28 research outputs found

    Object-Based Classification of UltraCamD Imagery for Identification of Tree Species in the Mixed Planted Forest

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    This study is a contribution to assess the high resolution digital aerial imagery for semi-automatic analysis of tree species identification. To maximize the benefit of such data, the object-based classification was conducted in a mixed forest plantation. Two subsets of an UltraCam D image were geometrically corrected using aero-triangulation method. Some appropriate transformations were performed and utilized. Segmentation was conducted stepwise at two levels and a hierarchical image object network was constructed. The classification hierarchy was developed and Nearest Neighbor classifier, using integration of different features was performed. Training samples and ground truth map were prepared through fieldwork. Accuracy assessment of the resulting maps in comparison with reference data showed overall accuracies and Kappa Index of Agreement of 90.2%, 0.82 (Area1) and 69.8%, 0.49 (Area2), respectively. Transformed images were advantageous to improve the results. The lower accuracy in Area2 can be attributed to high diversity and heterogeneous mixture of species. More detailed and accurate mapping of tree species would be fulfilled applying precise 3D data. The accuracy of detailed vegetation classification with very high-resolution imagery is highly dependent on the segmentation quality, sample size, sampling quality, classification framework and ground vegetation distribution and mixture

    Influence of gap size and development stages on the silvicultural characteristics of oriental beech (Fagus orientalis Lipsky) regeneration

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    We studied 11 gaps covered with beech saplings (< 1.30 m tall) in a reserve compartment (compartment 139, district one, Langa forest, watershed 36: Kazemrood) of the Caspian beech forest in N Iran. Two transects, each 2 m wide, were laid along the longest (N-S) and shortest (E-W) axis of each gap. Five micro sample plots, each 4 m2, were established: one at the center, and one at each corner. Qualitative and quantitative characteristics of saplings with a diameter at breast height less than 7.5 cm were examined in the micro sample plots. Analysis of variance (ANOVA) and Kruskal-Wallis test were performed using SPSS software for quantitative characteristics, and chi-square test for qualitative characteristics. Results indicated that medium-sized (200-500 m2) gaps promote the growth of oriental beech saplings of desirable silvicultural forms during decay and initial stages

    From Duty to Right: The Role of Public Education in the Transition to Aging Societies

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    This paper argues that the introduction of compulsory schooling in early industrialization promoted the growth process that eventually led to a vicious cycle of population aging and negative pressure on education policy. In the early phases of industrialization, public education was undesirable for the young poor who relied on child labor. Compulsory schooling therefore discouraged childbirth, while the accompanying industrialization stimulated their demand for education. The subsequent rise in the share of the old population, however, limited government resources for education, placing heavier financial burdens on the young. This induced further fertility decline and population aging, and the resulting cycle may have delayed the growth of advanced economies in the last few decades

    Modeling Annual Carbon Uptake by Saplings of Hybrid Poplar Clone (Populus euramericana 488) Through Allometric Equations

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    Modelling allometric equations for saplings of hybrid poplar clone produce a highly accurate estimate of pure productivity and C sequestration, leading to better sales and determination of the capacity of cellulose resources and bio-energy pools. Twenty five cuttings with 25 cm length were planted within a 1×1 m2 area in the Talookola nursery, Sari, in 2011. Ten saplings were selected from the two diameter classes (0-1, 1.1-2 cm). After separating the roots and stems, they were oven-dried at 85ºC for 48 hours. According to the diameter distribution, 24 and 6 saplings, respectively, from each diameter class were uprooted. Collar diameter and height were the twe variables used to model allometric equations. Carbon factor was obtained directly by exposing the wood samples in the oven and was estimated based on organic carbon to organic material ratio. Collar diameter and height were the variables to model allometric equations. The results of allometric modelling showed that multivariate linear model including natural logarithm of diameter, logarithm of height and diameter logarithm square with mean C factor of [C] = 0.44 is the optimal equation (R2adj = 0.732 CF = 1.056) for C sequestration of superior saplings

    Pine (Pinus Eldarica Medw.) needles as indicator for heavy metals pollution

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    In this study, the pine tree (Pinus Eldarica Medw.) needles were evaluated as the biomonitors of heavy metal contamination in Tehran, Iran. The pine needle samples supplied from the old trees according to the main wind direction (highest wind speed) were obtained from each parts of tree and then were homogeneously mixed. The samples were taken from different locations with different degrees of metal pollution (urban, industrial, highway and control sites). Then, the concentrations of lead, zinc, copper, nickel and chromium were measured using a flame atomic absorption spectrophotometer. The result of this study showed that the highest and the lowest metal concentrations were found in the heavy traffic sites and the control site, respectively. However, samples taken from highway sites contained the high concentrations of nickel, copper and lead. Moreover, industrial areas were found to have high contents of zinc and chromium. The variation in heavy metal concentrations between the studied locations is due to changes in traffic density and anthropogenic activities. This research proved significant correlations between the heavy metal concentrations in pine needle samples. Finally, it is concluded that Pinus Eldarica Medw. needles can be applied to monitor polluted sites

    Comparison of plant species diversity with different plant communities in deciduous forests

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    Species diversity is one of the most important indices used for evaluating the sustainability of forest communities. This study aims to characterize the forest communities and to identify and compare the plant species diversity in the study area. For this purpose, 152 relevés were sampled by a randomized-systematic method, using the Braun-Blanquet scale. Classification of the vegetation was conducted by the twinspan algorithm. Four communities, including Querco-Carpinetum betulii, Carpineto-Fagetum Oriental, Rusco-Fagetum Oriental and Fagetum Oriental were recognized. Species richness, Shannon, and Simpson indices were applied to quantify diversity of the different communities. Turkey test was used to investigate the differences in the species richness, diversity and evenness indices among the different communities. The results illustrate that Querco-Carpinetum betulii and Carpineto-Fagetum Oriental communities are significantly more diverse than Rusco-Fagetum Oriental and Fagetum Oriental communities. The spatial structure of the releves becomes more `homogenous&apos; and the dominance structure changes: the proportion of beech-forest species is gradually increasing. At the same time, the number of species per unit area decreases constantly, reaching eventually the value comparable to that recorded for hornbeam forest. Generally, species diversity is inversely correlated with the dominance of shade tolerant climax specie

    Flora diversity in burned forest areas in Dehdez, Iran

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    Flora identified within a region plays an important role in maintaining national natural reserves. Iran is one of the most important centers of plant diversity in the Old World (22% endemic species of 8000 plant species). Dehdez burned forest area is located in the southeastern Khuzestan province. The field data were obtained from 115 sample plots in a systematic random grid (20 m × 20 m). The attributes such as tree and shrub species type, the number of species and canopy coverage were recorded. Within each sample plot small and large crown diameters were measured. In order to record herbaceous species, the Whitaker’s snail plot method was applied (100 m² minimum plot area). In this study, 240 plant species were assessed and identified to 158 genera and 42 families. Asteraceae family with 33 species, Papilionaceae with 32 species, Poaceae with 29 species, Apiaceae w ith 27 s pecies a nd Lamiaceae with 18 species prevailed and constituted 57.9% of all the plants observed. Investigation of species life forms showed that Hemicryptophyte plants were most important. Chorological study showed that species found in Irano-Turanian and Common areas of Irano-Turanian and Mediterranean eruption were the most important ecological groups in the region, while other chorotypes were positioned far from the next in importance

    Flora diversity in burned forest areas in Dehdez, Iran

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    Flora identified within a region plays an important role in maintaining national natural reserves. Iran is one of the most important centers of plant diversity in the Old World (22% endemic species of 8000 plant species). Dehdez burned forest area is located in the southeastern Khuzestan province. The field data were obtained from 115 sample plots in a systematic random grid (20 m × 20 m). The attributes such as tree and shrub species type, the number of species and canopy coverage were recorded. Within each sample plot small and large crown diameters were measured. In order to record herbaceous species, the Whitaker’s snail plot method was applied (100 m² minimum plot area). In this study, 240 plant species were assessed and identified to 158 genera and 42 families. Asteraceae family with 33 species, Papilionaceae with 32 species, Poaceae with 29 species, Apiaceae w ith 27 s pecies a nd Lamiaceae with 18 species prevailed and constituted 57.9% of all the plants observed. Investigation of species life forms showed that Hemicryptophyte plants were most important. Chorological study showed that species found in Irano-Turanian and Common areas of Irano-Turanian and Mediterranean eruption were the most important ecological groups in the region, while other chorotypes were positioned far from the next in importance

    Understory vegetation as environmental factors indicator in forest ecosystems

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    Physiographic factors along with edaphic conditions play a crucial role in establishment of plant species throughout a region. Identification of the most effective factors is of high importance in sustainable management of a forest ecosystem. This study aims to investigate the relationships between understory vegetation and some environmental factors in natural forest ecosystems. This study has been carried out among the Fagetum orientalis communities of Ramsar Region, located in the north of Iran. For this purpose, 105 releves were sampled by a randomized-systematic method throughout the study area, using the Braun-Blanquet scale. Physiographic parameters such as elevation, as well as slope and orientation were measured. By identification of the herb-layer vegetation contained in each sampling, vegetation composition and cover abundance of species were separately identified. Then, the aforementioned properties of soil were entirely measured in the taken samples. Cluster analysis and detrended correspondence analysis have been applied to classify the site. Moreover, in order to determine the relation between species composition and environmental factors, canonical correspondence analysis was used. Results showed a significant relation between distribution of plant types and environmental factors. Eventually, environmental factors including slope, orientation, silt percent, pH, organic matter, soluble phosphorous were among the most effective factors in establishment of Hedera pastuchowii, Solanum kieseritzkii, Oplismenus undulatifolius, Sedum stoloniferum, Rubus hyrcanus and Saxifraga cymbalaria species
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