935 resultados para Trees in art
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.
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Chlorophyll fluorescence is currently used as a rapid diagnostic and nondestructive method to detect and quantify damage on the photosynthetic apparatus of leaves on weeds, crops and ornamental/coniferous trees in response to both environmental stress and herbicides. This study aimed to evaluate chlorophyll fluorescence in guanandi plants (Calophyllum brasiliense) after application of different postemergence herbicides. The experiment was performed in a completely randomized design, with six treatments (control, bentazon, sulfentrazone, isoxaflutole, atrazine and glyphosate) and five replications. The herbicide treatments were applied with a stationary sprayer, and electron transport rate (ETR) was subsequently analyzed with OS5p Multi-Mode Chlorophyll Fluorometer. In the monitored period, guanandi plants subjected to atrazine showed higher sensitivity to chlorophyll fluorescence than the other treatments. Although bentazon is a photosystem II inhibitor, it showed no major changes in electron transport for the studied species and in the monitored period. In summary, ETR is a good parameter to evaluate the effect of some herbicides on Calophyllum brasiliense plants.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study aims to analyze the thermal comfort in urban areas for different land uses. The ENVImet microclimatic model has been used for urban boundary layer simulation, providing the following thermal comfort indexes: PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfaction). The chosen area covers the central area in the city of Ourinhos, located in southeastern Brazilian city, with subtropical climate. Four simulations were accomplished: an area with real buildings and vegetation on site, a “grassy” area where buildings have been replaced by grass in the central area, another grassy area, known as “grass/tree”, with additional trees in, and a final area called “Park” also grassy, where trees were added all over the area. The structures which showed thermal comfort within the ISO 7730 standards were the grassy area with no trees at 9 a.m., and a paved area, as well as the park area at 3 p.m. Other situations have presented values of PMV and PPD off the limits required by the rules; they were very close to those values. The only point that presented a far cry from the comfort required was the spot in the asphalt at 9 a.m. The other situations showed PMV and PPD values not far from the limits of comfort. Only the point on the asphalt showed values far from the limit of comfort at 9 a.m.
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This register lists the largest trees of over 80 species identified in Nebraska. The name of the owner and nominator, size and location of each tree follow each listing. Many people across Nebraska have worked hard to make this register as comprehensive and accurate as possible, but the quest to find the largest trees in Nebraska is never over. Champion trees are by nature old, and old trees diminish and die. Larger trees are newly discovered. Thus, this list continually changes as new nominations are submitted.
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During the last decade, leaf tatters has been reported in white oak and hackberry across several Midwestern states. Herbicide spray drift studies have shown that chloroacetamides can induce leaf tatters. The objectives of this research were to: 1) identify vulnerable bud developmental stages in hackberry and 2) determine if different commercial chloroacetamides affect severity of leaf tatters. In 2008, a preliminary spray drift experiment was conducted on mature trees from a former hackberry provenance test stand. Acetochlor (Harness), S-metolachlor (Dual II Magnum), and dimethenamid (Outlook) were applied at concentrations approximating 27%, 54%, 81%, or 108% of the recommended field rate. Three developmental stages before bud burst were present on the selected trees. Leaf tatters did not develop on the selected hackberry trees. However, symptoms were observed on neighboring, non-target hackberry trees, which had been in the leaf unfolding and expanding stages at the time of spraying. In 2009, three year old hackberry seedlings were treated with 1%, 10%, and 100% of the recommended field rate of acetochlor (Harness), S-metolachlor (Dual II Magnum), and dimethenamid (Outlook). Folded buds and two unfolding leaf developmental stages were present on seedlings. Another spray study was conducted on 32 mature hackberry trees from the provenance stand. A solution of 5608 mg a.i./L dimethenamid (Outlook) was applied to trees in the unfolding and/or expanding leaf stage. Treated trees represented four provenances. Image analysis was used to calculate seedling and mature tree leaf areas and estimate the seedling percentage of leaf tissue loss. Foliar damage was not significantly different between seedlings treated with water, 1%, or 10% of the field rate. Foliar damage was significantly different between seedlings treated with 1% or 100% of the field rate, and between seedlings treated with 10% or 100% of the field rate. Foliar damage in seedlings was not significantly different between the developmental stages. Additionally, symptoms of leaf tatters were observed on the treated mature hackberry. Future studies should focus on chloroacetamide concentrations above 10% of the recommended field rate.
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The wildlife in Japan does more damage in outbreaks in forestry than in agriculture. Hares annually damage in excess of 250 thousand acres. Voles annually damage 50 to 100 thousand acres; in some areas great damage may occur suddenly. The giant flying squirrel damages areas of replanted trees in southern areas of Japan. The Himalayan black bear strips the bark on tree trunks. In agriculture, the sparrow and the duck do an excessive amount of damage in rice fields, and the boar does conspicuous harm in the plowed fields of mountain villages. In Okinawa, sugar cane is attacked by Rattus rattus, and in some years the loss is severe. Of even greater concern is the damage done by introduced vertebrates. The gem-faced civet was imported from Taiwan. Similarly introduced from Taiwan, the tree squirrel increased on Izu-Oshima. The nutria was introduced in 1940; they escaped from cages in Southern Honshu and have increased.
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Questions What are the main features of the seed rain in a fragmented Atlantic forest landscape? Can seed rain species attributes (life form, dispersal mode, successional status) relate to the spatial arrangement (size and number of fragments, edge density and presence of corridor) of forest fragments in the landscape? How does the rain forest landscape structure affect the seed rain? Location Atlantic rainforest, Sao Paulo State, Southeastern Brazil. Methods Seed rain samples were collected monthly throughout 1yr, counted, identified and classified according to species dispersal mode, successional status and life form. Seed rain composition was compared with woody species near the seed traps. Relationships between seed rain composition and landscape spatial arrangement (fragment area, presence of corridor, number of fragments in the surroundings, proximity of fragments, and edge density) were tested using canonical correspondence analysis (CCA). Results We collected 20142 seeds belonging to 115 taxa, most of them early successional and anemochorous trees. In general, the seed rain had a species composition distinct from that of the nearby forest tree community. Small isolated fragments contained more seeds, mainly of anemochorous, epiphytic and early-successional species; large fragments showed higher association with zoochorous and late-successional species compared to small fragments. The CCA significantly distinguished the species dispersal mode according to fragment size and isolation, anemochorous species being associated to small and isolated fragments, and zoochorous species to larger areas and fragment aggregation. Nevertheless, a gradient driven by proximity (PROX) and edge density (ED) segregated lianas (in the positive extremity), early successional and epiphyte species (in the negative end); large fragments were positively associated to PROX and ED. Conclusions The results highlight the importance of the size and spatial arrangement of forest patches to promote habitat connectivity and improve the flux of animal-dispersed seeds. Landscape structure controls seed fluxes and affects plant dispersal capacity, potentially influencing the composition and structure of forest fragments. The seed rain composition may be used to assess the effects of landscape spatial structure on plant assemblages, and provide relevant information for biodiversity conservation.
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This paper presents a survey of the insects that feed on fruits of Psittacanthus Martius (Santalales: Loranthaceae), a hemiparasitic mistletoe genus that infects trees in Brazil and other neotropical countries. The aim of the study was to identify candidate insects for biological control of Psittacanthus mistletoes. Unripe and mature fruits were collected in several localities of Cerrado, bordering South Pantanal, Southwestern Brazil, from 29 Apr 1998 to 30 Jul 2000. A total of 24,710 fruits (54 samples) of Psittacanthus acinarius infecting 15 species from 10 plant families were evaluated. Psittacanthus acinarius (Mart.) was the most abundant and frequent species of mistletoe parasitizing trees in the ecotonal Cerrado-Pantanal. From 24,710 fruits of Psittacanthus acinarius were obtained 1,812 insect larvae including 1,806 Neosilba McAlpine (Diptera: Lonchaeidae) species and 6 Thepytus echelta (Hewitson) (Lepidoptera: Lycaenidae). From these emerged 1,550 Neosilba spp. adults and 6 T. echelta. Neosilba pantanense Strikis was described from this research. Larvae of T. echelta occurred in fruits of P. acinarius parasitizing Cecropia pachystachya Trecul (Urticaceae) and Anadenanthera colubrina (Vellozo) Brenan (Fabaceae). Larvae of Neosilba caused no adverse effects on the germination of infected fruits of Psittacanthus, because they do not eat the embryo or viscin tissues. This differs from the larvae of T. echelta that interrupted the germination of seeds by feeding on those tissues. Thepytus echelta may be a promising insect for the biological control of P. acinarius in the ecotonal Cerrado-Pantanal, although its abundance and frequency were low throughout the sampling period.
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The knockdown and toxic effects of insecticides of different chemical groups and modes of action registered for citrus in Brazil were investigated for effective control of Bucephalogonia xanthophis, a sharpshooter vector of Xylella fastidiosa in citrus. The active ingredients dimethoate (1.2 mL/1.2L), imidacloprid (0.24 mL/1.2L) and lambda-cyhalothrin (0.24 mL/1.2L), as well as a control (water), were sprayed onto branches of potted-citrus nursery trees to evaluate the effect of residual contact. The insects were confined on sprayed branches by using sleeve cages, in groups of 10 per branch (5 branches/treatment). Lambdacyhalothrin showed a knockdown effect on B. xanthophis (>70% mortality within 2 h of exposure), and the residues were effective for approximately one wk. Imidacloprid, lambdacyhalothrin and dimethoate suppressed the vector populations for up to 3 wk after application, when the insects were exposed to sprayed plants for at least 24 h. In another experiment, 2 neonicotinoid insecticides (thiamethoxam and imidacloprid) were applied by soil drench to potted nursery trees, in order to study their systemic effect, i.e., mortality by ingestion on sharpshooter adults. Thiamethoxam and imidacloprid effectively controlled the vectors at all concentrations tested, when the insects were exposed to treated plants for 24 h (>80% mortality) or 48 h (near 100% mortality). The knockdown effect of thiamethoxam and lambda-cyhalothrin might be particularly important to prevent vector transmission of X. fastidiosa in citrus groves.
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Waste products from the forest industry are to be spread in forests in Sweden to counteract nutrient depletion due to whole tree harvesting. This may increase the bioavailability of calcium (Ca) and heavy metals, such as cadmium (Cd), copper (Cu) and zinc (Zn) in forest soils. Heavy metals, like Cd, have already been enriched in forest soils in Sweden, due to deposition of air pollutions, and acidification of forest soils has increased the bioavailability of toxic metals for plant uptake. Changes in the bioavailability of metals may be reflected in altered accumulation of Ca and heavy metals in forest trees, changes in tree growth, including wood formation, and altered tree species composition. This thesis aims at examining: A) if inter- or intra- specific differences in sensitivity to Cd occur in the most common tree species of Sweden, and if so, to study if these can be explained by the uptake and distribution of Cd within the plant: B) how elevated levels of Ca, Cd, Cu and Zn affect the accumulation and attachment of metals in bark and wood, and growth of young Norway spruce (Picea abies): C) how waste products from the forest industry, such as wood ash, influence the contents of Ca, Cd, Cu and Zn in wood and bark of young Norway spruce. Sensitivity to Cd, and its uptake and distribution, in seedlings of Picea abies, Pinus sylvestris and Betula pendula from three regions (southern, central and northern parts) of Sweden, treated with varying concentrations of Cd, were compared. Differences in root sensitivity to Cd both among and within woody species were found and the differences could to some extent be explained by differences in uptake and translocation of Cd. The root sensitivity assays revealed that birch was the least, and spruce the most, sensitive species, both to the external and to tissue levels of Cd. The central ecotype of the species tested tended to be most Cd resistant. The radial distribution, accumulation and attachment of, and interactions between Ca and heavy metals in stems of two-year-old Norway spruce trees treated with elevated levels of Cd, Cu, Zn and/or Ca, were investigated. Further, the influence of these metals on growth, and on root metal content, was examined. Accumulation of the metals was enhanced in wood, bark and/or roots at elevated levels of the metal in question. Even at low levels of the metals, similar to after application of wood ash, an enhanced accumulation was apparent in wood and/or bark, except for Cd. The increased accumulation of Zn and Cu in the stem did not affect the growth. However, Cu decreased the accumulation of Ca in wood. Higher levels of Cu and Cd reduced the stem diameter and the toxic effect was associated with a reduced Ca content in wood. Copper and Cd also decreased the accumulation of Zn in the stem. On the other hand, elevated levels of Ca increased the stem diameter and reduced the accumulation of Cd, Cu, Zn and Mn in wood and/or bark. When metals interacted with each other the firmly bound fraction of the metal reduced was in almost all cases not affected. As an exception, Cd decreased the firmly bound fraction of Zn in the stem. The influence of pellets of wood ash (ash) or a mixture of wood ash and green liquor dregs (ash+GLD), in the amount of 3000 kg ha-1, on the contents of Ca, Cd, Cu and Zn in wood and bark of young Norway spruce in the field was examined. The effect of the treatments on the metal content of bark and wood was larger after 3 years than after 6 years. Treatment with ash+GLD had less effect on the heavy metal content of bark and wood than treatment with ash alone. The ash treatment increased the Cu and Zn content in bark and wood, respectively, after 3 years, and decreased the Ca content of the wood after 6 years. The ash+GLD treatment increased the Ca content of the bark and decreased the Zn content of bark and wood after 3 years. Both treatments reduced, or tended to decrease, the Cd content in wood and bark at both times. To conclude, small changes in the bioavailability of Ca, Cu, Cd and Zn in forest soils, such as after spreading pellets of wood ash or a mixture of wood ash and green liquor dregs from the forest industry, will be reflected in an altered accumulation of metals in wood and bark of Norway spruce. It will not only be reflected in changed accumulation of those metals in which bioavailability in the soil has been enhanced, but also of other metals, probably partly due to interactions between metals. When metals interact the exchangeable bound fraction of the metal reduced is suggested to be the main fraction affected. The small alterations in accumulation of metals should not affect the growth of Norway spruce, especially since the changes in accumulation of metals are low, and further since these decrease over time. However, as an exception, one positive and maybe persistent effect of the waste products is that these may decrease the accumulation of Cd in Norway spruce, which partly may be explained by competition with Ca for uptake, translocation and binding. A decreased accumulation of Cd in Norway spruce will probably affect the trees positively, since Norway spruce is one of the most sensitive species to Cd of the forest trees in Sweden. Thus, spreading of waste products from the forest industry may be a solution to decrease the accumulation of Cd in Norway spruce. In a longer perspective, this will decrease the risk of Cd altering the tree species composition of the forest ecosystem. An elevated bioavailability of Ca in forest soils will, in addition to Cd, probably also decrease the accumulation of other less competitive heavy metals, like Zn and Mn, in the stem.
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Seit Beginn der Waldzustandserhebungen im Jahr 1984 verschlechterte sich der Zustand der Eiche sowohl auf Bundesebene als auch im Land Rheinland-Pfalz deutlich. 1998 konnten nur noch 5 % der rheinland-pfälzischen Eichen in die Kategorie "ohne Schadensmerkmale" eingestuft werden. Vor diesem Hintergrund ergab sich die Notwendigkeit, die biotischen Stress- und Schadfaktoren näher zu untersuchen. Im Rahmen der vorliegenden Arbeit lag der Fokus auf den holzbewohnenden Käfern von Traubeneichen (Quercus petraea) aus dem Pfälzerwald. Zu diesem Zweck wurden für die erste Probenserie Untersuchungsbäume aus den Vitalitätsstufen 'vital', 'geschädigt', 'ein Jahr tot' und 'zwei Jahre tot' ausgewählt und in die drei Straten Stammfuß, Kronenansatz und Derbholz unterteilt. In der zweiten Probenserie kamen keine 'vitalen' Stämme mehr zum Einsatz. Die einzelnen Proben wurden in Fasseklektoren überführt, in denen die xylobionten Käfer ihre Entwicklung beenden und schlüpfen konnten. Die erste Probenserie wurde im Herbst 1998 entnommen, die zweite Serie im darauffolgenden Herbst. Zusätzlich zu diesen Laboruntersuchungen wurden Freilanduntersuchungen mit Stammeklektoren an vier stehenden Eichen im Wald durchgeführt. Die gefangenen Tiere wurden nach Ordnungen sortiert und gezählt, die Käfer nach Möglichkeit bis zur Art bestimmt. Die Ergebnisse der ersten und zweiten Serie wurden in Abundanzen (Ind./m² Rindenoberfläche) umgerechnet, um einen Vergleich der Proben untereinander möglich zu machen. Insgesamt wurden aus den Fasseklektoren beider Serien Käfer mit einer Abundanz von 36.990 Ind./m² ausgewertet. In den Fallen der Stammeklektoren wurden insgesamt 1.487 Käfer gefunden. Den weitaus größten Teil der Käfer der Fasseklektoren stellen die Borkenkäfer (Scolytidae). Dieses Ergebnis schlägt sich auch in der Betrachtung der Dominanz der einzelnen Arten nieder. In nahezu allen Fällen gehörten die Hauptarten in die Familie Scolytidae. Der mit den Absterbeerscheinungen der Eichen in Verbindung gebrachte Prachtkäfer Agrilus biguttatus (Buprestidae) trat in deutlich geringeren Abundanzen auf. Aufgrund seiner Fraßtätigkeit (Ringelung der Larven im Kambialbereich der Bäume) gehört er aber zu den potentiell stark schädigenden Käfern. Neben A. biguttatus sind auch A. sulcicollis und die gefundenen Borkenkäfer in der Lage, vorgeschädigte und geschwächte Eichen zu befallen und noch weiter zu schwächen. Aus waldhygienischen Gründen sollten deshalb regelmäßige Kontrollen durchgeführt werden. Bei erkennbarem Befall sollten die betroffenen Bäume gefällt und aus dem Bestand entfernt werden. Langfristig können die Vermeidung von nicht-standortgerechtem Eichenanbau und das Anlegen von naturnahen Mischbeständen zu den waldbaulichen Maßnahmen gerechnet werden, die eine Reduktion des Infektionsrisikos zur Folge haben. Die 'ein Jahr toten' Bäume wiesen die mit Abstand höchste Abundanz an Lebendholzbesiedlern auf. Bäume, die bereits ein Jahr länger tot im Bestand standen, wurden von deutlich weniger Lebendholzbesiedlern befallen, d.h. von 'zwei Jahre toten' Bäumen ging ein potentiell geringerer Infektionsdruck aus als von 'ein Jahr toten' Eichen. Im Laufe des Verrottungsprozesses verringert sich diese Gefahr noch weiter, da die Holzfeuchte weiter abnimmt und die Lebendholzbesiedler keine Nahrungsgrundlage mehr vorfinden. Besonders die Gefahr des Neubefalls durch Agrilus von mindestens zweijährig toten Bäumen besteht kaum, weil zumindest die Larven der ersten Stadien des Prachtkäfers auf lebendes Gewebe angewiesen sind.