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1.
Ying Yong Sheng Tai Xue Bao ; 31(1): 45-54, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957379

RESUMO

Evaluation of landscape aesthetic quality is a key step in the management system of forest resource. Color is an important component of autumn landscape forest, and quantitative analysis of color and scientific evaluation of landscape aesthetic quality are important for the management of autumn landscape forest. We assessed the aesthetic quality of autumn landscape forest using scenic beauty estimation and analyzed the effects of color characteristics on ornamental value of autumn landscape forest based on color composition and color spatial pattern according to human's visual characteristics. The results showed that the overall landscape quality of subalpine region of western Sichuan could be divided into five grades according to beauty value (I to V). About 71.5% of autumn landscape forests could be classified into grade I, II, and III, indicating that autumn landscape forests of subalpine region in western Sichuan had higher ornamental value. According to the scenic beauty estimation value, the landscape aesthetic quality of broadleaved mixed forests was higher than that of coniferous and broadleaved mixed forests and pure forests. In terms of the comprehensive index evaluation system of color elements, the index weight coefficient order was landscape patch heterogeneity factors>autumn main color factors>color saturation and brightness factors>color diversity and evenness factors. With cluster analysis, autumn landscape forests of western Sichuan could be divided into three types. The forests with higher ornamental value showed following characteristics: larger degree of patch fragmentation and heterogeneity, higher percentage of orange and yellow and lower percentage of green in autumn, higher percentage of color saturation and brightness, and higher color diversity and uniformity index. The communities with higher richness, species diversity and evenness index would have higher beauty values. We concluded that species diversity and fragmentation of colors should be considered in the construction of autumn landscape forests, and that aesthetic quality of autumn landscape forest could be improved by planting and cultivating tree species with various and bright autumn leaf colors.


Assuntos
Florestas , Árvores , China , Cor , Estética , Humanos
2.
Ying Yong Sheng Tai Xue Bao ; 31(1): 55-64, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957380

RESUMO

The remotely sensed burned area (BA) products can provide continuous and spatiotemporally explicit characteristics of fire patches, which are critical data sources for understanding regional fire regimes. However, their accuracy remains to be improved. In this study, a global BA product (i.e., CCI_Fire) at 250 m resolution was integrated with global forest change (GFC) product at 30 m to generate a refined BA product, named CCI_GFC product, whose accuracy was evaluated through comparing the BA with pre-existing fire patches data. To reveal the characteristics of forest fire in China between 2001 and 2017, we conducted a grid analysis at 0.05°×0.05° spatial resolution based on the refined BA product and the spatial pattern of eco-regions at the macro scale. The results showed that the accuracy metrics including the recognition rate (RR), variance explained (R2), root mean squared error (RMSE), mean absolute percentage error (MAPE) of the CCI_GFC product (i.e., 83%, 0.91, 0.28, and 8.5% respectively) were all superior to the CCI_Fire product (i.e., 74%, 0.86, 0.36, and 11.8% respectively) and the MCD64A1 product (i.e., 35%, 0.78, 0.48, and 17.3% respectively). The total burned area of forest was approximately 12.11 million hm2 for the whole country from 2001 to 2017, while the annual burned area temporally decreased. Forest fires in China were dominated by the low-frequency [0

Assuntos
Fogo , Incêndios Florestais , China , Florestas , Estações do Ano , Árvores
3.
Ying Yong Sheng Tai Xue Bao ; 31(1): 65-71, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957381

RESUMO

China is one of the countries with serious forest fires. Besides the methods of strengthening management of fire source and increasing forest fire monitoring and rescue efforts, improving the ability of forest itself to resist fire is also the key to prevent forest fires. In this study, we examined the characteristics of the bark across 11 main tree species in Korean pine broad-leaved forest at Jiaohe Forestry Experimental Area in Jilin Province. Fire resistance of bark acorss the tree species was evaluated comprehensively with four indices of water content, ash content, calorific value and oxygen index, using the methods of entropy weight, variance analysis and cluster analysis. Results showed that water content of bark was the highest in Phellodendron amurense. Calorific value of bark was the lowest and ash content was the highest in Ulmus davidiana. Oxygen index of bark was the highest in Fraxinus mandshurica. Bark fire resistance of 11 tree species followed the order of U. davidiana > Acer mono > Acer triflorum > Acer mandshuricum > F. mandshurica > Quercus mongolica > P. amurense > Tilia amurensis > Juglans mandshurica > Pinus koraiensis > Betula costata. The tree species in Korean pine broad-leaved forest could be classified to five categories according to bark fire resistance: U. davidiana belonged to the category of strongest fire-resistance; A. mono and A. triflorum belonged to the category of strong fire-resistance; A. mandshuricum, F. mandshurica, Q. mongolica, P. amurense, T. amurensis belonged to the category of common fire-resistance; J. mandshurica and P. koraiensis belonged to the category of weak fire-resistance; and B. costata belonged to the category of poor fire-resistance.


Assuntos
Pinus , Árvores , China , Florestas , Casca de Planta
4.
Nature ; 577(7788): 29, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31892743

Assuntos
Árvores , China
5.
Oecologia ; 192(2): 449-462, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31960145

RESUMO

In forest communities, conspecific density/distance dependence (CDD) is an important factor regulating diversity. It remains unknown how and the extent to which gap creation alters the mode and strength of CDD via changes in the relative importance of pathogens and mycorrhizae. Seeds of two hardwoods (i.e., Acer mono associated with arbuscular mycorrhizae [AM] and Quercus serrata associated with ectomycorrhizae [EM]) were sown reciprocally at four distances from the boundary between Acer- and Quercus-dominated forests towards forest interior in each of forest understories (FUs) and gaps. The causes of seed and seedling mortality, seedling growth and colonization of mycorrhizal fungi were investigated. In Acer, seed and seedling mortality were highest in Acer forests and gradually decreased towards the interior of Quercus forests in FU, mainly due to severe attack of soil pathogens, invertebrates, and leaf diseases. The reverse was true in gaps, due to reduction of damping-off damage caused by distance-dependent colonization of AM. In Quercus, most seeds and seedlings were eaten by vertebrates in FUs. The seedling mortality caused by leaf diseases was not high, even beneath conspecific forests with higher colonization of EM in gaps, suggesting a positive EM influence. In both species, seedling mass was greatest in conspecific forests and gradually decreased towards the interior of heterospecific forests in gaps, due to higher colonization of mycorrhizae near conspecifics. In conclusion, light conditions strongly altered the mode of CDD via changes in relative influence of pathogens and mycorrhizae, suggesting that gap creation may regulate species diversity via changes in the mode of CDD.


Assuntos
Acer , Micorrizas , Animais , Florestas , Plântula , Árvores
6.
Ecol Lett ; 23(3): 483-494, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31922344

RESUMO

A 'resilient' forest endures disturbance and is likely to persist. Resilience to wildfire may arise from feedback between fire behaviour and forest structure in dry forest systems. Frequent fire creates fine-scale variability in forest structure, which may then interrupt fuel continuity and prevent future fires from killing overstorey trees. Testing the generality and scale of this phenomenon is challenging for vast, long-lived forest ecosystems. We quantify forest structural variability and fire severity across >30 years and >1000 wildfires in California's Sierra Nevada. We find that greater variability in forest structure increases resilience by reducing rates of fire-induced tree mortality and that the scale of this effect is local, manifesting at the smallest spatial extent of forest structure tested (90 × 90 m). Resilience of these forests is likely compromised by structural homogenisation from a century of fire suppression, but could be restored with management that increases forest structural variability.


Assuntos
Fogo , Traqueófitas , Incêndios Florestais , California , Ecossistema , Florestas , Árvores
7.
Ecol Lett ; 23(2): 336-347, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31802606

RESUMO

The traditional view holds that biological nitrogen (N) fixation often peaks in early- or mid-successional ecosystems and declines throughout succession based on the hypothesis that soil N richness and/or phosphorus (P) depletion become disadvantageous to N fixers. This view, however, fails to support the observation that N fixers can remain active in many old-growth forests despite the presence of N-rich and/or P-limiting soils. Here, we found unexpected increases in N fixation rates in the soil, forest floor, and moss throughout three successional forests and along six age-gradient forests in southern China. We further found that the variation in N fixation was controlled by substrate carbon(C) : N and C : (N : P) stoichiometry rather than by substrate N or P. Our findings highlight the utility of ecological stoichiometry in illuminating the mechanisms that couple forest succession and N cycling.


Assuntos
Ecossistema , Fixação de Nitrogênio , China , Florestas , Nitrogênio , Fósforo , Solo , Árvores
8.
Mol Genet Genomics ; 295(1): 107-120, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31506717

RESUMO

The oriental gall wasp Dryocosmus kuriphilus represents a limiting pest for the European Chestnut (Castanea sativa, Fagaceae) as it creates severe yield losses. The European Chestnut is a deciduous tree, having major social, economic and environmental importance in Southern Europe, covering an area of 2.53 million hectares, including 75,000 ha devoted to fruit production. Cultivars show different susceptibility and very few are resistant to gall wasp. To deeply investigate the plant response and understand which factors can lead the plant to develop or not the gall, the study of transcriptome is basic (fundamental). To date, little transcriptomic information are available for C. sativa species. Hence, we present a de novo assembly of the chestnut transcriptome of the resistant Euro-Japanese hybrid 'Bouche de Bétizac' (BB) and the susceptible cultivar 'Madonna' (M), collecting RNA from buds at different stages of budburst. The two transcriptomes were assembled into 34,081 (BB) and 30,605 (M) unigenes, respectively. The former was used as a reference sequence for further characterization analyses, highlighting the presence of 1444 putative resistance gene analogs (RGAs) and about 1135 unigenes, as putative MiRNA targets. A global quantitative transcriptome profiling comparing the resistant and the susceptible cultivars, in the presence or not of the gall wasp, revealed some GO enrichments as "response to stimulus" (GO:0050896), and "developmental processes" (e.g., post-embryonic development, GO:0009791). Many up-regulated genes appeared to be transcription factors (e.g., RAV1, AP2/ERF, WRKY33) or protein regulators (e.g., RAPTOR1B) and storage proteins (e.g., LEA D29) involved in "post-embryonic development". Our analysis was able to provide a large amount of information, including 7k simple sequence repeat (SSR) and 335k single-nucleotide polymorphism (SNP)/INDEL markers, and generated the first reference unigene catalog for the European Chestnut. The transcriptome data for C. sativa will contribute to understand the genetic basis of the resistance to gall wasp and will provide useful information for next molecular genetic studies of this species and its relatives.


Assuntos
Fagaceae/genética , Transcriptoma/genética , Vespas/patogenicidade , Animais , Europa (Continente) , Fagaceae/parasitologia , Perfilação da Expressão Gênica/métodos , Repetições de Microssatélites/genética , Anotação de Sequência Molecular/métodos , Doenças das Plantas/parasitologia , Polimorfismo de Nucleotídeo Único/genética , Fatores de Transcrição/genética , Árvores/genética , Árvores/parasitologia , Regulação para Cima/genética
9.
Int J Phytoremediation ; 22(2): 210-222, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31432685

RESUMO

Leaf and bark of trees are tools for assessing the effects of the heavy metals pollution and monitoring the environmental air quality. In this study, the possibility of using leaves and bark of two urban trees, namely, Ficus nitida and Eucalyptus globulus as a bioindicator of atmospheric pollution was evaluated by determining the composition of heavy elements in the tree leaves, bark, soil, and the atmospheric dust. Two common tree species, namely, F. nitida and E. globulus were selected in the heavily industrial zone of surrounding Minya governorate, Upper Egypt. Two urban areas with heavy traffic load (sites 1 and 2), three industrial zones (sites 3, 4, and 5) and an uncontaminated area as a control were selected (site 6). Sampling from leaf, bark, soil, deposited dust of trees was carried out in winter and summer seasons (from November 2016 to March 2017). The concentrations of heavy metals in dust, soil, leaves, and bark possess the same trend: Pb>Cu>Cd. The highest concentration of cadmium, lead, and copper was found in the leaf of F. nitida and E. globulus higher than bark samples of the studied species, supporting the idea suggesting that tree leaves can be used as a good indicator of heavy metals accumulation. A high and statistically significant correlation (p < .05) was found between Pb concentrations in the atmospheric dust and those in the leaves of both species throughout the two growing seasons, confirming that the main source of incorporated Pb is the atmospheric dust. Otherwise, the obtained results showed that F. nitida tree does not seem to be a good accumulator of Cu. According to the obtained results, F. nitida and E. globulus trees are more likely to capture cadmium and lead from air, so planting these trees in industrial areas with such atmospheric pollutants would be beneficial.


Assuntos
Poluentes Atmosféricos , Metais Pesados , Poluentes do Solo , Bioacumulação , Biodegradação Ambiental , Egito , Monitoramento Ambiental , Folhas de Planta , Árvores
10.
Water Environ Res ; 92(1): 106-114, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31344757

RESUMO

This study determines the exfiltration rates in six tree boxes with embedded sensors and analyzes their hydrologic performance for 2 years to quantify the effect of different parameters (i.e., water depth, temperature, and age) on the exfiltration rate. Each tree box is 1.5 m wide, 1.5 m long, and 1.8 m deep. A 46-cm-diameter shaft was drilled at the bottom of each tree box to reach the underlying permeable soil layer. The water level inside the shaft rose up to 500 cm. Exfiltration rate increased with water level and exfiltration rate in second year decreased significantly by 27%-37% compared with first year. Overall, in the second year, the decrease in geometric mean exfiltration rate was largest for moderate depths of the standing water inside the shaft, ranging between 100 and 130 cm from the bottom of the shaft. The exfiltration rate of the tree boxes was significantly larger for warmer season and significantly smaller for cooler season. The infiltration rate of the underlying soil is a controlling factor of the performance of tree box. PRACTITIONER POINTS: The study determines the exfiltration rates in six tree boxes and analyzes their performance over time. Exfiltration rate in second year decreased significantly by 27%-37% compared to first year. The exfiltration rate of the tree boxes was larger for warmer rain events and smaller for cooler rain events. Tree boxes with lower permeable underlying soil developed higher water level in the shaft.


Assuntos
Árvores , Movimentos da Água , Hidrologia , Chuva , Solo
11.
Ambio ; 49(1): 85-97, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31055795

RESUMO

Retention forestry implies that biological legacies like dead and living trees are deliberately selected and retained beyond harvesting cycles to benefit biodiversity and ecosystem functioning. This model has been applied for several decades in even-aged, clearcutting (CC) systems but less so in uneven-aged, continuous-cover forestry (CCF). We provide an overview of retention in CCF in temperate regions of Europe, currently largely focused on habitat trees and dead wood. The relevance of current meta-analyses and many other studies on retention in CC is limited since they emphasize larger patches in open surroundings. Therefore, we reflect here on the ecological foundations and socio-economic frameworks of retention approaches in CCF, and highlight several areas with development potential for the future. Conclusions from this perspective paper, based on both research and current practice on several continents, although highlighting Europe, are also relevant to other temperate regions of the world using continuous-cover forest management approaches.


Assuntos
Ecossistema , Agricultura Florestal , Biodiversidade , Conservação dos Recursos Naturais , Europa (Continente) , Florestas , Árvores
13.
Ecol Lett ; 23(1): 45-54, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31631473

RESUMO

Animal-mediated indirect interactions play a significant role in maintaining the biodiversity of plant communities. Less known is whether interspecific synchrony of seed rain can alter the indirect interactions of sympatric tree species. We assessed the seed dispersal success by tracking the fates of 21 600 tagged seeds from six paired sympatric tree species in both monospecific and mixed plots across 4 successive years in a subtropical forest. We found that apparent mutualism was associated with the interspecific synchrony of seed rain both seasonally and yearly, whereas apparent competition or apparent predation was associated with interspecific asynchrony of seed rain either seasonally or yearly. We did not find consistent associations of indirect interactions with seed traits. Our study suggests that the interspecific synchrony of seed rain plays a key role in the formation of animal-mediated indirect interactions, which, in turn, may alter the seasonal or yearly seed rain schedules of sympatric tree species.


Assuntos
Dispersão de Sementes , Árvores , Animais , Comportamento Alimentar , Florestas , Roedores , Sementes
14.
Sci Total Environ ; 698: 134129, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499344

RESUMO

Forest health status is negatively influenced by climate change, air pollution and other disturbances. Extreme droughts reduce stand productivity, increase vulnerability to pests, and can even provoke mortality. Growth dynamics at tree and forest stand levels are considered the main indicators of stability and productivity in forest ecosystem structures. The main climate drivers for tree growth were identified using basal area increment (BAI) as a synthetic indicator. BAI chronologies were obtained from increment cores for 1960-2012 period. Six species were analysed in an attempt to identify their growth limiting factors. For the most important oak species in Romania, resilience components were computed in order to analyse their response to drought events. Moreover, growth dynamics were analysed for two species in mixed and monoculture forests. The results suggest that - in comparison to Picea abies and Fagus sylvatica, the sensitivity of Quercus spp. is much higher (0.3-0.47). Oakspecies situated in the most drought-affected areas are sensitive to rainfall values from the previous autumn, current spring, and early summer, with April monthly values having the most significant effect on BAI increment (r = 0.47*) The most sensitive species to drought is Q. cerris and Q. frainetto. Their BAI reduction during drought is >50% compared with the BAI values before the drought period. The recovery capacity of tree growth following drought events is lower for Q. robur and Q. petraea and higher for Q. cerris and Q. frainetto. The mixed forest stands have not showed a constant higher resistance to drought.


Assuntos
Mudança Climática , Monitoramento Ambiental , Agricultura Florestal , Florestas , Árvores , Secas , Ecossistema , Fagus , Quercus , Romênia , Estações do Ano
15.
Sci Total Environ ; 698: 134074, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505359

RESUMO

This study aims to investigate the combined use of two types of remote sensing data - ALS derived and digital aerial photogrammetry data (based on imagery collected by airborne UAV sensors) - along with intensive field measurements for extracting and predicting tree and stand parameters in even-aged mixed forests. The study is located in South West Romania and analyzes data collected from mixed-species plots. The main tree species within each plot are Norway spruce (Picea abies L. Karst.) and Beech (Fagus sylvatica L.). The ALS data were used to extract the digital terrain model (DTM), digital surface model (DSM) and normalized canopy height model (CHM). Object-Based Image Analysis (OBIA) classification was performed to automatically detect and separate the main tree species. A local filtering algorithm with a canopy-height based variable window size was applied to identify the position, height and crown diameter of the main tree species within each plot. The filter was separately applied for each of the plots and for the areas covered with Norway spruce and beech trees, respectively (i.e. as resulted from OBIA classification). The dbh was predicted based on ALS data by statistical Monte Carlo simulations and a linear regression model that relates field dbh for each tree species with their corresponding ALS-derived tree height and crown diameter. The overall RMSE for each of the tree species within all the plots was 5.8 cm for the Norway spruce trees, respectively 5.9 cm for the beech trees. The results indicate a higher individual tree detection rate and subsequently a more precise estimation of dendrometric parameters for Norway spruce compared to beech trees located in spruce-beech even-aged mixed stands. Further investigations are required, particularly in the case of choosing the best method for individual tree detection of beech trees located in temperate even-aged mixed stands.


Assuntos
Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Árvores , Fagus , Florestas , Lasers , Luz , Picea , Romênia
16.
Sci Total Environ ; 699: 134285, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31520941

RESUMO

In the Mediterranean basin, diffuse-porous, semi-ring-porous and ring-porous tree species coexist in the same regions. Climate change might differently affect these types, but a mechanistic understanding of drought effects on their xylem structure is lacking. We investigated tree-ring width and xylem functional traits in ring-porous Quercus boissieri, semi-ring-porous Q. ithaburensis and diffuse-porous Q. calliprinos, at xeric (Galilee) and mesic (Golan) sites in the South-Eastern Mediterranean basin. We quantitatively assessed how dry and wet years affect growth and xylem traits in different porosity type oaks, and evaluated whether porosity type is preserved or altered during these years. We measured, counted or computed tree-ring width, vessel number, maximum lumen area, frequency, tree-ring and xylem theoretical hydraulic conductivity along 40-year ring series of 50 trees in total. We also quantified ring porosity in each year using two indices, the Gini coefficient and the porosity ratio of vessel area, and described vessel area intra-ring variations by distribution profiles. We then compared these parameters in the five driest and five wettest years of the 40-year period. Radial growth and functional trait variations were more similar between species in the same site (strong drought effects in Q. ithaburensis and Q. calliprinos in Galilee, moderate effects in Q. boissieri and Q. calliprinos in Golan) than between sites for the same species (Q. calliprinos was more affected in Galilee than in Golan). Ring porosity indices and distribution profiles showed that diffuse-porous xylem structure of Q. calliprinos was maintained even under dry conditions at both sites. However, Q. boissieri xylem shifted from ring-porous in wet and normal years to semi-ring-porous in dry years, i.e. the porous ring cannot be completely built under water constraint. This suggests that ring porous strategy, typical of temperate regions with strong seasonality, might not be realized under future drier conditions in the Mediterranean basin.


Assuntos
Monitoramento Ambiental , Quercus/crescimento & desenvolvimento , Chuva , Mudança Climática , Secas , Porosidade , Árvores/crescimento & desenvolvimento , Xilema
17.
Sci Total Environ ; 699: 134383, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31525545

RESUMO

The adverse effects of soil acidification are extensive and may result in hampered ecosystem functioning. Admixture of tree species with nutrient rich litter has been proposed to restore acidified forest soils and improve forest vitality, productivity and resilience. However, it is common belief that litter effects are insufficiently functional for restoration of poorly buffered sandy soils. Therefore we examined the effect of leaf litter on the forest floor, soil chemistry and soil biota in temperate forest stands along a range of sandy soil types in Belgium, the Netherlands and Germany. Specifically, we address: i) Which tree litter properties contribute most to the mitigation of soil acidification effects and ii) Do rich litter species have the potential to improve the belowground nutrient status of poorly buffered, sandy soils? Our analysis using structural equation modelling shows that litter base cation concentration is the decisive trait for the dominating soil buffering mechanism in forests that are heavily influenced by atmospheric nitrogen (N) deposition. This is in contrast with studies in which leaf litter quality is summarized by C/N ratio. We suggest that the concept of rich litter is context dependent and should consider Liebig's law of the most limiting: if N is not limiting in the ecosystem, litter C/N becomes of low importance, while base cations (calcium, magnesium, potassium) become determining. We further find that on poorly buffered soils, tree species with rich litter induce fast nutrient cycling, sustain higher earthworm biomass and keep topsoil base saturation above a threshold of 30%. Hence, rich litter can trigger a regime shift to the exchange buffer domain in sandy soils. This highlights that admixing tree species with litter rich in base cations is a promising measure to remediate soil properties on acidified sandy soils that receive, or have received, high inputs of N via deposition.


Assuntos
Fenômenos Ecológicos e Ambientais , Monitoramento Ambiental , Florestas , Animais , Bélgica , Biomassa , Alemanha , Países Baixos , Nitrogênio , Oligoquetos , Folhas de Planta , Solo/química , Árvores
18.
Sci Total Environ ; 699: 134277, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31689668

RESUMO

Oil sands developments release acidifying compounds (SO2 and NO2) with the potential for acidifying deposition and impacts to forest health. This article integrates the findings presented in the Oil Sands Forest Health Special Issue, which reports on the results of 20 years of forest health monitoring, and addresses the key questions asked by WBEA's Forest Health Monitoring (FHM) Program: 1) is there evidence of deposition affecting the environment?, 2) have there been changes in deposition or effects over time?, 3) do acid deposition levels require management intervention?, 4) what are major sources of deposited substances? and 5) how can the program be improved? Deposition of sulphur, nitrogen, base cations (BC), polycyclic aromatic compounds and trace elements decline exponentially with distance from sources. There is little evidence for acidification effects on forest soils or on understory plant communities or tree growth, but there is evidence of nitrogen accumulation in jack pine needles and fertilization effects on understory plant communities. Sulphur, BC and trace metal concentrations in lichens increased between 2008 and 2014. Source apportionment studies suggest fugitive dust in proximity to mining is a primary source of BC, trace element and organic compound deposition, and BC deposition may be neutralizing acidifying deposition. Sulphur accumulation in soils and nitrogen effects on vegetation may indicate early stages of acidification. Deposition estimates for sites close to emissions sources exceed proposed regulatory trigger levels, suggesting a detailed assessment of acidification risk close to the emission sources is warranted. However, there is no evidence of widespread acidification as suggested by recent modeling studies, likely due to high BC deposition. FHM Program evolution should include continued integration with modeling approaches, ongoing collection and assessment of monitoring data and testing for change over time, and addition of monitoring sites to fill gaps in regional coverage.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Florestas , Campos de Petróleo e Gás , Líquens , Modelos Teóricos , Nitrogênio/análise , Compostos Orgânicos , Pinus , Enxofre/análise , Árvores
19.
Chemosphere ; 238: 124528, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31425869

RESUMO

A dendrochemical study of cottonwood trees (Populus deltoides) was conducted across a childhood cancer cluster in eastern Sandusky County (Ohio, USA). The justification for this study was that no satisfactory explanation has yet been put forward, despite extensive local surveys of aerosols, groundwater, and soil. Concentrations of eight trace metals were measured by ICP-MS in microwave-digested 5-year sections of increment cores, collected during 2012 and 2013. To determine whether the onset of the first cancer cases could be connected to an emergence of any of these contaminants, cores spanning the period 1970-2009 were taken from 51 trees of similar age, inside the cluster and in a control area to the west. The abundance of metals in cottonwood tree annual rings served as a proxy for their long-term, low-level accumulation from the same sources whereby exposure of the children may have occurred. A spatial analysis of cumulative metal burdens (lifetime accumulation in the tree) was performed to search for significant 'hotspots', employing a scan statistic with a mask of variable radius and center. For Cd, Cr, and Ni, circular hotspots were found that nearly coincide with the cancer cluster and are similar in size. No hotspots were found for Co, Cu, and Pb, while As and V were largely below method detection limits. Whereas our results do not implicate exposure to metals as a causative factor, we conclude that, after 1970, cottonwood trees have accumulated more Cd, Cr, and Ni, inside the childhood cancer cluster than elsewhere in Sandusky County.


Assuntos
Monitoramento Ambiental , Neoplasias/epidemiologia , Populus/química , Oligoelementos/análise , Criança , Humanos , Ohio/epidemiologia , Solo/química , Análise Espacial , Inquéritos e Questionários , Árvores/química
20.
Int J Phytoremediation ; 22(1): 69-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31342787

RESUMO

The 2,4-D (2,4-dichlorophenoxyacetic acid) has low half-life in the soil, but it is capable of altering the soil microbial community. The objective of this study was to evaluate the influence of 2,4-D residues on the structure of the soil microbial community and the growth of tree species. The tolerance and phytoremediation potential of tree species were evaluated. The microbial analysis was performed by T-RFLP. The 2,4-D herbicide reduced the plant height of K. lathrophyton, number of leaves of C. ferrea and K. lathrophyton and root dry matter allocation for C. brasiliense, I. striata, P. heptaphyllum, and T. guianensis. Cucumis sativus intoxication on soil contaminated with 2,4-D was not significant. The structure of Fungi community in the rhizospheric soils of C. ferrea was altered. The herbicide 2,4-D increased the diversity of Fungi in rhizospheric soils of P. heptahyllum and R. grandis. Most tree species were tolerant, and the evaluation time was sufficient to remedy 2,4-D. The structures of the microbial communities Archaea, Bacteria, and Fungi were little influenced by 2,4-D. The diversity of the Archaea domain was not affected, the diversity of the Bacteria in Inga striata decreased while the fungi increased in Protium heptaphyllum and Richeria grandis with 2,4-D.


Assuntos
Microbiota , Solo , Ácido 2,4-Diclorofenoxiacético , Biodegradação Ambiental , Fungos , Microbiologia do Solo , Árvores
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