustine Gyedu ◽  
Irene Otwuwa Obeng

AbstractThe positive ecological interaction between gap formation and natural regeneration has been examined but little research has been carried out on the effects of gaps on natural regeneration in forests under different intensities of disturbance. This study evaluates the composition, diversity, regeneration density and abundance of natural regeneration of tree species in gaps in undisturbed, intermittently disturbed, and disturbed forest sites. Bia Tano Forest Reserve in Ghana was the study area and three gaps each were selected in the three forest site categories. Ten circular subsampling areas of 1 m2 were delineated at 2 m spacing along north, south, east, and west transects within individual gaps. Data on natural regeneration < 350 cm height were gathered. The results show that the intensity of disturbance was disproportional to gap size. Species diversity differed significantly between undisturbed and disturbed sites and, also between intermittently disturbed and disturbed sites for Simpson’s (1-D), Equitability (J), and Berger–Parker (B–P) indices. However, there was no significant difference among forest sites for Shannon diversity (H) and Margalef richness (MI) indices. Tree species composition on the sites differed. Regeneration density on the disturbed site was significantly higher than on the two other sites. Greater abundance and density of shade-dependent species on all sites identified them as opportunistic replacements of gap-dependent pioneers. Pioneer species giving way to shade tolerant species is a natural process, thus make them worst variant in gap regeneration.


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