Woody Plant Regeneration Research Articles

Effects of community structure of Cunninghamia lanceolata sprouting forests with different densities on ecosystem carbon density at the early stage of succession.

To explore potential responses of ecosystem carbon density to changes of community structure during natural regeneration of woody plants, we analyzed the relationships between ecosystem carbon density and its components, tree species diversity, structural diversity (CVDBH) and spatial structure parameters (mingling, aggregation, dominance, crowding) of Cunninghamia lanceolata forests with different sprouting densities (1154, 847 and 465 individuals·hm-2) at the early stage of succession in Baishanzu National Park. The results showed that tree species diversity (species richness index and Shannon diversity index) increased with the decrease of sprouting density of C. lanceolata. Among the stand structural parameters, CVDBH, stand density, and mingling increased with the decrease of sprouting density of C. lanceolata. The stand distribution pattern of different C. lanceolata densities was uniform, with sub-dominant stand growth status and relatively dense status. The carbon density of tree layer under high, medium, and low sprouting densities of C. lanceolata were 57.56, 56.12 and 46.54 t·hm-2, soil carbon density were 104.35, 122.71 and 142.00 t·hm-2, and the total carbon density of ecosystem were 164.59, 182.41 and 190.13 t·hm-2, respectively. There was little variation in carbon density of understory layer and litter layer among different treatments. The carbon density distribution characteristics of different C. lanceolata densities were following the order of soil layer (63.4%-74.7%) > tree layer (24.5%-35.0%) > understory layer and litter layer (0.8%-2.0%). The results of variance partitioning analysis indicated that the change of tree layer carbon density was mainly influenced by stand structure diversity, soil layer carbon density was influenced by both tree species diversity and stand structure diversity, while ecosystem carbon density was mainly influenced by tree species diversity. Stand spatial structure parameters had a relatively little effect on ecosystem carbon density and its components. The sprouting density of C. lanceolata significantly affected ecosystem carbon accumulation during the conversion from C. lanceolata plantations to natural forests. A lower remaining density of C. lanceolata (about 500 individuals·hm-2) was more conducive to forest carbon sequestration.

Effects of Selective Harvesting on Diversity, Structure, and Regeneration of Woody Plants in Mixed Plantation of Menagesha Suba Forest, Central Ethiopia

Effects of Selective Harvesting on Diversity, Structure, and Regeneration of Woody Plants in Mixed Plantation of Menagesha Suba Forest, Central Ethiopia

Structure, regeneration and carbon stocks of woody plants in the Litwang’ata village land forest reserve, Southwest Tanzania

Abstract The plant biodiversity status of many village land forest reserves is little known to support meaningful implementation of sustainable forest management objectives in Tanzania. This study was conducted to assess the status of Litwang’ata village land forest reserve in Ludewa district, Southwest Tanzania through 20 square sample plots of 10 × 10 m. A total of 20 woody plant species belonging to 12 families and 19 genera with DBH ≥ 5 cm were identified in the study forest. The most important species with their importance value index were Brachystegia spiciformis (78.02), Brachystegia boehmii (22.05), Faurea saligna (15.18), Uapaca kirkiana (14), Acacia amythethophylla (13.07), Pseudolachnostylis maprouneifolia (12.76) and Gardenia ternifolia (10.36). The forest had a Shannon diversity index (H´) of 2.27, indicating medium diversity. Stand structure comprised 1,330 ± 523 stems ha–1, basal area of 18.97 ± 6.81 m2 ha–1 and stand volume of 142.36 ± 52.17 m3 ha–1. The mean above- and belowground carbon stocks were 46.97 ± 17.23 Mg ha–1 and 23.90 ± 8.58 Mg ha–1 respectively. The higher tree densities, basal area, stand volume and carbon stocks recorded in this study compared to other Miombo woodlands indicate that Litwang’ata forest is still in good condition, and managment efforts should be strengthened to bolster biodiversity conservation for present and future generations.

Impacts of environmental conditions on woody plant diversity, structure and regeneration in forest patches of Guna Mountain: Este District, South Gondar Zone, Ethiopia

Impacts of environmental conditions on woody plant diversity, structure and regeneration in forest patches of Guna Mountain: Este District, South Gondar Zone, Ethiopia

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.

Species Diversity, Structure, and Regeneration Status of Woody Plants in Saleda Yohans Church Forest, South Wollo, Ethiopia.

The study was conducted to determine woody plant species composition, structure, and regeneration status in Saleda Yohans Church forest, South Wollo Zone, Ethiopia. Five transect lines oriented to north-south directions at a distance of about 500 m were laid down along transects across the forest. Fifty main plots of 20 m × 20 m were laid for tree/shrub data collection. Within each main plot, 5 small quadrats of 5 m × 5 m were laid in the corners and centre for the collection of seedling and sapling data of woody species. All vegetation data within the plots were counted and recorded. Tree height and diameters at the breast height of plants were also measured and estimated. Moreover, frequency, basal area, diversity, evenness, and other vegetation data were analyzed. The result showed that this Church forest is composed of 50 woody plant species distributed in 31 families. The Shannon-Wiener diversity index and evenness values of the forest were found to be 3.82 and 0.84, respectively. Lamiaceae was the dominant family followed by Fabaceae in their species composition. The density of trees/shrubs, saplings, and seedlings was 625, 650, and 935 ha-1, respectively. Based on the result, the entire vegetation of Saleda Yohans Church forest is in good regeneration status. In conclusion, although this Church forest appears to be in a good regeneration status, its species richness is low compared to a similar study of some other vegetation. Therefore, attention should be given to the rehabilitation of this forest.

Regeneration characteristics and influencing factors of woody plant on natural evergreen secondary broad-leaved forests in the subtropical, China

Natural regeneration occupies an important position in forest ecosystems and is affected by various factors. Exploring natural regeneration and its influencing factors is helpful to understand the forest community dynamic. Evergreen broad-leaved forest is an essential zonal vegetation type in China. However, the natural regeneration of evergreen broad-leaved forests in the northernmost margin of subtropical zone has not been reported. Here we investigated 22 observed variables, and selected four categories of latent variables stand factor, topographical factor, soil factor and tree diversity as influential factors based on the survey data of 50 (20 m × 20 m) permanent sample plots. The structural equation model was introduced to distinguish the direct, indirect and total effect of influencing factors on understory woody plant regeneration diversity and regeneration density, respectively. We found 51 regeneration species under 31 families and five dominant species Loropetalum chinense, Symplocos sumuntia, Quercus glauca, Ilex chinensis, and Eurya japonica in the study area. Soil factor was the primary control of regeneration, which had the greatest and negative total effect on regeneration diversity (-0.436) and regeneration density (-0.298). The main soil factors that affected regeneration diversity and regeneration density were total phosphorus and soil organic matter, respectively. Soil factor mainly affected indirectly regeneration by mediating through its impacts on tree diversity. Tree diversity and topographical factor all were significantly positively correlated with the regeneration diversity and regeneration density. Stand factor had a significantly negative correlation with regeneration density but a significantly positive with regeneration diversity. Our study provides the basis to introduce appropriate artificial auxiliary measures for improving the natural regeneration of forest stands, so as to promote sustainable forest management.

Relationship between stand and regeneration of Picea obovata Ledeb. and Abies sibirica Ledeb. in the primary and secondary forests of the Southern Ural Mountains

The aim of the research is to reveal the relationship between the age and composition of the forest stand and the regeneration of Picea obovata Ledeb. and Abies sibirica Ledeb. Null hypothesis: we can estimate young generations of P. obovata and A. sibirica under the forest canopy based on the composition and age of the forest stand. The studies conducted in the most widespread forest type of the South Ural Mountains confirmed our null hypothesis about the possibility of modelling the regeneration of P. obovata and A. sibirica by the structure of the stand. The number of young generations of P. obovata and A. sibirica showed high sensitivity to the age and composition of the stand. The graphical models developed by us can be used to combine with forest management data in order to obtain large-scale data on the regeneration of woody plants in the primary spruce small-grass-green mossy forests and secondary birch and aspen forests of the South Ural Mountains. In order to expand the scope of application of the developed models, it is planned to conduct additional studies for other forest types of the Urals.

Area exclosure with moisture harvesting structures relative to only exclosure facilitates the restoration of woody plants in a degraded area in Alaba Kulito, Southern Ethiopia

<p>The study aimed to evaluate the effect of area exclosure established in a degraded area with moisture harvesting structures (EX-SWC) relative to the adjacent exclosure area without moisture harvesting structures (EX) in restoring the woody plants. Vegetation data from a total of 30 plots that has an area of 20 m x 20 m, in the EX-SWC and the adjacent EX area were collected, independently. The density of trees and seedlings, diversity, vegetation structure and Importance Value Index (IVI) were analysed. Pearson’s correlation was also used for the data analysis. The Shannon diversity index was 1.6 and 1.57 in the EX-SWC and EX area, respectively. The relative density of trees (578 stems/ha) and seedlings (1530 stems/ha) in the EX-SWC area were relatively higher than the relative density of trees (466 stems/ha) and seedlings (1202 stems/ha) in the adjacent EX area. There was no significant relationship between the number of moisture harvesting structures established in each plot and the relative density of seedlings per plot (p <0.05, R<sup>2</sup>=0.18). The relative density of seedlings at the lower height classes (1 – 60 cm) in the EX-SWC area was relatively higher than the adjacent EX area. The IVI result for most of the recorded species in the EX-SWC area was also relatively higher than in the EX area. The overall results showed that the implemented moisture harvesting structures facilitated the regeneration of woody plants in the degraded area. Therefore, we recommend implementing soil and water conservation structures in degraded area restoration projects to facilitate the regeneration of woody plants. </p>

Transcriptome analysis reveals the effects of strigolactone on shoot regeneration of apple

We have demonstrated that strigolactone inhibitor, Tis108, could be used to improve shoot regeneration of apple, and provided insights into the molecular mechanism of strigolactone-mediated inhibition of adventitious shoot formation. Lack of an efficient transformation system largely stagnated the application of transgenic and CRISPR technology in apple rootstock. High shoot regeneration ability is an important basis for establishing an effective transformation system. In this study, we first demonstrated the inhibitory effects of strigolactones on the adventitious shoot formation of apple rootstock M26. Next, we successfully verified that strigolactone-biosynthesis inhibitor, Tis108, could be used to improve the shoot regeneration of woody plants. Our results also suggest strigolactone-biosynthesis gene, MdCCD7, can be a target gene for biotechnological improvements of shoot regeneration capacity. Furthermore, we have employed transcriptome analysis to reveal the molecular mechanism of strigolactone-mediated inhibition of adventitious shoot formation. Differentially expressed genes associated with photosynthesis, secondary growth, and organ development were identified. WGCNA suggests SLs might affect shoot regeneration through interaction with other hormones, especially, auxin, cytokinin, and ethylene. We were able to identify important candidate genes mediating the cross-talk between strigolactone and other hormones during the process of adventitious shoot formation. Overall, our findings not only propose a useful chemical for improving shoot regeneration in practice but also provide insights into the molecular mechanism of strigolactone-mediated inhibition of adventitious shoot formation.

Floristic Composition, Vegetation Structure and Regeneration Statues of Woody Plant Species of Sheleko Medihanialem State Forest in Fogera District, Ethiopia

This study was conducted in Shelekomedihanialem state forest in Fogera district, South Gondar Zone, Ethiopia, to identify the floristic composition, vegetation structure,diversity and regeneration status of the woody plant species. Systematic sampling method was used to collect vegetation data from 5 transect lines 200m far apart and 50(20m x20m) quadrates at distance of 100m. To collect data for seedling and sapling, five 1m x 1m sub-plots were laid in each of the main plot, where four were at the corners and one at the center. Diameter at breast height was measured DBH ≥2.5cm while height was≥2m.Shannon-WiennerDiversity Index was used to calculate species diversity, richness and evenness. The densities of mature, sapling and seedling of woody plant species were 2055.5,2240 and 2400.5 individuals/ha respectively and the basal area of the forest was 2.246 m 2 /ha.The result of vegetation structure of woody plant species and regeneration status analysis in the forest revealed that the forest was dominated by small-sized trees and shrubs indicating that it is in the stage of secondary development. Finally, this study indicated that the population structure of the most woody plant species in Shelekomedihanialem state forest is in a good status of regeneration recruitment level. From the point of view of managing forests for the sake of biodiversity conservation, if appropriate management measures are taken, the nature of the population structure of most of tree species could be improved. K e ywords : Ethiopia, Floristic composition, regeneration, Forest, vegetation structure DOI: 10.7176/JBAH/12-5-02 Publication date: March 31 st 2022

The influence of microhabitat factors on the regeneration and species composition of understory woody plants in Pinus tabuliformis plantations on the Loess Plateau

Chinese pine (Pinus tabuliformis) is one of the main tree species for water and soil conservation on the Loess Plateau. However, most of these plantations face a series of ecological problems, such as low diversity of understory plants and difficulty in natural regeneration. Our study focused on the microhabitat factors that affected the species composition of understory woody plants and the distribution and growth of regeneration in Chinese pine plantations. Plots of 50 × 50 m were randomly established in three typical mature plantations, and then each plot was divided into 100 5 × 5 m microplots to investigate the characteristics of canopy trees, Chinese pine regeneration, other understory woody plants, the light environment, litter and soil. The involved microhabitat factors jointly explained 37.68% of the variation in the species composition of understory woody plants, among which soil total phosphorus (2.66%) and available potassium (2.19%) were the main factors. In the regeneration layer, Chinese pine regeneration (7,261 stems·ha−1, 124.6 cm), Quercus liaotungensis (3,114 stems·ha−1, 117.0 cm) and Betula platyphylla (953 stems·ha−1, 305.7 cm) were considered the canopy replacement species with the most potential. Additionally, we found that the regeneration density was significantly affected by soil total nitrogen, available potassium and shrub density, while the differences in regeneration height growth mainly resulted from the density of other understory trees and shrubs, soil total phosphorus and diffuse non-interceptance. The density of saplings and juvenile trees of Chinese pine was more affected by microhabitat factors than that of seedlings, but the effect of the microenvironment on the former two was less different, indicating that the sapling stage may be the critical period for successful recruitment of the plantations. Therefore, gap creation or thinning is suggested to promote the growth of saplings and juvenile trees, thus increasing the opportunity for them to enter the canopy. At the stand scale, soil resources and interspecies interactions were the dominant microhabitat factors influencing the regeneration of Chinese pine, which inspired us to deeply explore the vegetation-soil-microbial systems and the relationship between regeneration and their neighbors in the future. Moreover, managers should pay more attention to the survival and growth of saplings and juvenile trees to promote the sustainable development of Chinese pine plantations. We believe that these plantations will be transformed into coniferous and broad-leaved mixed forests with high stability and species diversity (e.g., P. tabuliformis × B. platyphylla or P. tabuliformis × Q. liaotungensis).

A comprehensive experimental assessment of glyphosate ecological impacts in riparian forest restoration.

Competition with invasive grasses is one of the most important drivers of tree planting failures, especially in tropical forests. A widely disseminated weeding approach has been glyphosate spraying, the most used herbicide globally in forestry and ecosystem restoration. However, glyphosate use in restoration is highly controversial and requires further studies to elucidate its effects on restoration processes and the environment. We evaluated the use of glyphosate in riparian forest restoration and its impacts on tree planting costs, weed control efficiency, planted seedling performance, herbaceous and woody species regeneration, soil bacteria, and environmental contamination, using mowing treatments as a reference and based on a controlled experiment established in the Brazilian Atlantic Forest. Glyphosate spraying reduced by one-half and one-third the accumulated aboveground biomass of, respectively, weeds in general and of the invasive grass Urochloa decumbens compared to mowing treatments, and it reduced the cost by half. The performance of planted tree seedlings was markedly favored by glyphosate spraying compared to mowing treatments, as expressed by improved seedling height (~twice higher), crown area (~5× higher), and basal area (~5× higher); the regeneration of both native woody and ruderal herbaceous plants were also enhanced. Neither glyphosate nor its metabolite Aminomethylphosphonic acid (AMPA) residues were detected in either water runoff or soil samples, but they were found at relatively high concentrations in the runoff sediments (from 1.32 to 24.75 mg/kg for glyphosate and from 1.75 to 76.13 mg/kg for AMPA). Soil bacteria communities differed before and after glyphosate spraying in comparison to mowing plots (without glyphosate). Glyphosate spraying was far more cost effective than mowing for controlling U. decumbens and greatly improved the performance of planted tree seedlings and natural regeneration, while not leaving residues in soil and water. However, the changes in the structure of bacterial communities and high concentration of glyphosate and AMPA residues in runoff sediments highlight the need for caution when using this herbicide in riparian buffers. We present alternatives for reducing glyphosate use and minimizing its risks in tree planting initiatives.

Effects of exotic plantation expansion and management intervention on woody plant species diversity, regeneration and soil seed bank in Tarmaber district, Ethiopia

This study was carried out to determine the effect of plantation forest with management intervention on woody plant species diversity in Tarmaber district north shewa zone Ethiopia, regeneration and soil seed bank species composition in five different forest types. A total of 75 circular sample plots of 314 m2 were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples). Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed C. lusitanica (27), not managed C. lusitanica (9), managed E. globules (22) and not managed E. globules (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha-1 for natural forest, managed C. lusitanica, not managed C. lusitanica, managed E. globules and not managed E. globules respectively. Unmanaged C. lusitanica plantations had significantly lower densities of mature tree stems ha-1 as compared to managed C. lusitanica, managed E. globules and adjacent natural forest (F=14.03, p<0.05). Similarly in terms of sapling density ha-1 unmanaged C. lusitanica was significantly lower from other forest types (F=7.37, p <0.05). However managed C. lusitanica had significantly higher seedling regeneration (stem density ha-1) than other plantation and adjacent natural forests (F = 16.11, p < 0.05). Generally mean stem densities including tree, sapling and seedling of woody species among different forest types managed C. lusitanica was significantly higher among different forest types (F= 13.01, p<0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed C. lusitanica (11), unmanaged C. lusitanica (4), managed E. globules (7) and unmanaged E. globules (5). Generally, with appropriate management intervention, undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

Management intensity and landscape configuration affect the potential for woody plant regeneration in coffee agroforestry

With the current deforestation rates in tropical ecosystems, optimizing biodiversity in managed systems has become fundamental for conservation. Agroforestry has been suggested to conserve biodiversity and buffer deforestation rates, while also sustaining local livelihoods. While many studies have focused on the relation between local management intensity and biodiversity, processes at the landscape scale are often overlooked and remain a knowledge gap.In this study we identified drivers behind woody plant regeneration in coffee agroforestry on both local and landscape scale. We used univariate-, multivariate- and structural equation models to relate seedling species richness, diversity, density, community composition and height to local management intensity and location in the landscape of 60 coffee agroforestry sites in southwestern Ethiopia.Local management intensity, which simplifies and reduces canopy cover, negatively impacted species richness, diversity and density, presumably due to altered microclimatic conditions and a reduction in local seed sources. Seedling height was also reduced by management intensity, including slashing frequency and canopy cover. On the landscape scale, species richness and diversity of seedlings was higher at sites adjacent to continuous forests where seed sources are abundant, and declined with distance to the forest. In particular, late successional species were negatively affected, whereas common shade tree species and pioneers occurred as seedlings throughout the landscape and in more managed systems. This suggests that dispersal limitation is detrimental for the regeneration of late successional species, especially in agroforestry systems where the standing woody plant diversity is largely reduced.Our results indicate that natural regeneration of woody plants still occurs in coffee agroforestry systems, primarily when the canopy structure is dense and diverse and/or when sites are located nearby continuous forests. Management intensification and deforestation will limit the potential for many woody plant species to regenerate in coffee agroforestry sites, by altering the local microclimate, reducing local seed sources and disrupting seed dispersal from the surrounding landscape. This will likely result in a positive feedback loop, as a reduction in woody plant regeneration reduces future seed sources. We therefore stress that both a local and a landscape perspective should be incorporated in conservation and restoration approaches.

Effects of Exotic Plantation and Management Intervention on Woody Plant Species Diversity, Regeneration and Soil Seed Bank in Tarmaber District, Ethiopia

Plantations have many economic and environmental benefits, but exotic plantations are widely viewed negatively mainly in relation to biological diversity conservation, and regenerations to prove this dilemma this study is necessary. This study was carried out in Tarmaber district north shewa zone Ethiopia to determine the effect of plantation forest with management intervention on woody plant species diversity, regeneration and soil seed bank species composition in five different forest types. A total of 75 circular sample plots of 314 m² were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples) to examine the similarity between the soil seed bank and aboveground flora. Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed <i>C. lusitanica</i> (27), not managed <i>C. lusitanica</i> (9), managed <i>E. globules</i> (22) and not managed <i>E. globules</i> (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha^-1 for natural forest, managed <i>C. lusitanica</i>, not managed <i>C. lusitanica</i>, managed <i>E. globules</i>and not managed <i>E. globules</i>respectively. Unmanaged <i>C. lusitanica</i>plantations had significantly lower densities of mature tree stems ha^-1 as compared to managed <i>C. lusitanica</i>, managed <i>E. globules</i>and adjacent natural forest (F=14.03, p<0.05). Similarly in terms of sapling density ha^-1 unmanaged <i>C. lusitanica</i> was significantly lower from other forest types (F=7.37, p <0.05). However managed <i>C. lusitanica</i>had significantly higher seedling regeneration (stem density ha^-1) than other plantation and adjacent natural forests (F = 16.11, p < 0.05). Generally meanstem densities including tree, sapling and seedling of woody species among different forest types managed <i>C. lusitanica</i> was significantly higher among different forest types (F= 13.01, p<0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed <i>C. lusitanica</i> (11), unmanaged <i>C. lusitanica</i> (4), managed E. globules (7) and unmanaged <i>E. globules</i> (5). The similarity of the soil seed bank was more or less similar to the above ground flora with maximum Sorenson’s similarity values of 0.633. Generally with appropriate management intervention undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

木本植物萌生更新研究进展

木本植物萌生更新研究进展

Patterns of woody plant epiphytism on tree ferns in New Zealand

Tree fern trunks provide establishment surfaces and habitat for a range of plant taxa including many understorey shrubs and canopy trees. The importance of these habitats for augmenting forest biodiversity and woody plant regeneration processes has been the subject of conjecture but has not been robustly assessed.

Remaining eucalypt trees may hamper woody plant regeneration in a neotropical savanna

When an area previously used for agricultural or sylvicultural purposes is abandoned, it may undergo natural regeneration. However, the outcome of such regeneration depends on a number of factors, including the presence of non-native invasive plants, and, when production forests such as eucalypt plantations are considered, remaining non-native trees may also affect the natural regeneration possibilities. We studied how remaining eucalypt trees affect woody species regeneration and invasive grasses in an abandoned Eucalyptus grandis plantation in a regenerating Brazilian savanna site. We sampled the woody vegetation and invasive grasses in 30 8 × 8-m plots and surveyed the eucalypt trees within these plots and in 3 m-wide strips around them. Eucalypts negatively affected the cover of the C4 invasive African grass Melinis minutiflora and the total abundance and basal area of native woody plants in general and of two dominant species, suggesting an overall negative effect on native plant regeneration notwithstanding the also negative effects on African grasses. Conversely, they had no effect on species richness, species diversity nor mean height of woody plant communities nor on the abundance of three other dominant native woody species. Interestingly, a low eucalypt abundance had small effects on native woody species but much stronger effects on the cover of M. minutiflora, possibly due to shading. Thus, our results indicate that remaining eucalypt trees may hamper the natural regeneration of native woody plants, but also suggest that maintaining a low density of eucalypt trees may be a cost-effective strategy, given the high costs associated with the complete removal of remaining trees and the difficulties in controlling invasions by African grasses.

Influence of Deer Hunting and Residual Stand Structure on Tree Regeneration in Deciduous Forests

ABSTRACTChronically overabundant white‐tailed deer (Odocoileus virginianus) populations have made it difficult to regenerate desirable woody species throughout much of their range in the eastern United States and southern Canada. Neither silvicultural prescriptions nor deer management alone have resulted in successful forest regeneration. We tallied woody stems (≥1 m tall, &lt;10 cm diameter) on 62 hunted and 46 nonhunted forest stands throughout Connecticut, USA, during autumn 2015 to spring 2018; all stands had a timber regeneration harvest from 2–12 years prior to our study (2003–2016). Our objective was to examine the influence of the combination of deer management and residual stand structure on woody regeneration diversity, density, and composition. After accounting for the influence of stand structures over a range of residual basal areas from 0–23 m2/ha, we found that deer had a negative effect on regeneration diversity, density, and species composition. Moreover, we found that the combination of state‐regulated deer hunting and forest‐overstory removal resulted in greater woody‐plant regeneration rates with increased diversity. Stem densities of oak–hickory (Quercus spp.–Carya spp.), maple (Acer spp.), and minor species, as well as combined species, were greater in hunted versus nonhunted stands, and in clearcuts as opposed to 2‐aged and shelterwood stands. American beech (Fagus grandifolia) and shrub species did not differ in stem density regardless of hunting or treatment prescription. Our study indicates that for properties where the management goal is to create dense vegetation with high tree, shrub, and herbaceous species diversity, managers should both encourage hunting to reduce pressure on browse‐sensitive species and leave as few postharvest residual trees as possible to maximize growing space for regeneration. A lack of deer harvest and overstory removal in southern New England resulted in low diversity vegetation dominated by lesser preferred species such as birch (Betula spp.) or American beech. The use of hunting as a tool to relieve browsing pressure will improve both woody and herbaceous plant regeneration where light is not limited. © 2020 The Wildlife Society.