Leaf biomass and leaf area equations for three planted trees in Iran

Leaf area (LA) and leaf biomass (LB) are important variables for most physiological, horticultural and agronomic studies involving plant growth, development rate, radiation use efficiency, and water or nutrient use. Measuring these variables need destructive and aggressive sampling. Fortunately, evolving allometric equations can help for low cost and non-destructive estimation of such variables. The aims of this study are Estimate, compare and develop allometric models of LA and LB per tree and per stand for Alnus subcordata (AS), Populus deltoides (PD) and Taxodium distichum (TD) plantations. We selected 12 sample trees in each stand. Leaf Fresh weight of randomly selected branches was weighted in the field. Branch-level LA was modeled as a function of branch diameter (R2 > 0.8) and total fresh weight of LB has been calculated for each sampled tree. For each species, 100 leaves from all canopy directions of trees were randomly selected and transported to the laboratory. At the lab, leaf area has been measured using leaf area meter. Allometric equations were derived using regression analysis. For all species, derived equations showed high accuracy (R2 ranged from 0.837 to 0.947). However, with respect to mean square error, power regression equations (individual leaf area = a(L×W)b and LA or LB = a DBHb) are best models to estimate Individual Leaf Area, LA, and LB of AS, PD, and PD. The highest LAI was in the order of 16.9 > 5.5 > 4.5 for AS, PD, and TD, respectively. DOI: http://dx.doi.org/10.5281/zenodo.26791

Mechanical Characteristics of the Fine Roots of Two Broadleaved Tree Species from the Temperate Caspian Hyrcanian Ecoregion

In view of the important role played by roots against shallow landslides, root tensile force was evaluated for two widespread temperate tree species within the Caspian Hyrcanian Ecoregion, i.e., Fagus orientalis L. and Carpinus betulus L. Fine roots (0.02 to 7.99 mm) were collected from five trees of each species at three different elevations (400, 950, and 1350 m a.s.l.), across three diameter at breast height (DBH) classes (small = 7.5–32.5 cm, medium = 32.6–57.5 cm, and large =57.6–82.5 cm), and at two slope positions relative to the tree stem (up- and down-slope). In the laboratory, maximum tensile force (N) required to break the root was determined for 2016 roots (56 roots per each of two species x three sites x three DBH classes x two slope positions). ANCOVA was used to test the effects of slope position, DBH, and study site on root tensile force. To obtain the power-law regression coefficients, a nonlinear least square method was used. We found that: 1) root tensile force strongly depends on root size, 2) F. orientalis roots are stronger than C. betulus ones in the large DBH class, although they are weaker in the medium and small DBH classes, 3) root mechanical resistance is higher upslope than downslope, 4) roots of the trees with larger DBH were the most resistant roots in tension in compare with roots of the medium or small DBH classes, and 5) the root tensile force for both species is notably different from one site to another site. Overall, our findings provide a fundamental contribution to the quantification of the protective effects of forests in the temperate region

Biomass Expansion Factors (BEFs) and Carbon Stock for Brant's Oak (Quercus brantii Lindl.) Forests in West-Iran

Investigating a tree’s biomass can provide basic information about forest carbon stock. The Biomass Expansion Factor (BEF) is a variable for estimating carbon stock of forests. The aim of this study was to analyse the Above Ground Biomass (AGB) allocation, developing the BEF and carbon stock for two vegetation forms of Brant’s Oak (Quercus brantii Lindl.) based on forest inventory data. BEF is defined as the ratio of AGB to crown volume variables. The study data were taken from 30 trees that include 16 individual trees with single stem and 14 coppice shoots located in West-Iran. The trees selected were felled and separated into different components including: bole, main branches, lateral branches, twigs and leaves. The fresh weight of the trees was obtained with a portable hanging scale and several samples were taken from each tree component. The results of this study showed significant differences between component biomass proportions of the two vegetation forms of Brant’s Oak trees and determined average biomass and carbon content of the forms studied. We also conclude that BEF of Brant’s Oak could be improved by applying crown variables. According to the results, BEFs are tree-size dependent variables. Finally, this study indicates that age-dependent BEFs cannot be applied to conditions where stand development deviates from the conditions that in which the BEFs were developed

Plant species diversity in relation to physiographical factors at Dehsorkh Woodland

Species diversity is an important characteristic of bio-communities. Organisms diversity, diversity measurement and hypothesis test in relation to diversity causes are issues which the ecologists are interested in for long period. The aim of the trial was to study plant species diversity in Dehsorkh woodland at Javanroud, Kermanshah province, Iran. For this reason 300 sampling plots were used from which 60 at 256 m2 and 240 at 2.25 m2 area. At each plot six diversity indices (Shannon's (H), Simpson's reciprocal, Hill's N1, Pielou's (J/), Alatalo's F and Molinari's G) with respect to physiographical factors (slope, aspect and altitude) were investigated. The results showed that species diversity was the greatest at north aspects and slopes less than 30% and there was not significant difference between altitude and species diversity. The correlation between species number and indices analysis at each plot and the tendency and the role of each index at different analysis processes showed that the Simpson's reciprocal index is a best index for such research trials

Preliminary results of estimating above- ground biomass using Randomized Branch Sampling method for planted Mulberry and Black Locust in Mobarakeh Steel region

Estimation of biomass has many applications in forestry practices and researches. Randomized Branch Sampling (RBS) is one of the methods, which is used for estimating tree biomass. In this research, RBS method was introduced and the accuracy of biomass estimation was tested for total and crown biomass of 5 trees in the plantations of two species including Mulberry (Morus alba) and Black Locust (Robinia pseudoacacia). The plantations are located in Mobarake Steel Complex area in the semi-arid regions of Esfahan province in Iran. Actual biomass was measured by weighting all tree components and estimated biomass was calculated by RBS method. Actual and estimated biomass was compared by paired t –test. Results showed that there is no significant difference between crown and total amount of actual and estimated biomass for both species. Relative bias varied between 3.3 to 7.6 percent. Although results of this research by cutting 5 trees seem to be Preliminary, this research showed that RBS method can be considered as an accurate method for estimating tree biomass

Allometric equations for estimating above and below-ground carbon storage of four broadleaved and coniferous trees

Considering the climate change and global warming topics, importance of tree biomass and its measurement is increasing. Direct biomass measurement, especially for root section, is very costly, time consuming and difficult to implement. Usually, in such cases biomass can be estimated, using allometric equation. The aim of this research was to establish equations for estimating carbon content at above and below ground and whole tree biomass for four species, including Mulberry (Morus alba), Black Locust (Robinia pseudoacacia), Eldar Pine (Pinus eldarica) and Arizona cypress (Cupressus arizonica) planted around Mobarakeh Steel complex. For this purpose, 15 trees for each species (totally 60 trees) with appropriate diameter and height distribution, selected randomly and fell down and cut to different segments. Then the different components were separated and total fresh weight was measured at the field. Also roots of 20 trees fully excavated and after fresh weight measurement, some samples for dry weight determination were taken. Dry weight and carbon content of each sample were measured at laboratory. Allometric relationships between independent variables and carbon storage of different components and whole tree were established by nonlinear regression analysis. Overall, 96 models were derived for the four species and only eight of them were not statistically significant. The results showed that for Pine and Cypress, DBH (Diameter at Breast Height) and for Mulberry diameter at 0.3 m established models with highest coefficient of determination at all cases. For Black Locust, there was not special variable which can establish model with high coefficient of determination in all cases. For estimating the whole above- and below ground carbon storage of different organs, tree height had the highest coefficient of determination. Generally, concerning the both above and below ground biomass, modeling allometric relationships resulted in higher coefficient of determination of modeling for coniferous rather than for broadleaved species