28 research outputs found
Object-Based Classification of UltraCamD Imagery for Identification of Tree Species in the Mixed Planted Forest
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
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
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
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
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
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' 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
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
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
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