Academic literature on the topic 'Seedling bank'
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Journal articles on the topic "Seedling bank"
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Duchesneau, Robin, and Hubert Morin. "Early seedling demography in balsam fir seedling banks." Canadian Journal of Forest Research 29, no. 10 (1999): 1502–9. http://dx.doi.org/10.1139/x99-090.
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Following the 1995 mast year, we conducted detailed seedling demography surveys to characterize some ecological factors affecting germination and early establishment in understory balsam fir (Abies balsamea (L.) Mill.) seedling banks and verify if recruitment from a cohort can potentially renew the balsam fir seedling bank. Twenty-five seed traps paired with 32 demography subplots were located in each of four permanent plots and regularly monitored over a 2-year period. Spatial patterns of newly emerged seedlings generally corresponded to those found for seed dispersal. However, at the end of the monitoring period, the spatial pattern of surviving seedlings was independent of the seed dispersal pattern. Seedbed types and understory light environments were the main factors explaining seedling mortality. Sphagnum mosses and decaying wood were the most favorable seedbeds for early establishment. The 0- to 25-cm seedling populations grew in size because of the addition of new recruits. If, in the years to come, mortality rates of the 1995 cohorts were similar to those of already established 0- to 25-cm seedlings, mast years of seed production, at least during endemic periods, would be crucial for recruitment and renewal of balsam fir seedling banks.
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Morgan, P., and L. F. Neuenschwander. "Seed-bank contributions to regeneration of shrub species after clear-cutting and burning." Canadian Journal of Botany 66, no. 1 (1988): 169–72. http://dx.doi.org/10.1139/b88-026.
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Seed banks contributed significantly to regeneration of early seral shrubs after clear-cutting and fall broadcast burning of dense coniferous forests of the Thuja plicata/Clintonia uniflora habitat type in northern Idaho. Seeds were separated from 36 samples of soil and surface organic matter from 15 uncut forest stands. Total seed density averaged 1151 ± 1896 seeds/m2, and seed density for individual shrub species ranged from 1 ± 3 to 690 ± 1728 seeds/m2. Canopy cover of the "obligate" seed bank species, such as Ceanothus sanguineus and Prunus emarginata, was low or nonexistent in uncut forests, seed constancy and density in seed bank were high, and seedling regeneration on 2-year-old burns was abundant. Species that were "non-reliant" on seed banks, including Symphoricarpos albus and Rosa gymnocarpa, resprouted and no seedlings were found after burning. Response of "opportunistic" seed-bank species such as Rubus parviflorus and Rubus ursinus was intermediate; both seedling and sprout regeneration occurred after cutting and burning. These species existed in uncut stands both in the seed bank and in the understory. Burn severity affected germination and (or) seedling survival of Ceanothus sanguineus. Its percent canopy cover was greater on high-severity than on low-severity 2-year-old burns.
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Leon, Ramon G., and Micheal D. K. Owen. "Artificial and natural seed banks differ in seedling emergence patterns." Weed Science 52, no. 4 (2004): 531–37. http://dx.doi.org/10.1614/ws-03-048r2.
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Artificial weed seed banks are practical for studying seed bank depletion and weed seedling emergence because the number, depth, and species composition of seed banks can be managed. However, no studies have determined whether artificial seed banks are representative of natural seed banks. We compared the emergence of velvetleaf, giant foxtail, and common waterhemp in a natural seed bank, an artificial seed bank with stratified seeds, and an artificial seed bank with nonstratified seeds. Velvetleaf seedling emergence was higher in the nonstratified seed bank in 2001, but no differences were observed in 2002. The number of viable velvetleaf seeds at the end of the experiment was lower in the natural seed bank than in the artificial seed banks in 2002. Velvetleaf emergence occurred earlier in the natural seed bank than in the artificial seed banks. Giant foxtail emergence was higher in the artificial seed banks (58 to 82%) than in the natural seed bank (5 to 23%). Common waterhemp emergence ranged from 7 to 65% in the artificial seed banks and from 1 to 5% in the natural seed bank. In general, the distribution of emergence with time differed in the natural seed bank compared with the artificial seed banks. These differences were attributed to differences in soil temperature and soil bulk density between the natural and artificial seed banks. Artificial seed banks showed lower soil bulk density and greater temperature fluctuation than the natural seed bank. However, there was no consistent relationship between growing degree days and emergence timing in the three treatments for any of the species studied.
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Vieno, M., M. Komulainen, and S. Neuvonen. "Seed bank composition in a subarctic pine–birch forest in Finnish Lapland: natural variation and the effect of simulated acid rain." Canadian Journal of Botany 71, no. 3 (1993): 379–84. http://dx.doi.org/10.1139/b93-042.
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The seed bank composition and seedling densities were determined for a subarctic pine–birch forest. Samples (12 × 12 cm) were taken from plots that had received sulphuric acid and (or) nitric acid irrigation of pH 3 for 5 years and from irrigated control plots. The average seedling density per plot calculated from seedbank samples was 912/m2, varying from 191 to 5240. All the main aboveground taxa were present in the emerging seedlings with Betula sp. and Empetrum nigrum ssp. hermaphroditum being dominant. Other common seed-bank species included Vaccinium uliginosum, Vaccinium vitis-idaea, and Festuca ovina. Acid treatment did not have any significant impact on the composition of the seed bank or on germinative capacity in general. These findings indicate the existence of a viable soil seed bank in northern subarctic forests and the persistence of viability in spite of moderate acid deposition. Key words: seed bank, simulated acid rain, subarctic forest, seedling.
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Komulainen, M., M. Vieno, V. T. Yarmishko, T. D. Daletskaja, and E. A. Maznaja. "Seedling establishment from seeds and seed banks in forests under long-term pollution stress: a potential for vegetation recovery." Canadian Journal of Botany 72, no. 2 (1994): 143–49. http://dx.doi.org/10.1139/b94-019.
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Seed germinability of some common dwarf shrubs and seed-bank composition were studied in young pine forests along a pollution gradient from Severonickel smelter in Monchegorsk, northern Russia. Samples for seed germination and seed-bank trials were taken from sites representing different zones of pollution. Generally, germinability of dwarf shrub seeds was not affected by distance from pollution source, except for Empetrum nigrum ssp. hermaphroditium. The average density per site of seedlings that emerged from seed-bank samples varied between 278 and 416 seedlings/m2. Empetrum nigrum ssp. hermaphroditum and Betula sp. dominated in seed banks. Calluna vulgaris was also numerous at one site. As a whole, seed-bank taxa were well represented in the above ground vegetation. There were no significant differences in seedling density between sites for dominant taxa. Our results indicate that seeds can retain viability even under a heavy pollution load and thus form a potential for vegetation recovery in polluted sites. Key words: seed germination, seed bank, recovery, pollution, coniferous forest.
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Peltonen-Sainio, Pirjo, Katri Pahkala, Hannu Mikkola, and Lauri Jauhiainen. "Seed loss and volunteer seedling establishment of rapeseed in the northernmost European conditions: potential for weed infestation and GM risks." Agricultural and Food Science 23, no. 4 (2014): 327–39. http://dx.doi.org/10.23986/afsci.41530.
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Rapeseed soil seed bank development and volunteer plant establishment represent substantial risk for crop infestation and GM contamination. This study was designed to complement such investigations with novel understanding from high latitude conditions. Four experiments were designed to characterise seed loss at harvest, persistence, viability and capacity for volunteer seedling establishment, as well as impact of management measures on soil seed bank dynamics. Oilseed rape was the primary crop investigated due to the availability of GM cultivars and because of the increasing importance. Harvest losses and soil seed bank development were significant. Volunteer seedlings emerged at reasonably high rates, especially in the first autumn after harvest, but about 10% of buried seeds maintained their viability for at least three years. Soil incorporation methods had no major effect on numbers of volunteer seedlings, but herbicide treatments controlled volunteer seedlings efficiently, though not completely, due to irregular timing of seedling emergence.
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Zhang, Jianhua, and Paul B. Cavers. "Seedling emergence after maternal bentazon application to 10 cocklebur (Xanthium strumarium) populations." Canadian Journal of Plant Science 74, no. 4 (1994): 863–66. http://dx.doi.org/10.4141/cjps94-157.
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Maternal environments have been reported to affect various seed and seedling characteristics in many plants. In this study, we examined the effect of bentazon application to the mother plants on seed germination and seedling emergence of 10 cocklebur populations from wetlands or cultivated land. The mortality or longevity of fully developed seeds was affected significantly by bentazon application. Rate of seedling emergence showed little response, whereas percentage seedling emergence and percentage viable seeds in the soil were reduced by bentazon treatment to the mother plants. Populations from wetlands produced seedlings earlier than those from cultivated land. Key words: Seedling emergence, seed bank, herbicide, bentazon, cocklebur, Xanthium strumarium
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Grewell, Brenda J., Morgane B. Gillard, Caryn J. Futrell, and Jesús M. Castillo. "Seedling Emergence from Seed Banks in Ludwigia hexapetala-Invaded Wetlands: Implications for Restoration." Plants 8, no. 11 (2019): 451. http://dx.doi.org/10.3390/plants8110451.
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Soil seed banks play a critical role in the maintenance of wetland plant communities and contribute to revegetation following disturbances. Analysis of the seed bank can therefore inform restoration planning and management. Emergence from seed banks may vary in response to hydrologic conditions and sediment disturbances. To assess the community-level impact of exotic Ludwigia hexapetala on soil seed banks, we compared differences in species composition of standing vegetation among invaded and non-invaded wetlands and the degree of similarity between vegetation and soil seed banks in northern California. To determine potential seed bank recruitment of L. hexapetala and associated plant species, we conducted a seedling emergence assay in response to inundation regime (drawdown vs. flooded) and sediment depth (surface vs. buried). Plant species richness, evenness, and Shannon’s H’ diversity were substantially lower in standing vegetation at L. hexapetala invaded sites as compared to non-invaded sites. Over 12 months, 69 plant taxa germinated from the seed banks, including L. hexapetala and several other exotic taxa. Seedling density varied among sites, being the highest (10,500 seedlings m−2) in surface sediments from non-invaded sites subjected to drawdown treatments. These results signal the need for invasive plant management strategies to deplete undesirable seed banks for restoration success.
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Chejara, V. K., P. Kristiansen, B. M. Sindel, R. D. B. Whalley, and C. Nadolny. "Seed-bank and seedling dynamics in Hyparrhenia hirta are influenced by herbicide application and mowing management." Rangeland Journal 34, no. 2 (2012): 199. http://dx.doi.org/10.1071/rj11057.
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Hyparrhenia hirta (L.) Stapf (Coolatai grass) is a summer-active, C4 perennial tussock grass, native to southern Africa and the Mediterranean region, which has invaded areas of native flora in Australia in recent decades. Understanding its seed and seedling dynamics and how various management treatments (e.g. mowing, herbicide and no management) affect these may assist in identifying the conditions and management strategies required to limit its invasion. The population dynamics of H. hirta have not been comprehensively studied previously. A 2-year field experiment (December 2005–December 2007) was conducted to determine the seed-bank size, pattern of seedling emergence and survival of H. hirta seedlings at three sites in northern New South Wales, Australia, under three treatments: unmanaged (control), mowing and herbicide treatments. The density of H. hirta seeds in the soil at each experimental site under different treatments was measured in December 2005 at the start of the experiment, in December 2006 before the application of the second round of treatments and again at the end of the experiment in December 2007. Hyparrhenia hirta seedlings were assessed at monthly intervals in permanent quadrats (0.5 × 0.5 m) to determine seedling emergence and survival. Seedling emergence occurred on many occasions during the 2-year period of the experiment in each treatment and at all sites but the main seedling flushes were observed from mid summer to early autumn. In 2007, at all sites, seedling emergence declined by more than 90% on the mowing and herbicide treatments compared with the control treatment. Seedling survival was greater in the mowing and herbicide treatments than in the control treatment. The seedling cohorts emerging in winter had a lower survival. This study showed that H. hirta infestations have a large viable seed-bank (~3000 m–2), dependent on the level of infestation and climatic conditions, but that the seed-bank declines rapidly when seed addition is prevented. Some form of direct control of established H. hirta plants in combination with providing appropriate grazing management to encourage competition between grasses will assist in the control of H. hirta.
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Salazar, Ana, Guillermo Goldstein, Augusto C. Franco, and Fernando Miralles-Wilhelm. "Timing of seed dispersal and dormancy, rather than persistent soil seed-banks, control seedling recruitment of woody plants in Neotropical savannas." Seed Science Research 21, no. 2 (2011): 103–16. http://dx.doi.org/10.1017/s0960258510000413.
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AbstractA large fraction of tree species forming persistent soil seed-banks and with dormant seeds are expected to be found in strongly seasonal ecosystems such as Neotropical savannas, where seedling recruitment could be highly variable. In the savannas of Central Brazil, we studied seed characteristics (type of dormancy, longevity and moisture content) of 14 representative woody species differing in seed dispersal season. We also studied the dynamics of soil seed-banks and similarity patterns in woody species composition among seed rain, soil seed-bank, seedling bank and standing vegetation along shallow topographic gradients that differ in canopy cover. Woody species composition of the soil seed-bank largely differed from the standing vegetation, the seed rain and the seedling bank species composition, suggesting low recruitment of woody species from the soil seed-bank. Seeds of the 14 woody species remained viable for less than 16 months in laboratory dry-storage conditions. Of those, most seeds dispersed in the dry season were dormant and exhibited low moisture content, while most seeds dispersed in the wet season were non-dormant and exhibited high moisture content. Longevity of these seeds dispersed in the dry and the wet seasons did not differ significantly. This study shows that both timing of seed dispersal and dormancy appear to control timing of seed germination and seedling recruitment of most Neotropical savanna woody species, which did not form persistent soil seed-banks. This study contributes to the understanding of tree/grass coexistence and tree density variations along topographic gradients in tropical savannas.
Dissertations / Theses on the topic "Seedling bank"
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Welling, P. (Pirjo). "Regeneration by seeds and vegetation structure in alpine plant communities, subarctic Finland." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:951426861X.
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Abstract
The aims were to examine the importance of regeneration by seeds, the
influence of plant traits and disturbances, and the role of seed-seedling
conflicts in regeneration and in the determination of vegetation structure.
The study was carried out at in a subarctic alpine area (Kilpisjärvi
69°01'N 20°50E', Finland).
Seed bank and seedling densities were high in many plant communities
(ranges 99 -1109 viable seeds/m2 and 0.2-227
seedlings/m2, respectively). Effective seedling
recruitment is reflected in vegetation as a high proportion of plants with
poor or no vegetative reproduction ability. This development may take place
in meadows and snowbeds where herbs (e.g. Gnaphalium
supinum, Sibbaldia procumbens,
Veronica alpina and Viola
biflora) are abundant. On the other hand, the low proportion of
these plants in heath vegetation reflects ineffective seedling
recruitment.
Floristic similarities between the consecutive phases in the
regeneration pathway may be low despite effective seedling recruitment.
Clonality, large and small seed sizes and appendaged diaspores limit the
movement of species from phase to phase.
Generally, disturbances facilitate effective regeneration by seeds.
Grazing promotes species with large seed banks and is therefore one reason
for high seed bank densities. Freezing and melting processes negate a
negative influence of altitude on seed bank densities in the phase of
seedlings. However, if disturbances are severe and continuous and the soil
is compact, unstable or dry, disturbances are not beneficial. The same is
true if there is a shift in the species composition of seedlings from gaps
to closed vegetation. This phenomenon occurred in a rich meadow.
Seed-seedling conflicts limit regeneration by seeds in low-herb
snowbeds and Ranunculus glacialis-Gymnomitrion
snowbeds. Vegetative reproduction and infrequent pulses of seedling
recruitment negate an influence of short-term seedling recruitment on the
spatial structure of vegetation. Extreme conditions, such as low
temperatures, instability of the soil and late snowmelt modify the
influence of factors that are important in more moderate conditions.
To conclude, all transitions limit regeneration by seeds. However,
favourable conditions (e.g. moist conditions in a meadow) partly eliminate
the obstacles against seedling emergence. Regeneration by seeds therefore
has a major impact on the dynamics and structure of vegetation. In heath
vegetation, where bare soils are dry and the moss cover is thick, large
seed banks and seed rains do not guarantee effective seedling recruitment.
The regeneration process is reduced in the early phases, and plants that reproduce primarily by seeds have a minor role in vegetation. The accumulation of seed banks is effective in these circumstances.
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Nielsen, Michele Erin. "Seed and seedling dynamics of the seagrass, Zostera japonica Aschers. and Graebn. and the influence of Zostera marina L." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30172.
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The seagrass Zostera japonica Aschers. and Graebn. occurs as pure populations and in mixture with Zostera marina L. along the intertidal regions of southwest British Columbia. At the Roberts Bank study area seed and seedling dynamics were studied in three vegetation zones: a landward monospecific zone of Z. japonica, a zone of co-existing Z. japonica and Z. marina, and a seaward monospecific zone of Z. marina. Many more seeds were produced than were found in the sediment, and even fewer germinated. Zostera japonica seeds were most abundant in the seed bank in the upper zones where there is high Z. japonica density. Even though seeds remained in the water column for up to two months, very few seeds dispersed into the lower zone populated by Z. marina. thus limiting Z. japonica's colonization of the lower zones. It is unclear what limits the dispersal of Z. japonica seeds. Of the seeds that were incorporated into the sediment few germinated (5% or less). When seeds were planted in buckets placed into the sediment, with and without Z. marina, Z. japonica was able to germinate, grow, and reproduce in one year throughout the study area. Seedlings that emerged earliest (in April) either did not establish or did not survive as long as those seedlings that emerged later in May and June. Seedlings were often found uprooted, floating in the water. The rim of the buckets and the presence of Z. marina shoots appeared to protect the Z. japonica seedlings, preventing uprooting, but the results were not conclusive. Once seedlings became established, they spread vegetatively at a rapid rate and can persist throughout the winter, either as reduced shoots or as overwintering rhizomes. These overwintering plants contribute greatly to the following year's population.<br>Science, Faculty of<br>Botany, Department of<br>Graduate
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[Verfasser], Adane Girma Gebreselasse. "Plant Communities, Species Diversity, Seedling Bank and Resprouting in Nandi Forests, Kenya / Adane Girma Gebreselasse." Koblenz : Universitätsbibliothek Koblenz, 2012. http://d-nb.info/1019454393/34.
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Keammerer, Holly Barton 1983. "Community structure, plant interactions, seedling performance and seed bank composition of salt marshes along an estuarine gradient in Coos Bay, Oregon." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11256.
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xviii, 160 p. : ill. (some col.)<br>Salt marshes are intertidal communities dominated by halophytic vascular plants that are subjected periodically to tidal inundation. These species have developed various adaptations to this stress, including tolerances of fluctuating salinity, extended periods of inundation and intervals of anoxic conditions. The marshes are divided into zones of different plant communities based on species' tolerances of ambient estuarine conditions.
Abiotic stresses change along the estuarine salinity gradient (marine to riverine), potentially altering development and composition of plant communities. Abiotic gradients associated with tides are not the only factors that contribute to development of plant community composition in salt marshes. Both negative (competition) and positive (facilitation) biological interactions are also important. Factors that influence community structure in salt marshes, particularly on the eastern North American seaboard, have been well studied. In contrast, salt marshes along the Oregon coast are smaller and more discrete and have received comparatively little attention.
The community structure and seed bank composition of six marshes along an estuarine salinity gradient were evaluated. Four major community types dominated marshes that varied in the salinity of inundating tidal waters. Community types were relatively consistent throughout the estuary despite the distances between the marshes. Unlike the emergent plant communities, marsh seed bank composition was more similar within a marsh than within a community type.
The low and high marsh community types were separated by a distinct boundary in the marine marshes. Although abiotic factors influence the physical separation of communities, competitive interactions commonly determine the upper limit of a species. In Metcalf marsh, however, the upper boundary for two dominant low marsh species was not determined by competition with the high marsh dominant species.
Positive biotic interactions between seedlings and existing vegetation in a community are important factors in determining species distributions, particularly in stressful estuarine environments. In salt marshes, where abiotic stress can be harsh, presence of existing vegetation can ameliorate these conditions and enhance germination and seedling establishment. However, interaction between seedlings and the emergent marsh community was highly competitive, though germination of one species was enhanced in the presence of existing vegetation.
This dissertation includes un-published co-authored material.<br>Committee in charge: Dr. Scott Bridgham, Chairperson;
Dr. Richard Emlet, Advisor;
Dr. Steven Rumrill, Member;
Dr. Alan Shanks, Member;
Dr. Gregory Retallack Outside Member
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Andrade, Greice Kelly Oliveira. "Avaliação da regeneração natural em áreas de reflorestamento, no município de Laranjeiras-SE." Universidade Federal de Sergipe, 2015. https://ri.ufs.br/handle/riufs/3004.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>Many researches have been focused on reforestation projects, taking advantages on the self recuperation mechanism of the frorest such as seed rain, soil seed bank and seedling banks. Seed rain is an initial process which develops the dynamic, organization and structuration of the forest. However, the seed bank is one of the most important factors for natural recolonization of affected areas which start the succession process. Through this natural regeneration, a set of individuals are able to be recruited to the upper stages. In this way, the present study was performed aiming to evaluate the plant species establishment strategies through natural regeneration, in an area in the city of Laranjeiras-SE. Thirty plots were installed, and in center of these plots, collectors were installed (1m x 1m) to estimate the seed rain. To characterize the seed bank, was collected from August 2014 (corresponding to the rainy season in the region) to February 2015 (dry season), a soil sample from the center of each subplot (1m x 1m) through a metal jig which was introduced into the soil to remove a 5 cm layer. In the seedling bank evaluation, height and diameter of seedlings were analyzed between August 2014 (rainy season) and Februare 2015 (dry season) in subplots (1m x 1m). In seed rain were found 7,788 seeds, in which Shinus terebinthifollius Raddi (aroeira) presented a higher number of seeds collected with 6,799 samples and its frequency was 87.84% in relation with others species. The autochoric syndrome of dispersion was observed to Centrosema brasilianum (L.) Benth., Fabaceae 2 and Anadenanthera colubrina (Vell.) Brenan, for Asteraceae 1 and Bignoniaceae 1 the dispersion syndrome observed was anemocoric and to Schinus terebinthifollius and Passiflora mansoi (Mart.) Mast, the dispersion syndrome was zoochoric. In the study of seed bank, it was found a total of 171 seeds. The seed bank analyzes by the rainy season and dry season, Schinus terebinthifollius prevailed with more individuals in the rainy season. However, Fabaceae sp prevailed in the dry season. The distribution of species per plot was heterogeneous in both seasons, but presented a better distribution in the rainy season. In the study of seedlings bank, samples were found belonging to seven families and thirteen species. Shinus terebinthifollius represented 28% of total specimen, followed by Genipa Americana L. with 20%. The rainy season showed better seedling distribution along the plots. The processes of natural regeneration at studied area have presented a diversity of species into three regeneration kinds evaluated in different fructification seasons, establishing int this way, a steady supply of seeds, enabling the development of new individuals for future process.<br>Inúmeras pesquisas têm sido voltadas a projetos de reflorestamentos, aproveitando o próprio mecanismo de recuperação da floresta como chuvas de sementes, bancos de sementes do solo e bancos de plântulas. A chuva de sementes é um processo inicial que desenvolve a dinâmica, organização e estruturação da floresta. No entanto, o banco de sementes é um dos fatores mais importantes para a recolonização natural das áreas afetadas dando início ao processo sucessional. Por meio dessa regeneração natural, um conjunto de indivíduos são capazes de ser recrutados para os estádios superiores. Dessa forma, o presente trabalho foi realizado objetivando avaliar as estratégias de estabelecimentos das espécies vegetais por meio da regeneração natural, numa área em reflorestamento, no município de Laranjeiras-SE. Foram instaladas 30 parcelas, e no centro dessas parcelas foram instalados coletores (1m x 1m) para estimar a chuva de sementes. Para a caracterização do banco de sementes, foi coletada, no mês de agosto de 2014 (correspondente a estação chuvosa na região) e fevereiro de 2015 (estação seca), uma amostra de solo no centro de cada subparcela (1m x 1m), através de um gabarito metálico que foi introduzido no solo para remover uma camada de 5 cm. Na avaliação do banco de plântulas, foram realizadas análises de altura e diâmetro das plântulas, entre agosto de 2014 (estação chuvosa) a fevereiro de 2015 (estação seca), em subparcelas (1m x 1m). Na chuva de sementes foram encontradas 7.788 sementes, dentre as quais a espécie Schinus terebinthifollius Raddi (aroeira) apresentou maior número de sementes coletadas, com 6.799 amostras possuindo frequência de 87,84% em relação as outras espécies. A síndrome de dispersão autocórica foi observada para as espécies Centrosema brasilianum (L.) Benth., Fabaceae 2 e Anadenanthera colubrina (Vell.) Brenan, para Asteraceae 1 e Bignoniaceae 1 a síndrome de dispersão observada foi anemocorórica e para as espécies Schinus terebinthifollius e Passiflora mansoi (Mart.) Mast, a síndrome de dispersão presente foi a zoocórica. No estudo do banco de sementes, foi encontrado um total de 171 sementes. Nas análises por estação chuvosa e seca do banco de sementes, a espécie Schinus terebinthifollius prevaleceu com maior número de indivíduos na estação chuvosa. Contudo, prevaleceu a espécie Fabaceae 1 na estação seca. A distribuição das espécies por parcela foi heterogênea em ambas as estações, porém apresentou uma melhor distribuição no período chuvoso. No estudo do banco de plântulas, foram encontradas amostras pertencentes a sete famílias e treze espécies. A espécie Schinus terebinthifollius representou 28% dos espécimes amostrados, seguida por Genipa americana L. com 20%. Na estação chuvosa houve uma melhor distribuição de plântulas ao longo das parcelas. O processo de regeneração natural da área de estudo apresentou uma diversidade de espécies nas três formas de regeneração avaliadas com diferentes épocas de frutificação, estabelecendo assim, uma constante oferta de sementes, viabilizando o desenvolvimento de novos indivíduos para processos futuros.
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Nave, André Gustavo. "Banco de sementes autóctone e alóctone, resgate de plantas e plantio de vegetação nativa na fazenda Intermontes, município de Ribeirão Grande, SP." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-02062005-153506/.
Full textAbstract:
O acúmulo significativo de conhecimento sobre a ecologia de restauração nos últimos anos tem conduzido a mudanças na orientação dos programas de manejo e restauração florestal. A escolha ou criação de um modelo de restauração é um processo em constante aprimoramento, exigindo a necessidade de estudos que não apenas diminuam os custos envolvidos, mas também, que garantam a efetividade do objetivo proposto. Neste sentido, este trabalho testa novas metodologias de restauração visando a obtenção de informações técnicas sobre: A) a expressão do banco de sementes autóctone e alóctone na restauração florestal de diferentes situações de degradação antrópica.; B) o resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes; C) a eficiência de um modelo de plantio que utiliza conceitos de Preenchimento e Diversidade e; D) a evolução da paisagem. Para análise dos bancos de sementes autóctone e alóctone foram feitos levantamentos da densidade e das espécies arbustivo-arbóreas regeneradas. No resgate de indivíduos de espécies arbustivo-arbóreas regenerantes, as plântulas e indivíduos jovens foram resgatadas em uma floresta e levadas para adapatação em viveiro, onde tiveram seus indivíduos e espécies contabilizados em termos de densidade e sobrevivência. No modelo de plantio estudado, as espécies foram reunidas em grupos de Preenchimento e Diversidade e tiveram a cobertura de copa de cada indivíduo quantificada. A evolução da paisagem foi realizada através de fotointerpretação e principalmente checagem de campo periódica. Os principais resultados dessas metodologias foram: A) As situações identificadas na Fazenda Intermontes apresentaram diferentes expressões de regeneração natural em função do número de indivíduos germinados banco de sementes autóctone. O aproveitamento dessa expressão poderá ser realizado através de metodologias diferenciadas de restauração para cada situação estudada: B) No estudo do Banco de sementes alóctone, a densidade dos indivíduos germinados se foi de 409.334 indivíduos/ha, revelando a possibilidade de uso no programa de restauração. Os indivíduos arbóreos apresentaram na área adubada um acréscimo de 137,3 % em sua altura média em relação aos indivíduos da área não adubada. C) No resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes, a densidade dos indivíduos foi muito próxima para as duas épocas do ano, sendo 38.700 ind./ha e 37.900 ind./ha, mas com uma diferença significante para os indivíduos sobreviventes que apresentaram 16.500 ind./ha e 26.600 ind./ha para os meses de julho e dezembro de 2002, respectivamente. A técnica de resgate utilizada se mostrou viável uma vez que foi possível alcançar até 70,9% de sobrevivência para os indivíduos resgatados; D) No estudo sobre o modelo de plantio foram amostrados 143 espécies, demonstrando que a função do grupo da diversidade vem sendo mantida e aumentando as chances de efetivação dos processos de sucessão. Os resultados mostraram que o grupo de Preenchimento apresentou-se com uma porcentagem de cobertura significativamente maior que a do grupo de Diversidade, sendo 73,6% e 83,3% para 1,5 e 2,5 anos respectivamente.<br>Significant accumulation of know-how about restoration ecology has been changing forest restoration management programs trends during the last years. Choosing or elaborating a restoration model is a process that requires constant improvement and ecological studies that not only reduces the costs involved but also warrants the achievement of the aimed proposal. This study explores new restoration methodologies, searching for technical information about: A) autochthonous and allochthonous seed bank expression on forest restoration at different situations degraded by anthropogenic disturbances; B) seedlings and woody growing individuals rescue; C) efficiency of a planting model based on fulfillment and diversity concept; D) landscape development. The autochthonous and allochthonous seed bank were analyzed through regenerating woody species and density scouting. For the rescue of regenerating woody species, seedling and young individuals were taken from a forest and transferred to a plant nursery for adjustment, where number and species were counted regarding density and survival. In this studied planting model, species were organized and gathered into a fulfillment or diversity group, and each individual had its crown area quantified. Landscape development was analyzed by photointerpretation and specially by periodical field checking. Results from these methodologies showed that: A) Identified degraded situations at Intermontes farm displayed distinguished natural regeneration expression, influenced by the number of germinated seeds of the autochthonous seed bank. Advantage can be taken from these different outcomes by using distinct restoration methodologies for each studied situation. B) For the autochthonous seed bank study, germinated seed density was 409,334 ind./ha, indicating its potential role on restoration programs. Woody individuals at fertilized sites had a medium height enhancement of 137,7% when compared to those at non fertilized sites. C) For seedlings and woody growing individuals rescue, individual density was similar for both seasons (38700ind./ha and 37900ind./ha) but significantly distinct for individual survivor, with values of 16500ind./ha for July and 2600ind./ha for December. Rescue technique turned out to be a viable possibility since it achieved survival of 70,9% for rescued individuals. D) This planting model study registered 143 species, indicating that the diversity groups role has been maintained and enhances the chance of successional process success. The fulfilling group had a significant higher percentage of crown area than the diversity group, with 73,6% and 83,3% for 1,5 and 2,5 years, respectively.
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Silva, Shelka Alcântara da. "Germinação e morfoanatomia do desenvolvimento pós-seminal de espécies de Vellozia Vand. de campos rupestres brasileiros." Universidade Federal de Uberlândia, 2013. https://repositorio.ufu.br/handle/123456789/12434.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Velloziaceae is a relatively small family from Pandanales, including approximately 250
species that are very common in the brazilians campos rupestres . The Velloziaceae have a
high degree of endemism, and some species are threatened with extinction. Several species
of Velloziaceae have potential ornamental use, both for plant architecture as the foliage, or
due to the beauty of their flowers. However, few studies investigate the germinative
behavior and the post-seminal development of these species. In order to contribute with the
knowledge of the germination and post-seminal development of Velloziaceae were analyzed
seeds of twelve species of Vellozia Vand. from Minas Gerais and Goiás campos rupestres .
The seeds were sown in Emanueli chambers and the experiments were installed in
germination chamber under controlled light and temperature. The data about germinative
behavior and post-seminal development morphology and anatomy were obtained using the
usual techniques for each case. The seeds of the studied species are small, preferentially
photoblastic and most of them exhibit high germinability (G ≥ 60%) and high values of
mean germination rates (0,06 ≤ v ≤ 0,21 day-1). The coefficient of variation of the
germination time and the measurements of uncertainty and synchrony revealed that the
species can be separated in two groups: in the first group are the species exhibiting
heterogeneous and spread germination through the time and in the second group were
coupled the species exhibiting homogenous germination more concentrated over time. The
photoblastism and fast germination, yet spread in time, suggest relative dormancy, which is
common in seeds from species adapted to adverse environmental conditions and indicate
that the seeds of these species can form seed banks. The seeds are small and
bitegumented. The embryo is small and exhibits a single vascular bundle in the cotyledon.
Germination begins with the protrusion of the cotyledon s base and radicle and the seedling
is criptocotylar. The primary root is persistent and forms lateral roots. Eophyll and
methaphyll are similar. Seedling vascularization is reduced. The Vellozia exhibited similar
morphological and anatomical characters during the post-seminal development, which
reinforces the genera identity.<br>As Velloziaceae, uma família relativamente pequena da ordem Pandanales, com
aproximadamente 250 espécies, são frequentemente encontradas nos campos rupestres do
Brasil, onde apresentam alto grau de endemismo, bem como, algumas espécies encontramse
ameaçadas de extinção. Várias espécies de Velloziaceae apresentam potencial
ornamental, tanto pela folhagem, quanto pela beleza das flores. No entanto, poucos são os
estudos que investigam o comportamento germinativo e o desenvolvimento pós-seminal
dessas espécies. Visando contribuir com esses estudos, sementes de doze espécies de
Vellozia Vand. foram coletadas nos campos rupestres de Minas Gerais e Goiás. As sementes
foram semeadas em Câmaras de Emanueli e os experimentos instalados em câmara de
germinação, sob luz e temperatura controladas. Os dados sobre o comportamento
germinativo e a morfoanatomia foram obtidos utilizando-se as técnicas usuais para cada
caso. As sementes das espécies estudadas são preferencialmente fotoblásticas e a maioria
delas apresentou alta germinabilidade (G ≥ 60%) e velocidade média de germinação alta
(0,06 ≤ v ≤ 0,21 dia-1). O coeficiente de variação do tempo de germinação, as medidas de
incerteza e de sincronia revelaram que essas espécies podem ser agrupadas em dois
grupos: no primeiro, aquelas que apresentam germinação heterogênea e espalhada no
tempo e, no segundo, as que exibem germinação homogênea e mais concentrada no tempo.
O fotoblastismo e a germinação rápida, porém espalhada no tempo, sugerem dormência
relativa, que é comum para sementes de espécies adaptadas às condições ambientais
adversas e indica o potencial dessas sementes para formar banco de sementes. As sementes
de Vellozia são pequenas e bitegumentadas. O embrião é pequeno e exibe um único feixe
vascular no cotilédone. A germinação inicia-se com a protrusão da base do cotilédone e da
radícula e a plântula é criptocotiledonar. A vascularização da plântula é reduzida. A raiz
primária é persistente e forma raízes laterais. Eofilo e metafilo são semelhantes. As Vellozia
estudadas apresentaram caracteres morfoanatômicos semelhantes durante o
desenvolvimento pós-seminal, o que reforça a identidade do gênero.<br>Mestre em Biologia Vegetal
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Santos, Bruna Silva. "Comunidade de regeneração natural de uma área de cerradão /." Bauru, 2020. http://hdl.handle.net/11449/192546.
Full textAbstract:
Orientador: Veridiana de Lara Weiser Bramante<br>Resumo: O Cerrado é considerado um dos 25 hotspots mundiais, uma das áreas prioritárias para a conservação da biodiversidade mundial, por apresentar uma alta biodiversidade, um alto grau de endemismo e suas espécies estarem ameaçadas de extinção. Sendo assim, é fundamental o desenvolvimento de estudos na vegetação de cerrado para subsidiar trabalhos de conservação, manejo e restauração ecológica. O presente estudo visou conhecer as espécies que constituem o estrato de regeneração natural de uma área de cerradão na Gleba II do Refúgio de Vida Florestal Aimorés, em Bauru, centro-oeste do estado de São Paulo, sudeste do Brasil. Por meio do método de parcelas, realizamos o inventário da regeneração natural em duas classes de altura. A classe I (H ≤ 50 cm), chamamos de banco de plântulas e amostramos em subparcelas de 2 m x 2 m e a classe II (50 cm < H ≤ 1 m) chamamos de jovens regenerantes, amostramos em subparcelas de 5 m x 5 m. Alocamos as duas subparcelas no canto inferior esquerdo de 25 parcelas permanentes de 10 m x 10 m. Para cada classe de altura da regeneração natural analisamos os parâmetros de riqueza e abundância, calculamos o índice de diversidade de Shannon (H’) e equabilidade (J), os índices de regeneração natural por classe (RNC) e total (RNT).Utilizamos o índice de Sorensen para avaliar a similaridade florística entre as classes de altura da regeneração natural e entre a regeneração natural como um todo e o estrato arbóreo amostrado em dois períodos, 2005 e 2019. Amostram... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The Cerrado is considered one of the 25 hotspots, one of the priority areas for the conservation of global biodiversity, as it presents a high biodiversity, a high degree of endemism and its species are threatened with extinction. Therefore, it is essential to develop studies in the cerrado vegetation to support conservation, management and ecological restoration work. The present study aimed to know the species that constitute the natural regeneration stratum of woodland cerrado area in the Wildlife Refuge Aimorés, in Bauru, middle west of the state of São Paulo, southeastern Brazil. Using the plot method, we carried out the inventory of natural regeneration in two height classes. Class I (H ≤ 50 cm), we call the seedling bank and sample in subplots of 2 m x 2 m and class II (50 cm <H ≤ 1 m), young regenerators, we sample in sub plots of 5 m x 5 m. We allocated the two subplots in the lower left corner of 25 permanent plots of 10 m x 10 m. For each height class of natural regeneration, we analyzed the parameters of species richness and abundance, calculating the Shannon diversity index (H') and equability (J), the natural regeneration indices by class (RNC) and total (RNT). We used the Sorensen index to assess the floristic similarity between the height classes of natural regeneration and between natural regeneration and the tree strata sampled in two periods, 2005 and 2019. We sampled 617 individuals from the seedling bank, belonging to 44 species and 680 young regenerating... (Complete abstract click electronic access below)<br>Mestre
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Avila, Angela Luciana de. "MECANISMOS DE REGENERAÇÃO NATURAL E ESTRUTURA POPULACIONAL DE TRÊS ESPÉCIES ARBÓREAS EM REMANESCENTE DE FLORESTA OMBRÓFILA MISTA, RIO GRANDE DO SUL." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/8664.
Full textAbstract:
Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>The ecology of regeneration and population dynamics is necessary information to the conservation and management of forest ecosystems. Thus, this study aimed to characterize: a) the mechanisms of natural regeneration in a Mixed Rain Forest remnant and b) the population
structure of Araucaria angustifolia (Bertol.) Kuntze, Blepharocalyx salicifolius (Kunth) O. Berg and Ilex paraguariensis A. St.-Hil. Therefore, the structure of the sample project PELD/CNPq was utilized, which was installed in the National Forest of São Francisco de Paula, RS, Brazil to evaluate six clusters (1 ha), with 16 plots (20 x 20m) each, disregarding 10m surround. The mechanisms of regeneration that have been evaluated were seed rain (SR), soil seed bank (SB) and a seedling bank (SeB) (individuals ≥ 30cm in height and diameter at breast height (DBH)
<1cm). Additionally, natural regeneration establishment (RNE) (1 ≤ DBH <4.8 cm) sampled in cells of 3.16 x 3.16m, the size class I (SC I) ( 4.8 ≤ DBH <9.55 cm) in plots 10 x 10m and SC II (DBH ≥ 9.55 cm) shown on 96 plots of 20 x 20m were also considered for the study of populations. These data were collected in 2008, also being measured the DBH and sociological position. The mechanisms of regeneration were evaluated for the floristic composition and horizontal structure. In addition, the cluster analysis method TWINSPAN (Two-way Indicator Species Analysis) and canonical correspondence analysis (CCA) were performed for the SeB. The population structure of the three species was examined by characterization of the
sociological position, spatial distribution and frequency in size classes. In SR, we sampled 81 species, 46 genera and 28 families, in SB, 103, 65 and 41 and in SeB, 88, 57 and 36, respectively. The analysis by TWINSPAN ordered the formation of three groups in SeB, with their history of interference and environmental conditions. The CCA indicated the slope as environmental variable with the greatest influence on the distribution of plots and species. Group 1 had higher deposition of seeds, however, the lowest densities for the SB and SeB, which is
correlated with a decrease in slope. The highest values in SR, SB and SeB were observed in Group 2, with the highest level of anthropogenic interference. Group 3, with lower SR and intermediate density for the other mechanisms, had its plots distributed in accordance with the increase in slope. Allophylus edulis (A. St.- Hil., Cambess & A. Juss.) Radlk., Piper xylosteoides Steud. and Piper aduncum L. showed positive correlation with the increase in slope. The population structure of the three species that were studied showed clustered distribution. Araucaria angustifolia, which is an emerging species, showed high density of individuals regenerating in environments with higher levels of alteration. Blepharocalyx salicifolius and Ilex paraguariensis, have distributed themselves predominantly in the upper and middle strata, and
have shown higher population stability within the group on more advanced successional stage. Consequently, it is possible to conclude that the groups determine different patterns in forest regeneration and the structure of populations; therefore, they should be considered in case of possible interventions in the ecosystem.<br>A ecologia da regeneração e a dinâmica de populações constituem informações necessárias à conservação e ao manejo dos ecossistemas florestais. Assim, este estudo teve como objetivos caracterizar: a) os mecanismos de regeneração natural em um remanescente de Floresta
Ombrófila Mista; e b) a estrutura populacional de Araucaria angustifolia (Bertol.) Kuntze, Blepharocalyx salicifolius (Kunth) O. Berg e Ilex paraguariensis A. St. Hil. Deste modo, utilizou-se
a estrutura amostral do projeto PELD/CNPq, instalada na Floresta Nacional de São Francisco de Paula, RS, Brasil, sendo avaliados seis conglomerados (1ha), com 16 parcelas (20 x 20m) cada, desconsiderando 10m de bordadura. Os mecanismos de regeneração avaliados foram chuva de
sementes (CS), banco de sementes do solo (BS) e banco de plântulas (BP) (indivíduos com altura ≥ 30cm e diâmetro à altura do peito (DAP) < 1cm). Adicionalmente, para o estudo das populações, considerou-se: a regeneração natural estabelecida (RNE) (1 ≤ DAP < 4,8cm) amostrada em células de 3,16 x 3,16m; a classe de tamanho I (CT I) (4,8 ≤ DAP < 9,55cm) em subparcelas 10 x 10m; e a CT II (DAP ≥ 9,55cm) inventariada nas 96 parcelas de 20 x 20m. Esses dados foram coletados em 2008, sendo mensurados o DAP e a posição sociológica. Os mecanismos de regeneração foram avaliados quanto à composição florística e estrutura horizontal. Além disso, para o BP foi realizada a análise de agrupamento, pelo método TWINSPAN (Two-way Indicator Species Analysis) e análise de correspondência canônica (CCA). A estrutura populacional das três espécies foi analisada pela caracterização da posição sociológica, distribuição espacial e frequência em classes de tamanho. Na CS, foram amostradas 81 espécies, 46 gêneros e 28 famílias, no BS, 103, 65 e 41 e no BP, 88, 57 e 36, respectivamente. A análise pelo TWINSPAN determinou a formação de três grupos no BP, com
respectivos históricos de interferência e condições mbientais. A CCA indicou a declividade como variável ambiental com maior influência sobre a distribuição das parcelas e espécies. O
Grupo 1 apresentou elevada deposição de diásporos, porém, as menores densidades para o BS e BP, estando correlacionado com a diminuição na declividade. Os maiores valores, na CS, BS e BP foram observados no Grupo 2, com maior nível de interferência antrópica. O Grupo 3, com
menor CS e densidade intermediária para os demais mecanismos, teve suas parcelas distribuídas de acordo com o aumento na inclinação do terreno. Allophylus edulis (A. St.-Hil., Cambess & A. Juss.) Radlk., Piper xylosteoides Steud. e Piper aduncum L. apresentaram correlação positiva com o aumento na declividade. A estrutura populacional das três espécies estudadas indicou distribuição espacial agregada. Araucaria angustifolia, espécie emergente, apresentou elevada densidade de indivíduos regenerantes em ambientes com maior nível de alteração. Blepharocalyx salicifolius e Ilex paraguariensis distribuíram-se, predominantemente,
nos estratos superior e médio respectivamente, e apresentaram maior estabilidade populacional no grupo em estádio sucessional mais avançado. Pelo exposto, concluí-se que os agrupamentos determinam padrões diferenciados, na regeneração da floresta e na estrutura das populações,
devendo ser considerados em caso de possíveis intervenções no ecossistema.
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Parks, Geoffrey Richmond. "Longleaf pine sandhill seed banks and seedling emergence in relation to time since fire." [Gainesville, Fla.] : University of Florida, 2007. http://purl.fcla.edu/fcla/etd/UFE0021193.
Full textBooks on the topic "Seedling bank"
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Levy, Louise. The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in Southeast Alaska. U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 2010.
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Houston, David R. Effect of harvesting regime on beech root sprouts and seedlings in a north-central Maine forest long affected by Beech bark disease. USDA Forest Service, 2001.
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3
J, Peterson M. Die-back of container-grown Douglas-fir seedlings: Associated microclimate. 1987.
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J, Peterson M. Die-back of container-grown Douglas-fir seedlings: Associated microclimate. 1987.
Find full textBook chapters on the topic "Seedling bank"
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Abe, Shin. "Seedling/Sapling Banks and Their Responses to Forest Disturbance." In Diversity and Interaction in a Temperate Forest Community. Springer Japan, 2002. http://dx.doi.org/10.1007/978-4-431-67879-3_12.
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Ericsson, Anders, Rolf Gref, Claes Hellqvist, and Bo Lågström. "Wound Response of Living Bark of Scots Pine Seedlings and Its Influence on Feeding by the Weevil, Hylobius abietis." In Mechanisms of Woody Plant Defenses Against Insects. Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3828-7_14.
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Chaudhuri, Subhamita, Punarbasu Chaudhuri, and Raktima Ghosh. "The Impact of Embankments on the Geomorphic and Ecological Evolution of the Deltaic Landscape of the Indo-Bangladesh Sundarbans." In River Deltas - Recent Advances [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94163.
Full textAbstract:
The deltaic landscape of the Ganga-Brahmaputra delta has evolved through a complex interplay of geomorphic processes and tidal dynamics coupled with the anthropogenic modifications brought over in course of the reclamation of the islands since the late 18th century. The reclamation process was characterized by clearing lands for paddy farms and fish ponds by building a mesh of earthen embankments along creek banks to restrict saltwater intrusion. The length of the embankments in the Indian Sundarbans alone is 3638 km (World Bank, 2014) which altered the tidal inundation regimes, sediment accretion and geomorphic character of the deltaic inlets. The mean annual sedimentation rate (2.3 cm y−1) in the central Ganga-Brahmaputra delta is over two times higher than sedimentation within the natural intertidal setting of the Sundarbans (Rogers et al., 2017). The tidal range has also increased inland due to polder construc¬tion, with high water levels within the polder zone increasing as much as 1.7 cm y−1 (Pethick and Orford, 2013). Embankments have impacted on the biodiversity and physiological adaptations of mangroves within the sphere of tidal ingression, habitat fragmentation and seedling establishment. The chapter attempts to reappraise the impact of dykes on the geomorphology of the deltaic landscape and on the functionalities of mangrove forests.
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Gomes Bordon, Natali, Niwton Leal Filho, and Tony Vizcarra Bentos. "Ecology of the Seed Bank in the Amazon Rainforest." In Ecosystem and Biodiversity of Amazonia. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94745.
Full textAbstract:
The seed bank is directly related to forest resilience because it contributes to the greatest number of regenerants after the occurrence of disturbances. Changes in seed density, floristic composition, and life forms completely alter the successional trajectory of forest environments. These changes are directly related to land use. For example, suppression of the seed bank can occur in pastures, that experience frequent fires with increase of density of seeds and predominance of herbs are typical of highly degraded areas, such as Poaceae, Rubiaceae, Asteraceae, and Cyperaceae. Melastomataceae seedlings are an important component of the seed bank in the Amazon rainforest. On the other hand, Urticaceae has greater representation in forests that exhibit low-impact land use. Any change in seed bank functionality is bound to compromise the diversity, regeneration potential and overall maintenance of tropical forests. Therefore, it is necessary to expand studies that investigate seed banks in the Amazon rainforest. It is as important to prioritize sampling methods and pursue standardization of data presentation, as well as improve the identification of species that occur in the seed bank.
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Maun, M. Anwar. "Seed germination and seedling establishment." In The Biology of Coastal Sand Dunes. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780198570356.003.0010.
Full textAbstract:
For the transformation of a seed to a seedling complex physical and biochemical changes occur within a seed before germination can proceed. Germination is controlled by diverse seed dormancy mechanisms in plant species that delays germination until the conditions are most favourable for seed germination and seedling establishment (Thompson 1970). Baskin and Baskin (1998) identified four benefits for the evolution of seed dormancy in plants: (i) persistence in risky environments as seed banks, (ii) decreased intraspecific competition, (iii) improved chances of seedling establishment and (iv) increased fitness (seed production) of the individual and the species as a whole. They showed that seed dormancy may be caused by any one of physiological, morphological, physical, chemical and mechanical constraints or by a combination of more than one of these factors. For instance, seeds may possess an embryo with a physiological inhibiting mechanism, immature embryo, impermeable seed coat or may contain chemical inhibitors and hard woody fruit walls. In all of these cases seed dormancy is eventually broken by one or more of the following treatments: after ripening, heat treatment, cold temperature stratification, prolonged exposure to high temperatures, exposure to light, softening of seed coat by microbes or physical scarification, leaching of inhibiting chemicals, ageing of seeds and other subtle changes in the habitat. In temperate North America with snow cover during winter months the seeds of a large majority of sand dune species—Cakile edentula, Ammophila breviligulata, Calamovilfa longifolia, Iva imbricata, Croton punctatus, Uniola paniculata—and others require cold stratification at <4°C for 4–6 weeks to break their dormancy requirements. Seeds of some species such as A. breviligulata and U. paniculata that require cold stratification at the northern end of their range lose this requirement in the south (Seneca 1972). At southern locations exposure to high temperatures may be required to fulfil the dormancy requirements. Winter annuals, Vulpia ciliata, Cerastium atrovirens, Mibora minima and Saxifraga tridactylites, that grow and mature their seeds in early summer on sand dunes at Aberffraw, North Wales, require exposure to high soil temperatures to overcome a state of dormancy in a certain proportion of seeds at the time of dispersal (Carey and Watkinson 1993; Pemadasa and Lovell 1975).
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Wohl, Ellen. "June: The Thin Green Line." In Saving the Dammed. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190943523.003.0009.
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June, when the snows come hurrying from the hills and the bridges often go, in the words of Emily Dickinson. In the beaver meadow, the snows are indeed hurrying from the surrounding hills. Every one of the 32 square miles of terrain upslope from the beaver meadow received many inches of snow over the course of the winter. Some of the snow sublimated back into the atmosphere. Some melted and infiltrated into the soil and fractured bedrock, recharging the groundwater that moves slowly downslope and into the meadow. A lot of the snow sat on the slopes, compacted by the weight of overlying snow into a dense, water-rich mass that now melts rapidly and hurries down to the valley bottoms. North St. Vrain Creek overflows into the beaver meadow, the water spilling over the banks and into the willow thickets in a rush. I can hear the roar of water in the main channel well before I can see it through the partially emerged leaves of the willows. Overhead is the cloudless sky of a summer morning. A bit of snow lingers at the top of the moraines. Grass nearly to my knees hides the treacherous footing of this quivering world that is terra non-firma. I am surrounded by the new growth of early summer, yet the rich scents of decay rise every time I sink into the muck. I walk with care, staggering occasionally, in this patchy, complex world that the beavers have created. I abruptly sink to mid-thigh in a muck-bottomed hole, releasing the scent of rotten eggs, but less than a yard away a small pocket of upland plants is establishing a roothold in a drier patch. A seedling spruce rises above ground junipers shedding yellow pollen dust and the meticulously sorted, tiny pebbles of a harvester ant mound. I extract my leg with difficulty and continue walking. As I walk around the margin of another small pond, the water shakes. Sometimes the bottom is firm in these little ponds, sometimes it’s mucky—I can’t tell simply by looking through the water.
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Lorbiecki, Marybeth. "Save That Game: 1915– 1919." In A Fierce Green Fire. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199965038.003.0012.
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On January 15, 1915, a week after returning from his father’s funeral and two days before his twenty-eighth birthday, Leopold handed in a memo on how to restore game in District 3. He proposed that Forest Service policy should: • Consider game animals as forest “products” (just as trees are); • Manage the wild species scientifically for count and quality; Set aside land for game refuges where hunting permits would be sold and limited; • Use the profits to pay rangers to work on predator control and enforce state game laws. A plan that covered these points, claimed Leopold, could successfully bring game back to the forests of the Southwest. Ringland gave the memo his ardent approval. He recognized that, in essence, Leopold was asking the Forest Service to expand its definition of its responsibilities, and the proposal had importance for forests nationwide. Ringland advised Leopold to schedule a meeting with a representative from the Washington, DC office, Leon Kneipp. Kneipp rejected Leopold’s plan. The Forest Service would not sink any money into an expensive gamble. Kneipp felt that rangers should protect game out of a sense of public duty, and not expect any pay or time off from their tasks to do so. Nor would the Forest Service set aside land for game refuges until the public demanded it. Needless to say, Leopold was disappointed. The rejection came at a time when he faced head on the shortsightedness of the Forest Service’s policies in the grazing office. Leopold could see no way to encourage new seedlings without granting fewer grazing permits. His supervisor, John Kerr, cared only about revenues. He pushed Leopold to increase the number of permits, as well as to work out the forms and petty details. The two ended up in daily headlocks. Frustration built up in Leopold like a mountain storm. Ringland hated to see one of his most innovative foresters wasted in paperwork. He knew he would lose Leopold if he didn’t act quickly to find a position that suited Aldo’s ambitions and abilities.
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Keefer, Robert F. "Fertilizers." In Handbook of Soils for Landscape Architects. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195121025.003.0017.
Full textAbstract:
Fertilizers for soil on which plants grow come in a variety of forms, such as organic, inorganic, single nutrient, double nutrient, complete fertilizer (contains N, P, and K in that order), speciality fertilizers, composts, and manures. Information about each of these forms follows. Most of the N used in fertilizers is derived from a synthetic process developed by Europeans called the “Claude-Haber process.” This process uses nitrogen gas (N2) from the atmosphere along with hydrogen gas (H2) from natural gas in a device where pressure can be increased and temperature can be raised. The reaction is accelerated using an iron catalyst and removing the product (NH3) as it is formed. The Fe catalyst is subject to poisoning from impurities, such as As, Co, P, or S. Anhydrous ammonia has the highest percentage of N and the cheapest per unit of N since no processing is involved. Anhydrous (without water) ammonia is a gas but when compressed changes to a liquid. For application to soils a pressurized tank is required with a device to inject the liquid ammonia into the soil. Upon release of pressure, the liquid changes back to a gas; however, the ammonia gas reacts with the moisture in the soil to form NH4+ that is available for plants. One problem with ammonia is that NH3 gas is toxic to seedlings and growing plants, so must be applied prior to planting. This limits its use for landscape projects. Salt solutions of aqua ammonia are obtained by dissolving ammonia gas, ammonium nitrate, or urea in water. The amount dissolved will vary the concentration of N in the final product. This can be used in landscape projects, but care must be used as this material can salt out and plug up orifices when sprayed onto a soil. There is no real difference between liquid or solid fertilizers, provided the percentage of N is the same. Ammonia Nitrate [NH4NO3] (33.5% N) Ammonium nitrate is formed by ammonia gas reacting with nitric acid: . . . NH3 + HNO3 → NH4NO3 . . . This material is hygroscopic (absorbs water from the air) and requires moisture-proof bags for storage.
Conference papers on the topic "Seedling bank"
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Sokolova, V. V., and E. M. Gusev. "The state of Ginkgo biloba L. in Moscow." In Растениеводство и луговодство. Тимирязевская сельскохозяйственная академия, 2020. http://dx.doi.org/10.26897/978-5-9675-1762-4-2020-152.
Full textAbstract:
The plantings of ginkgo biloba in Moscow were examined. Trees were studied in courtyards, at children's and educational institutions, in parks and botanical gardens of the city. Ginkgo trees and young seedlings are generally in good condition, with in some cases minor bark damage, few dry branches in the crowns and a slope of the trunk. Conclusions are made about the advisability of further study and reproduction of a valuable relict plant for medical purposes and for gardening.
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MIEZĪTE, Olga, Jeļena RŪBA, Lāsma FREIMANE, Imants LIEPA, and Edgars DUBROVSKIS. "THE HEALTH STATUS AND NATURAL REGENERATION OF PINUS SYLVESTRIS L. AFTER THE SURFACE FIRE IN VACCINIOSA FOREST TYPE IN LATVIA." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.100.
Full textAbstract:
From abiotic factors the most effecting influence on forest ecosystems has fire. Two years after surface fire in the pine stands growing in Vacciniosa forest type. Two PL (hereinafter PL) were installed in medium-aged (49 years old, 2.3 ha) and two PLs - in maturing (96 years old, 2.5 ha) stands. In each PL (20x20 m), the numbering of the trees was carried out and their placement was fixed, as well as the diameter, height and height of the green crown were measured. The sanitary condition of each tree was evaluated. For registration of one-year and two-year seedlings in each sample plot 25 sampling units (1 m2) were used. The similar sampling units were used for evaluation of ground cover (5 in each PL diagonally arranged), the obtained samples were weighed. The purpose of the study was to analyze the health status and natural regeneration of P.sylvestris after the surface fire. The ground vegetation was completely burned out in the medium-aged stand, but in the maturing stand both ground vegetation and organic layer - mosaically. The average burning height of trees in the medium-aged forest stand was 0.6±0.64 m, in the maturing stand - at 2.3±0.34 m. The natural regeneration was not detected in the first year after surface fire in the medium-aged forest (only 58800 one-year seedlings were recorded at the second year after fire), while in the maturing stand it was at this time (46600 one-year and 14200 two-year seedlings). Insect damage and cracked bark was not detected.
Reports on the topic "Seedling bank"
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Levy, Louise S. Y., Robert L. Deal, and John C. Tappeiner. The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in southeast Alaska. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 2010. http://dx.doi.org/10.2737/pnw-rp-585.
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Houston, David R. Effect of harvesting regime on beech root sprouts and seedlings in a north-central Maine forest long affected by beech bark disease. U.S. Department of Agriculture, Forest Service, Northeastern Research Station, 2001. http://dx.doi.org/10.2737/ne-rp-717.
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