The objective of this study was to measure and determine the allometric equation of LEAF dry mass, specific LEAF AREA and LEAF AREA index of Rhizophora mucronata species located in Sirik city, Hormozgan province, Iran. In this study, in addition to the actual determination of the leaves, the specific LEAF AREA and the LEAF AREA index of Rhizophora mucronata trees were calculated using vegetative characteristics. Then, the correlation between different components, and their allometric equations were calculated. Determining the LEAF AREA index was performed directly by collecting 88 leaves from 22 trees and weighing them and the mean LEAF AREA, the canopy AREA and LEAF dry mass were calculated through collecting one-eighth of the tree canopy and determining the fresh and dry weight. Correlation and model determination were determined using stepwise regression (P≤ 0. 01). According to the results, the mean dry mass, specific LEAF AREA and LEAF AREA index were 3. 33 kg/tree, 39. 74 cm-2/g per tree and 0. 76, respectively. The LEAF AREA index, with two factors of LEAF AREA and tree height, (correlation coefficient=0. 82) explained 65% of the variations in the dependent variable. In determining the specific LEAF AREA, only LEAF AREA factor was introduced as the most effective factor in the equation and explained 56% of the variations. Results showed that tree factors, canopy AREA, LEAF AREA and height can have key role in tree ecological indices (LEAF dry mass, LAI and SLA) estimation and also in evaluation of mangrove stand changes and health.

Estimating dry biomass is one of the important parts of production estimation. Among vegetation indices, LEAF AREA index (LAI) is the most common used index to estimate water demand and yield. In this study, attempts have made to estimate LAI without destroying plant and by using the AccuPAR-LP80 crop scanner device. The case study performed in Magsal Agro-Industrial Company Qazvin, Iran with the aim of introducing relations to estimate the amount of dry biomass via LAI for three plant- maize, sugar beet and alfalfa. LAI values of above mentioned plants measured through nondestructive method by calibrated AccuPAR-LP80 crop scanner. Statistical evaluation showed that the highest correlation was for maize with R2=0.96 and the lowest was for alfalfa with R2=0.87. In addition, measured dry biomass was a linear function of fraction of photosynthesis active radation (fPAR). Statistical evaluation showed that correlation coefficient varies from 0.94 to 0.90 and PMSE from 2.85 to 3.3 kg ha-1 for maize and alfalfa, respectively.

Study of the performance of different drainage systems is essential for canola cultivation in the paddy fields of Mazandaran Province. For this purpose, an experiment was conducted at the drainage pilot of the Sari Agricultural Sciences and Natural Resources University in 2017-2018 cropping season. At 8 stages of canola growth, sampling were done under randomized complete block design with three replications in subSURFACE drainage systems and SURFACE one (Control) in order to determinate LEAF AREA (LA), LEAF AREA index (LAI), numbers of leaves (SLN) and LEAF dry weight (LDW). Then, statistical analysis was carried out to study the effect of drain depth and spacing on the mentioned growth indices and the mathematical relationships between LEAF AREA and its dry weight were found through evaluating linear and nonlinear regression models under different drainage systems. Maximum LA in all treatments occurred about 90 day after planting. Mathematical relations between LA and LDW described by linear and power models were suitable (with a correlation coefficient of 0. 98). Among the mathematical functions, reverse polynomial functions with degrees 4 and 5, logarithmic equations and inverse logarithmic equations with degrees 3, 4, and 5 showed better results than other mathematical functions The relations obtained in this experiment can be used in simulation models for winter canola growth under water table control conditions.

LEAF AREA Index (LAI), is a key component in estimating crop yield and environmental stresses. Given the importance of accurate determination of these parameters, the present study was aimed to estimate the LAI of rice plant. For this purpose, 20 paddy fields were selected. The data required to perform the operations in the study AREA were corrected by land impressions (direct method) and measured by AccuPAR (indirect method). Field work to gathering LAI were taken at intervals of 16 days from seedling stage to the flowering stage of rice plants. The results showed that the lowest and highest levels of LAI belongs to seedlings and flowering stages, respectively. The LEAF AREA obtained by both methods, were almost the same for each farm during different stages of plant growth. Consistent with the obtained values by both methods, indicate that the index can be calculated from a derived empirical relationship. Based on this empirical formula for every stage of plant growth, weka 3.7 software was adopted to calculate the mentioned relationship.

The objective of this research was to estimate the biomass, carbon storage and LEAF AREA index of hawthorn species (Crataegus aronia L.) in Sartaf forests of Ilam city. For this purpose, using random sampling method, 30 hawthorn trees were selected and variables of collar diameter, tree height, crown length and large and small diameter of the crown were measured. Then, the leaves from 1/4 or 1/8 of the crown of sample trees were collected. After drying the leaves in the oven, the dry weight of the leaves was determined. After burning a sufficient amount of dried leaves in an electric oven, the weight of organic matter and carbon content of the leaves were obtained. The weight method was used to calculate the LEAF AREA index. The results showed that the average LEAF biomass, LEAF carbon sequestration, and carbon dioxide absorption from the atmosphere were 99.18, 46.61, and 170.59 kg per hectare, respectively. The average LEAF AREA index of hawthorn species was calculated as 9.08 for each tree and 0.095 per hectare in study AREA. The results of allometric relationships using different regression models showed a positive and significant correlation between the variable of mean crown diameter with the variables of biomass and LEAF AREA index of hawthorn trees in Ilam forests. In general, the results of this research show the ability of using allometric equations to measure biomass, carbon sequestration, and LEAF AREA index of Crataegus aronia.

Forest trees are considered as most important and huge carbon pools in the forest ecosystems and have a great influence on the reduction of carbon emission in the atmosphere. Therefore, how to measure and estimate the carbon stored in the trees is the main issue for ecologists. The aim of this study was to estimate of LEAF biomass and LEAF carbon sequestration of Cercis siliquastrum L. in Arghavan forests reserves of Ilam. For this purpose, 30 trees were selected using random sampling method and height, mean diameter of crown, number of sprout and crown length variables were measured. All leaves of 1/4 crown AREA were collected. After of drying, dry weighted of leaves calculated. Enough quantity of leaves was burned in electrical kiln to calculate the carbon storage. To calculate of LEAF AREA index was used gravimetric method. Mean tree method was used to generalize the result to the whole forest. Based on results, mean of LEAF biomass, mean of LEAF carbon sequestration and mean of atmosphere CO2 absorption were 53. 55, 23. 4 and 86. 02 kg per hectare, respectively. Mean of LEAF AREA index in studied AREA was 0. 058. The results of allometric using of linear regression showed that there was a significant and positive correlation between of mean diameter of crown with LEAF biomass, carbon sequestration and LEAF AREA index variables in Ilam forests.

Yasuj forests are regarded as the representative of south Zagros forests that are especially important due to density and species diversity. Two major species of these forests are Quercus brantii and Pistacia mutica. In this research LEAF biomass and LEAF AREA index (LAI) were assessed by the measurement of various parts of trees and finding correlation between different variables. In order to perform this research, a number of trees were selected by systematic randomized method and different variables such as diameter at breast, height, height of tree crown and small and large diameters of tree crown were measured. Also the leaves of a sector of the tree crown were picked off and after weighting, their dry weight were measured in laboratory. Gravimetric method was applied for calculating LAI in which the relationship between LEAF AREA and its dry weight is used to estimate the total AREA of whole trees leaves. Mean Tree Method was used to generalize the result to the whole forest. The results showed that the amount of LEAF biomass for Quercus brantii and Pistacia mutica were 1317.3 and 57.2 (kg/ha), respectively. For rapid estimation of this index allometric equations were suggested. Mean LAI in studied site was estimated to be about 1.2. Also analysis tests were done for more evaluation of the amount of elements in leaves.

Background and Objectives: Accurate measurements of LEAF AREA are important for agronomic and physiological studies. LEAF AREA can be calculated in two ways: direct and indirect. Direct methods for determining LEAF AREA are a destructive method and need a planimeter to measure the total LEAF AREA attached to shoots which are all time-consuming and tedious approaches. All direct methods are similar in that they are difficult, extremely labor-intensive, require many replicates to account for spatial variability in the canopy, and are therefore costly in terms of time and money and also destructive. In the indirect methods, LEAF AREA was estimated through some crop vegetative characteristics which are less costly and time-consuming. Therefore, the objective of the present study is to examine different relationships between LEAF AREA and some vegetative characteristics in safflower and to select the best characteristic for estimating LEAF AREA.Materials and Methods: The field experiment was conducted with four safflower cultivars (411, Sina, Esfahan and Sofeh) in three planting dates (4April, 25 April and 16 May 2012) as arrangement factorial in randomized complete blocks design. During the growing season, every 5 or 10 days, the LEAF AREA was measured by the planimeter (T Devices, Cambridge, UK). At the same time, LEAF dry weight (LDW), stem dry weight (SDW), vegetative dry weight (VDW), node number on main stem (MSNN) and LEAF number on main stem (MSLN) were measured. The relationships between LEAF AREA and these vegetative characteristics were examined by the regression. Consequently, the best characteristic for estimating LEAF AREA was selected by the high R2, r and low RMSD.Results: In this study, regression models were developed for estimating LEAF AREA (LA) from measurements of main stem LEAF number (MSLN), and main stem node number (MSNN), LEAF dry weight (LDW), stem dry weight (LDW) and vegetative dry weight (VDW). On the basis of RMSD and coefficient correlation (r) between predicted and observed LEAF AREA, LDW was found to be the best independent characteristic for determining the LEAF AREA by the linear model. The values of RMSD varied from 39.9 to 61.4 and the values of r were higher than 0.96. Once there was no significant difference between model coefficients across cultivars we pooled all data and obtained a generalized linear model for estimating LA in all cultivars (LA=10.6+102.2LDW) with RMSD=52 and r=0.96.Discussions: Overall, this study suggests that in the absence of planimeter device, it may be appropriate to estimate LEAF AREA using the relationship between LA and LDW. Also, because of the close relationship between LDW and LA than other relationships, this relationship can be used to estimate LEAF AREA in simulation models.