Bibliografie tematiche / Seedling regeneration

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Letteratura scientifica selezionata sul tema "Seedling regeneration"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 2 febbraio 2022

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Articoli di riviste sul tema "Seedling regeneration"

Fukasawa, Y., Y. Komagata e S. Ushijima. "Fungal wood decomposer activity induces niche separation between two dominant tree species seedlings regenerating on coarse woody material". Canadian Journal of Forest Research 47, n. 1 (gennaio 2017): 106–12. http://dx.doi.org/10.1139/cjfr-2016-0218.

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Decomposition subsystems have an essential role in forest dynamics but few studies demonstrate the effect of microbial decay traits on seedling regeneration. In the present study, we focused on seedling regeneration on coarse woody material (CWM), which is an important regeneration site for forest tree species, and the effects of wood decay type according to fungal decay preference for wood structural components on seedling colonization. Effects of log properties including wood decay type and other environmental variables on seedling density were evaluated by ordination methods and generalized linear models. In total, 22 woody species were recorded as seedlings on Pinus densiflora logs. By ordination analysis, white rot in heartwood and brown rot in sapwood, as well as canopy openness and log diameter, showed significant association with seedling communities. The factors selected for a generalized linear model for explaining seedling densities of the two dominant seedling species Cryptomeria japonica and P. densiflora included brown rot in sapwood and white rot in heartwood, but the effects were different: a positive effect of brown rot on C. japonica and a negative effect of white rot on P. densiflora. These results suggested that wood decay type could induce niche separation between dominant tree species regenerating on CWM.

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Béland, Martin, Yves Bergeron e Richard Zarnovican. "Natural regeneration of jack pine following harvesting and site preparation in the Clay Belt of northwestern Quebec". Forestry Chronicle 75, n. 5 (1 ottobre 1999): 821–31. http://dx.doi.org/10.5558/tfc75821-5.

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A 36-ha experiment was carried out to assess the possibility of naturally regenerating jack pine stands following harvesting on clay soils of northwestern Quebec. Although differences between treatments were not statistically significant, there was a trend toward a positive effect of one treatment combining on-site delimbing and scarification with the Silva Wadell™ cone scarifier on jack pine seedling density (up to 10 000/ha) and distribution (50% of 1 m2 plots with at least one seedling, corresponding to 94% with 4 m2 plots), two years after harvest. However, scarified microsites contained fewer seedlings than expected and undisturbed humus contained more seedlings than expected. This result, contrary to what is generally reported in the literature may be explained either by the fairly humid conditions, favourable to germination and seedling establishment, occurring on clay sites or by the scarifier spreading the cone-bearing slash outward. Seedling abundance and distribution improved substantially from the first year to the second year following treatment. Although the irregular branch distribution over the cutover area appears to have limited regeneration success, combining on-site delimbing with soil scarification could lead to relatively good stocking of jack pine regeneration that could be enhanced by some fill-planting. This regeneration method could constitute an alternative to planting jack pine on clay. However, vegetation control to remove aspen competition might be necessary. Key words: jackpine, silviculture, natural regeneration, boreal mixed wood

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Johnson e Yeakley. "Microsites and Climate Zones: Seedling Regeneration in the Alpine Treeline Ecotone Worldwide". Forests 10, n. 10 (3 ottobre 2019): 864. http://dx.doi.org/10.3390/f10100864.

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Microsites, local features having the potential to alter the environment for seedling regeneration, may help to define likely trends in high-elevation forest regeneration pattern. Although multiple microsites may exist in any alpine treeline ecotone (ATE) on any continent, some microsites appear to enhance density of seedling regeneration better than others. Known seedling regeneration stresses in the ATE include low temperature, low substrate moisture, high radiation, drought, wind, and both high and low snowfall amount. Relationships among various microsite types, annual temperature, annual precipitation, and tree genera groups were assessed by synthesizing 52 studies from 26 countries spanning six continents. By categorization of four main microsite types (convex, concave, object, and wood) by mean annual precipitation and temperature, four major climatic zone associations were distinguished: cold & dry, cold & wet, warm & dry, warm & wet. Successful tree recruitment varied among microsite types and by climatic zones. In general, elevated convex sites and/or decayed wood facilitated earlier snow melt for seedlings located in cold & wet climates with abundant snowfall, depressions or concave sites enhanced summer moisture and protected seedlings from wind chill exposure for seedlings growing in cold & dry locations, and objects protected seedlings from excessive radiation and wind in warm & dry high locations. Our study results suggest that climate change will most benefit seedling regeneration in cold & wet locations and will most limit seedling regeneration in warm & dry locations given likely increases in fire and drought. Study results suggest that high-elevation mountain forests with water-limited growing seasons are likely to experience recruitment declines or, at best, no new recruitment advantage as climate warms. Climate envelope models, generally focusing on adult trees rather than seedling requirements, often assume that a warming climate will move tree species upward. Study results suggest that climate models may benefit from more physically-based considerations of microsites, climate, and current seedling regeneration limitations.

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Peters, Vernon S., e Darcy R. Visscher. "Seed Availability Does Not Ensure Regeneration in Northern Ecosystems of the Endangered Limber Pine". Forests 10, n. 2 (10 febbraio 2019): 146. http://dx.doi.org/10.3390/f10020146.

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Research Highlights: When biotic interactions such as disease alter both the seed production capacity of stands, and seedling survivorship, the relative importance of seed availability versus substrate specificity may alter future regeneration opportunities for plant populations. Background and Objectives: We investigated the importance of disease severity, seed availability, and substrate limitation to the regeneration dynamics of the endangered limber pine, Pinus flexilis, in two ecosystems with varying forest composition, and different histories of white pine blister rust infection (WPBR; Cronartium ribicola). Materials and Methods: A total of 17 stands from the montane ecoregion (Alberta, Canada) were sampled for seed production between 2007–2010, seedling density, and age structure. Model selection using an information theoretic approach compared a series of a priori models and their combinations, based on our hypotheses on the role biotic variables play in the regeneration process. Results: Despite higher rates of WPBR infection, 2.3 times more seed was available for avian dispersers in the southern ecosystem. Recent seedling regeneration did not correspond to seed production (83 versus 251 seedlings/ha, in southern versus northern ecosystems, respectively), resulting in a seven-fold difference in seed to seedling ratios between ecosystems. Models suggest that disease and vegetation cover were important factors explaining the absence of regeneration in 79.4% of the plots sampled, while basal area (BA) of live limber pine, rocky substrates, ecosystem, South aspects, and slope enhanced limber pine regeneration. Seedling age structures suggest that recent regeneration is less likely in more diseased landscapes, than it was historically (40% versus 72.8% of seedlings < 20 years old, respectively, in southern versus northern ecosystems). Conclusions: At the northern limits of limber pine’s range, seed availability does not ensure regeneration, suggesting that other environmental or biotic factors hinder regeneration. Regeneration was consistently predicted to be lower in the southern ecosystem than in the northern ecosystem, suggesting that natural regeneration and the potential for population recovery are ecosystem dependent. We recommend that monitoring recent seedlings will aid the identification of biotic and abiotic factors affecting regeneration.

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St-Pierre, Hélène, Réjean Gagnon e Pierre Bellefleur. "Distribution spatiale de la régénération après feu de l'épinette noire (Picea mariana) et du pin gris (Pinus banksiana) dans la forêt boréale, Réserve faunique Ashuapmushuan, Québec". Canadian Journal of Botany 69, n. 4 (1 aprile 1991): 717–21. http://dx.doi.org/10.1139/b91-097.

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Post-fire spatial distribution of black spruce (Picea mariana (Mill.) BSP) and jack pine (Pinus banksiana Lamb.) regenerations were studied in the Réserve faunique Ashuapmushuan, Quebec. The main factors analysed were (i) effects of organic matter thickness on growth and regneration, (ii) spatial distribution type of the regeneration, (iii) effects of burned stems on this distribution, and (iv) links between spatial distribution of the regeneration and the thickness of the post-fire residual organic matter. A strong correlation was observed between the presence of seedlings and the thickness of the post-fire residual organic matter. However, jack pine was much more efficient in getting established on microsites with thicker organic matter. Spatial distribution of the regeneration has a tendency to spread, following Blackman's dispersion coefficient, while adult individuals of the original population follow a more random pattern; this suggests that some seedling mortality, induced by seedling density, is to be expected. Regeneration shows a spatial link (point correlation coefficient) with trees of the original population, thus showing up the post-fire perpetuation of the individuals on the same microsites. Finally, the residual organic matter thickness on the ground seems without significant influence on the overall growth of jack pine and black spruce seedlings. Key words: Picea mariana, Pinus banksiana, spatial distribution, fire, regeneration. [Journal translation]

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Alfaro-Sibaja, Laura, Daniela Barquero-Salgado, Alicia Fonseca, Randall A. Montoya-Solano, Vanesa Morales-Cerdas e Daniel Ramírez-Arce. "Vegetation structure and composition of mangrove Palo Seco Quepos, Costa Rica". UNED Research Journal 7, n. 2 (15 dicembre 2015): 325–32. http://dx.doi.org/10.22458/urj.v7i2.1161.

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The Palo Seco mangrove in the Pacific coast of Costa Rica is in a tropical wet forest-perhumid forest transition. The nearby human population and tourism are threatening its borders. We studied mangrove’s structure, composition and regeneration as a base for future comparisons. We sampled eight 10m x 10m plots. Within them, 1m2 and 16 m2 plots were established to measure seedlings and saplings. We measured 153 trees in an 800 m2 area, with an average density of 0,19 ± 0,12 Ind/m2. Avicennia germinans was the dominant species, and Avicennia bicolor the less abundant. While seed- ling’s basal area and density were high, we found a low sapling density. We found a strong positive correlation between seedling density and trees richness and density, whereas that a strong significant negative correlation between the seedling regeneration index and tree stem height, diameter and basal area. We found a positive correlation be- tween the seedling regeneration index and mangrove tree’s richness and density. We conclude that several variables have an influence in the seedling’s establishment, survival and growth, intervening in the mangrove’s maintenance and regeneration. Strong competition with other vegetation can be a major factor in sapling growth. Palo Seco mangrove has a great potential for regeneration, and stem height and diameter evidence of an old-growth ecosystem.

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Youngblood, Andrew P. "Effect of shelterwood removal methods on established regeneration in an Alaska white spruce stand". Canadian Journal of Forest Research 20, n. 9 (1 settembre 1990): 1378–81. http://dx.doi.org/10.1139/x90-182.

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Seedling damage during overstory removal was compared among different yarding methods; almost three times more mortality was associated with rubber-tired ground skidding than with skyline cable yarding. Seedlings ranging in height from 0.4 to 1.0 m generally received less damage or had lower mortality rates from cable yarding than did shorter or taller seedlings. Snowpack disturbance and percentage of seedling mortality were positively correlated. Results suggested that with attention to seedling height growth and yarding method, the shelterwood regeneration system is a viable option for white spruce (Piceaglauca (Moench) Voss) stand regeneration in interior Alaska.

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Lunt, Ian D., Heidi C. Zimmer e David C. Cheal. "The tortoise and the hare? Post-fire regeneration in mixed Eucalyptus - Callitris forest". Australian Journal of Botany 59, n. 6 (2011): 575. http://dx.doi.org/10.1071/bt11151.

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Seedling regeneration after a high intensity wildfire was assessed in a mixed forest dominated by Eucalyptus species and Callitris endlicheri (Parl.) F.M. Bailey. Patterns were compared against the ‘slow seedling’ or ‘tortoise-and-hare’ theory of competitive interactions between gymnosperms and angiosperms. Browsing effects were documented using fenced plots, and seedling density, mortality and height were assessed over 6 years, from 2004–10. Consistent with expectations, Eucalyptus seedlings grew faster than Callitris seedlings in most situations. Callitris seedlings grew faster and produced seed cones sooner in plots with fewer Eucalyptus seedlings compared with plots with dense Eucalyptus seedlings. The local growth rates of Callitris seedlings were not associated with long-term site suitability for Callitris, as many plots with diminutive Callitris seedlings and dense Eucalyptus seedlings were dominated by Callitris trees before the 2003 fire. Contrary to expectations, few Callitris seedlings died during the 6-year period, so competition during the regeneration phase did not regulate co-existence. Strong drought tolerance and the ability to persist in dense, unthinned stands may enable Callitris to persist beneath dense Eucalyptus regeneration. Nevertheless, Callitris seedlings growing with dense Eucalyptus seedlings have a longer primary juvenile period than seedlings in sites with fewer seedling or adult eucalypts, which places these stands at greater risk of mortality in future fires and greater risk of browsing in the meantime.

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Brose, Patrick H. "A comparison of the effects of different shelterwood harvest methods on the survival and growth of acorn-origin oak seedlings". Canadian Journal of Forest Research 41, n. 12 (dicembre 2011): 2359–74. http://dx.doi.org/10.1139/x11-143.

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Timely development of newly germinated oak (Quercus spp.) seedlings into competitive-sized regeneration is an essential part of the oak regeneration process. The amount of sunlight reaching the forest floor partly governs this development, and foresters often use the shelterwood system to expose oak seedlings to varying degrees of insolation. To further understand the seedling development–sunlight–shelterwood relationships, I conducted a multiyear study at five locations in Pennsylvania. Each location had four stands either uncut or recently treated with one of three shelterwood harvest methods (preparatory cut, first removal cut, or final removal cut) resulting in four different levels of sunlight reaching the forest floor. In each stand, four 32 m2 plots were prepared, and each was planted with 400 acorns of black (Quercus velutina Lam.), chestnut (Quercus montana Willd.), northern red (Quercus rubra L.), or white oak (Quercus alba L.) and protected from wildlife. Germination success was universally high and for the next 8 years, I monitored seedling survival and measured seedling growth. The final and first removal cut treatments had higher seedling survival than the preparatory cut and uncut treatments. Oak seedling growth was positively related to sunlight availability; seedlings in the final removal cut grew the most, followed in descending order by those in the first removal cut, preparatory cut, and uncut treatments. These findings provide insight into the subtleties of regenerating oak forests with the shelterwood system.

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Jones, Robert H., Ralph D. Nyland e Dudley J. Raynal. "Response of American Beech Regeneration to Selection Cutting of Northern Hardwoods in New York". Northern Journal of Applied Forestry 6, n. 1 (1 marzo 1989): 34–36. http://dx.doi.org/10.1093/njaf/6.1.34.

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Abstract Root sprout and seedling regeneration of American beech was sampled in two maple-dominated northern hardwood stands 13-14 years after single-tree selection cutting. The largest stems had been advance regeneration, and seedlings comprised a substantial and well-distributed portion of these. Among stems established after the cut, root sprouts outnumbered seedlings. Total beech regeneration abundance was correlated with basal area of overstory beech. For long-term beech control, it may be useful to reduce beech seedling populations before selection cutting, and to cut large diameter beech trees. North. J. Appl. For. 6:34-36, March 1989.

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Più fonti

Tesi sul tema "Seedling regeneration"

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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Hanley, Michael Edward. "The influence of molluscan herbivory on seedling regeneration in grassland". Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296377.

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MacAllister, Sarah Louise. "Regeneration of Scots pine (Pinus sylvestris L.) under drought". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/19560.

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Drought-induced tree mortality is a phenomenon affecting many forest ecosystems and is predicted to increase under ongoing climate change. Forest stability partly depends on regeneration: the process of renewing mature forest with subsequent generations. As seedlings are more susceptible to drought effects than mature trees, mortality of the seedling bank can represent a major bottleneck controlling forest structure and species composition. Scots Pine (Pinus sylvestris L.) is the most widely distributed of the Pinus species, covering a broad latitudinal gradient of ecological conditions. The thesis aims to deepen understanding of drought-induced mortality, while analysing intra-specific variation in the phenotypic and metabolic profile of Pinus sylvestris seedlings subjected to drought stress. I also consider the relevance of the results to the broader conceptual framework of drought-induced mortality. The experiments utilise seeds from different populations of origin (provenances) across the north-south axis of the European range of Pinus sylvestris, in order to determine the extent of regeneration capacity in this species under drought. Seeds were collected from different populations (provenances) that, along with other climatic and edaphic differences, span a gradient of water availability: from wet (Scotland) to intermediate (Austria, Poland) to dry (Spain). In Chapter 2, the effects of osmotic stress on the initial seedling establishment stage were studied by comparing phenotypic responses across provenances. Seedling germination, early growth, osmotic stress tolerance and survival were investigated using a polyethylene glycol irrigation treatment as a proxy for rapid and severe drought. Treatment, provenance and interaction effects were found for rate of germination, final proportion of seeds germinated, seedling size, and superoxide dismutase activity (an antioxidant enzyme). Root investment was affected by both provenance and time to germination. Although there was no significant effect of provenance on survival, a trend towards increased probability of survival under osmotic stress was indicated for the southernmost (driest) as compared with the northernmost (wettest) provenance. Chapter 3 investigates the responses of older seedlings (at 10 months) to a drying down of soil moisture for 40 days. Morphological and physiological data were collected to assess intra-specific and intra-population variation in the seedling stress response under drought. A metabolomics analysis using Ultra performance Liquid chromatography followed by mass spectrometry (UPLC/MS) was carried out to investigate whether metabolic markers could be identified that are suggestive of heightened oxidative stress and whether populations in different climatic and edaphic environments show variation in metabolic activity under drought. Preliminary results suggest large intra-population variability yet clear differentiation in metabolic responses to drought over the time course of the experiment. Univariate and multivariate analyses indicated that among the most significant increases in response to drought were those involved in osmoprotective and antioxidant capabilities, including the free amino acid proline and a quercetin derivative (a flavonoid). Interestingly, provenances, either under experimental drought or not, did not show significantly different metabolite profiles, even though provenance and its interaction with drought treatment did significantly affect seedling biomass and photochemical efficiency. In Chapter 4 the effects of provenance, maternal parentage and seed weight on germination rate, final germination percentage, as well as seedling drought responses in biomass allocation and the expression of selected antioxidant genes were analysed. Seed weights were measured individually and seed weight was found to have a strong positive effect on: germination rate, seedling dry weights, and number of needles. Expression of two antioxidant enzymes increased under drought. Seed weight was strongly determined by provenance and maternal parentage as well as their interaction. However, root to shoot biomass allocation depended on provenance and maternal effects that were not mediated by seed weight effects. Principal component analysis indicated that the Spanish provenances could be characterised by a higher root to shoot ratio and stem weight. Specific leaf area was also found to be lowest for the Spanish provenances.

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Mallinson, Julian Robert. "The impact of herbivores on the natural regeneration of temperate deciduous woodland". Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4591/.

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Many studies have reported deficient or intermittent patterns of natural regeneration in temperate deciduous woodland. The present study aimed to assess the relative impact of herbivore-mediated plant mortality on the natural regeneration dynamics of representative tree species (Acer pseudoplatanus, Betula pendula, Fraxinus excelsior, Ilex aquifolium, Sorbus aucuparia, Taxus baccata and Ulmus glabra) in representative temperate deciduous woodland (Shipley Wood and Derwent Gorge, County Durham). Sapling density and the density, spatial association and size distribution of adult tree populations varied significantly between tree species and study sites, reflecting contrasting patterns of current and historical regeneration. Rates of post-dispersal seed predation and seedling herbivory were quantified using field-based 'cafeteria' trials. Rodents were the principal agents responsible for seed predation, whereas seedling herbivory was attributable to a mixed suite of herbivores including invertebrates, rodents and larger mammals. Rates of seed predation and seedling herbivory varied significantly between tree species, most likely reflecting individualistic, trade-off responses to chemical and physical attributes. Fine-scale spatial variation most likely reflected the preferential foraging of rodents beneath protective vegetation cover. There was no consistent evidence to support the hypothesis that dispersed seeds may escape disproportionately high offspring mortality beneath parent plants resulting from increased herbivore activity. Natural seedling density varied significantly between years and between tree species, according to the abundance of viable seeds produced by conspecific adult trees. Although seedling survivorship varied significantly between species, the survivorship of each species was similar between years and between cohorts of the same year. Canopy cover, field layer cover or correlated factors were significant determinants of seed germination and seedling emergence, establishment and survival, according to age- and species-specific tolerances. In relative terms, patterns of natural regeneration were primarily herbivore- limited (Acer and Taxus), microsite-limited (Betula, Fraxinus, Ilex and Ulmus) or limited by herbivores and microsites (Sorbus). The availability of viable seeds may have also limited the recruitment of Ilex, Sorbus, Taxus and Ulmus. Vegetative expansion, mast seeding, seed bank regeneration and repeated, prolonged reproduction may have reduced the actual impact of herbivory on natural regeneration, such that long-lived iteroparous tree species were unlikely to have been critically dependent on current recruitment.

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Holgén, Per. "Seedling performance, shelter tree increment and recreation values in boreal shelterwood stands /". Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5854-4.pdf.

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West, Lee. "Effects of Soil Fungi on Tree Seedling Establishment in a Southeastern Coastal Plain Forest". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46180.

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Effects of fungi and overstory composition on tree seedling survival and growth were investigated in closed canopy upland forests in the coastal plain of South Carolina. Seedlings of Quercus alba, Cornus florida and Pinus taeda were planted in the understory of two forest types -naturally regenerated hardwood and planted pine. Fungal species composition and biomass were experimentally manipulated with a treatment of the fungicide captan. In contrast with other studies conducted in different systems (sand dune, grassland, and old field), the effects of soil fungi were minor in a closed canopy forest. Only Q. alba showed a significant response to the fungicide (p < 0.05) treatment with increased growth. Overstory composition had no significant effect on growth or survival for any of the species. Both of the commercially desirable species (Q. alba and P. taeda) had reasonable survival ( @ 60%). Both also maintained positive, though modest, growth. This suggests that an advance regeneration pool could be established successfully by artificial regeneration.
Master of Science

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Warrillow, Michael P. "Ecological Impact of Glaze Storm Damage in an Appalachian Oak Forest". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/31507.

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Glaze damage to canopy trees, gap size and seedling regeneration was surveyed relating to site topographic features after a major glaze storm at Fishburn Forest in the central Appalachian mountain region. The survey sites were stratified according to aspect and landform, and sample plots were randomly assigned to each topographic category. The canopy trees in the plots were tallied and their damage was visually classified. The results demonstrated that different species had different susceptibilities to glaze damage and susceptibility of species varied as topography changed. Virginia pine was the most susceptible species. In general, trees had the greatest damage on steep slopes and eastern aspects, and least damage on toe-slopes. Some species varied greatly in their susceptibility to glaze damage across the topographic categories, such as red maple, while some species varied little, like blackgum. Basal area was reduced 6% and varied due to species and topography. Where glaze damage was severe, gaps in the forest canopy were created. Gap sizes and the effects of gap size and topography on seedling regeneration within gaps caused by glaze damage were assessed. Seedlings were tallied by species and height in microplots within each sample plot and in the nearest gap, where gap size was measured. Gap size varied from 14,000 m2 to less than 20 m2. Average gap size was 255 m2. Canopy tree damage, forest type and topography were the most important factors affecting gap size. Gaps tended to be larger on steep backslopes. Common seedling species in both gaps and understory were sassafras, serviceberry and red maple. Disturbance affected both seedling height and density, as did topography. However gap size had effect only on seedling height. The future forest in this area is unlikely to change significantly, as species composition of seedlings was largely unaffected by the glaze storm damage.
Master of Science

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Pearce, Christopher Deane. "Effectiveness of Treatments to Reduce Rhododendron maximum and Promote Tree Seedling Regeneration in the Southern Appalachians". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/41885.

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Rosebay rhododendron (Rhododendron maximum L.) is an evergreen ericaceous shrub that plays a dynamic role in the southern Appalachian forests. Commonly located on mesic sites, this understory shrub forms dense thickets that greatly reduce the amount of light available to herbaceous and woody plants found on the forest floor. Past research has shown that silvicultural methods can be used to eradicate R. maximum, however it is unclear which of these methods is most efficient and what effects other than stem mortality may occur. In this study, treatments involving prescribed fire, mechanical cutting, and herbicide applications were applied to R. maximum dominated forests in southwestern Virginia to determine what effect seven different silvicultural treatments had on 1) controlling of R. maximum as a forest weed 2) fuel loading inside of a R. maximum thicket, and 3) canopy tree seedling regeneration. Mechanical cutting treatments were successful in reducing R. maximum basal area per acre; however stump sprouting and increased fuel loading occurred. Herbicide applications were successful in controlling only the smallest diameter class of R. maximum stems. Prescribed fire reduced litter layers and caused delayed mortality on R. maximum stems three years following treatment. Hemispherical photographs taken within each plot showed that silvicultural treatments that successfully increased the amount of light entering each plot were influential in seedling establishment three years following treatments. Results from this study can be used to further perfect silvicultural applications that alleviate R. maximum cover on the forest landscape.
Master of Science

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Frankenberg, Sarah J. "Fire, Forest, Ice, and Fungi: Exploring The Mesh Of Relationships Driving Seedling Regeneration In The Siberian Arctic". University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1596147602477988.

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White, Helen Marie. "Biotic and Abiotic Factors of Picea rubens (Red Spruce) Seedling Regeneration in Disturbed Heathland Barrens of the Central Appalachians". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/101088.

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During the late 19th and early 20th centuries, extensive logging reduced the forests of red spruce (Picea rubens) by nearly 99% through portions of West Virginia. In the wake of this disturbance, red spruce has begun regenerating on the ridge and mountaintop areas of Canaan Valley, West Virginia, where heath and grassland communities have both persisted in natural barrens and expanded into formerly forested areas. To understand abiotic and biotic conditions guiding the advance of the red spruce stand, I conducted a broad-scale assessment of thirty-one demographics plots spread across two sites (north Cabin Mountain and Bear Rocks/Dolly Sods), and a more focused assessment of red spruce species associations within thirty-two paired plots at Cabin Mountain. At the 15m x 15m demographics plots, I conducted a count of all P. rubens present, measured specimen height, DBH or diameter at ground level (DGL) for specimens < 1.37m tall, and assessed the relative percent cover of rock, shrub, herbaceous, and tree cover. These data, along with additional abiotic components derived from a DEM, formed the basis of my assessment using a generalized linear mixed model (GLMM) to identify the most significant biophysical variables related to P. rubens count. In the paired plots, I used the relative interactions index (RII) to compare the total cover of each present non-graminoid vascular species and the grouped cover types Rock, Graminoid, Lichen, Litter, and Moss in one 45cm-radius plot with a < 1.37m P. rubens specimen, and one paired 45cm-radius plot in open heath. The significance of differences in total cover were assessed with the Wilcoxon test and Tukey HSD. The GLMM identified percent rock cover and distance from the nearest P. rubens stand to be important correlates of P. rubens count at the demographic plots. Graminoid cover was found to be higher in P. rubens 45cm-radius plots than in paired heath plots, and Vaccinium angustifolium cover was found to be concentrated in 45cm radius plots beyond the first 15cm from the P. rubens stem. These findings reinforce a complex interplay between both the biotic and abiotic characteristics of a microsite and the successful germination and regeneration of a red spruce seedling in the heathland.
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Libri sul tema "Seedling regeneration"

Manchester, Edwin H. Tree shelters show promise for oak regeneration. Atlanta, Ga: U.S. Dept. of Agriculture, Forest Service, Cooperative Forestry, 1988.

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Manchester, Edwin H. Tree shelters show promise for oak regeneration. Atlanta, Ga: U.S. Dept. of Agriculture, Forest Service, Cooperative Forestry, 1988.

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Ratliff, Raymond D. Grazing on regeneration sites encourages pine seedling growth. Albany, Calif: U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station, 1995.

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Institute, Petawawa National Forestry. Modelling seedling emergence using soil monoliths. Chalk River, Ont: Petawawa National Forestry Institute, 1995.

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McDonald, Philip M. Seedfall, regeneration, and seedling development in group-selection openings. Albany, Calif. (P.O. Box 245, Berkeley 94701-0245): U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station, 1994.

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Minore, Don. Effects of site preparation on seedling growth: A preliminary comparison of broadcast burning and pile burning. Portland, Or: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 1986.

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Alexander, Robert R. Engelmann spruce seed production and dispersal and seedling establishment in the central Rocky Mountains. Fort Collins, Colo: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1986.

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Alexander, Robert R. Engelmann spruce seed production and dispersal, and seedling establishment in the central Rocky Mountains. Fort Collins, Colo: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1986.

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Mallik, A. U. Vegetative and seedling regeneration of pin cherry (Prunus pensylvanica): Efficacy of herbicide treatment. Sault Ste. Marie, Ont: Great Lakes Forestry Centre, 1996.

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Capitoli di libri sul tema "Seedling regeneration"

Mexal, John G., e David B. South. "Bareroot Seedling Culture". In Forest Regeneration Manual, 89–115. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3800-0_6.

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Johnson, Jon D., e Michael L. Cline. "Seedling Quality of Southern Pines". In Forest Regeneration Manual, 143–59. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3800-0_8.

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Jack, Steven B., e Stephen D. Pecot. "Regeneration Dynamics, Competition, and Seedling Response". In Ecological Restoration and Management of Longleaf Pine Forests, 71–88. Boca Raton : CRC Press, 2017.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315152141-4.

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Brissette, John C., James P. Barnett e Thomas D. Landis. "Container Seedlings". In Forest Regeneration Manual, 117–41. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3800-0_7.

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Díaz Vélez, M. Celeste, Ana E. Ferreras e Valeria Paiaro. "Seed dispersal interactions promoting plant invasions." In Plant invasions: the role of biotic interactions, 90–104. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789242171.0090.

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Abstract Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.

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Carlson, William C. "Lifting, Storing, and Transporting Southern Pine Seedlings". In Forest Regeneration Manual, 291–301. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3800-0_16.

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Whitmore, T. C. "Potential Impact of Climatic Change on Tropical Rain Forest Seedlings and Forest Regeneration". In Potential Impacts of Climate Change on Tropical Forest Ecosystems, 289–98. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-2730-3_13.

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Lundqvist, Lars, e Sven Wagner. "Regeneration techniques and the seedling environment from a European perspective". In Restoration of Boreal and Temperate Forests, 153–71. CRC Press, 2004. http://dx.doi.org/10.1201/9780203497784.ch10.

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O. Numbere, Aroloye. "Mangrove Restoration under Different Disturbances Regime in the Niger Delta, Nigeria". In Mangrove Ecosystem Restoration [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96127.

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Mangroves of the Niger Delta are the largest in Africa and are the source of numerous ecosystem services such as firewood, seafood, building materials and medicinal herbs. Their sustainable use and protection are important for future generations. However, anthropogenic activities such as oil and gas exploration, urbanization, industrialization, dredging, overexploitation and sand mining are the major disturbances that have pushed the mangroves to the brink of extinction. Therefore, in other to restore lost areas of the mangroves natural and artificial means can be adopted to bring them to a restored state. More often than not emphasis of recovery had been placed on artificial remediation and restoration, where polluted sites are cleaned with chemicals and nursery seedlings transplanted to remediated such sites. Nevertheless, this chapter discusses the possibility of utilizing natural means of forest recovery through seedling recruitment and regeneration. This can be achieved by establishing the right environmental conditions such as setting up of a hydro-channel to ensure smooth inflow and out flow of river water carrying seeds, availability of parent mangrove trees to supply the seeds, and the availability of the right soil condition to enable seedling germination and growth. The use of dried and ground mangrove parts as a new way for restoring polluted soil is discussed; in addition, the unconventional proposition of using low key pollution to manage and increase forest resilience is highlighted in this work even though further studies are recommended. Future direction of mangrove restoration should be tilted towards the application of the force of nature, which has the potentials of reversing the adverse effect of anthropogenic activities in well managed and protected sites.

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Bazzaz, F. A., e P. M. Wayne. "Coping with Environmental Heterogeneity: The Physiological Ecology of Tree Seedling Regeneration across the Gap—Understory Continuum". In Exploitation of Environmental Heterogeneity by Plants, 349–90. Elsevier, 1994. http://dx.doi.org/10.1016/b978-0-12-155070-7.50018-4.

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Atti di convegni sul tema "Seedling regeneration"

DUMINS, Karlis, Toms STALS e Dagnija LAZDINA. "FOREST REGENERATION QUALITY ASSESSMENT BY ASTA SYSTEM". In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.178.

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In Latvia one third of the total forest area is regenerated by planting tree seedlings and therefore it is important to choose the appropriate soil preparation method and the right type of regeneration material for each forest type. Usually the success of afforestation is evaluated by how high is the average seedling survival rate and growth parameters like height, annual increment, diameter at breast height while the location of the seedling is disregarded. This may be of great importance since in such stands the environmental conditions typically are not entirely homogenous. Micro topography differences impact seedling growth, because it modifies water regime, temperature, micronutrient availability, sun radiation and other factors. Therefore, aim of this work is to improve monitoring methods and determine the most efficient soil preparation and seedling preparation combination to improve the quality of forest regeneration. That could be done using ASTA documentation system originally developed to show seedling and mound location and density in planting area during mechanic planting. But it also allows to link the precise location of the seedling and growing conditions with its growing rate and survival and therefore it is easier to exclude seedlings that are affected by other factors than those that you are interested in, so you can gain more representative results. This also could be used in forest management. When using ASTA system it is also possible to display how different tree disease are distributed in the stand, if they have spread eventually or localized only in some parts of the stand, also it can be used for browsing and other tree damage monitoring in the stand. In conclusion: in harsh environmental conditions on unprepared forest soil and soil prepared in furrows made by disc trench larger seedlings show better survival rate. Survival of seedlings is significantly impacted by micro topography, whereas mounded micro sites equalize local environmental conditions that reduce impact of micro topography.

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Pats, E. N. "CRITERIA OF SEEDLING COLONIZATION IN SIBERIAN STONE PINE FORESTS IN TOMSK OBLAST". In Prirodopol'zovanie i ohrana prirody: Ohrana pamjatnikov prirody, biologicheskogo i landshaftnogo raznoobrazija Tomskogo Priob'ja i drugih regionov Rossii. Izdatel'stvo Tomskogo gosudarstvennogo universiteta, 2020. http://dx.doi.org/10.17223/978-5-94621-954-9-2020-12.

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The current state of reforestation of Siberian stone pine stands in the near-village Siberian stone pine forests in Tomsk Oblast is given by criteria of dark coniferous seedling colonization. Structure of the natural regeneration is very diverse and quite specific.

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Fukasawa, Yu, Yoko Ando, Satoshi Suzuki, Yoshitaka Oishi, Kimiyo Matsukura, Kunihiro Okano e Zewei Song. "A long-term impact of forest disturbance on spruce seedling regeneration on coarse woody debris". In 5th European Congress of Conservation Biology. Jyväskylä: Jyvaskyla University Open Science Centre, 2018. http://dx.doi.org/10.17011/conference/eccb2018/107752.

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MIEZĪTE, Olga, Jeļena RŪBA, Lāsma FREIMANE, Imants LIEPA e 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.

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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.

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Rapporti di organizzazioni sul tema "Seedling regeneration"

Ratliff, Raymond D., e Renee G. Denton. Grazing on Regeneration Sites Encourages Pine Seedling Growth. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, 1995. http://dx.doi.org/10.2737/psw-rp-223.

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McDonald, Philip M., e Celeste S. Abbott. Seedfall, regeneration, and seedling development in group-selection openings. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, 1994. http://dx.doi.org/10.2737/psw-rp-220.

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Ristau, Todd E., e Susan L. Stout. Can cover data be used as a surrogate for seedling counts in regeneration stocking evaluations in northern hardwood forests? Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station, 2014. http://dx.doi.org/10.2737/nrs-rn-198.

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Leis, Sherry. Vegetation community monitoring at Lincoln Boyhood National Memorial: 2011–2019. National Park Service, aprile 2021. http://dx.doi.org/10.36967/nrr-2284711.

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Lincoln Boyhood National Memorial celebrates the lives of the Lincoln family including the final resting place of Abraham’s mother, Nancy Hanks Lincoln. Lincoln’s childhood in Indiana was a formative time in the life our 16th president. When the Lincoln family arrived in Indiana, the property was covered in the oak-hickory forest type. They cleared land to create their homestead and farm. Later, designers of the memorial felt that it was important to restore woodlands to the site. The woodlands would help visitors visualize the challenges the Lincoln family faced in establishing and maintaining their homestead. Some stands of woodland may have remained, but significant restoration efforts included extensive tree planting. The Heartland Inventory and Monitoring Network began monitoring the woodland in 2011 with repeat visits every four years. These monitoring efforts provide a window into the composition and structure of the wood-lands. We measure both overstory trees and the ground flora within four permanently located plots. At these permanent plots, we record each species, foliar cover estimates of ground flora, diameter at breast height of midstory and overstory trees, and tree regeneration frequency (tree seedlings and saplings). The forest species composition was relatively consistent over the three monitoring events. Climatic conditions measured by the Palmer Drought Severity Index indicated mild to wet conditions over the monitoring record. Canopy closure continued to indicate a forest structure with a closed canopy. Large trees (>45 cm DBH) comprised the greatest amount of tree basal area. Sugar maple was observed to have the greatest basal area and density of the 23 tree species observed. The oaks characteristic of the early woodlands were present, but less dominant. Although one hickory species was present, it was in very low abundance. Of the 17 tree species recorded in the regeneration layer, three species were most abundant through time: sugar maple (Acer saccharum), red bud (Cercis canadensis), and ash (Fraxinus sp.). Ash recruitment seemed to increase over prior years and maple saplings transitioned to larger size classes. Ground flora diversity was similar through time, but alpha and gamma diversity were slightly greater in 2019. Percent cover by plant guild varied through time with native woody plants and forbs having the greatest abundance. Nonnative plants were also an important part of the ground flora composition. Common periwinkle (Vinca minor) and Japanese honeysuckle (Lonicera japonica) continued to be the most abundant nonnative species, but these two species were less abundant in 2019 than 2011. Unvegetated ground cover was high (mean = 95%) and increased by 17% since 2011. Bare ground increased from less than 1% in 2011 to 9% in 2019, but other ground cover elements were similar to prior years. In 2019, we quantified observer error by double sampling two plots within three of the monitoring sites. We found total pseudoturnover to be about 29% (i.e., 29% of the species records differed between observers due to observer error). This 29% pseudoturnover rate was almost 50% greater than our goal of 20% pseudoturnover. The majority of the error was attributed to observers overlooking species. Plot frame relocation error likely contributed as well but we were unable to separate it from overlooking error with our design.

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