Journal articles: 'Established natural regeneration' – Grafiati (2024)

Abstract:

Despite the considerable loss of natural area in the Pampa biome, the number of scientific studies carried out here is low; it is lower in terms of natural regeneration. Therefore, the present study analyzed arboreal shrub and natural regeneration as well as the influence of environmental variables on the distribution of a riverine forest of the Espinilho stream in the Pampa biome, Rio Grande do Sul. A hundred plots were systematically set for arboreal shrub sampling. To evaluate the regenerating component, two classes were established: Class I and Class II. The main species in the arboreal shrub were Ocotea acutifolia (Nees) Mez and Pouteria salicifolia (Spreng.) Radlk., while those in natural regeneration were Eugenia uniflora L. and Blepharocalyx salicifolius (Kunth) O.Berg. The characteristics of the relief, soil, and canopy conditioned the species of the arboreal shrub and regenerating strata.

Abstract:

Scots pine (Pinus sylvestris L.) is a widespread species in Eurasia, but its natural range can be significantly altered by a variety of stressors. The ability of pine to regenerate naturally is significantly reduced by its occurrence in unsuitable habitats. The processes of natural selection of pine from select habitats can be followed in stands of national parks where forestry activities are excluded. The possibility of pine regeneration is influenced by the following factors: characteristics of produced seeds, competition, and genetic characteristics. In the present study, selected factors associated with limiting the natural regeneration potential of pine were analysed. The present work generated important information related to the natural regeneration potential of pine in Central and Eastern Europe. The main objective of the analyses was to discuss the possibility of the natural regeneration of pine stands without human intervention. In addition, the genetic diversity of naturally germinating seedlings was analysed. The obtained results confirmed the high reproductive potential of pine despite the advanced age of the studied trees. The obtained seeds produced by old growth Scots pine trees had high viability, while a significant difference was observed in terms of the average number of cones per dominant tree between studied stands. Thus, the number of cones was the main element determining the regeneration potential of the stands. It should be emphasised that the number of cones did not influence the occurrence of natural regeneration. Based on the obtained results, the regeneration potential of pine stands depends mainly on the habitat and the competitive pressure. In addition, a correlation between genetic parameters and the regeneration potential of stands should be established, which may be the beginning of further research on the process discussed in this publication.

Abstract:

Abstract The ‘Czmoń’ nature reserve (23.65 ha) was established in 1998 to protect one of the best-retained areas of natural oak-hornbeam forest (Galio-Carpinetum) in the center of the Wielkopolska Region. Apart from oak-hornbeam forest, the ash-elm riparian forest (Querco-Ulmetum) and alder riparian forest (Fraxino-Alnetum) are found in the reserve. These plant communities, both natural and degenerated as a consequence of previous forest management, have created the convenient conditions for assessment the phytocoenoses’ regeneration potential. The aim of this study was to assess the age and species structure of woody species natural regeneration of the whole area of the nature reserve. To achieve that target, during August and September 2012, 142 sample plots were established with the total area 3550 m2 on which tree and shrub composition and densities were calculated. Woody species regeneration created various diverse communities among individual sub-units, however oak-hornbeam forest species were predominant in the whole regeneration layer. The character of a ‘natural’ forest was retained on a part of the stands. Moreover, regeneration in degenerated parts of the ‘Czmoń’ nature reserve stands is changing according to potential vegetation. Whereas, the establishment of gaps in the Scots pine stands using artificial regeneration was not worthwhile. The natural regeneration structure under the canopy layer of Scots pine stands unambiguously supports the claim that phytocoenoses can regenerate on their own. In spite of the oak regeneration being infrequent, all stands within the ‘Czmoń’ nature reserve retain substantial rejuvenation potential

Abstract:

The article presents results of research focused on the development of natural regeneration of beech stands in the National Natural Reserve Voděradské bučiny, based on information acquired in regeneration plots established in 2004 and 2009. After five years of the study, 5 different generations of beech, representing 97.4% of the whole woody regeneration, were registered. In the second year of life, the two oldest generations of seedlings had the highest mortality registered so far. The last year survival of seedlings was not influenced by increased canopy openings as a result of harvest or mortality. The data from a new plot with higher stand density confirmed the negative effect of high parent stand density on the formation of new regeneration. An elevated proportion of litter in the ground cover was found to be negatively related to the establishment and survival of beech seedlings.

Abstract:

Regeneration process was studied within twentytwo gaps produced from natural falling of trees in a semivirgin mixed forest of oriental beech in Iran. The area of the openings varied between 163 m2 and 1683 m2, caused by falling of 1 to 6 trees. Natural regeneration depended on the gap size, and was established within the openings with different compositions.

Abstract:

The most common way of pedunculate oak regeneration on the floodplain sites in the Czech Republic is artificial regeneration by clear-cutting. However, what is the real potential of natural regeneration of pedunculate oak? In our research object (3,355 ha of floodplain forest in the southern part of the Czech Republic – Zidlochovice region), we inventoried about 8 ha of successful natural regeneration of pedunculate oak with density ranging between 15,000 and 100,000 individuals per ha on the plots after final cut. All harvested oak dominated parent stands showed a lower stock density that ranged between 0.5 and 0.8. In the next analysis of the survival of oak natural regeneration spontaneously established in different light conditions under the shelter of parent stands we observed the highest occurrence of saplings closer to the forest edge. A sufficient density of regeneration (above 10,000 individuals per ha) was found at the distance up to 18 m from the edge, where more than 24% of direct and 30% of indirect site factor were discovered. In the stand with the full canopy closure (DSF  about 10% on average and ISF about 24%) the oak regeneration is missing and was replaced by other tree species (especially ash and field maple). In the examined area the natural regeneration of pedunculate oak should be one of the possible alternatives of floodplain forest regeneration if certain conditions are met.  

Abstract:

Pre- and post-harvest regeneration levels were compared for Abiesbalsamea (L.) Mill. –Betulapapyrifera Marsh. –Picea spp. forests in an area of the southern clay belt of northwestern Quebec. Results revealed abundant advance softwood regeneration (mean = 65 000 stems/ha), almost entirely of Abies prior to harvest. The survey following mechanical and manual whole-tree harvesting suggested a 92% reduction of softwood regeneration and a shift from softwood to a mixed or hardwood-shrub dominated regeneration. Ninety percent of softwood seedlings collected after harvest were pre-established. Destruction of advance regeneration was generally greater on fine-textured soils. Hierarchic cluster analysis of ecological types based on softwood, hardwood, and shrub tree regeneration data as variables, revealed nine groups that could serve as a basis for operational silvicultural decision making. In general, Salix spp. and Alnusrugosa (Du Roi) Spreng. are the major competitors on poorly drained sites; Betula sp., Acerspicatum Lam., and Prunuspensylvanica L.f. dominate on thin organic deposits and coarse deposits, whereas Populustremuloides Michx. and Acerspicatum dominate on fine-textured deposits. These findings suggest that a good understanding of physical site factors can provide useful information for harvesting and silvicultural planning.

Abstract:

Identifying emerging invasive species is a priority to implement early preventive and control actions. In terms of the number of invasive tree species, forestry represents the second largest pathway of introduction, with an invasive debt likely existing for alien conifers in Europe. In the early 1900s, a network of arboreta was established in southern Belgium to assess the wood production potential of prospective conifer and broadleaved species. Here, we use eight arboreta as natural experiments to identify alien conifers presenting invasive behavior. Through systematic sampling, we quantified the natural regeneration of alien conifers and recorded local environmental variables. For each species, regeneration density, dispersal distances, and age structure were analyzed. Generalized mixed effects models were fitted to test the effect of planted area and tree-stand type on regeneration. The environmental space occupied by regenerating alien conifers was evaluated using principal component analysis. Out of 31 planted alien species, 15 (48%) were identified in natural regeneration, of which eight (26%) exhibited important regeneration density and dispersal distances. The most invasive species were Tsuga heterophylla and Abies grandis, confirming earlier field observations. Both large planted areas and areas planted with alien conifer species increased the density of regeneration. Species that had the highest regeneration density tolerated a wide range of environmental conditions, including shaded understory, which could lead to the invasion of mature, undisturbed forests. This study showed that 17% of the studied alien conifers are potentially invasive because they show important regeneration, long-distance dispersal, and, of importance, have already produced offspring that have matured and are capable of creating new satellite populations. In conclusion, our results provide a guideline for future planting operations, recommending extreme caution when planting these species in the temperate forests of Western Europe.

Abstract:

Magnetorheological (MR) regenerative suspension system can not only achieve excellent comprehensive suspension performance but also effectively recover and utilize vibration potential energy, which has been a research hotspot in the field of vehicle engineering. In this paper, for the 1/4 vehicle’s MR regenerative suspension system parallel with a tubular permanent magnet linear motor (TPMLM), the dynamic model of the MR semi-active suspension system and the TPMLM finite element model are established separately to form a joint simulation platform. The simulation analysis of the comprehensive suspension performance and regeneration performance under different road excitations is performed. The results show that installing TPMLM does not change the natural resonance frequency of the suspension system, which ensures good driving comfort and handling stability. At the same time, it has considerable regeneration power. This research can provide a reference for the stability analysis and popularization of the vehicle’s MR regenerative suspension system.

Abstract:

Abstract Natural regeneration cannot be effectively evaluated by tree density because of spatial heterogeneity typically observed. A proper interpretation of natural regeneration will consider some evaluation of area stocked. However, stocking estimates for natural regeneration are plot-size-dependent. Stocking at the 1-milacre scale is not generally comparable to that on a 4-milacre scale unless a generalized relation with stand density can be established. A generalized relation was first suggested to hold in a paper by Lynch and Schumacher (1941), but this has not been confirmed in subsequent studies. The Lynch and Schumacher hypothesis of a generalized regeneration density-stocking relation across plot size was tested using observations on 60 stands. Results were consistent with Lynch and Schumacher (1941). With evidence of a well-defined relation for plots ranging from 1 to 10 milacres, it appears possible to approximate, for ponderosa pine and associated species, the natural regeneration stocking percentage for a range of stocking standards based solely on observations of regeneration density. Confidence intervals were derived for a range of stocking standards in English units from 1 to 10 milacre and for metric units from 0.0005 hectares to 0.0040 hectares.

Abstract:

The subject of our research was to verify effects of the mechanical preparation of soil in the natural regeneration of pedunculate oak in a floodplain forest. On the site of a hard-wooded floodplain forest at the confluence of the Morava and Dyje rivers (Czech Republic), several sample plots were established differing in the preparation of soil during regeneration, in weeding the plots and in the period of the implementation of soil surface scarification before and after the fall (or distribution) of acorns. On the basis of results obtained, mechanical preparation of soil on non-weed-infested plots in the heavy seed year is not necessary, however, it supports seedling emergence from acorns and eliminates weed tree emergence and weed. However, it is better to realize it only after the fall of acorns and to incorporate them into soil and thus their emergence will be increased. Soil scarification can be carried out also in the course of harvesting the parent stand through the extraction of wood and slash from the regenerating area. In weed-infested stands, however, the thorough preparation of soil before the fall of acorns appears to be a necessity.

Abstract:

It was studied processes of ion-exchange water purification from ammonium ions from model solutions on cation exchangers and on zeolite. It was established dependencies ammonium sorption on the form of ion exchanger, the ratio of ammonium and calcium in water and the level of ion concentrations in solution. It was shown that the strongly acid cation exchanger KU-2-8 in Na+-form has a low selectivity for ammonium ions, in comparison with the H+-form. It was established that the sorption efficiency of ammonium ions on cation exchangers KU-2-8 and Dowex Mac-3 decreases in the presence of calcium ions. It was determined that regeneration of cation exchanger KU-2-8 was more effective when hydrochloric acid solutions were used. It was shown that ammonium sorption on zeolite from tap water goes in the same way as from model solutions. It was determined the boundary capacity of the zeolite for ammonium ions and it was amounted 40 mg/g. The regeneration of zeolite with a sodium chloride solution was investigated and it was established that the degree of regeneration reached 100 %. Bibl. 16, Fig. 6, Tab. 1.

Abstract:

Tropical forest continues to decline in Nepal’s lowlands, with a serious negative consequence for biodiversity conservation. Even a strict natural reserve is subjected to have some degree of human disturbances. The newly established Banke National Park of Nepal provides an excellent context to evaluate effects of human disturbances on the forest regeneration status. This article assesses the regeneration status of the park. A total of 1,067 plots were laid out within the park area. In each plot, three concentric rings of radii of 10 m, 5 m, and 1 m were established. Data of seedling/sapling and human disturbance variables were collected from each of the concentric plots. Principal component analysis (PCA) of all disturbance variables was carried out to generate a disturbance index. The findings of this study alienates with intermediate disturbance hypothesis. Cut wood, lopped tree, human/livestock trails, people number - are the significant variables for the impact of sapling and seedling density in the park. The induced human disturbances up to the limit avails the highest regeneration status in the park. These human disturbances might have induced the spatial heterogeneity and internal dynamics which help in the regeneration. The main challenge for the forest managers and scientists is to identify the indicators of environmental damage of forest and their threshold levels at which human disturbances will result in an irreversible decline of the vegetation and its regeneration.Banko Janakari, A Journal of Forestry Information for NepalVol. 25, No. 1Page: 39-49

Abstract:

This study examines the operational feasibility of six treatments to regenerate jack pine (Pinus banksiana Lamb.) naturally without fire following harvesting on clay soils in the southeastern boreal forest of Quebec. The experiment is a randomized complete block design. Techniques used were a final cutting in 1993 with manual on-site delimbing or roadside delimbing combined with three methods of soil scarification (WadellTM, La TaupeTM and a control) performed in the Spring of 1994 compared to an adjacent jack pine plantation established in 1994 after Wadell scarification. Seven growing seasons later, the present article compares stand composition, competing vegetation, regeneration and growth of jack pine between the different treatments as well as an adjacent plantation. Natural regeneration produced mixed stands with an adequate 52% average jack pine stocking. Roadside and on-site delimbing produced similar jack pine stocking on average. However, the plantation showed 83% stocking and better performance than natural regeneration in terms of height (2.48 m vs. 1.7 m for natural regeneration), diameter (41 mm vs. 22 mm for natural regeneration) and jack pine dominance. Therefore, if natural regeneration is desired, roadside delimbing is to be recommended since it provides sufficient seed and does avoid early jack pine growth reductions caused by slash. On clay soils, scarification seems to have been optional. Nevertheless, it slightly increased seedling growth and in this way, the treatment combining road-side delimbing and an extensive scarification can be an effective jack pine natural regeneration treatment.Key words: Pinus banksiana Lamb., natural regeneration, stocking coefficient, delimbing, scarification, boreal mixed wood, seedlings

Abstract:

During the 1980s, reforestation programs using exotic species (Pinus spp.) were established in the páramo ecosystem of Ecuador. The aims of this study were: (1) to compare the natural regeneration between pine plantations (Pi) and natural grassland (NG) across an elevational gradient and (2) to identify the attributes of Pi and soil properties that were influencing herbaceous and woody plant composition and their plant cover. In total, six independent Pinus patula (Schltdl. & Cham. plantations (two per each elevation) were selected and distributed in an elevational range (3200–3400, 3400–3600, 3600–3800 m a.s.l.). Adjacent to Pi, plots in NG were established for recording natural regeneration. Both, namely the attributes and the soil samples, were measured in Pi. The results showed that natural regeneration differs significantly between both types of vegetation. As expected, NG holds more plant diversity than Pi; the elevational range showed a clear tendency that there was more herbaceous richness when elevation range increases, while the opposite was found for woody species. Moreover, attributes of Pi influenced herbaceous and woody vegetation, when saturated hydraulic conductivity (Ksat) in the soil, basal area (BA) and canopy density (CD) increased, herbaceous species richness and its cover decreseased; and when Ksat and the acidity in the soil increased, woody plants richness and its cover decreased. The plantations have facilitated the establishment of shade tolerant species. More studies are needed to evaluate if removal with adequate management of pine plantations can improve the restoration and conservation of the native vegetation of the páramo ecosystem.

Abstract:

Invasive tree species decrease ecosystem resilience with negative impacts on natural regeneration. The influence of alien tree species on ecosystems is unevenly recognized and does not always account for different habitat specificity. We assessed the impacts of the three most frequent invasive tree species in European forests: Prunus serotina Ehrh., Quercus rubra L., and Robinia pseudoacacia L. on natural regeneration diversity, species composition, and density. We hypothesized that invaded forest types, in comparison with non-invaded, will differ in terms of species composition, will have lower taxonomic, functional, and phylogenetic diversity of natural regeneration, and will have lower densities of native tree species. We used a set of 189 study plots (200 m2) in a systematic design, established in various forest types in Wielkopolski National Park (West Poland). We analyzed impacts of forest type, accounting for soil C:N ratio, soil pH, and light availability on natural regeneration (woody species up to 0.5 m height) species composition, diversity, and density. We found an overlap of species composition among invaded and non-invaded forests and low impacts of invasive species on taxonomic diversity and functional richness. We found no impacts on phylogenetic diversity and other functional diversity components. In contrast, we found that the natural regeneration of forest-forming tree species reached lower densities in invaded than non-invaded forest types. However, sub-canopy and shrub species reached higher densities in invaded than non-invaded forest types. We confirmed that invasive tree species affect natural regeneration by decreasing the regeneration density of native tree species (in eight of nine tree species studied), species composition hom*ogenization, and supporting natural regeneration of sub-canopy and shrub species. Therefore, the restoration of invaded forests requires eradication of invasive tree species to decrease propagule pressure and to stop decreases in the abundance of native tree species’ natural regeneration.

Abstract:

Abstract The density of established and newly germinated commercial tree regeneration was assessed on 33 stands in northeastern Pennsylvania representing both northern hardwood and oak-hickory forest types. The purpose of the study was to determine the amount of regeneration on stands with differing amounts of residual basal area after harvest. Most stands were on nonindustrial private lands that had been harvested between 2-8 yr ago. The density of new germinants decreased while the density of seedling and sapling regeneration greater than 3 ft tall increased with increasing basal area removal. This result suggests that recruitment of taller seedlings and saplings improves with increasing intensity of harvests. Evidence of browsing by white-tailed deer (Odocoileus virginianus Zimmermann) was observed on nearly all species and was 50% or higher for seven species. High fern cover was most evident in heavily browsed areas. Neither slash cover nor height of slash was related to the density of any of the regeneration classes. This suggests that slash may not always afford adequate protection from deer. As in other parts of the state, a relative scarcity of sapling regeneration and high browsing incidence on many commercially valuable species indicates that problems with deer and competing species, like fern, need to be addressed in order to achieve sustainable forest management in northeastern Pennsylvania. North. J. Appl. For. 15(3):130-134.

Abstract:

Successful mixedwood management in the boreal forest of Alberta requires better knowledge of the occurrence and success of natural white spruce regeneration. In this study we developed statistical models to predict the natural establishment and height growth of understory white spruce (Picea glauca (Moench) Voss) in the boreal mixedwood forest in Alberta using data from 148 provincial permanent sample plots, supplemented by measurements of the amount and height growth of regenerating white spruce, and the amount and type of available substrate. A discriminant model correctly classified 73% of the sites as to presence or absence of a white spruce understory based on the amount of spruce basal area, rotten wood, ecological nutrient regime, soil clay fraction and elevation, although it explained only 30% of the variation in the data. On sites with a white spruce understory, a regression model related the abundance of regeneration to rotten wood cover, spruce basal area, pine basal area, soil clay fraction, and grass cover (R2 = 0.36). About half of the seedlings surveyed grew on rotten wood, and only 3% on mineral soil, and seedlings were 10 times more likely to have established on these substrates than on litter. Exposed mineral soil was rare, covering only 0.3% of the observed transect area, rotten wood covered 4.5%, and litter/undisturbed forest floor covered the remainder. The regression models developed for average relative height growth rate included feather moss cover, stand age and birch basal area for seedlings ≤ 1 m (R2 = 0.23), and feather moss cover, elevation, other moss cover and soil clay fraction for seedlings between 1 m and 3 m (R2 = 0.27). Key words: Picea glauca, seedling establishment, seedbeds, site factors, coarse woody debris, predictive models, mixedwood management

Abstract:

After nearly two centuries of contact with Europeans, the Māori language of New Zealand was, by the 1960s, threatened with extinction. Accompanying a movement for ethnic revival, a series of grassroots regeneration efforts that established adult, preschool, and autonomous school immersion programs has over the past two decades increased substantially the number of Māori who know and use their language, but this has not yet led to the reestablishment of natural intergenerational transmission. More recently, responding to growing ethnic pressures, the New Zealand government has adopted a Māori language policy and is starting to implement it. Seen in its widest social, political, and economic context, this process can be understood not as colonial language loss followed by postcolonial reversing language shift activities, but as the continuation of a long process of negotiation of accommodation between autochthonous Māori and European settlers.

Abstract:

Aim of the study: To describe the effect of stand edge after clearcut on the process of Scots pine (Pinus sylvestris L.) natural regeneration along the edge-to-interior gradient. The density, height, horizontal structure and quality of natural regeneration was evaluated.Area of the study: Kokořínsko Protected Landscape Area, Northern Bohemia (Czech Republic). The study sites naturally host Scots pine Pinetum oligotrophicum with cover of Vaccinium myrtillus L. and Vaccinium vitis-idaea L. in the herbal storey.Material and methods: Two 40 × 40 m permanent research plots were situated at the forest edge, two adjacent plots were established within the forest stand as control plots. Differences in regeneration characteristics were tested by analysis of variance (ANOVA) followed by the Tukey HSD test. Interactions between regeneration characteristics and the distance from the edge were evaluated by Pearson correlation. The relationship between the top storey and natural regeneration was depicted by pair-correlation function. Principal components analysis was carried out to assess overall data structure.Main results: Generally, the further from the stand edge, the lower natural regeneration density (r ≤ -0.64, p<0.001), mean height (r ≤ -0.54, p<0.001) and the best-quality promising individuals (r = -0.40, p<0.05) were found, whereas significant influence on overall average pine quality was not observed. The highest regeneration density (15,250 pcs/ha) was reached at a distance of 5-10 m from the stand edge.Research highlights: The forest edge interior can become favourable location for natural regeneration and can be implemented into traditional regeneration approaches in pine regions.

Abstract:

ABSTRACT Veredas (palm swamps) is a type of vegetation associated with watercourses, characterized by the presence of Mauritia flexuosa palm trees. These systems are not well understood and suffer from high anthropogenic pressure. The aims of this study were to describe the natural regeneration of two swamp forests in vereda systems with different anthropogenic impacts and investigate if the variation in these plant communities are associated to edaphic conditions. The study was performed in preserved and impacted sites located in the Environmental Protection Area of the Pandeiros River in northern Minas Gerais. At each site, one hundred 25 m2 plots were established for surveying regenerating shrubs and trees (≥1 cm diameter at the base of the stem and < 3 cm diameter at breast height). Vegetation structure was evaluated by phytosociological parameters, similarity index, and size distribution of individuals. Regenerating strata was correlated with chemical and physical soil analyses. The vegetation at the preserved site was characterized by a higher number of individuals and a lower diversity but contained species that were typical of flooded areas. The results also showed differences in soil nutrient availability between sites that influenced the distribution of species at the two study sites.

Abstract:

In a 0.75-ha plot in a Norway spruce (Picea abies Karst.) – silver fir (Abies alba Miller) stand in Comelico (Italian eastern Alps), we analysed (i) the distribution and growth of natural regeneration of Norway spruce and silver fir as affected by stand structure and (ii) the age structure of all saplings between 0.2 and 10 m in height in a 30-year-old gap. In both species, most natural regeneration was clumped and located at the margin of the gaps; however, fir saplings were more represented in understorey environments and less represented in gaps as compared with spruce. Age structure of natural regeneration in the selected gap revealed that the majority (75%) of saplings appeared after the formation of the gap; however, for regeneration taller than 2 m (which has a better chance of reaching the uppermost canopy layer), saplings already present at gap formation predominated. We conclude that (i) gap edges represent a preferential regeneration niche in this forest and (ii) saplings established before gap formation can play an important role in gap refilling. These results provide useful information to ensure, through silvicultural practices, favourable conditions for the temporal and spatial continuity of the regeneration process.

Abstract:

The aims of the investigation were to (i) quantify the changes in natural regeneration and stand structure, (ii) determine the role of deadwood in the process of regeneration following the disturbance, and (iii) determine the effect of disturbance severity on tree recruitment. The study was conducted in the Szast Protected Forest, which was established after a blowdown in 2002. The results showed that the trees were mainly wind-snapped. The basal area of the slightly disturbed stands increased over time. Herb cover increased, whereas moss cover decreased in 2011. The disturbance severity influenced the density of tree species regeneration, moss and herb ground cover, species diversity, average tree height, tree vitality, and damage caused by herbivores. The density of natural regeneration increased and new species became established after the disturbance. Scots pine (Pinus sylvestris L.) was the dominant tree species during the regeneration process except in the severely disturbed stand from which wood had been removed; in this case, birch was the dominant species. Wind disturbance increased species diversity and created a new forest with a particular species structure and trees that varied in age and height. The results of this study will be useful for foresters and policymakers to change the existing approaches to large-scale disturbances in the Polish forests.

Abstract:

In the history of European cities, public spaces always played a pivotal role, representing key places for developing social interactions and for enhancing the sense of community. Squares, commercial streets, market places as well as traditional retail and art-and-crafts areas can be considered the core of the city. The social, economic and demographic crisis and the loss of cultural identity has affected the capacity of attraction of local small retailers, giving the floor to the aggressive strategies of suburban shopping malls, centers, arcades or precinct, forming a complex of shops, movie theaters, restaurants and food courts with interconnecting walkways [. Typical expressions of a globalized economy, the different categories of suburban shopping mall have transformed behaviors and paths at a large scale [. One consequences can be identified in the loss of traditional commercial activities within the city centre, producing a situation of urban decline, mirrored by the impoverishment of public spaces [[. This paper suggests that, by activating the existing cultural and socio-economic capital it is possible to undertake a successful regeneration process based on a participative approach and on public and private integrated tools. By focussing on the experience of the Centri Commerciali Naturali (Natural Commercial Centres) established in Italy as partnership between Municipalities, cultural operators, public services providers and associations of shops owners to exploit the commercial activities in the historical centers the ongoing research is oriented to explore successful experiences of private-public partnership to be implemented in a regeneration process of areas traditionally dedicated to retail and art-and-craft small enterprises. The paper discusses the potentiality and the criticism of the NCC as engine for the redevelopment and regeneration of the inner city abandoned retail areas. In so doing, the experience developed in Campania (Southern Italy) will be analyzed in order to show how the activation of the social capital within the framework of the CCN could contribute in renovating the traditional commercial identity of the area, supporting the public spaces regeneration process. This paper aspires to offer useful insights to all those policy makers, city managers and planners who seek to revitalise traditional market areas in European city centres.

Abstract:

Abstract Some plant species have a striking capacity for regeneration in nature, including regeneration of the entire individual from explants. However, due to the lack of suitable experimental models, the regulatory mechanisms of spontaneous whole plant regeneration are mostly unknown. In this study, we established a novel model system to study these mechanisms using an amphibious plant within Brassicaceae, Rorippa aquatica, which naturally undergoes vegetative propagation via regeneration from leaf fragments. Morphological and anatomical observation showed that both de novo root and shoot organogenesis occurred from the proximal side of the cut edge transversely with leaf vascular tissue. Time-series RNA-seq analysis revealed that auxin and cytokinin responses were activated after leaf amputation and that regeneration-related genes were upregulated mainly on the proximal side of the leaf explants. Accordingly, we found that both auxin and cytokinin accumulated on the proximal side. Application of a polar auxin transport inhibitor retarded root and shoot regeneration, suggesting that the enhancement of auxin responses caused by polar auxin transport enhanced de novo organogenesis at the proximal wound site. Exogenous phytohormone and inhibitor applications further demonstrated that, in R. aquatica, both auxin and gibberellin are required for root regeneration, whereas cytokinin is important for shoot regeneration. Our results provide a molecular basis for vegetative propagation via de novo organogenesis.

Abstract:

Two permanent sample plots (both 0.25 ha) were established in a mixed forest in the Orlické hory Mts. Protected Landscape Area (northeastern Bohemia) to analyze the natural regeneration of Norway spruce (<I>Picea abies</I> [L.] Karst.) and silver fir (<I>Abies alba</I> Mill.). All the seedlings (height 0.1–0.5 m), saplings (height 0.5 m, <I>d</I>_1.3 3 cm) and trees (<I>d</I>_1.3 > 3 cm) were localized and measured. The analysis of the spatial pattern and statistical evaluation were carried out by means of Ripley’s <I>K</I>-function. All the growth stages of the spruce and the fir showed an aggregated (clump) pattern, whereas the regeneration of fir was positively correlated with mature spruces and the regeneration of spruce was in a positive relation with mature firs. The results indicate that for germination and stable growth in the first stages of development, the fir can find more favourable conditions under the crowns of spruce trees and the spruce under mature firs.

Abstract:

The study focused on the effects of gap size on natural regeneration of European beech (fa*gus sylvatica L.) and Norway spruce (Picea abies L.) and micro-environmental soil conditions in gaps of different sizes under temperate mixed forest in the Czech Republic. Six gaps comprising two for small (≥ 200 m²), medium (≥ 500 m²) and big (≥ 900 m²) each were selected. Ten circular 1 m² subsampling plots were established at 2 m intervals along individual North-South-East-West transects, including one at the gap centre. Regeneration was monitored in 2014 and repeatedly in 2019. Soil conditions were only measured in 2019. Gap size was found to be a significant parameter for European beech natural regeneration in 2014. Besides, the quick occupation of European beech in gaps at natural beech zone provoked its prolific regeneration compared to Norway spruce in 2014. However, in 2019 the recent threat of weather variabilities was responsible for the general abysmal growth performance of natural regeneration. Division of gap microsites into different within-gap positions based on prevailing light or shade conditions was helpful in assessing the significant variations of soil conditions within-gap positions and among gap sizes. Soil temperature and moisture significantly influenced the regeneration of European beech and Norway spruce, respectively.

Abstract:

The paper presents the results of field studies of tendencies in plant communities self-regeneration processes in the zone of their technogenic disturbance and on the surfaces of rock spoil heaps. It has been established that in the former case the key factor determining the nature of development of self-regeneration processes is the correspondence of the width of the transitional community to the length of transfer of seeds of primary plant community edificatory and assectator species. In the latter case, the key self-regeneration succession sere passes the bifurcation point at a very early stage of its development.

Abstract:

AbstractThe potential utilisation of natural regeneration of European beech (fa*gus sylvatica L.) for forest conversion has received little attention to date. Ecological knowledge is necessary to understand and predict successful natural regeneration of beech. The objective of this study was to improve understanding of what drives the occurrence of beech regeneration and, once regeneration is present, what drives its density. In the study, we utilised a forest inventory dataset provided by Sachsenforst, the state forestry service of Saxony, Germany. The dataset was derived from 8725 permanent plots. Zero-altered negative binomial models (ZANB) with spatial random effects were used to analyse factors influencing occurrence and density simultaneously. The results provided by the spatial ZANB models revealed that the probability of the occurrence of beech regeneration is highly dependent on seed availability, i.e. dependent on source trees in close proximity to a plot. The probability of beech regeneration rises with the increasing diameter of a potential seed tree and decreases with increasing distance to the nearest potential seed source. The occurrence of regeneration is affected by overstorey composition and competition exerted by spruce regeneration. Where sites are affected by groundwater or temporary waterlogging, the impact on the occurrence of regeneration is negative. Although distance to the nearest potential seed source has an influence on occurrence, this variable exerts no influence on density. A high regeneration density arises in conjunction with a high beech basal area in the overstorey. Beech regeneration density, but not occurrence, is negatively affected by browsing intensity. These variables can be used to predict the occurrence and density of beech regeneration in space to a high level of precision. The established statistical tool can be used for decision-making when planning forest conversion using natural regeneration.

Abstract:

Density of regeneration in European subalpine Norway spruce (Picea abies) forests is typically low with regeneration primarily located on dead or decaying wood. The post-disturbance development of this regeneration is crucial for natural forest succession. The aim was to identify the influence of disturbance on regeneration on decaying logs immediately after a severe disturbance event. Study plots were established in two subalpine spruce forests: the first, an undisturbed site located in the Hrub&yacute; Jesen&iacute;k Mts. and the second site in the &Scaron;umava Mts. that has experienced recent severe disturbance. Regeneration density increased between 2008 and 2011 by 7% (0.29 individuals per square meter of log) at the undisturbed site and by 33% (3.24 individuals per square meter of log) at the disturbed site. The increased regeneration density observed at the disturbed site was mostly associated with the smallest saplings. The highest increase in regeneration density was observed on logs with the largest diameters. Three years after severe disturbance caused 100% mortality of the parent stand in the Bohemian Forest, no significant effect was recorded on the growth rate and survival of established spruce saplings on dead wood. &nbsp;

Abstract:

Tissue engineering (TE) and regenerative medicine integrate information and technology from various fields to restore/replace tissues and damaged organs for medical treatments. To achieve this, scaffolds act as delivery vectors or as cellular systems for drugs and cells; thereby, cellular material is able to colonize host cells sufficiently to meet up the requirements of regeneration and repair. This process is multi-stage and requires the development of various components to create the desired neo-tissue or organ. In several current TE strategies, biomaterials are essential components. While several polymers are established for their use as biomaterials, careful consideration of the cellular environment and interactions needed is required in selecting a polymer for a given application. Depending on this, scaffold materials can be of natural or synthetic origin, degradable or nondegradable. In this review, an overview of various natural and synthetic polymers and their possible composite scaffolds with their physicochemical properties including biocompatibility, biodegradability, morphology, mechanical strength, pore size, and porosity are discussed. The scaffolds fabrication techniques and a few commercially available biopolymers are also tabulated.

Abstract:

This study assessed the dynamics of gap development in postharvest regeneration in five stands in northwestern Alberta dominated by trembling aspen (Populus tremuloides Michx.). The pattern of gap development over time was determined from analysis of air photographs taken preharvest and 1, 4, 10, and 12 years postharvest. The area of each stand covered by gaps increased after harvest because of the addition of harvest-related gaps over and above those that had been present prior to harvest. The blocks we studied had a combined gap area of up to 29% of stand area 12 years postharvest. We measured regeneration characteristics, microsite, soil, light, and browse conditions in 30 aspen regeneration gaps (gaps in regeneration that were not gaps preharvest and were not due to obvious harvest-related disturbance) 14 years following harvest. Although deciduous trees within postharvest regeneration gaps were the same age as those outside (i.e., in a fully stocked matrix of newly established even-aged aspen stems), they were often suppressed, with significantly lower density and growth. Within the 14-year-old postharvest regenerating aspen stands, aspen height varied from 1 to 11 m; this substantial variability appeared to be largely due to the influence of browsing. There was little evidence of ongoing regeneration within postharvest regeneration gaps, indicating that these gaps will probably persist over time. This may impact future deciduous stocking and volume. It is unknown what may have initiated the formation of these gaps, although results suggest that they are not due to edaphic conditions or disease in the preharvest stands. There is evidence that bluejoint (Calamagrostis canadensis (Michx.) Beauv.) cover and browsing are important factors in the maintenance of postharvest regeneration gaps. The spatial heterogeneity resulting from gaps could be advantageous, however, either as part of ecosystem-based management emulating natural disturbance or as a template for mixedwood management, where white spruce (Picea glauca (Moench) Voss) are established in gaps.

Abstract:

An experimental stand was established as a monoculture by planting Norway spruce on a clear-felled area in 1925. In 1958, a research thinning experiment was established there. Control plots and the study of their development without anthropic interventions are of interest in particular. The spruce monoculture nearly disintegrated and the stand-forming role was taken over by species which occurred there originally as admixed ones. The stand became sparser and it was associated with the spontaneous regeneration of broadleaves. Out of the eight control plots three plots were selected differing significantly in stocking and extent of natural regeneration. The development of regeneration was studied in detail on these plots. The undergrowth consisted of 24 woody species in a total number of <br />6,000 individuals per hectare and about two thirds of them belonged to trees. The results of the study show a possibility to convert a spruce monoculture to a broadleaved commercial forest using the spontaneous regeneration of trees.

Abstract:

Boreal forest disturbance regimes have changed during the past century, in turn changing regeneration and stand dynamics of these forests. This is occurring at the same time that the forest industry is emphasizing operations that take advantage of pre-established natural regeneration. This study has therefore investigated the effect of various ecological factors on the abundance of Abiesbalsamea (L.) Mill., Piceaglauca (Moench) Voss, Piceamariana (Mill.) BSP, Thujaoccidentalis L., Betulapapyrifera Marsh., and Populustremuloides Michx. natural regeneration in some boreal stands in the Abitibi region of Quebec. Abiotic ecological site classification variables were found to be poorly correlated with seedling densities for most species. Parent trees, as a seed source, and stand type, for its influence on the quality of the seedbed, were strongly correlated with abundant conifer regeneration. As expected, time since fire was positively correlated with seedling abundance for late successional species, whereas it was not related to the abundance of early successional species. Post-fire disturbances, such as those due to spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks, accounted for the variations in seedling densities observed with respect to stand age. The presence of budworm-caused gaps was positively correlated with regeneration abundance, whereas shrub competition, which was greatest in large gaps, was negatively correlated with advance regeneration density. Forest management based on abundance of pre-established regeneration should focus mainly on mixed stands because seedling density is very low in hardwood stands and because of the strong competition found in large gaps of resinous forests. The low number of seedlings observed, especially in coniferous stands, may limit the effectiveness of operations that take advantage of advance regeneration. The large variability observed among site and stand types limits their operational use in predicting seedling densities.

Abstract:

The study of regeneration features of forest vegetation that has come out of agricultural land is one of the urgent problems of Russia. This article presents the results of studying the spatial and age structure of the natural renewal of abandoned hayfields under the conditions of spruce and pine forests in comparable forest conditions of the Middle Urals. It has been established that, according to the quantitative indicators of settlement for both all and individual tree species, hayfields in the conditions of the pine forest are resumed much more efficiently than hayfields in the conditions of the grass spruce forest. The density of hayfield population of all tree species under conditions of both grass spruce and berrying pine shows a pronounced tendency to decrease with distance from seed sources. When woody vegetation is populated by hayfields under the conditions of grass spruce, the group type of tree distribution is predominant characteristic of both the whole and individual tree species - spruce and birch. Regular type of distribution is typical for the conditions of berrying pine forests, and with active renewal of deciduous group type of settlement, both as a whole and separately for tree species. The first stage of overgrowing of spruce hayfields in the conditions of grass spruce occurs gradually. It starts from about 3-4 years after termination of exposure and lasts for a minimum of 20 years. Intensive settlement of pine begins from 2-3 years, reaching maximum values at 4-5th year after the termination of haying.

Abstract:

In 1974, two clearcuts, two shelterwoods, and two sets of eight group selections (equally divided between two elevation zones) were harvested on the Coram Experimental Forest in northwestern Montana. Four levels of tree and residue utilization were compared. Moist fuels on approximately half of each area were poorly burned by prescribed fires in September 1975. Natural regeneration on these treatments was compared in 1979, 1987, and 1992. Regeneration of western larch (Larix occidentalis Nutt.) began in 1975 on soil exposed during yarding of logs and continued mostly in 1977 and 1979 on these scarified sites and other burned areas. Competing vegetation curtailed establishment of larch seedlings much past 1979 on these sites. Few Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) regenerated before 1979 but aggressively established through 1992. Engelmann spruce (Picea engelmannii Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt) regeneration began in 1979 and is increasing slowly throughout the area. Western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western red cedar (Thuja plicata Donn.) also slowly regenerate moister areas of the lower elevation units.

Abstract:

Annual height growth of natural regeneration was measured in 18- to 21-year-old clear-cuts of black spruce stands growing on sites of contrasted drainage, in two ecological regions of the Haute-Gatineau-et-Cabonga management unit in western Quebec. Most regeneration was established by layering and was growing slowly on all sites at time of release by clear-cutting of the main stand. Height growth rates increased rapidly thereafter on mesic sites: about 7 to 8 years after release, it reached 15 cm or more per year, and 32 to 45 cm per year 20 years after harvest. On moist sites, growth rates of 15 cm per year were attained only 10 to 15 years after release, and did not exceed 25 cm at age 20. These results show that growth of black spruce natural regeneration is controlled more by site quality than by the mechanism responsible for reproduction.

Abstract:

Scots pine (Pinussylvestris L.) were selectively seeded in 1990, 1991, 1992, and 1994 in bottom layer vegetation of Pleuroziumschreberi (Bird.) Mitt, in a clearcut created in 1989 and in an adjacent undisturbed Scots pine forest of Vaccinium type, in northern Sweden. Seedlings from the 1990 seeding established considerably better on the clearcut than in the forest. In contrast, seeding done in 1991, 1992, and 1994 gave no significant difference in seedling establishment between the two sites. Seedlings that established in the clearcut in 1990 grew significantly larger and had a higher content of macro- and micro-nutrients than those in the forest. For seedlings that established in 1992, biomass and nutrient content of seedlings in the clearcut did not differ from those in the forest. Seedlings established in the clearcut in 1990 increased their nutrient content in relation to seed supply, while seedlings established in the clearcut in 1992 and those in the forest had in general gained less or even lost nutrients (especially P) in relation to seed reserve. These results indicate that Pleuroziumschreberi-dominated microsites can constitute a favourable microhabitat for pine regeneration following stand disturbance, although the positive effect quickly diminishes with time after disturbance. The higher establishment and growth of emerging seedlings the 1st year after cutting compared with later established cohorts in the clearcut may be caused by changes in nutrient availability. We propose that environmental stress after cutting temporarily diminishes the effect of the nutrient barrier formed by Pleuroziumschreberi, ericoid mycorrhiza, and ericaceous dwarfshrubs. We conclude that successful natural pine regeneration in Pleuroziumschreberi-dominnted vegetation induced by clear-cutting can be severely time restricted. This is an important consideration when dealing with forestry methods that depend on natural regeneration.

Abstract:

Bamboos in the understory of Abiesfaxoniana Render & Wilson forests in China impede tree regeneration when they are mature. However, bamboos die back every few decades and may synchronize tree seedling establishment on the forest floor. Tree seedling regeneration patterns were studied beneath 20 canopy gaps and adjacent closed forest in an old-growth A. faxoniana forest where understory bamboos died back in 1976. Most seedlings of A. faxoniana, Acercaudatum Wallich, and Betulautilis D. Don in gaps established 2 years after dieback of the bamboo Fargesiadenudata Yi. Acercaudatum seedlings in gaps were taller than those of B. utilis or A. faxoniana, and B. utilis seedlings were fourfold more abundant in gaps than the other species. All species (except A. caudatum) had greater seedling densities in gaps, but there were no density differences among species beneath closed forest. Bamboo cover and maximum culm height were greater under gaps than forest, and it takes bamboo seedlings about 18 years to grow to full height. Bamboo seems to reduce the success of an advanced regeneration strategy and promotes synchronized seedling establishment in gaps after it dies back.

Abstract:

The work is devoted to the study of the recovery processes of the sorption properties of diatomite contaminated with oil products (NP) when it is processed in a dielectric barrier discharge (DBD). Dependences of the sorption capacity on the initial concentration of petroleum products (PP) for the three types of sorbents (diatomite, schungite, zeolite) were determined and working ranges of PP concentrations for the investigated sorbents were established. It was shown that pretreatment of uncontaminated diatomite in DBP led to an increase in its sorption capacity, i.e. there was an "activation" of the sorbent, associated with a change in the properties of its surface, namely, with an increase in the surface of the active centers. The maximum number of cycles of regeneration of the sorbent in DBD, under which it does not lose its physical properties, is eight cycles. Optimum parameters of treatment of contaminated PP diatomite in DBD were established: processing time - 1 min, flow rate of plasma forming gas - 1 l / min, power input into discharge - 8.9 W/cm3. After treatment of the sorbent in the plasma-chemical reactor under optimal conditions, the sorption capacity of diatomite increases by 2.4 times. Thus, based on the results of the conducted studies, it was revealed that when treating contaminated sorbents, the dielectric barrier discharge has a synergistic effect: activates the surface of the sorption material and leads to the destruction of oil products presenting in the sorbent, i.e. this method can be effectively used for the purification of environmentally objects polluted with oil.Forcitation:Gusev G.I., Gushchin A.A., Grinevich V.I., Osti A.A., Izvekova Т.V., Kvitkova E.Yu. Regeneration of natural sorbents contaminated with oil products in dielectric barrier discharge plasma. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 72-76.

Abstract:

Direct assessment of forest regeneration from remote sensing data is a previously little-explored problem. This is due to several factors which complicate object detection of small trees in the understory. Most existing studies are based on airborne laser scanning (ALS) data, which often has insufficient point densities in the understory forest layers. The present study uses plot-based terrestrial laser scanning (TLS) and the survey design was similar to traditional forest inventory practices. Furthermore, a framework of methods was developed to solve the difficulties of detecting understory trees for quantifying regeneration in temperate montane forest. Regeneration is of special importance in our montane study area, since large parts are declared as protection forest against alpine natural hazards. Close to nature forest structures were tackled by separating 3D tree stem detection from overall tree segmentation. In support, techniques from 3D mathematical morphology, Hough transformation and state-of-the-art machine learning were applied. The methodical framework consisted of four major steps. These were the extraction of the tree stems, the estimation of the stem diameters at breast height (DBH), the image segmentation into individual trees and finally, the separation of two groups of regeneration. All methods were fully automated and utilized volumetric 3D image information which was derived from the original point cloud. The total amount of regeneration was split into established regeneration, consisting of trees with a height > 130 cm in combination with a DBH < 12 cm and unestablished regeneration, consisting of trees with a height < 130 cm. Validation was carried out against field-based expert estimates of percentage ground cover, differentiating seven classes that were similar to those used by forest inventory. The mean absolute error (MAE) of our method for established regeneration was 1.11 classes and for unestablished regeneration only 0.27 classes. Considering the metrical distances between the class centres, the MAE amounted 8.08% for established regeneration and 2.23% for unestablished regeneration.

Abstract:

ABSTRACTBackground: The article reports basic science research that establishes that adipose tissue (AT)-derived mesenchymal stem cells (MSCs) have a potential to transgerminal translation. Study Design: MSC confirmation was obtained by phenotypic spindle-shaped cells as well as with four positive and three negative markers. The translineage translation of adipose-derived MSCs (ADMSCs) was established. Materials and Methods: The lipoaspirate was subjected to enzymatic digestion with collagenase. Stromal vascular factor (SVF) was isolated. With two passages, pure culture of ADMSCs was obtained. They were translated to all the three germinal layers. Results: AT-derived SVF contains ~30% MSCs. They are capable of being translated into endoderm, mesoderm and ectoderm. Conclusion: AT is a rich source for MSCs, with immense research possibilities for regeneration and rejuvenation.

Abstract:

Abstract Between 1940 and 1964 Bernard M. and Belle W. Baruch did regeneration cuts (residuals of less than 50 ft²/ac) on 3,700 acres of pine forest on Hobcaw Barony. By 1975 pine regeneration was adequate on only 1,400 acres. Loblolly pine was successfully established only on well-drainedsites along the edges of the peninsula. Pines were not regenerated by seed tree cutting and periodic burning on the poorly drained soils characteristic of the center of interstream divides. Proper understory control was more important as drainage decreased. Land owners on the lower coastalplain should be aware that understory control is vital to success of natural regeneration on poorly drained lands. South. J. Appl. For. 13(1):25-28.

Abstract:

Natural regeneration of understory conifers was studied in 1988, 9–14 years after thinning of even-aged stands of western hemlock (Tsugaheterophylla (Raf.) Sarg.) and Sitka spruce (Piceasitchensis (Bong.) Carr.) on upland sites in southeast Alaska. Two age-classes of stands were compared: young stands, <30 years old that before thinning had open forest canopies and understories of conifer regeneration, shrubs, herbs, and forbs; and older stands, 31–98 years old, that before thinning had closed forest canopies and little or no understory vegetation. In 1988, dominant understory conifers in young stands were 2–4 m tall, and about the same age as trees in the overstory. In the older stands there was dense new regeneration that germinated 2–3 years after thinning and averaged 0.6–1.5 m tall. Seventy-two to 100% of all regeneration was hemlock. The rest was Sitka spruce. The amount of regeneration increased and the percentage of hemlock decreased with increasing thinning intensity. Thinning of young stands on upland sites appears to benefit understory conifers, which rapidly expand to fill in the available growing space. Heavy thinning in older stands promotes dense germination of understory conifers making it difficult for other understory plants to become established.

Abstract:

We examined the potential of natural regeneration for stocking 1-ha patch cuts in high-elevation Engelmann spruce (Picea engelmannii Parry) – subalpine fir (Abies lasiocarpa (Hook.) Nutt.) forests. Using the Sicamous Creek Silvicultural Systems site, which was harvested during winter 1994–1995, we established 1-m2 plots in patch cuts, forest edge, and untreated control forest. We marked and recorded microsite characteristics for all advanced regeneration and new recruits for up to 5 years; over 12 000 individuals were included. Advanced regeneration was abundant and was about one-quarter spruce. Spruce and fir germinants occurred in all years, but numbers varied greatly, with a very large cohort in 1998. Both advanced regeneration and new recruits were concentrated on decaying logs. Mortality of advanced regeneration was high in the patch cuts following harvest, but subsequent survival was good, approaching rates in the untreated forest within 4 years. Survival rates were higher for spruce than fir, but differed little among surface types and microtopographic positions. Survival of new recruits was high, approximately 50% the first year and 70% during the second, and was similar between spruce and fir. If the 1998 cohort has similar survival, the patch cuts could be adequately stocked. Use of natural regeneration, in combination with infill planting, is a viable option for stocking small openings in wet high-elevation forests in southern British Columbia.

Abstract:

Using a factorial combination of understory removal and trenching treatments, we examined the influences of belowground competition from understory and overstory vegetation on growth of naturally established Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) saplings in thinned stands of Douglas-fir on moderately productive, glacially derived soils near Tacoma, Washington. Under limited light (26% ± 16% of full sun), sapling height and diameter growth were significantly reduced by belowground competition from overstory trees. Regardless of presence or absence of belowground competition from trees, understory vegetation did not have a detectable effect on sapling growth. Nitrogen deficiency in saplings was not detected in the presence of belowground competition: where tree roots were excluded, foliar nitrogen concentration and content increased without an increase in foliar mass. Belowground competition from overstory trees had a greater negative effect on growing season soil water content than did understory vegetation. Under the conditions of restricted light availability in this study, limitations in soil water content from competition had a strong growth-limiting effect on Douglas-fir regeneration. As potential canopy trees in a future uneven-aged stand, this sapling cohort would benefit from root gaps created during harvests.

Abstract:

Natural regeneration and structure and their relationship to environmental variables were studied in three sections of a gallery forest, in Eastern Mato Grosso, Brazil (14º43′S and 52º21′W). The assumption was that natural regeneration is constrained by environmental determinants at all stages of development of the tree community. The objective was to analyse the forest structure and to verify the relationship between species distribution and abundance at different stages of regeneration and environmental variables. In each section, 47 contiguous (10x10m) permanent plots were established to sample trees (gbh≥15cm), following a systematic design. Seedlings (0.01 to 1m height), saplings (1.01 to 2m) and poles (from 2.01m height to gbh<15cm) were sampled in sub-plots of 1x1m, 2x2m and 5x5m, respectively. In each plot, soil properties, gaps projection, bamboos, rocky cover, declivity and depth of ground watertable were determined. The relationships between the environmental variables with trees and seedling communities were assessed by canonical correspondence analysis. In spite of the sections being near to each other, they presented large differences in floristics, structure and site conditions. The forest soil presented a low cation exchange capacity and a high level of Al saturation. The occurrence of bamboos and gaps and the depth of ground watertable limited the occurrence of poles and trees. The high degree of structural heterogeneity for each regeneration category was related primarily to a humidity gradient; but soil fertility (Ca+Mg) was also a determinant of seedling and sapling communities.

Abstract:

The paper analyses functional efficiency of stand with soil-conservation erosion control function. The object of research was the subcompartment 1160 d on the forest unit Banská Bystrica – Uľanka. In the stand was established the network of six permanent sample plots, where the basic characters of structure were recorded and functional efficiency of trees was estimated. The subject of the research was also an analysis of abundance of natural regeneration. As follows from the research, the stand fulfils the requirement placed on ecosystems with the preferential soil-conservation erosion control function. From the total number of trees, 51 % was assessed as functionally highly efficient. On all permanent sample plots there is natural regeneration in progress. On the basis of functional efficiency practical measures were proposed to improve the existing state.

Abstract:

Population studies of a relic Mediterranean species Juniperus excelsa Bieb. in the southeastern Crimea were conducted. We laid out test plots in such sites of the region: Semidvorje (a natural landmark of local significance); Kanaka (a botanical reserve of national significance); Novy Svet (a botanical reserve of national significance); Kiziltash (a natural landmark having no any conservation status); Karadag (a state nature reserve). The density of Greek juniper populations is approximately similar, varying within 400–500 plants/ha. We have estimated age structure, age index and regeneration index of studied populations. They are dominated by normal left-sided age spectra. It has been established that the current level of recreational load does not pose a threat to the existence of juniper communities: the intensity of natural regeneration is rather high. However, the threats for juniper forests may be a reduction their area due to the construction of new resort facilities and their infrastructure, as well as illegal tree cutting.

Abstract:

The research was focused on exploring the dynamics and forms of regeneration processes and structural diversity of the Norway spruce virgin forest in Babia hora NNR in relation to altitude. In each developmental stage <br />19 sample plots were established. The structural diversity was assessed by the indices proposed by Clark and Evans (1954), F&uuml;ldner (1995) and Jaehne and Dohrenbusch (1997). Concerning the spatial distribution of the trees in the virgin forest no tendency to their clustering with the increasing altitude was found in the zones below 1,460&nbsp;m. The influence of the altitude was confirmed in the zone above 1,461&nbsp;m where the groups of &ldquo;family spruces&rdquo; are typical. Diameter differentiation was significantly higher in the growth stage. Evaluation of this attribute in terms of the altitude detected significant diameter differentiation at an altitude below 1,260&nbsp;m in the growth stage. According to the F&uuml;ldner index the virgin forest has generally medium differentiated diameter structure. According to the complex index by Jaehne and&nbsp;Dohrenbusch (1997) the differentiation of the virgin forest decreases with the ascending altitude up to 1,460&nbsp;m, where the compact forest ends. Evaluation of the seedbed revealed that 46.2% of the naturally regenerated individuals were growing on mineral soil, 52.4% on dead wood and 1.4% on wind-thrown roots. Regarding the developmental stages 46% of the individuals were found in growth stage, 23% in optimum stage and 31% in breakdown stage.