Evaluation of natural forest regeneration as a part of land restoration in the Khentii massif,Mongolia

Forest stands in the semi-arid environment of northern Mongolia have an essential role in controlling ongoing desertification in the surrounding landscape.Over the last decade,the total forest area has decreased dramatically.The aim of this study was to evaluate the potential of natural regeneration as an essential element for ensuring sustainability of these forests.Based on field measurements from 120 plots in six sites,our assessment tool revealed five qualitative categories of forest regeneration,allowing us to assess impacts of both grazing and environmental conditions on the regeneration process.Grazing is a crucial factor and adversely affects regeneration.For sites with relatively low grazing intensity,low soil moisture levels represent the main reason for reduced regeneration.The approach to classification proposed in this study allows for the identification and interpretation of stand conditions where natural regeneration has failed.This study provides an important foundation to inform decisionmaking related to land protection and restoration actions.Our findings could be used in comparative studies and,importantly,may aid further mapping of Mongolian forests.

Remote Sensing for Analyzing Forested Landscape Structure and Land-Use Histories in Guyana’s Bauxite Mining Landscapes

Monitoring secondary forest regrowth is a priority in forest restoration strategies. A site history helps in understanding the present status of natural regeneration in the three landscapes impacted by bauxite mining. Nonetheless, high rainfall in bauxite residue storage areas can facilitate natural regeneration of forest. This research analyzed the natural regeneration of forest after thirty years of different land use histories at three bauxite mining areas of the Upper Demerara—Berbice region of Guyana. There are no man made forest plantations in the three landscapes being reviewed. The methodology included: 1) the selection of three sampling landscapes with different land use histories 2) the generation Land Use/Land Cover maps using KMeans unsupervised classification of satellite images in each landscape and 3) the assessment of landscape structure of the land cover classes for year 2020 at class and landscape level using landscape metrics. The assessment of landscape structure of the land cover classes was carried-out with landscape metrics for the comparisons at class and landscape level. Principal component analysis enables the identification of main patterns among landscape-level metrics and land cover classes. Discriminant classification of the landscape classes was analyzed with the different metrics. The results suggest that Normalized Difference Vegetation Index and KMeans unsupervised classification can be used to evaluate the difference in natural forest regeneration among landscapes with differing land use histories. The landscape metrics revealed secondary stages of forest succession. The Landscape Shape Index and Edge Density were the most significant for landscape differentiation. The result of the various land uses reveals a mosaic of early, intermediate, and late successional sequences.

Native Species Composition and Diversity of Valuable Woody Plants Regeneration during Fallow Period in Kamwatta, Moruca, Guyana

An intelligent method of shifting cultivation to regenerate vegetation after a long fallow period is critical information for restoration strategies. The literature review identified that the assessment of woody plant species on abandoned farmland has never been done before in Kamwatta, Moruca Region 1. In addition, more information should be available in indigenous communities and at the national level, including more documentation of the utilization of natural resources by the Warrau community. This study assessed the valuable woody plant species that grew during the fallow periods. Nine farmlands were randomly selected along a 100 m transect, each with varying fallow periods. In order to collect information on the age of farm abandonment, the researcher employed a mixed-methods approach. First, we found how long each farm had been fallow by administering a semi-structured questionnaire. Then, we conducted a flora survey to gain information on the variety and abundance of valuable plants using the age of farm abandonment as a dependent variable. The data analysis included the number of valuable woody trees with a diameter of >10 cm, seedlings and saplings with a diameter of <10 cm, the location of identified trees, and the uses of identified tree species. Microsoft Excel was used to code and analyze the questionnaire, while QGIS, Shannon’s Index of Diversity, and Simple Linear Regression were used to analyze the inventory data. The results showed that the respondents listed 38 valuable woody species, and 79% occurred in the studied area. The field verification revealed that the dominant family in the area was Mimosaceae. Species abundance increased with fallow up to 10 years before declining in the latter years. Plant diversity and abundance had a weak relationship with the age of abandoned farmlands for woody trees, while the seedlings and saplings showed no relationship.

Species diversity, regeneration and dominance as influenced by canopy gaps and their characteristics in tropical evergreen forests of Western Ghats, India

Canopy gaps play a significant role in maintaining structure and composition of tropical forests. This study was carried out in tropical evergreen forests of central Western Ghats in India to understand the influence of canopy gap size and the relationship of gap regime attributes to diversity measures and regeneration. The average gap size in the study area was found to be 396 m2 and around half of gaps were 4–8 years old. Gaps created by natural single tree fall were smaller in size but significantly higher in number. Diversity and regeneration of woody species were compared with canopy gaps and intact vegetation. Species richness and diversity was higher in gaps than in intact vegetation. Macaranga peltata, a shade intolerant species dominated gaps while intact vegetation was dominated by shade tolerant Kingiodendron pinnatum.Gap size significantly influenced species diversity and regeneration. Gap area and age were significantly and negatively correlated with diversity measures but positively correlated with regeneration. Among all the attributes of gaps, regeneration was significantly positively correlated with light intensity. Gaps maintained species diversity and favored regeneration of woody species. In addition to gap size and age, other gap ecological attributes also affected species diversity and regeneration.

Effect of competition on spatial patterns of oak forests on the Chinese Loess Plateau

Reforestation or natural forest regeneration is an alternative measure for controlling soil erosion in degraded land on the Chinese Loess Plateau（CLP）. However, our understanding of the temporal dynamics and the spatial patterns of forest regeneration remains inadequate. Two oak forests at different development stages were investigated to determine the spatial patterns of competitions（intraspecies and interspecies） during different successional stages. The intraspecies and interspecies spatial relationships among different tree diameters at breast height were analyzed at multiple scales by Kriging interpolation method and univariate and bivariate O-ring statistics. Our analytical results indicated that self-correlation and competition intensity were relatively high between oak and pine trees in the early development stage of oak forests due to their clumped distributions of heavy seeds. Birch trees had a lower competition in comparison to oak trees although birch was the dominant species. Therefore, asymmetric competition of oak trees was most likely to have led to their edge dispersal and their success in replacing the pioneer species. Asymmetric competition means that larger individuals obtained a disproportionately large share of the resources and suppressed the growth of smaller individuals. Kriging interpolation analysis showed a tendency towards homogenization caused by interspecies competition during the succession of oak forests. Our results demonstrated that the competition was the driving factor in the spatial distribution of oak forests on the CLP.

Does a shift in shade tolerance as suggested by seedling morphology explain differences in regeneration success of northern red oak in native and introduced ranges?

Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native and introduced ecosystems, and examine the genetic and environmental bases of observed differences in plant traits.

A 40-year evaluation of drivers of African rainforest change

Background:Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change.Yet,the drivers of forest dynamics are poorly understood.This is in large part due to the lack of long-term data on forest change and changes in drivers.Methodology:We quantify changes in tree abundance,diversity,and stand structure along transects first enumerated in 1978 and resampled 2019 in Kibale National Park,Uganda.We tested five predictions.First,based on the purported role of seed dispersal and herbivory and our quantification of changes in the abundance of frugivores and herbivores,we tested two predictions of how faunal change could have influenced forest composition.Second,based on an evaluation of life history strategies,we tested two predictions concerning how the forest could have changed following disturbance that happened prior to written history.Finally,based on a 50-year climate record,we evaluate the possible influence of climate change on forest dynamics.Results:More trees were present on the assessed transects in 2019(508)than in 1978(436),species richness remained similar,but diversity declined as the number of dominant species increased.Rainfall increased by only 3 mm over the 50 years but this had not significant effect on forest changes measured here.Annual average monthly maximum temperature increased significantly by 1.05℃ over 50 years.The abundance of frugivorous and folivorous primates and elephants increased over the 50 years of monitoring.Neither the prediction that an increase in abundance of seed dispersing frugivores increases the abundance of their preferred fruiting tree species,nor that as an increase in folivore abundance causes a decline in their preferred species were supported.As predicted,light-demanding species decreased in abundance while shade-tolerant species increased as expected from Kibale being disturbed prior to historical records.Finally,while temperature increased over the 50 years,we found no means to predict a priori how individual species would respond.Conclusions:Our study revealed subtle changes in the tree community over 40 years,sizable increases in primate numbers,a substantial increase in the elephant population and an increase in local temperature.Yet,a clear picture of what set of interactions impact the change in the tree community remains elusive.Our data on tree life-history strategies and frugivore/herbivore foraging preferences suggest that trees species are under opposing pressures.

Effect of scots pine forest management on soil properties and carabid beetle occurrence under post-fire environmental conditions——a case study from Central Europe

Background: Fires have a fundamental impact on phytocoenoses and, depending on the size of the fire, can have a positive or negative effect. The role of fires in the formation of the species composition of plants, restoration of stands and changes in soil properties is well studied. However, the long-term relationship between forest management methods, soil properties and epigeic entomofauna assemblages in post-fire areas is still not clear. The effects of Scots pine stand management methods on biochemical soil properties and ground beetle assemblages in the largest post-fire area in Central Europe after the second World were investigated. The study was conducted in the Rudy Raciborskie Forest district in southern Poland. The soil properties and epigeic beetle community structure were analysed. The research covered areas with natural and artificial pine regeneration, which were subjected to various care treatments.Results: The tendency for higher accumulations of organic matter in the soil of stands that underwent natural regeneration was proven. The stimulating role of soil organic carbon on the activity of dehydrogenases in the soil of naturally renewed areas with silvicultural treatment(NRAT) was noted. Regardless of the manner of stand regeneration, the activity of β-glucosidase was higher in the areas in which breeding treatments were practised.Furthermore, managed forest stands presented a higher abundance of carabid beetles than stands without treatment practices. Thirteen epigeic beetle species from the families Geotrupidae, Carabidae, Curculionidae,Cerambycidae and Silphidae were captured, with beetles from the first two families being the most numerous. Rare epigeal carabid species in the fauna of Poland and Europe, such as Carabus glabratus(Paykull) and Carabus auronitens Fabr., found appropriate habitat conditions for survival in the post-fire areas. Compared with the other areas, in the NRAT area, there were better stand and soil properties and more features conducive to epigeic entomofaunal occurrences. The highest post-fire content of polycyclic aromatic hydrocarbons was recorded in the soils of the sites that underwent artificial regeneration. The results suggest that preparing the soil before the introduction of new vegetation affects the amount of aromatic hydrocarbons(PAHs).Conclusions: The better performance of the NRAT stand draws attention to the positive aspects of the use of natural regeneration, both from ecological and economic perspectives. The effects of forest management on the amount of soil organic matter after fires have been proven. The natural regeneration of stands was conducive to the accumulation of organic matter. The enzymatic activity of soils is influenced by the renewal method and forest management strategy. The NRAT area was characterized by the highest number of carabid species.

Strategies for Achieving Sustainable Logging Rate in the Brazilian Amazon Forest

Data of increment of the remnant trees after logging, ingrowth and mortality was obtained by assessment before logging and after 6 years, two sites of 50 ha, in Amazon forest. Logging scenarios were simulated to identify the logging rate potential for each studying site, by diameter class projection method. The cycle of 35 years and the logging rate of 30 m3.ha-1 exceed the time required for recovery in the primary forest, in the studied site. The simulation showed that in the studying area, a well-planned logging, with minimum logging damage would be possible to implement an initial cycle of 25 years to the forest to recover 30 m3.ha-1, if 50% of the timber stock were reserved. The forest increment, beyond important factors such as the increase of individual species, is quite dependent on the remnant trees.

Diversity,population structure and regeneration status of arboreal species in the four sacred groves of Kushalnagar,Karnataka

Assessment of tree species diversity, structure and regeneration status of four sacred groves of Kushalnagar,southern Karnataka was carried out. The random quadrat method was employed in each grove for enumeration of tree diversity and regeneration status. A total of 98 tree species belonging to 38 families were found from the sampled areas.These groves possess higher diversity and basal area. Some67 % of species have shown regeneration, while 17 % of species had no regeneration. Another 15 % of species were reappearing or immigrating. It is observed that increased disturbance was directly proportional to number of reappearing or immigrating species and inversely proportional to the diversity in all the sacred groves. Significant impact on diversity, species richness and regeneration status of the flora due to manifold anthropogenic activities have been recorded.

The Organization and Management System of Closing Hillside for Forest as a Regeneration Project (CHFRP)

By investigation, the thesis analyses and summarizes the forming and developing of CHFRP In Xupu county. We select the Mayandong stock cooperation forest farm as object, adopt the methods such as semi-structure interview, analysing second data and surveying sample plots, analyse and study the process to clarify the property right, the profits allocated forms and the management forms. The results show that CHFRP can tentatively resolve the contradiction between the forestland using right scattered to eve...

Comprehensive Results of Closing Hill for Forest as Regeneration Project (CHFRP)

In order to approach the comprehensive results of CHFRP, Mayandong stock cooperation forest farm was selected as research object in Xupu county. These methods such as semi-structure interview, second data analysis and sample sites survey were used to investigate and study the ecological results, economical results and social results of CHFRP. The results show that CHFRP can restore the forest vegetation, promote forest growth, improve the physical and chemical properties and nutrition condition of fores...

Surface runoff and soil erosion in a natural regeneration area of the Brazilian Cerrado

The Brazilian Cerrado has been converted to farmland,and there is little evidence that this expansion will decrease,mainly because agriculture is the country's main economic sector.However,the impacts of intense modification of land use and land cover on surface runoff and soil erosion are still poorly un-derstood in this region.Here,we assessed surface runoff and soil loss in a woodland Cerrado area under a former pasture area,which was abandoned and has undergone a natural regeneration process for 7 years(RC).Its results were compared with that found in an undisturbed area of woodland Cerrado(CE),40-month-old eucalyptus(3.0×1.8 m)(EU),and pasture under rotational grazing(PA).The study was conducted on Red Acrisol located in the Brazilian Cerrado.We performed rainfall simulations on a plot of 0.7 m2 and using three constant rainfall intensities of 60,90,and 120 mm h-1 for 1 h.For each rainfall intensity,we carried out four repetitions using different plots in each treatment,i.e.12 plots per treat-ment studied and 48 plots in total.We noted that the soil physical properties were improved in RC and,consequently,water infiltration and soil erosion control;RC presented surface runoff and soil loss different from EU and PA(a=0.05).The macroporosity and soil bulk density affected surface runoff in RC and PA because the RC was used as pasture and is currently regenerating back to the cerrado vegetation.As the rainfall intensity increased,EU became more similar to PA,which showed the highest surface runoff and soil loss.Our findings indicate that natural regeneration processes(pasture to the cerrado vegetation)tend to improve the soil ecosystem services,improving infiltration and reducing surface runoff and soil erosion.

Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island,South China:(Ⅰ)Seed Rain

Seed dynamics is an important part of stand dynamics in forest ecosystems. In this paper, 26 gaps were randomly selected to study the influence of gaps on the spatial and temporal patterns of seed rains in a tropical montane rainforest of Hainan Island, South China. Three zones for each gap, including outside gap zone （Non-gap）, transitional gap zone （EG-CG）, and central gap zone （CG）, were designed, and fourseed traps （each lm x lm in size） were placed in each zone. Seed rains were collected by these traps every 10 days from June 2001 to May 2002. Seed rain varied greatly with season and generally exhibited a pattern of unimodal change during the study period： seed abundance and species richness were both greater in the wet season than in the dry season. Gaps significantly influenced the temporal patterns of both species richness and density of seed rains. Gaps had no significant influences on the spatial distribution patterns of seed rain species richness, but significantly affected the spatial distribution pattern of seed rain densities. Among the three different zones of gaps, the outside gap zone generally received more seeds inputs than the two other gap zones.

Arrested development? Investigating the role of bamboo in Araucaria Forest succession in Southern Brazil

Aims Assessing the role of a dominant native bamboo species on tree species diversity and structure in the medium term.Methods Over a 7-year period,we studied the natural regeneration of two dominant forest types in Southern Brazil(Araucaria Forest or AF;Bamboo Forest or BF)after a bamboo(Merostachys skvortzovii Send.)die-off between 2004 and 2006.The study was carried out in the Embrapa Research Station in Cacador,Santa Catarina State,Brazil.Important Findings The die-off provided ideal conditions for the establishment of several species and it kickstarted forest succession dynamics,which in turn affected regeneration diversity.Tree species richness was relatively stable with a transitory increase between 2007 and 2014 in both AF and BF.However,species richness rose in BF because of a relative increase in abundance of some species(especially late and secondary species)while a plunge in some pioneer species drove an increase in diversity.Overall,we found that BF has a lower diversity of recruits and that density declined over time,while AF is more diverse,with a more stable density.In BF,the bamboo die-off created optimal conditions for initial regeneration development(mainly fast-growing pioneer trees),which quickly transited to higher size classes.Yet,after this initial stage of pioneer recruitment,the number of recruits dropped followed by a virtual absence of growth regardless of the species group as a result of a quick bamboo reestablishment.As bamboo recreated a dense understory it reduced species diversity to original levels,suggesting a self-maintaining cycle that halts forest succession.On the other hand,the bamboo die-off had little impact on AF where a slow recruitment process typical of old-growth forests was observed.The results indicate that the die-off event had a temporary effect on species diversity i.e.restricted to forests where bamboos are dominant in a similar process described in other southern South American forests.As the first study to observe the medium-term forest dynamics related to bamboo die-off,we can conclude that when being dominant,native bamboos can hinder forest regeneration,maintaining lower levels of diversity and arresting forest succession that lasts well beyond the short-term,post-die-off effects.Many forest fragments in the region are dominated by bamboos,thus their potential for conservation is at risk and requires appropriate management.

Structural development of vegetation on rehabilitated North Stradbroke Island:Above/belowground feedback may facilitate alternative ecological outcomes

Introduction:This study depicts broad-scale revegetation patterns following sand mining on North Stradbroke Island,south-eastern Queensland,Australia.Methods:Based on an ecological timeline spanning 4–20 years post-rehabilitation,the structure of these ecosystems(n=146)was assessed by distinguishing between periods of‘older’(pre-1995)and‘younger’(post-1995)rehabilitation practices.Results:The general rehabilitation outlook appeared promising,whereby an adequate forest composition and suitable levels of native biodiversity(consisting of mixed-eucalypt communities)were achieved across the majority of rehabilitated sites over a relatively short time.Still,older sites(n=36)appeared to deviate relative to natural analogues as indicated by their lack of under-storey heath and simplified canopy composition now characterised by mono-dominant black sheoak(Allocasuarina littoralis)reaching up to 60%of the total tree density.These changes coincided with lower soil fertility parameters(e.g.,total carbon,total nitrogen,and nutrient holding capacity)leading us to believe that altered growth conditions associated with the initial mining disturbance could have facilitated an opportunistic colonisation by this species.Once established,it is suspected that the black sheoak’s above/belowground ecological behaviour(i.e.,relating to its leaf-litter allelopathy and potential for soil-nitrogen fixation)further exacerbated its mono-dominant distribution by inhibiting the development of other native species.Conclusions:Although rehabilitation techniques on-site have undergone refinements to improve site management,our findings support that putative changes in edaphic conditions in combination with the competitive characteristics of some plant species can facilitate conditions leading to alternative ecological outcomes among rehabilitated ecosystems.Based on these outcomes,future studies would benefit from in depth spatio-temporal analyses to verify these mechanisms at finer investigative scales.