While most recent investigation in satellite- based remotely sensed data has concentrated upon the biophysical characteristics of overstory vegetation for large area, little attention has been given to the reflectance contribution of their associated understory, versus overstory plantation reflectance to the recorded pixel value. In this research, shrubs and herbs were considered as consistent backgrounds which have an inverse effect, in contrast to plantation overstory, to the recorded pixel value in terms of their surfaceexposure to satellite sensors. Given the fact that planted tree crown closure is correlated with their height and diameter at breast height (DBH) in the early stages of the plantation, it is expected that a relationship exists between tree canopy closure, height, DBH and their associated reflectance values. The proposed concept was tested in a case study for a Jack Pine (pinus banksina) plantation using Landsat Thematic Mapper (T. M.). The crown width height, and DBH of planted trees were measured in an area of 30m X 30m, for every 2-year age interval from 1 to 21 years. Other understory natural regeneration within a 2m radius was recorded. Crown closure, mean height, and DBH of each plot (with shrub and herb understory of more than 60%) were plotted against their associated Digital Numbers (DN(s)) for 6 T. M. bands (1, 2, 3, 4, 5 and 7). The visible region of the spectrum (bands 1, 2 and 3) showed a narrow range of reflectance and was not suitable for this purpose. Band 4 revealed a greater range of DN(s) than bands 1, 2 and 3. A strong inverse linear relationship between DN(s) and their associated canopy closure, height, and DBH were found in band 5 as r2 = 0.863, 0.941, 0.873 respectively. Band 7 showed a stronger relationship with canopy closure (r2 = 0. 81) than did the other T. M. bands (except band 5). Overall, the results of this study have shown the importance of T. M. band 5 for estimating DBH and the height of plantations based on the contrast between reflectance of the overstory and understory.

Recent advances in unmanned aerial vehicles (UAVs) technology, as well as the development of lightweight sensors, offers a great possibility for the measurement of different tree features with relatively low costs compared to traditional methods. In this research, the precision and accuracy of tree height measurement and estimation using imagery by a low-cost UAV were studied. For this aim, 854 images with an altitude of 100 m above the ground were taken and the images were processed and dense point cloud was extracted by applying Structure from Motion (SFM) algorithm. The study was conducted in 34. 79 ha of Sisangan forest park and 28 sample plots (30 × 30 m) were located in the field and tree heights were measured. Also, tree height was measured using the canopy height model. Linear regression was applied to estimate the actual tree heights based on CHM derived tree eights. The accuracy and precision of the estimates were assessed using relative bias and relative root mean square error. The differences between the field measured and CHM derived tree heights were statistically significant. Based on the results, the relative root means the square error of the height estimation of Buxus hyrcana, Carpinus betulus, Parrotia persica, and other species was 20. 39, 20. 39, 20. 57 and 20. 52 percent, respectively. The results showed that tree height measurement based on UAV images and methods that were applied in this research, is biased and the estimations are highly uncertain.

Background and objectives: Efficient and high-quality information about the current and future state of the forest is needed for sustainable management and basic planning of forest resources. Zagros forests, as one of the most important vegetation areas of Iran, have a very important effect on water supply, soil conservation, climate adjustment and economic and social balance in the whole country, hence, the sustainable protection and management of these forest ecosystems The main concern of researchers and managers in this area has become vegetation. The dominant species of these forests is Iranian oak (Quercus brantii Lindl). According to geographical and environmental conditions, this species has various habitats in the vegetation zone of the middle Zagros. Considering the noble position of the Iranian oak species in the forests of Zagros, the importance of developing more researches regarding this species is essential. The characteristics of tree diameter and height are the most important components needed in forest statistics. These variables are one of the main variables for measuring the appearance characteristics of forest trees and are used in cases such as determining the volume and drawing the height curve. Considering that measuring the height of all forest trees is a long and expensive operation, hence the use of diameter and height models to estimate the height of trees has been developed. The purpose of this research is to investigate the linear and non-linear diameter-height models of Iranian oak species (Q. brantii Lindl) in the high forests of the Middle Zagros in order to find the answer to the question of whether it is possible to estimate the height of Iranian oak high forest trees as There is a function of the diameter of the chest in this vegetative zone or not.Methodology: This research was conducted in Sefidkoh protected area of Lorestan. The dominant tree cover of this area is made of oak, like other areas of Zagros, but other plants and trees such as Cratagus persica pojark, Amygdalus sp, Astragalus sp, etc. can be mentioned in it. To carry out this research, by conducting numerous forest tours and getting to know the forests of the region, a stand with an area of approximately five hectares, which had a high forest vegetation structure, was selected. In the selected forest stand, the characteristics of DBH and total height of all Iranian oak trees whose DBH was more than 12.5 cm were counted as 100%. In total, 642 Iranian oak trees were measured in DBH and height. Linear and non-linear models were used to fit the data of DBH and height of trees, which include various models of exponential, power, density-product, growth, sigmoid and other functions. In this research, 80% of the data were used in the modeling process and 20% were used for evaluation, as well as for fitting the data and estimating the indicators of each of the models from the Curve Expert Professional software, which is a software Comprehensive software was used to fit the curves. In the modeling process, diameter data were used as independent variables and height data were used as dependent variables. In the upcoming research, to verify the accuracy of the obtained models, the RMSE, MAEand Bias in absolute and relative terms, as well as the R2 and the AIC was calculated as validation indices.Results: Based on the descriptive statistics of Iranian oak trees, the average, minimum and maximum DBH was 42.42, 12.5 and 150 cm, respectively, and the height was 6.3, 1.2 and 17 meters, respectively. Based on R2 values, the used models explained 62 to 86% of the total changes in tree height. The results of tree height-diameter modeling showed that Gompertz, MMF and Richard models have the highest explanatory coefficient (0.86, 0.86, 0.86), respectively, and the lowest standard error (307. 1, 1/307, 1/307) and AIC information criterion were (276/04, 277/13, 277/03). The results of the criteria used to validate the used models showed that the Gompertz, MMF and Richard models have RMSE of 22.22, 22.20 and 22.20%, respectively, as well as MAE respectively. 16.69, 16.74 and 16.79 percent were better able to estimate the characteristics of the height of trees. According to the mentioned results, it was found that Gompertz, MMF, and Richard models have a higher ability to estimate the characteristic height of Iranian oak trees compared to other models.Conclusion: Overall, the results of this research showed that linear and non-linear models have the ability to estimate the height of Iranian oak high forest trees in the growing region of the middle Zagros, and among these models, three non-linear models are Gompertz, MMF and Richard based on evaluation criteria. The performance was more accurate. Therefore, these models can be used in the forest areas of the middle Zagros vegetation zone, which have the same structure and habitat conditions as the studied area. It is suggested to use the generalized models of height and diameter in future researches.

Graph partitioning is a well-known problem in the literature. In this paper, path partitioning of trees in which the given tree is partitioned into edge-disjoint paths is considered. A linear time algorithm is given for computing a path partitioning of minimum height.

Symbol is one of the means that leads to cognition and is the most fundamental way of expressing the ideas which without symbolism they cannot be revealed. Therefore, symbols fulfill a prominent function in the area of religious ideas. Religious traditions are full of myths and in this sphere only the symbolic language could be useful. In other words, symbol is the language of the myth. Among the religious symbols Height is one that has played an important role from the primitive age until now. It has always been identified with a kind of value that connects human’s mind to superiority, transcendence and divinity. This article firstly tries to survey the concept of symbol and symbolism and then the function of it in the area of religion and myth. Finally it studies the symbol of Height and its major manifestations such as sky and mountain.

We obtain the generating function for the number of columns of fixed height $r$ in a bargraph (classified according to semi-perimeter). As initial case for two distinct methods we first find the generating function for columns of height $1$. Then using a first-return-to-level-$1$ decomposition, we obtain the rational function version of the continued fraction generating function which allows us to derive separate recursions for its numerator and denominator. This then allows us to get the asymptotic average number of columns for each $r$. We also obtain an equivalent generating function by exploiting a sequential decomposition for bargraphs in terms of columns of height $r$.