Natural Regeneration Potential Research Articles

Potential of natural regeneration of Quercus robur L. in floodplain forests in the southern part of the Czech Republic

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.  

Implications of crude oil pollution on natural regeneration of plant species in an oil-producing community in the Niger Delta Region of Nigeria

The study evaluated the impact of crude oil pollution on natural regeneration of plant species in a major oil-producing community in the Niger Delta region of Nigeria. Three sites—unpolluted site (US), polluted and untreated site (PUS), and polluted and treated site (PTS)—were purposively chosen for the study. The seedling emergence method was used to evaluate soil seed banks in the various sites at two depths, 0 to 10 cm and 10 to 20 cm. Woody-plant species richness, abundance, and diversity were higher in the US seed bank than in the PUS and PTS seed banks. The highest number of non-woody plants was observed in the US, followed by the PTS, and then the PUS. Both species richness and diversity of non-woody plants were highest at the US, followed by the PUS, and lowest in the PTS. Woody species in the US seed bank were 87.5% and 80% dissimilar with those of the PUS and PTS at 0–10 cm and 10–20 cm respectively. No variation was observed between woody species in the PUS and PTS seed banks. Non-woody species at 0–10 cm US seed bank were 73.08% dissimilar with those of PUS at the two soil depths and 81.48/88.46% dissimilar with those of the 0–10/10–20 cm of the PTS respectively. At 10–20 cm, non-woody species of the US were 69.66% dissimilar with those from each of the two soil depths in PUS; and 73.91/81.82% dissimilar with those of 0–10/10–20 cm of the PTS respectively. Non-woody species variation between the PUS and PTS was higher at 10–20 cm than 0–10 cm. The poor seed bank attributes at the polluted sites demonstrates that crude oil pollution negatively affected the natural regeneration potential of the native flora because soil seed banks serve as the building blocks for plant succession. Thorough remediation and enrichment planting are recommended to support the recovery process of vegetation in the polluted areas.

Seed rain as a source of propagules for natural regeneration in a temperate forest in Mexico City1

The regeneration of temperate forests is important, especially for those located in urban areas. Sources of propagules, such as seed rain, shape the structure and composition of systems where the availability of diaspores from forest species contribute to both local biodiversity and ecosystem services; these elements are crucial in Mexico City. Over the course of one year, we estimated natural regeneration potential through an analysis of the seed rain deposited in traps that were placed at soil level in plots in three vegetation types: oak, fir and pine forests. We addressed the following questions: Do abundance, density, species composition and diversity of seed rain differ among vegetation types and seasons? How similar is the seed rain to the standing vegetation? Is seed rain a potential source for the natural regeneration of temperate forests? The results showed that the abundance and density of seeds were significantly higher for oak and fir forests due to a higher number of herb, shrub, and tree species in the standing vegetation. The most abundant species in the total seed rain was Ageratina enixa (B.L. Rob.) R.M. King & H. Rob. (12%), but inside individual forest plots, the most abundant were Quercus rugosa Née (16%), Abies religiosa (Kunth) Schltdl. & Cham. (17.5%) and Pinus hartwegii Lindl. (41%). Diversity index values differed among vegetation types but not seasons. Most diaspores in the seed rain corresponded to native species (97%). The similarity between seed rain and the standing vegetation was 40%. In total, 62% of the species are anemochorous, as a result of the high number of Asteraceae species present, and endozoochory is the second most important (17%) dispersal syndrome. A slight asynchrony was observed between the peaks of anemochorous and zoochorous species.

Modeling the long-term natural regeneration potential of woodlands in semi-arid regions to guide restoration efforts

Understanding forest regeneration at sites previously used for agriculture underlies the establishment of science-based woodlands management policies. This is especially relevant in semi-arid areas, where the tree cover is critical in ameliorating the effects of aridity and in preventing desertification and land degradation. Natural regeneration in semi-arid areas occurs very slowly, which in part explains why it has hardly been studied. In the present work, we sought to devise a method to predict the natural regeneration potential of woodlands in semi-arid areas, to be used in guiding restoration efforts. Specifically, we evaluated holm oak coverage at a long-term ecological research site and then designed and validated a model to predict the natural regeneration of holm oak based on a few environmental variables. Unlike available studies, we obtained long-term information on tree regeneration (making use of >60 years of aerial photography) and climate (using long-term climate and microclimate data). We found that microclimate, measured using the potential solar radiation as a proxy, was a key driver of natural regeneration: after 60 years of agricultural abandonment, less sun-exposed areas attained a tree cover >90 %, whereas in more sun-exposed areas it remained below 20 %. We then used the model to map the natural regeneration potential, first in the study area and then in an area where holm oak plantations had been unsuccessfully introduced. In the latter case, the model successfully predicted the failure of this reforestation effort. Our results support the use of this model by decision makers to optimize management practices, as it will encourage the concentration of efforts in areas more prone to successful reforestation and allow the identification of areas more likely to benefit from natural regeneration processes.

Estrutura populacional e potencial de regeneração de <i>Attalea phalerata</i> Mart. ex Spreng. (Acuri)

http://dx.doi.org/10.5902/1980509812356Visando subsidiar o estabelecimento de planos de manejo sustentáveis para Attalea phalerata, apresenta-se resultado da avaliação da estrutura de uma população desta espécie e seu respectivo potencial de regeneração natural. Com base nos dados obtidos, avaliou-se a capacidade potencial de produção de frutos e óleo relacionada à área estudada. A pesquisa foi realizada em área (1 ha) representativa de Mata com Acuri Denso, localizada na RPPN SESC PANTANAL (Mun. Barão de Melgaço, MT, Brasil). Registrou-se 1164 indivíduos, sendo 462 representantes do estádio adulto reprodutivo e 209 representantes do estádio adulto imaturo. Em área amostral parcial (0,1 hectare) foram registrados 123 indivíduos incluídos no estádio jovem e 370 no estádio plântula. A população apresentou estrutura etária do tipo J-invertido, comum a populações estáveis que apresentam potencial de regeneração constante. A produtividade potencial imediata mínima detectada foi de aproximadamente 323 a 970 Kg ha-1 de óleo do mesocarpo e 370 a 601 Kg ha-1 de óleo de amêndoa. A produtividade imediata máxima seria de ca. 970 a 2910 Kg ha-1 de óleo de mesocarpo e 1109 a 1802 Kg ha-1 do óleo de amêndoa.

Natural regeneration potential of abandoned agricultural land in the southern Gadarif Region, Sudan: implications for conservation

AbstractThe present study seeks to provide a contribution to the understanding of vegetation regrowth on abandoned agricultural land by investigating the impacts of the previous cultivation period and the duration of the fallow on the subsequent natural regeneration in terms of vegetation composition, structure and diversity. The results of the study show that both factors have significant effects on the subsequent regeneration of plant species and thus the vegetation development in the southern Gadarif Region, Sudan. The oldest abandoned farmlands were recolonized by tree/shrub species, whereas recently abandoned ones are covered with herbaceous vegetation. There is a general tendency regarding the number of species to decrease with an increase in the period of cultivation. The plant species diversity pattern shows domination of herbaceous species with some scattered woody species. Vegetation changes due to land abandonment may have implications for the conservation of plant species diversity and composition of fauna harboured in the region. Although natural regeneration could be recommended as means of restoring natural vegetation that previously dominated that region, the current regeneration capacity might not be sufficient to reach the climax vegetation except for some pockets, which received more regenerative resources.

Comparative mast seed production in unmanaged and shelterwood white pine (Pinus strobus L.) stands in central Ontario

The effect of the seed cut of the uniform shelterwood silvicultural system on white pine seed production, seed characteristics, and seed viability during 2 mast seeding events was examined in operationally harvested second growth, white pine-dominated forest stands in central Ontario. Seed traps placed along transects in unmanaged and shelterwood stands in each of 3 blocks were used to monitor seed production in 2000 and 2006 (4 and 10 years after harvesting). During these 2 mast seed years between 386,000 and 2,730,600 seed ha−1 were produced among study stands. Total seed production expressed on a per hectare and unit pine basal area basis did not differ by harvest treatment or among blocks in either year. Variability in seed production among stands was primarily due to differences in stand structure, with seed production positively related to white pine basal area. Seed characteristics were largely similar between harvested and unmanaged stands and between seed years. Seed viability was relatively high in both years, with seed from shelterwoods germinating slightly slower than those from unmanaged stands. Seed quality, as estimated by laboratory germination performance, was higher in 2006 than 2000, likely due to improved seed development and maturation in the warmer, wetter growing season of 2006. Our results suggest that the seed cut of the uniform shelterwood system applied to second growth white pine stands is unlikely to adversely affect white pine seed production, seed quality, or potential for natural regeneration during mast seeding events.

Natural regeneration and ecological recovery in Mau Forest complex, Kenya

This study investigated natural ecological recovery in parts of Western and Southwestern blocks of theMauForestcomplex that had experienced varied levels of disturbance. The extent and speed of regeneration in the disturbed regions since the eviction of the setter population were not known. This study thus now provides current baseline data on plant distribution, germination of soil bank seeds, and soil nutrient content. The number of tree species recorded at different levels of disturbance were in increas- ing order: moderately disturbed (MDF) > undisturbed (UDF) > heavy disturbed forest (HDF). Forest clearing reduced forest basal area and forest stocking of big trees (dbh ≥40 cm) in the HDF by more than 4 and 6 times, respectively, than those in UDF. Tree importance values indicated a reduction in commercially valuable species in HDF. Early colonizers and fire tolerant species were predominant in the HDF whereas non-commercial species dominated MDF. Viable soil seed reserves decreased with soil depth in all forests but content between 0 -20 cmsoil depth showed a potential to support regeneration. Total N, organic C and available P decreased with increase in forest disturbance. Overall, the disturbed sites showed a general potential for ecological recovery and natural regeneration to UDF status.

Potencial da regeneração natural como método de restauração do entorno de nascente perturbada

Objetivou-se avaliar o potencial da regeneração natural na restauração da vegetação de área em torno de nascente perturbada, após isolamento de impactos, em ambiente florestal e de pastagem abandonada. Assim, analisou-se a estrutura do estrato arbóreo e das regenerações naturais sob dossel e em área aberta no entorno de uma nascente em processo de recuperação, localizada em Nazareno, Minas Gerais. Levantou-se o estrato arbóreo em 4 parcelas permanentes (10×50 m), amostrando-se as árvores com DAP 5 cm, medindo-lhes diâmetro e altura e identificando-as. Na regeneração natural, lançaram-se 16 parcelas (10×2 m), identificando e medindo em altura os indivíduos arbóreos com altura > 10 cm e DAP < 5 cm. As amostragens se deram aos 7 e 51 meses após o isolamento da área. Calcularam-se os parâmetros fitossociológicos do estrato arbóreo e regenerativo por espécie, classificando-as por síndrome de dispersão e grupo ecológico; calcularam-se os índices de diversidade de Shannon e equabilidade de Pielou por comunidades, também comparadas por índice de Sorensen. As áreas mostraram-se dissimilares, com mais espécies na regeneração sob dossel, indicando aporte no sistema. As comunidades apresentaram alta proporção de espécies zoocóricas e padrão de aumento de espécies climácicas exigentes de luz e diminuição na proporção de pioneiras entre os inventários, indicando avanço na sucessão natural. A densidade de indivíduos na regeneração sob dossel foi muito superior, provavelmente pela dominância de braquiária na área aberta, mostrando que, para esse caso, a utilização da regeneração natural como método exclusivo de recuperação não deve ser aplicada.

Seed wasp invasions promoted by unregulated seed trade affect vegetal and animal biodiversity

Cone and seed insects are considered the most important predators of tree seeds during the pre-dispersal phase of development. Among them, exotic seed chalcids in the genus Megastigmus invaded Europe as a result of the rapidly-increasing and mostly unregulated seed trade for afforestation and ornamental plantations. Unlike their economic impact in seed orchards, until recently, little attention was paid to the ecological impact of these insects. In the present study, selected case studies of alien Megastigmus spp. were considered to assess their specific impact on the potential of natural regeneration of native woody plants and on the native entomofauna competing for seed resource. We re-analyzed data from former studies that did not focus on these ecological interactions and, here, present previously unpublished results. Seeds of Douglas-fir, true cedars, true firs and wild roses were sampled all over Europe, and the relative importance of the native and invasive chalcid species was assessed as well as their specific impact on seed yield. In most cases, the recent arrival of alien chalcids resulted in a significant decrease in the regeneration potential of the host trees. In the absence of competitors, alien chalcids occupied the entire seed niche in Douglas-fir, but their impact tended to decrease after the arrival of invasive seed bugs. In firs, alien chalcids tended to displace the native chalcids, but not in wild roses and cedars, where their damage was increasing. Different biological traits that might explain invasive success of alien chalcids are discussed. However, no general invasive patterns seem to exist.

REGENERAÇÃO NATURAL EM SUB-BOSQUE DE Corymbia citriodora NO NOROESTE DO ESTADO DO PARANÁ

O desenvolvimento de espécies nativas plantadas em consórcio com eucaliptos, ou regeneradas naturalmente em povoamentos dessas espécies, vem sendo acompanhado em propriedades rurais do noroeste do estado do Paraná. Esses sistemas se destacam por constituir uma opção para a recuperação da cobertura florestal em ambientes degradados pela pecuária e agricultura intensivas, propiciando rentabilidade econômica, com possibilidade de atender a legislação ambiental para Reserva Legal. O presente trabalho visa conhecer o potencial de recomposição da vegetação nativa em sub-bosque de Corymbia citriodora, nas condições ambientais e de uso do solo daquela região. Assim, foi avaliada a composição florística e a estrutura da vegetação formada sob a rebrota de um povoamento dessa espécie, situado em São Pedro do Paraná (PR). Foram encontradas cinquenta e três espécies oriundas de regeneração natural numa densidade de 4.725 plantas por hectare. As plantas, identificadas até o nível de espécie, foram enquadradas segundo seu grupo ecológico e/ou usos potenciais.Foram observados parâmetros estruturais que mostraram o elevado potencial de regeneração natural e crescimento da vegetação em sub-bosque de C. citriodora, indicando que, com manejo adequado, essa espécie pode ser usada como uma facilitadora para fins de recomposição de vegetação nativa.Palavras-chave: Regeneração natural; plantação florestal; composição florística. AbstractNatural regeneration in understory of Corymbia citriodora plantation, in north-west of Paraná state, Brazil. Natural regeneration in eucalyptus stands, as well as forest plantations that combine eucalyptus and native species, have been monitored in rural areas in the north-west of Paraná State, Brazil. Such forest systems involving eucalyptus represent an alternative for forest recovery and regeneration in areas degraded by livestock and intensive agriculture. Furthermore, such plantations offer new economic opportunities for landowners while providing incentives for their compliance with environmental regulations for saving a minimum amount of forested land (Reserva Legal). This study aims to understand the potential of natural vegetation recovery in the understory of Corymbia citriodora stands, due to the context of current environment and land use in the region. Thus, it evaluates floristic composition and vegetation structure in the understory re-growth within such plantation stands, in São Pedro do Paraná (Paraná State). As result, it identified 53 species from natural regeneration at a density of 4725 plants per hectare. Such plants, identified at the species level, were organized accordingly to their ecological group and/or potential uses. The observed structural parameters pointed to a high potential for natural regeneration and growth of vegetation in the understory of C. citriodora, which reveals that, with appropriated management, these species could be used to make native restoration vegetation easer in the region.Keywords: Natural regeneration; forest plantations; floristic composition.

Fragmentation drives tropical forest fragments to early successional states: A modelling study for Brazilian Atlantic forests

Land use leads to massive habitat destruction and fragmentation in tropical forests. Despite its global dimensions the effects of fragmentation on ecosystem dynamics are not well understood due to the complexity of the problem. We present a simulation analysis performed by the individual-based model FORMIND. The model was applied to the Brazilian Atlantic Forest, one of the world's biodiversity hot spots, at the Plateau of São Paulo. This study investigates the long-term effects of fragmentation processes on structure and dynamics of different sized remnant tropical forest fragments (1–100 ha) at community and plant functional type (PFT) level. We disentangle the interplay of single effects of different key fragmentation processes (edge mortality, increased mortality of large trees, local seed loss and external seed rain) using simulation experiments in a full factorial design. Our analysis reveals that particularly small forest fragments below 25 ha suffer substantial structural changes, biomass and biodiversity loss in the long term. At community level biomass is reduced up to 60%. Two thirds of the mid- and late-successional species groups, especially shade-tolerant (late successional climax) species groups are prone of extinction in small fragments. The shade-tolerant species groups were most strongly affected; its tree number was reduced more than 60% mainly by increased edge mortality. This process proved to be the most powerful of those investigated, explaining alone more than 80% of the changes observed for this group. External seed rain was able to compensate approximately 30% of the observed fragmentation effects for shade-tolerant species. Our results suggest that tropical forest fragments will suffer strong structural changes in the long term, leading to tree species impoverishment. They may reach a new equilibrium with a substantially reduced subset of the initial species pool, and are driven towards an earlier successional state. The natural regeneration potential of a landscape scattered with forest fragments appears to be limited, as external seed rain is not able to fully compensate for the observed fragmentation-induced changes. Our findings suggest basic recommendations for the management of fragmented tropical forest landscapes.

The effect of anthropogenic disturbances on population structure and regeneration of Scorodophloeus fischeri and Manilkara sulcata in coastal forests of Tanzania

Scorodophloeus fischeri (Fabaceae, subfamily Caesalpinoideae) and Manilkara sulcata (Sapotaceae) are examples of tropical African hardwood species and are endemic to East African coastal forests. These plant species are threatened by human activities beyond natural recovery in some forests. This study aimed to assess the effects of anthropogenic disturbance on the natural regeneration potential of S. fischeri and M. sulcata in the selected coastal forests of Tanzania. Transects were established in various vegetation communities and a nested quadrat technique was used to assess the natural regeneration. Scorodophloeus fischeri regenerates best in Zaraninge forest with high density of trees with diameter at breast height (DBH) between 10–50 cm and a higher seedling density than in other forests. Similarly, M. sulcata regenerates best in Pande forest, although many trees had a DBH of 10–30 cm, implying that the trees with size classes above these are missing. It was concluded that the minimum level of human disturbances in Zaraninge favoured high potentials of natural regeneration of S. fischeri. Disturbances through human activities contributed to the variation in the natural regeneration potentials for S. fischeri and M. sulcata in these forests. Conservation attention is likely to improve population structure and natural regeneration patterns of S. fischeri and M. sulcata in East African coastal forests.

Stand structure and natural regeneration of degraded forestland in the northern mountainous region of Vietnam

Vietnam experienced significant alterations of forest environments during the last half of the twentieth century, and reforestation efforts have increased since the 1990s. This study developed comparisons of naturally regenerated and plantation forestlands in northern Vietnam in order to gain a better understanding of reforestation options for the dual objectives of biodiversity and commercial tree production. Stand structure of secondary natural forest after logging and shifting cultivation were investigated at two study sites (Hoa Binh Province and Phu Tho Province). Natural regeneration of seedlings between the secondary natural forests and nearby mixed species plantations were measured and compared. The dominant tree species consisted of Aporosa villosa, Ficus racemosa, Machilus bonii and Vernicia montan at the Hoa Binh site and Cinnamomum parthenoxylum, Ormosia balabsae and Lithocarpus gigantophyllus at the Phu Tho site, which are mostly pioneer species. The secondary natural forests had higher abundance and diversity indices of seedlings than the mixed species plantations. Soil fertility of the secondary natural forests was better than that of the mixed species plantations (P < 0.05). An important finding is that, for the study sites examined, secondary natural forest resulted in more diverse and better-stocked forests than plantation forestry, implying that in areas where reforestation is undertaken the silvicultural potential of natural regeneration should not be underestimated.

Analysis of herbicide effects on Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) natural regeneration

Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) natural regeneration under parent stand after weed suppression was investigated in the area of the Training Forest Enterprise in Kostelec nad Čern&amp;yacute;mi lesy. The study evaluates two measurements made in a two-year interval. The parent stand, where Douglas fir grows in mixture with our domestic tree species, is one of the oldest and most productive stands at the Training Forest Enterprise in Kostelec nad Čern&amp;yacute;mi lesy. Herbicides for the control of weeds were applied onto three permanent experimental plots under the parent stand. Measurements done on the plots show a high potential of natural regeneration in areas where the negative impact of forest weeds was suppressed. This conclusion is acknowledged by the high seedling number found on research plots treated with herbicides. The number of Douglas fir seedlings varied from 21,600 per hectare counted on the plot treated with Dominator to 26,650 seedlings on the plot with Velpar treatment even six years after the soil preparation. Statistical analysis confirmed that the seedling number on the plot without any chemical preparation was significantly lower, only 950 individuals per hectare (&amp;chi;&lt;sup&gt;2&lt;/sup&gt; = 926.84, df = 3, P &amp;lt;&amp;lt; 0.01). &amp;nbsp;

Re‐establishing a saltmarsh vegetation structure in a changing climate

Summary A major management decision in an ecological restoration or rehabilitation project is whether supplementary planting or natural vegetation regeneration is the better alternative or if a combination can be applied. Management decisions are further complicated when the project involves saltmarsh as tidal cycles, the effects of salinity and sea level rise add to the complexity of decisions. The ecological values of the saltmarsh community in Australia were only recognized relatively recently but the endangered ecological community listing in 1994 (under the New South Wales Threatened Species Conservation Act 1995) highlighted the need to protect, rehabilitate and restore saltmarsh.This project measured vegetation change after soil profile reconstruction in saltmarsh surrounding Sponsors Lagoon, Fingal Peninsula in north coastal New South Wales, Australia. Restored sites (planted and non‐planted) were compared with nearby disturbed (control) and reference sites. The dominant species in the community to be restored were Saltwater Couch (Sporobolus virginicus), Suaeda (Suaeda australis), Sarcocornia (Sarcocornia quinqueflora ssp. quinqueflora and Sea Rush (Juncus kraussii ssp. australiensis). Changes in percentage cover of the species in the first three years after soil reconstruction work showed that the dominant Saltwater Couch established only from vegetative growth arising from remnant vegetation but there was strong seedling regeneration of several other species. It was concluded that planting is important for species that are less vagile, in larger, denuded parts of this site where their resilience is lower and natural regeneration potential is limited. An understanding of the biology of the individual species is therefore likely to be essential in saltmarsh restoration projects. A combination of techniques, incorporating planting of slower establishing species and encouragement of seed‐germinated colonizers is useful for initial site stabilization and progressive ecological recovery at this site. The inclusion of migration zones in the planning phase will allow for the long‐term viability of this restoration project.

Forest Restoration in Campgrounds at Kings Canyon National Park, California

Intensive campground use at the Grant Grove area of Kings Canyon National Park, California, has compacted the soil and left areas without understory vegetation or tree recruitment. To better inform the restoration of these sites after closure, we tested natural regeneration potential and planting and soil restoration methods. The tested methods included planting with container stock and direct seeding, fencing, and soil treatments of tilling, mulching, and gypsum and humus additions. Container stock had high survivorship (69‐100%), while germination and survival from direct seeding was low (0.6‐4.1%). Wood chip mulch was beneficial to planting woody species, but detrimental to resident herbaceous species. Plots treated with tilling and gypsum, and humus amendments exhibited highest growth rates of container stock and greatest herbaceous species richness and cover. However, tilling without the other soil treatments reduced herbaceous cover and seedling recruitment (natural and sown). In tilled plots, gypsum treatments and humus treatments often had neutral or detrimental effects individually, but their combination greatly increased the success of direct seeding, growth of container stock, and herbaceous cover and richness. Fencing increased volunteer tree recruitment tenfold compared to outside the plots. Some treatments in this study were beneficial to species of one morphological group but detrimental to another.

A preliminary study on natural regeneration of savanna tree species

Forest reserve areas can sustain themselves of their valuable species through an effective regeneration system. At present, most of the preserved woodland areas are being vandalized and valuable species illegally removed. Based on the desertification problem, which leads to the extinction of important plant species, it became necessary to study natural regeneration potential in Ribako Woodland Reserve of Kaduna State.An inventory of natural regeneration was conducted on Savanna tree species available in Ribako Woodland Reserve of Kaduna State. The survey indicated that 31 savanna parent trees, Isolberlina doka 159, Danielia oliveri 26, Hymenocardia acida and Lannea acida having 19 stands each, formed most abundant tree species in the reserve. Both Danielia oliveri and Hymenocardia acida accounted for 46% and 23% of the seedlings respectively and these formed the largest amount of seedlings encountered. Generally, the natural regeneration of all tree species in the woodland is low. Application of good management and adoption of in-situ and ex-situ conservation will ensure successful natural regeneration of woodland areas of Ribako. Keywords: Woodland, In-situ, ex-situ, Inventory, natural regenerationJOAFSS Vol. 4 (1) 2006: pp. 143-149

Effect of forest fire on trees, shrubs and regeneration behavior in Chir Pine forest in northern aspects under Solan forest division, Himachal Pradesh

Effect of forest fire on woody vegetation and regeneration behavior was studied in Chir pine forest situated between 1150-1800 m in Solan Forest Division in Himachal Pradesh, India. Four fire affected Sites and one control Site were surveyed for floristic composition, density, basal area, IVI, A/F, Shannon-Weaver index, Simpson’s Index of dominance (Cd), Species richness (d), Sorenson index (S) and natural regeneration potential of tree and shrubs. A total of 3 tree species and 10 shrub species were recorded on the five experimental sites. Fire resistant species were observed more in selected Chir pine forests. There was not observed any consistent trend for density, basal area, IVI, H. Sorenson’s index of similarity between fire affected and control sites for trees. Density and basal area in fire affected sites were lesser than control sites for shrubs. Contagious pattern of distribution for trees and shrubs was common. Seedlings density of trees and shrubs was higher on occasional fire affected sites than control sites. Density of saplings of trees was higher in control sites than fire affected sites.

The potential of natural regeneration of rocky outcrop vegetation on rupestrian field soils in "Serra do Cipó", Brazil

An area's innate potential to regenerate represents a crucial factor for its conservation and management. The seed rain and seed bank are important agents in the regeneration process. Seed banks are particularly important in communities where there is a high proportion of obligate seeders. Rocky outcrops are habitats where most part of the plant species depends on their seeds to reproduce and maintain viable populations. Therefore, seed banks ought to be important in this vegetation physiognomy. We test the hypotheses that the seed bank of the rocky outcrops found in the rupestrian fields of Serra do Cipo, Brazil, is richer in species and denser than those formed on different vegetation physiognomies neighboring the outcrops. We then compared species abundance, species richness and composition in the rocky outcrops' seed banks with those of sandy and peaty bogs, forests, gallery forests, and cerrados. Furthermore, we report on the natural regeneration potential of these soils by assessing a greenhouse study on seedling emergence. Soil samples were collected from 0 to 5 and 5 to 10 cm of depth. Rocky outcrops had the poorest in species and less dense seed bank and showed segregation in species composition. Emergence was greater in the most superficial layer. However, soils on rocky outcrops showed the greatest proportion of endemic threatened species in their seed banks, demonstrating their importance for biodiversity conservation of the Serra do Cipo rupestrian fields.