Regeneration Of Woody Species Research Articles

Diversity and growth patterns of woody species in the Mediterranean Coastal range of Chile: A case study in Altos de Cantillana

Background: The Altos de Cantillana mountain range (ACMR) in central Chile is composed of different vegetation communities, and is currently a priority site for conservation, due to its high endemism, high anthropogenic pressure and vulnerability to climate change. Research on biodiversity and carbon stocks in ACMR is essential to comprehend the resilience of these forests and to define conservation strategies. This study examines the spatial variability of biodiversity and tree biomass patterns along the entire altitudinal gradient of the ACMR. Methods: Six tree species communities were studied in Altos de Cantillana Nature Sanctuary, along an altitudinal gradient ranging from 415 to 2010 m. Woody species regeneration and inventory plots, as well as dendrochronological sampling in ~150 trees were carried out. Diversity patterns were analyzed using the Jaccard index and alpha index. Growth patterns of dominant trees species were analyzed by ring-width and trunk biomass chronologies, focusing on the recent megadrought period since 2010. Results: The forest inventory revealed a notable decline in alfa diversity patterns with increasing elevation. The moist sclerophyllous forest exhibited the highest diversity. However, we did not find a pattern between elevation and diversity (and abundance) at the seed regeneration inventory level. Additionally, we identified three clusters of woody species similarity: (i) sclerophyllous, shrubs and hygrophilous forest (<1,000 m.a.s.l.); (ii) high-elevation sclerophyllous forest (>1,500 m.a.s.l); and (iii) deciduous forests (~ 2,000 m.a.s.l). Furthermore, declining growth rates were observed in all communities studied beginning in the 1980s, with even a stronger reduction in radial growth (35% on average) and biomass accumulation (56% on average) when comparing the megadrought with six decades earlier. Conclusions: We concluded that there is a negative correlation between woody species diversity and elevation. However, there are no altitudinal patterns in seedling regeneration diversity and abundance, which puts the natural succession in ACMR at risk. Additionally, we have determined that the accumulation of trunk biomass in dominant woody species has been significantly impacted by the recent megadrought period. This has affected the sink capacity of forest communities in ACMR. Therefore, our findings can significantly contribute to more efficient and timely decision-making processes regarding the conservation and restoration of this globally unique ecosystem.

Green deserts, but not always: A global synthesis of native woody species regeneration under tropical tree monocultures.

Tree monocultures constitute an increasing fraction of the global tree cover and are the dominant tree-growing strategy of forest landscape restoration commitments. Their advantages to produce timber are well known, but their value for biodiversity is highly controversial and context dependent. Therefore, understanding whether, and in which conditions, they can harbor native species regeneration is crucial. Here, we conducted meta-analyses based on a global survey of the literature and on a database created with local, unpublished studies throughout Brazil to evaluate the regeneration potential of native species under tree monocultures and the way management influences this regeneration. Native woody species regeneration under tree monocultures harbors a substantial fraction of the diversity (on average 40% and 68% in the global and Brazilian surveys, respectively) and abundance (on average 25% and 60% in the global and Brazilian surveys, respectively) of regeneration observed in natural forests. Plantations with longer rotation lengths, composed of native tree species, and located adjacent to forest remnants harbor more species. Pine plantations harbor more native individuals than eucalypt plantations, and the abundance of regenerating trees is higher in sites with higher mean temperatures. Species-area curves revealed that the number of woody species under pine and eucalypt plantations in Brazil is 606 and 598 species, respectively, over an aggregated sampled area of ca. 12 ha. We highlight that the understory of tree monocultures can harbor a considerable diversity of regenerating native species at the landscape and regional scales, but this diversity strongly depends on management. Long-rotation length and favorable location are key factors for woody regeneration success under tropical tree monocultures. Therefore, tree monocultures can play a role in forest landscape restoration and conservation, but only if they are planned and managed for achieving this purpose.

Teak (Tectona grandis Linn. f) and Edaphic Factors Affecting the Regeneration of Woody Species and Their Functional Traits in Economic Forest Plantation, Northern Thailand

Improved understanding of relationships among plant traits, stand characteristics, and soil properties can provide insights into the regenerating tree communities of commercial teak plantations. We investigated whether plant traits could be used to predict the natural regeneration of woody species in teak plantations with different soil and stand conditions. Data were collected in fifty 20 m × 20 m plots that were established in teak plantations of varying ages in northern Thailand. We analyzed differences in stand characteristics, soil properties, and community-level functional traits among sites. The RLQ analysis was performed to explore the associations among species abundances, plant traits, and a combined set of soil variables and stand characteristics. Our results showed that tree species with high leaf dry matter contents and high wood density dominated communities in an older teak plantation and were associated with high OM and N concentrations. Trees with larger leaves are increased in plantations that had experienced their first teak thinning, and were rich in organic matter. Species with high specific leaf areas increased in sites with high teak basal areas and which had experienced more intense thinning on fertile soils. Thick-leaved species had high importance values on sites with high densities of teak and infertile soils. Our results indicated that tree communities with similar conspecific traits were associated with specific soil and stand conditions in teak plantations. A knowledge of these regeneration dynamics may allow forest managers to encourage increased natural regeneration and enhanced diversity in commercial teak plantations.

Study of the Soil Seed Bank Composition in Arjo-Diga Humid Afromontane Forest under Different Land Use Types and Its Implications for the Restoration of Degraded Lands in Western Ethiopia

The soil seed bank present in forests serves as a crucial indicator of soil resilience following disturbances. The objective of this study was to investigate the composition, density, and vertical distribution of the soil seed bank in the Diga District of Western Ethiopia across four land use types: forestland, grassland, bare land, and shrubland. Soil samples were collected from plots measuring 225 square centimeters with a depth of 9 cm. A total of 108 soil samples were collected, representing the four land use types. Each plot was sampled at three different soil layers: 0–3 cm, 3–6 cm, and 6–9 cm depths. From the soil seed bank, 51 plant species were identified, with 46 (90.2%) being herbs, 3 (5.88%) trees, and 2 (3.92%) shrubs. The Asteraceae (13.30%), Poaceae (11.53%), and Fabaceae (9.61%) families exhibited the highest species composition, accounting for 38.44% of the total. Species richness varied significantly across all land use types and soil layers (p<0.05), with shrubland having the highest species richness and bare land having the lowest count. The total seed bank density in the soil across all plots was 92153 seeds/m2, with the highest density observed in the top 3 cm of the soil layer. The first and second soil layers exhibited a high Jaccard similarity coefficient of 0.76. Forestland and shrubland displayed the highest Jaccard coefficient of similarity (0.72), while the lowest was observed between bare land and shrubland (0.43). There was greater species similarity between the first and second soil layers (0.76) and lower similarity between the middle and bottom layers (0.32). The study found limited similarity between aboveground vegetation and the soil seed bank due to the low regeneration of woody species. Forestland and shrubland exhibited a high Jaccard similarity coefficient to aboveground vegetation, while grassland had the lowest similarity coefficient. Based on the findings, it can be concluded that the shrubland land use types had high soil seed bank composition and density. Therefore, the conservation of shrubs in the Arjo-Diga Forest should be considered for the restoration of degraded areas, taking into account the soil seed bank in the shrubland ecosystem.

A crop for a forest: Opuntia ficus-indica as a tool for the restoration of Mediterranean forests in areas at desertification risk

IntroductionThe Mediterranean is the European region with the lowest woody cover and the highest level of habitat degradation, being highly susceptible to climate change effects and desertification risk. In such worrying conditions, increasing woody cover and restoring forests is a major goal established in several international commitments. However, recruitment limitation of woody species is rather frequent both within natural regeneration processes and active restoration programs, particularly due to drought, overgrazing, and a lack of post-planting tending operations. Therefore, finding suitable tools to improve the recruitment success of native woody species is of crucial importance.MethodsWe assessed woody natural regeneration under abandoned prickly pear orchards, olive trees, and nearby open areas in three sites under high desertification risk in central Sicily (Italy). Then, we tested for differences in density, richness, diversity, height, and basal diameter of the woody recruiting species between these three habitats.Results and discussionNatural regeneration was widespread under prickly pear, with 94.6% of the sampled plots showing at least one recruit, in comparison to 61.6% of plots under olive and 22.3% in open areas. Natural regeneration density under prickly pears (114 ± 99 individuals m−2) was significantly higher (p < 0.001) than under olive trees (60.4 ± 76.4) and open areas (4.6 ± 9.3). Recruits’ diversity, basal diameter, and height were also significantly higher under prickly pear, concentrating 94.4% of the individuals higher than 100 cm and all late successional species. Our results indicate a great potential for prickly pears to accelerate the natural regeneration of Mediterranean woody species in pear instead of pears under desertification. However, a site-specific evaluation must be made taking into account prickly pear’s historical presence, temporary income as a crop, management capacity and, especially, its invasive potential.

Control of bracken by promoting regeneration of woody vegetation in the Yucatan Peninsula

In the tropical dry forest of the Yucatan Peninsula in southern Mexico, as in many parts of the Neotropics, deforested areas have been colonized by the highly competitive invasive bracken (Pteridium arachnoideum), which inhabits naturally regenerated and successional forests on abandoned farmland. The purpose of this study was to compare the efficiency of different treatments for the control of ferns through the mechanical removal of their fronds in rocky soils of the Yucatan Peninsula. In 2013, we implemented an experiment using different frequencies of cutting of ferns (cutting ferns every 30, 60, 90, and 120 days and control). One year after establishing experiment, data was gathered regarding bracken rhizome biomass, basal area, height, density, and species richness of naturally regenerating vegetation for all treatments. As expected, the lowest rhizome biomass was achieved with the 30- and 60-day cutting treatments and the fern control had a positive effect on the regeneration of woody species. We conclude that promotion of natural regeneration following agricultural land use may be essential for long-term elimination of bracken.

Facilitation by pioneer trees and herbivore exclusion allow regeneration of woody species in the semiarid ecosystem of central Chile

AbstractQuestionsFacilitation by pioneer plants and herbivore exclusion may contribute to plant regeneration and restoration of degraded semiarid ecosystems. In this study we evaluated the main and interactive effects of the exclusion of large and medium‐sized mammal herbivores and the presence of the pioneer tree Vachellia caven on natural regeneration of woody species in degraded savannas.LocationTwo localities of the native sclerophyllous forest of central ChileMethodsTwelve 30 × 40 m exclosures and twelve non‐exclosure areas located near native forests were established in savannas of V. caven in each locality. Regeneration coming from seeds and resprouts was sampled both under the canopy of V. caven and without canopy in each exclosure and non‐excluded area.ResultsAfter seven years, species richness and density of older regeneration (0.5–2 m high) were positively affected by herbivore exclusion and the presence of V. caven. No significant interaction between herbivore exclusion and V. caven was observed. Younger regeneration (<0.5 m high) was positively affected by herbivore exclusion and the presence of V. caven only in some years with almost no interactive effect.ConclusionsThe exclusion of large and medium‐sized exotic herbivores and facilitation by pioneer trees are complementary for regeneration. The variable but permanent presence of younger and older regeneration within exclosures and under V. caven during the experiment may lead to an increase of density and diversity of adult plants and recovery of the native forest. However, this process may be slow due to other limiting factors, for instance, reduced precipitation associated with climate change.

Woody species diversity and regeneration status of Sub-Alpine forest of Mount Adama exclosure site, Northwestern highlands of Ethiopia

Forests provide a wide range of ecosystem services. Despite these facts, the expansion of agriculture and settlement at the expense of forest resources has threatened the forest resources and results in biodiversity loss. To halt this problem, various conservation practices that believed to restore the degraded lands and biodiversity of the country have been implemented. Area exclosure is among the conservation strategies that have been used to restore the degraded lands in Mount Adama forest. However, its role in woody species regeneration in Mount Adama was not investigated. Thus, the objective of the study was to evaluate the impact of area exclosure on woody plant species composition, regeneration status, structure and diversity in Mount Adama. A systematic transect sampling method was used to collect vegetation data. Hence, 53 plots with 400 m2 area were laid along 11 transects. Then, within the main plots, five subplots with 1 m2 were laid to determine the abundance and frequency of seedlings. The results showed that about 31 woody species that belong to 30 genera and 19 families including four endemic species were identified. The majority (67.74%) of the species were categorized under shrub habitat, while the remaining 19.35% and 12.90% were trees and lianas or climbers, respectively. Asteraceae family was dominant by contributing 4 species followed by Rosaceae and Solanaceae each contributed 3 species. Hypericum revolutum was the dominant species with 53.38 important value index followed by Erica arborea and Hagenia abyssinica with 49.12 and 40.05, respectively. The overall Shannon- Wiener diversity index and Shannon evenness in the exclosure site were 2.6 and 0.73, respectively. Furthermore, the number of seedlings and saplings were higher in the exclosure than the untreated site. The results of the study evidently showed that area exclosure that implemented in Mount Adam successfully contributed to the biodiversity restoration. Therefore, further conservation efforts targeting species with low IVI values are needed for sustainable management and ecological recovery of the area.

Early vegetation recovery following a mid to high‐severity fire in the Andean‐Patagonian forests

AbstractA change in fire regimes is occurring worldwide, affecting post‐fire succession. Under this context, there is an increasing need to prioritize restoration areas and focus on their particular goals. To assess the emergent understorey represents the first approximation of post‐fire re‐vegetation, necessary to establish appropriate restoration guidelines. In this study, we aimed to assess the initial post‐fire response in a mid to high‐severity fire in the Andean‐Patagonian forests. We (1) compared plant community structure among fire severities, (2) evaluated the response of plant community structure to the interaction between fire severity and forest type, (3) compared plant composition among fire severity‐forest type categories and (4) evaluated woody species regeneration after fire. We found that the vegetation cover of the lower stratum began to recover early after the fire and to a greater extent in mid than in high severity, whereas the upper stratum was incipient in the mid and nil in high severity. Native species predominated in burned and unburned plots, although they were less in the burned plots. Among the growth form, shrubs and trees were similarly affected by fire, independently of the forest type. Plant community composition varied among most fire severity‐forest type categories. The frequency of woody species regenerated by resprouts and by seeds was lower in burned than unburned plots. These results suggest that although there is an early recovery of vegetation, the high cover of exposed soil and the loss of the upper vegetation stratum may favour erosion and difficult tree establishment. Besides, tree species that only regenerate from seeds will probably not recover naturally. In addition, the presence of exotic species with high invasive risk may need control. Thus, since fire severity and forest type may drive different post‐fire natural recovery scenarios, different restoration actions should be taken to promote resilient systems for the future.

Forest canopy and mistletoe infestation alter the facilitative effects of Juniperus oxycedrus s.l. on woody seedlings on Mount Lebanon (Lebanon)

AbstractQuestionsIn this study we investigated the direct effect of the shrub Juniperus oxycedrus s.l. on Mediterranean woody species regeneration, and how this interaction can be modified by the juniper habit, the forest canopy and/or infestation of the juniper by the plant parasite Arceuthobium oxycedri. We also aimed at identifying species response groups in relation to their ecological requirements and successional strategies.LocationNorth of Mount Lebanon, in Horsch Ehden natural reserve, a humid montane Mediterranean forest.MethodsWe compared the regeneration of all occurring woody species below and outside 111 Juniperus oxycedrus canopies using the random pair sampling method. We calculated eight relative interaction intensity indexes (RIIJuniper) corresponding to the eight treatment combinations of the three factors: forest canopy (forest/gap), mistletoe infestation (with/without) and juniper habit (spreading/erect). We analyzed the RII values at three different levels: community (all species grouped), species group and species.ResultsOverall, the regeneration of the woody community was facilitated by Juniperus oxycedrus. However, the forest cover significantly reduced the facilitative effect of Juniperus oxycedrus when the latter was not infested by Arceuthobium oxycedri. We identified three species response groups (A: highly facilitated; B: slightly facilitated to neutral; and C: neutral) determined by their response to both Juniperus oxycedrus canopy and forest cover. The most facilitated species were shade‐tolerant/drought‐intolerant late‐successional species.ConclusionsThe results suggest the importance of shade tolerance in the complex mechanism of forest regeneration that is also affected by a parasite plant (Arceuthobium oxycedri), which boosts regeneration dynamics under forest cover by reducing shrub canopy cover.

Investigation of Woody Species Structure and Regeneration Status in the Central Rift Valley, Sidama Regional State, Ethiopia

Protected areas are the most commonly used tool for in situ conservation of biodiversity. Selective removal of species proposed by the local communities living surrounding the national park and grazing pressure negatively affect the composition, structure, and regeneration of woody species. Assessment of vegetation structure and regeneration status of woody species is essential for orienting management activities. The purpose of this study was to investigate the floristic composition, population structure, and regeneration status of woody species in the Loka Abaya National Park, to design conservation strategies. A total of 99, 20 m × 20 m quadrats were systematically laid along an established line transect to collect a list of woody species, abundance, height, and diameter at breast height (DBH), while five 3 m × 3 m subquadrats within the main quadrats were established to assess the regeneration status of woody species. In each quadrat, all woody species were identified, counted, and recorded. In each quadrat, all tree and shrub species higher than ≥2 m in height and ≥2 cm in diameter at breast height were measured by a calibrated wooden stick and by a caliper, respectively. Density, frequency, basal area, importance value index (IVI), height, and diameter at breast height (DBH) were used for description of vegetation structure, while the density of mature trees, saplings, and seedlings was used for assessment of regeneration status of woody species. A total of 101 woody plant species representing 40 families in 69 genera were collected, identified, and documented. Fabaceae was the most diverse family representing 16 (15.84%) species, followed by Euphorbiaceae 9 species (8.91%) and Anacardiaceae with 6 species (5.94%). Four families including Combretaceae, Moraceae, Olacaceae, and Tiliaceae were represented by 4 species each. 4 families were also represented by 3 species each, 12 families were represented by two species each, and 18 families were represented by one species. The density of trees was 831.31 individuals ha−1, while the total basal area was 73.18 m2·ha−1. D. angustifolia, C. molle, E. schimperi, R. natalensis, O. europaea L. subsp. cuspidataD. cinerea, A. brevispica, I. mitis, and E. tirucalli were ecologically important woody species. The majority (75%) of woody plant species had a less than 5% importance value index (IVI). The diameter class distribution of selected tree species demonstrated various patterns of population structure, implying the existence of different population dynamics among ecologically important tree species. The regeneration assessment results demonstrate that 32.35% had poor regeneration, 19.12% had good regeneration, 16.17% had fair regeneration, 8.82% lacked regeneration, and 14.08% appeared as newly regenerated species in the national park. The majority of woody species had a small population size, and some of them were found in specific habitats which need attention for conservation, and those woody species lack regeneration study soil seed bank and propagation methods for sustainable conservation.

Restoration of diversity and regeneration of woody species through area exclosure: the case of Maun International Airport in northern Botswana

Background and objectives: Deforested and degraded areas can be cheaply and conveniently restored through establishment of exclosures. An area exclosure excludes animals and humans from accessing an area to promote natural regeneration of plants and rehabilitate ecological condition of the area. The study was aimed at: (1) determining the diversity (species richness, diversity and evenness); (2) assessing the stand structure (densities); and (3) assessing regeneration status of woody species inside and outside exclosed Maun International Airport, northern Botswana. Methods: Vegetation sampling was conducted from April to May 2018. A total of 48 and 37 quadrats of 20 × 20 m were laid down at 50 m intervals along transect lines inside and outside Maun International Airport, respectively. Identity, number of all live individuals and height of all woody species were recorded in all the quadrats. The diversity of all woody species was analysed by using the Shannon Diversity Index (H’) and regeneration status of each woody species was assessed using frequency distribution of height class. Results: The diversity, evenness and species richness were significantly higher inside than outside Maun International Airport. Colophospermum mopane was the most abundant species both inside (75% of all woody species) and outside (96% of all woody species) Maun International Airport. More species showed more regeneration inside than outside Maun International Airport. The inside of Maun International Airport recorded more alien invasive woody species compared with the outside, owing to its original use as a residential area. The local communities might have introduced these species as ornamental trees. Conclusion: This study, while limited in scale, contributes to understanding of the role of exclosures in enhancing woody species richness, diversity and evenness as well as facilitating regeneration of woody species. Degraded woodlands and other similar ecosystems could be cheaply and conveniently restored through establishment of exclosures, but more research and monitoring are required to fully understand the processes and impacts.

Does exclosure restore woody species regeneration in degraded lands? The case of Loma Bosa District of Dawuro zone, Southwestern Ethiopia

Exclosure becomes popular as a naming of the practice of excluding degrading agents from degraded lands for natural rehabilitation. However, its role on woody species regeneration in the Loma Bosa District of the southwestern Ethiopia has not been investigated. Therefore, this study examines the role of exclosure on woody species regeneration by comparing exclosure, open woodland, and degraded land areas. A systematic transect sampling method was employed to collect vegetation data in sampling quadrats, each with a size of 20 × 20 m, evenly distributed along parallel transect lines. All the woody plant species in each plot were identified and measured for DBH and height. Twenty-six woody species, representing 16 plant families, were recorded at the study area, of which only eight were recorded all in the exclosure, open woodland and open degraded land. Species Diversity Index (H′) was 2.62, 2.38, and 1.56 for woody species in exclosure, open woodland area, and open degraded land area. Wood species density were 2225 ha−1, 1642 ha−1, and 297 ha−1 for exclosure, open woodland area, and open degraded land area, respectively. The distribution of the height and DBH of the recorded species in exclosure exhibited an inverted “J” shape pattern suggesting a healthy regeneration status of the important species, while others revealed irregular and less interpretable pattern. Overall results from this study indicated that exclosure is important for improvement of woody species regeneration in degraded lands in the study area.

Natural regeneration of woody plant species along an elevational and disturbance gradient at Mt. Kilimanjaro

The continuous decline and degradation of tropical rainforests is currently mainly driven by land-use change. Over the long term, climate change will further exacerbate the situation for the remaining forests. To develop sustainable conservation strategies, we need to understand the natural forest-recovery potential after disturbance and the impact of climate on forest recovery. So far, little is known about regeneration of woody species in tropical landscapes, especially in tropical Africa. We investigated the regeneration of woody plant species in six natural and seven anthropogenically disturbed habitat types along a 3.6 km elevational gradient from savanna woodland to afro-alpine vegetation at Mt. Kilimanjaro, Tanzania. We recorded and identified all saplings of woody plants in a total of 65 plots, each measuring 100 m2. The total number of recorded sapling individuals amounts to 4,738 saplings from 110 species of 50 families. Along the elevational gradient, sapling numbers in natural plots showed a hump-shaped distribution peaking at mid elevation, where rainfall and overall woody biomass were highest, while species number and diversity of saplings were continuously decreasing with increasing elevation. The sapling layer in the savanna zone had three times as many species as the layer of adult trees and shrubs in the same plots, but the species composition of saplings differed strongly from the one of trees and shrubs, indicating strong spatial or temporal heterogeneity. Active agricultural plots at lower elevations also showed natural regeneration of woody species, even though numbers of sapling individuals and species were much lower than in natural low-elevation plots. Forests formerly disturbed by fire and logging showed either comparable or even increased numbers of sapling individuals and species than natural plots at the same elevation, indicating ongoing succession. Finding regeneration of woody species in all disturbed habitat types, even in agriculturally managed habitats, strongly suggests that natural regeneration is a very powerful tool to recover forest diversity after disturbances. Furthermore, our sapling dataset provides an important baseline for future monitoring of the consequences of climate and land-use change on regeneration.

Vegetation Pattern and Regeneration Dynamics of the Progressively Declining Monotheca buxifolia Forests in Pakistan: Implications for Conservation

Monotheca buxifolia (Falc.) A. DC., a wild edible fruit-yielding tree species, has economic and ecological importance, yet there is a lack of studies concerning its distribution pattern and regeneration dynamics at a larger-scale. This study aims to produce the first country-level classification of Monotheca forests based on their unique floristic composition and influential abiotic factors, besides their natural regeneration dynamics, across the environmentally diverse landscapes in Pakistan. For this purpose, floristic inventory was carried out in 440 plots where environmental variables, stand dendrometric characteristics and woody-species regeneration were recorded. During this survey, 3789 individuals of 27 woody tree species belonging to 25 genera and 22 families were sampled. These native and exotic tree species were mostly dicot (73%) with predominately mega-phanerophytic (88%) lifeforms, which largely reflect strong chorological differentiation and distinct linkage (55%) to the Sino-Japanese phytogeographical region. M. buxifolia and co-occurring species exhibiting similar environmental affinities were grouped into four ecologically distinct communities by Ward’s cluster analysis. Ordinations further highlight the special effects of topographic and edaphic factors besides anthropogenic interference on the sampled plots. Generally, Monotheca stands were moderately dense, with the average density varying considerably, ranging from 296 to 325 individuals/ha, with basal area ranging from 41.26 to 93.35 m2 ha−1. In the understory stratum, natural regeneration of Monotheca was mostly scant and mainly covered by Dodonaea shrubs. Size class structure of the dominant species shows pronounced effect of anthropogenic intervention as reflected by the presence of fewer individuals of juveniles and larger trees. Overall, the cut stump frequency was higher at juvenile and mature stages, which may be attributed to over-harvesting and extraction of fuelwood apart from the adverse effect of climate change in the region. We concluded that both topographic and edaphic factors coupled with biotic interventions are more influential in the distribution and persistence of M. buxifolia and co-occurring woody species and might be considered in its restoration and conservation. Thus, we recommend an urgent management plan to favor Monotheca regeneration for allowing the renewal of these rapidly declining remnant stands in Pakistan.

Woody Species Diversity, Community Structure, and Regeneration Capacity in Central Ethiopian Urban Forest Patches

Land cover change in Addis Ababa, Ethiopia’s capital, is driven by recurring drought and the economic problems of society-initiated afforestation. The goal of this study was to learn about the state of woody species regeneration in Yeka’s urban forest patches. Thirty plots (20 m × 20 m in size) were sampled to identify plants for this purpose. All wooden trees with a height greater than 1.3 m in each plot were identified, enumerated, and their diameter were measured. Acacia decurrens was determined to be the predominant species, with an importance value index (IVI) of 161.09, followed by Acacia melanoxlon (IVI = 44.69). The bootstrapping PERMANOVA test was used to show how the species in the community overlapped. The result reveals that dissimilarity is low (p > 0.05), which is supported by the assumption of multivariate dispersion homogeneity. The area’s generalized linear model (GLM) showed all species statistically significant for characteristics associated with closure year and presence of mature trees and the entire closure year. Two of the twenty tree species, i.e., Acacia decurrens and Acacia melanoxylon were found in nearly equal numbers in all three growth stages as well as having strong regenerating potential. The rapid expansion of exotic Acacia spp. necessitates careful attention to their regeneration. To reinforce and improve ecosystem services, conservation and restoration efforts should encourage the regeneration of native plant species.

Woody species regeneration through exclosure and perception of local community on mountain Damota, Wolaita, Ethiopia

Restoring the degraded lands through the area exclosure has been practiced and promoted widely in different parts of Ethiopia for the past three to four decades. However, the effectiveness of the approach both in terms of supporting woody species regeneration and the socio-economic conditions around the Wolaita area has not been well studied. We assessed the regeneration status of woody species in seven years old exclosure area and the perception of the local community towards the area exclosure on Damota Mountain in Southern Ethiopia. Vegetation inventory was made in 15 (20 × 20 m) quadrats laid following two transect lines running parallel. Systematically selected 71 households from the surrounding villages were interviewed and group discussions were also made. A total of 26 species from 19 families, with a total density of 2864 individuals (DBH ≥ 2 cm) per hectare were recorded. The basal area, Shannon diversity index, and evenness in the area exclosure were 15.84 m2/ha, 2.54, and 0.39, respectively. The importance value index (IVI) revealed that Maesa lanceolata, Ozoroa insignis, Maytenus arbutifolia, Nuxia congesta, Rhamnus prinoides, and Rapanea simensis were the most dominant species. About 87.3% of the respondents support further expansion and management of the area exclosure whereas the remaining 12.7% were against the intervention. All interviewed agree on the improvement of the vegetation cover since the establishment of the exclosure. However, all wanted improved access to the grass in the exclosure area so as to use it in a cut-and-carry system. We conclude that exclosure-biological-social issues need to be handled carefully to make the effort of using area exclosure for degraded land management effective and sustainable.

Variation in soil seed bank and relationship with aboveground vegetation across microhabitats in a savanna‐woodland of West Africa

Soil seed bank (SSB) characteristics may vary with habitat heterogeneity. We investigated the SSB density in three microhabitats (under canopy, eroded soil and bare soil) in five vegetation types (abandoned farm, dense woodland, gallery forest, grassland and open woodland) at varying soil depths (0–5, 5–10 and 10–15 cm) in a savanna‐woodland in Burkina Faso, West Africa. Total germinable SSB densities varied between 4 and 308 seeds per dm3 of soil. Herbaceous taxa were the major constituent of the germinable SSB across the microhabitats, regardless of vegetation type. Seedlings of 30 species emerged from the SSB, of which 24 were annual species and only 4 woody species, indicating that natural regeneration of woody species via seed dispersal is limited. Both microhabitat and vegetation type contributed to the variation in taxa richness, and germinable seed density and diversity. There was a significant difference in SSB density and richness between microhabitats in the different vegetation types (p < 0.05). The SSB densities were higher under tree canopies than outside tree canopies (eroded soil and bare soil) and highest in the upper soil layers in all vegetation types. The aboveground vegetation (AGV) and flora within the SSB shared many herbaceous species but many woody species present in the AGV were absent in the SSB. Under tree canopies are the ecological niches that favor accumulation of a diversity of seeds, suggesting the preservation and conservation of adult trees in savanna‐woodland ecosystems is critical to facilitating the restoration of these ecosystems.

Factors Influencing the Adoption of Area Closure Practices in Loma Bosa District of Dawuro Zone, Southwestern Ethiopia

ABSTRACT This study aims to assess the role of area closure on the improvement of regeneration and composition of woody species in the Loma Bosa district of Dawuro zone, southwestern Ethiopia. It also examines factors affecting the adoption of area closure practices in the study area. The study confirmed that the socio-economic characteristics of the household have an incredible role on the adoption of area closure practices. Establishment of area closure has several benefits; among these, it improves the regeneration of woody species abundance, the ecological balance of the micro-environment, economic benefits for human beings, improves land productivity and minimizes land degradation and soil erosion. This study focuses on three key factors of disturbance for the area closure: illegal cutting of trees and shrubs, overgrazing, and wildfire. In line with this, the study observed a significant difference in farmers’ perception on the level of disturbance regime between the closed and open woody land areas. This paper indicates that area closure establishment is a key pathway for improving the regeneration and composition of woody species over the other benefits. Econometric results indicate that age, education level, family size, landholding, number of livestock owned, and access training are the main factors affecting the adoption of area closure practices.

Effects of logging on the trade-off between seed and sprout regeneration of dominant woody species in secondary forests of the Natural Forest Protection Project of China

BackgroundPromoting natural regeneration (including seed and sprout regeneration) of dominant woody species is essential for restoring secondary forests. However, such restoration processes have been decelerated by the enclosure under Natural Forest Protection Project of China (NFPP). It remains unclear how to implement appropriate management measures (e.g., whether to apply logging and the suitable intensity) to facilitate natural regeneration according to the responses of two regeneration modes to management measures. We monitored the early stages of seed regeneration (seed rain, soil seed bank, and 1–3-year-old seedlings) and sprout regeneration (stump sprout rate, stump survival rate, probability of sprouting, and number of sprouts per stump) over the first 3 years (2017–2019) after logging under three intensity regimes (control [0%], 25%, and 50% logging intensity) in secondary forests.ResultsThe seed rain density decreased markedly, seedling density increased insignificantly after logging, and logging promoted seedling survival at an increasing conversion rate of 3-year-old seedlings (37.5% under 0%, 100% under 25%, and 80.95% under 50% logging) compared to those of the control. The proportion of 3-year-old seedlings increased with logging intensity and was the highest (16.2%) at 50% logging intensity. Sprout density was not affected by logging intensity, however, under 25% and 50% logging, it decreased by 27% and 6% in 2018, and by 37% and 33% in 2019, respectively. Seedling density was 41.65- and 15.31-fold higher than that of sprouts in the 50% and 25% logging treatments, respectively. Based on the relative contributions of the two regeneration modes after logging, three groups of natural regeneration patterns were classified for dominant woody species in temperate secondary forests, i.e., seed regeneration preference (Betula dahurica, Carpinus cordata and Fraxinus mandshurica), sprout regeneration preference (Acer mono and Acer pseudosieboldianum) and no preference (Quercus mongolica, Fraxinus rhynchophylla, and Juglans mandshurica).ConclusionIn addition to enclosure, appropriate logging can be applied according to the responses of various natural regeneration patterns of dominant woody species to logging in temperate secondary forests under the NFPP.