scholarly journals Different views on tree interception process and its determinants

2014 ◽  
Vol 75 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Anna Klamerus-Iwan

Abstract The subject of the study is the process of interception by plants defined as the process of retaining rainfall water on plant surface, counting retention by individual plant parts or the vegetation cover as the whole. In the quantitative approach, interception capability of plants may be compared to a reservoir, the capacity of which is determined mostly by the surface of plants. Among many approaches to describe interception processes, a lot of attention has been focused on research concerning the forest vegetation with reference to atmosphere - forest stand - soil balance. Hence, in the present paper interception issues are addressed in view of forest ecosystems. The emphasis is also put on the methods and results of studies carried out under laboratory conditions. Up-to-date literature on interception is abundant. The authors tackling this issue regularly define their own variable and complex sets of terms. This paper is an attempt to review and organise knowledge presented in existing literature on the subject.

2012 ◽  
Author(s):  
Thomas J. Brandeis ◽  
Elvia J. Meléndez-Ackerman ◽  
Eileen H. Helmer

2003 ◽  
Vol 83 (5) ◽  
pp. 581-587 ◽  
Author(s):  
J. D. MacDonald ◽  
W. H. Hendershot

The concentrations of metals in soils are spatially heterogeneous and soil sampling carried out when studying metals in forest ecosystems is often inadequate. We examined the spatial variability of Cd, Cu, Mn, Ni, Pb and Zn in northern forest ecosystems on a transect with distance from two point source emitters with the goal of providing basic information about the distribution and variability of metals in these soils. Samples were taken under six sampling points at four depths from three experimental sites on each of the two transects. Soils were analysed for acid digestible metals, pH and organic carbon content. Standard deviation, coefficients of variation, mean and medians were analysed for each horizon of each site. It was observed that Cu and Mn variability is higher in closer proximity to the point source while the variability of Zn increased with decreasing soil pH. In Sudbury, emitted metals Ni and Cu accumulate together in soils, whereas in Rouyn-Noranda, with the exception of Cd and Zn, metal concentrations were not related in forest floors. Observations suggest that physical factors influencing where metals are deposited as well as the inherent variability in soil chemical characteristics, and the distance from the point source can all act together to result in high variability in soil metal concentrations in a single forest site. Sampling in the interest of relating vegetation metal concentrations or response to soil metals should be carried out on an individual plant basis with multiple samples taken for each individual. Soil samples taken at intervals of 1 to 1.7 m will provide relative error in estimating soil concentrations of 10% or 20%, respectively. Key words: Spatial variability, trace metals, podzolic soils, smelter emissions


2002 ◽  
Vol 15 (4) ◽  
pp. 398-403 ◽  
Author(s):  
Karen Cornelis ◽  
Tania Maes ◽  
Mondher Jaziri ◽  
Marcelle Holsters ◽  
Koen Goethals

The phytopathogenic bacterium Rhodococcus fascians provokes shoot meristem formation and malformations on aerial plant parts, mainly at the axils. The interaction is accompanied by bacterial colonization of the plant surface and tissues. Upon infection, the two bacterial loci required for full virulence, fas and att, were expressed only at the sites of symptom development, although their expression profiles differed both spatially and temporally. The att locus was expressed principally in bacteria located on the plant surface at early stages of infection. Expression of the fas locus occurred throughout infection, mainly in bacteria that were penetrating, or had penetrated, the plant tissues and coincided with sites of meristem initiation and proliferation. The implications for the regulation of virulence genes of R. fascians during plant infection are discussed.


1988 ◽  
Vol 66 (1) ◽  
pp. 11-17 ◽  
Author(s):  
K. A. Robson ◽  
R. K. Scagel ◽  
J. Maze

Comparisons of differences between morphological means of individual plant parts indicate that the greatest source of variation in two populations of Balsamorhiza sagittata is the individual plants within populations; within-population diversity is greater than among-population diversity. Variable covariance and correlations differ between individual plants and there are subgroups of interrelated variables that can be tied to developmental phenomena. The relationship between developmental phenomena and these groups of variables suggests a relationship between organizational, as reflected in variable interrelationships, and ontogenetic variation. These results are not adequately explained by neoDarwinian theory but are explained more comprehensively by a theory of evolution that views biological change over time as an intrinsically driven self-organization, accompanied by an increase in complexity (a manifestation of the "Second Law of Thermodynamics" as it applies to open systems).


2017 ◽  
Vol 8 (4) ◽  
pp. 771-790 ◽  
Author(s):  
Homin Kim ◽  
Jagath J. Kaluarachchi

Abstract Several models have been developed to estimate evapotranspiration. Among those, the complementary relationship has been the subject of many recent studies because it relies on meteorological data only. Recently, the modified Granger and Gray (GG) model showed its applicability across 34 diverse global sites. While the modified GG model showed better performances compared to the recently published studies, it can be improved for dry conditions and the relative evaporation parameter in the original GG model needs to be further investigated. This parameter was empirically derived from limited data from wet environments in Canada – a possible reason for decreasing performance with dry conditions. This study proposed a refined GG model to overcome the limitation using the Budyko framework and vegetation cover to describe relative evaporation. This study used 75 eddy covariance sites in the USA from AmeriFlux, representing 36 dry and 39 wet sites. The proposed model produced better results with decreasing monthly mean root mean square error of about 30% for dry sites and 15% for wet sites compared to the modified GG model. The proposed model in this study maintains the characteristics of the Budyko framework and the complementary relationship and produced improved evapotranspiration estimates under dry conditions.


Environments ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 121
Author(s):  
Mohammad Emran Hasan ◽  
Li Zhang ◽  
Riffat Mahmood ◽  
Huadong Guo ◽  
Guoqing Li

Overdependence and cumulative anthropogenic stresses have caused world forests to decrease at an unprecedented rate, especially in Southeast Asia. The Cox’s Bazar–Teknaf Peninsula of Bangladesh is not an exception and follows the global deforestation trend. Despite being one of the country’s richest forest ecosystems with multiple wildlife sanctuaries, reserve forests, and influential wildlife habitats, the peninsula is now providing shelter for nearly one million Rohingya refugees. With the global deforestation trend coupled with excessive anthropogenic stresses from the Rohingya population, the forests in the peninsula are continuously deteriorating in terms of quality and integrity. In response to deforestation, the government invested in conservation efforts through afforestation and restoration programs, although the peninsula faced a refugee crisis in August 2017. The impact of this sudden increase in population on the forest ecosystem is large and has raised questions and contradictions between the government’s conservation efforts and the humanitarian response. Relocation of the refugees seems to be a lengthy process and the forest ecosystem integrity needs to be preserved; therefore, the degree of stresses, level of impacts, and pattern of deforestation are crucial information for forest conservation and protection strategies. However, there are a lack of quantitative analyses on how the forest ecosystem is deteriorating and what future results would be in both space and time. In this study, the impact of the sudden humanitarian crisis (i.e., Rohingya refugees) as anthropogenic stress in Cox’s Bazar–Teknaf peninsula has been spatiotemporally modeled and assessed using Sentinel-2 satellite imagery and other collateral data. Using the density and accessibility of the Rohingya population along with the land cover and other physiographic data, a multi-criteria evaluation (MCE) technique was applied through the Markov cellular automata technique to model the forest vegetation status. The impact of deforestation differs in cost due to variability of the forest vegetation covers. The study, therefore, developed and adopted three indices for assessment of the forest ecosystem based on the variability and weight of the forest cover loss. The spatial severity of impact (SSI) index revealed that out of 5415 ha of total degraded forest lands, 650 ha area would have the highest cost from 2017 to 2027. In the case of the ecosystem integrity (EI) index, a rapid decline in ecosystem integrity in the peninsula was observed as the integrity value fell to 1190 ha (2019) from 1340 ha (2017). The integrity is expected to further decline to 740 ha by 2027, if the stress persists in a similar fashion. Finally, the findings of ecosystem integrity depletion (EID) elucidated areas of 540 and 544 hectares that had a severe EID score of (−5) between 2017 and 2019 and 2017 and 2027, respectively. The displacement and refugee crisis is a recurrent world event that, in many cases, compromises the integrity and quality of natural space. Therefore, the findings of this study are expected to have significant global and regional implications to help managers and policymakers of forest ecosystems make decisions that have minimal or no impact to facilitate humanitarian response.


2019 ◽  
Vol 13 (1) ◽  
pp. 125-132
Author(s):  
Kovalenko Ihor ◽  
Skliar Iurii ◽  
Klymenko Hanna ◽  
Kovalenko Nataliia

Background: The vitality level of the populations has turned out to be statistically reliably associated with such coenotic factors: age and density of forest stand. In general, the vitality spectra vary widely: the quality index Q of the populations ranges from 0,00 to 0,50, that is, it fully covers the theoretically possible scale of the values of this coefficient, which indicates the sensitivity of the vitality structure of the populations to the ecological-coenotic conditions and determines high informative value of the vitality analysis. Objective: The aim of the study is to assess the vitality structure of the populations of vegetative motile plant species – typical representatives of the grassy layer of forest ecosystems of the North-East of Ukraine as a factor that determines their stability and dynamics. Methods: The analysis of the vitality structure is based on the field studies of the populations of 4 vegetative motile species of plants – Aegopodium podagraria L., Asarum europaeum L., Carex pilosa Scop. and Stellaria holostea L. in forest ecosystems of the North-East of Ukraine. Vitality analysis was carried out according to Yu. A. Zlobin’s methodology. Vitality analysis procedure, classically, is carried out in three stages: 1) Selection of quantitative features that characterize the vital status of the individual plant; 2) Evaluation of vitality of individual plants that were included in the sample; 3) Integral assessment of the population’s vitality. Depending on the ratio in the population of plants of classes a, b and c, the population belongs to one of three vitality types: prosperous, equilibrium or depressive. Results: The obtained estimates of the vitality structure of populations of the clone-forming plants in the grass-shrub layer of forests of the North-East of Ukraine can be considered quite reliable, because they are based, in general, on a complete analysis of the morphological structure of about 13 thousand ramets of the studied species of plants. The statistical reliability of estimates of the population’s vitality structure is predominantly between 70 and 99% and only in some cases lower than 70%. As the clone grows older, its ramet’s vitality decreases and the clone degrades. New young clones, that start to form on the basis of genets, replace old ones. Such ramets have increased vitality, greater stress and competitive resistance. Due to the mechanisms of clone substitution in the living cover, the dominance of nemoralis herbs persists for a long time. Conclusion: The vitality spectra of the populations of the studied species of plants vary widely: the quality index Q of the populations ranges from 0,00 to 0,50, that is, it covers full theoretically possible scale of the values of this coefficient, which indicates the sensitivity of the vitality structure of the populations to the ecological-coenotic conditions and determines high informative value of vitality analysis. Prosperous populations: two populations A. europaeum of the associations Quercetum (roboris) coryloso (avellanae) – convallariosum (majalis) and Quercetum (roboris) coryloso (avellanae) – convallariosum (majalis), two populations A. podagraria of the associations – Pinetum (sylvestris) vacciniosum (myrtilli) and Querceto (roboris) – Pinetum (sylvestris) convallarioso (majalis) – vacciniosum (myrtilli), one population S. holostea of the association Querceto (roboris) – Pinetum (sylvestris) vacciniosum (myrtilli) and one population C. pilosa of the association Querceto (roboris) – Pinetum (sylvestris) vaccinioso (myrtilli) – convallariosum (majalis).


Author(s):  
Alexey Osipov ◽  
Georgy Osipov ◽  
Vasily Kovyazin

Biogenic pollution of water bodies and their eutrophication is one of the most serious environmental problems of our time. One of the sources of water pollution with biogenic substances is forests, which belong to the background sources of biogenic load. Currently available methods for assessing the removal of nutrients from the forest vegetation cover do not provide the desired results, which causes an urgent need for their improvement. This article describes the method developed by the authors of geoinformation modeling of removal of biogenic substances from the forest vegetation cover to water bodies, taking into account the spatial distribution of vegetation in the catchment area, its species composition and absorption of biogenic substances during their migration. The Eastern part of the Gulf of Finland was adopted as the object of testing of the developed method. this is due to the fact that eutrophication processes are actively manifested within its water area. The volume of the background biogenic load on the Gulf of Finland, formed during the decomposition of the fall of the natural vegetation cover in the catchment area, was determined based on the specific removal of biogenic substances from plant communities and their absorption during migration “plant community — water object”. The total background biogenic load on the eastern part of the Gulf of Finland, formed as a result of decomposition of natural vegetation cover, was 170.21 t/year for the northern catchment for nitrogen, 12.14 t/year for phosphorus, and 207.31 t/year for the southern catchment for nitrogen , and 15.68 t/year for phosphorus. The data obtained do not contradict the results of other authors who study the background biogenic load on the Gulf of Finland. The method can be effectively used in the development of measures to reduce the nutrient load on water bodies and planning of economic activities in catchments.


2009 ◽  
pp. 95-110 ◽  
Author(s):  
Ratko Kadovic ◽  
Snezana Belanovic ◽  
Milan Knezevic ◽  
Jelena Belojica ◽  
Jasmina Knezevic

In the last two decades, S and N critical loads have been used as indicators of ecosystem sustainability to soil acidification. The effect of acidification on the soil in forest ecosystems and their further development was the subject of numerous studies, based on which several mathematical models were developed. This paper presents the results of the analysis of acidification processes in brown podzolic soil on granodiorites in the stands of spruce and spruce and fir in the area of NP 'Kopaonik'. Critical loads of sulphur and nitrogen in these soils are presented using VSD model.


2017 ◽  
Vol 3 (6) ◽  
pp. 504
Author(s):  
Ullya Nindyaningtyas ◽  
Meri Indri Hapsari

The purpose of this research is to assess the role played by Baitul Maal Wattamwil (BMT) in increasing welfare of its member. This research adopts a quantitative approach through empirical analysis using Pahlawan Baitul Maal Wattamwil (BMT) located in Tulungagung as the subject of research.Several tools of analysis used in this research are: The Headcount Ratio, The Poverty Discrepancy Ratio, The Income Discrepancy Ratio, The Fooster, Greer and Thorbeck (FGT) index and the Threshold of Trade.


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