Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature ...Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter （DBH） to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter （age） typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%-64.3%, 15 cm-75 cm, and 2.0-19.5 m, respectively. With increasing trunk diameter, the propor- tion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological charac- teristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter 〉1 m do not provide valu- able round wood for industries and cause to raise wood production costs. We recommend that these trees 〉1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.展开更多
Despite the importance of Hyrcanian forests for biodiversity conservation, a few studies with biomass destruction has been done to predict biomass and carbon pools from this forest and there is a lack of knowledge in ...Despite the importance of Hyrcanian forests for biodiversity conservation, a few studies with biomass destruction has been done to predict biomass and carbon pools from this forest and there is a lack of knowledge in our country. Biomass and leaf area index (LAI) are important variables in many ecological and environmental applications and forest management. In this paper, allometric biomass and leaf area equations were developed for three common Hyrcanian tree species, Oriental Beech (Fagus orientalis Lipsky), Hornbeam (Carpinus Betulus Lipsky) and Chestnut- leaved Oak (Quercus castaneifolia C. A. Mey). To evaluate and estimate the leaf biomass and leaf area index of Oriental Beech, Horbeam and Chestnut-leaved Oak, 21, 27 and 17 individuals were selected and felled down, respectively. Tree characteristics such as diameter at breast height, total height, crown length and perpendicular diameters were measured. Destructive sampling was applied for determination of leaf biomass and LAI. Allometric equations were calculated for estimation of leaf biomass and LAI using simple linear regression and nonlinear regression analysis. The equations were compared based on several modelling parameters. Model comparison and selection were based on R2, Akaike’s information criterion (AIC), prediction error sums of squares, model standard error estimate (SEE), ΔAIC, and a correction factor. Based on the results, the mean values of leaf area, leaf biomass and LAI for Oriental Beech were 53.05 cm<sup>2</sup>, 0.176 gr, 2.16, for Hornbeam were 27.2 cm<sup>2</sup>, 0.128 gr, 1.13 and for Chestnut-leaved Oak were 62.419 cm<sup>2</sup>, 0.401 gr, 2.26, respectively. The highest significant correlation for Oriental Beech was found between LAI and total height (R2</sup>adj</sub>= 0. 931), the highest significant correlation for Hornbeam was found between LAI and Dbh (R<sup>2</sup><sub>adj</sub> = 0. 956) and the highest significance for Chestnut-leaved Oak was found between LAI and SqrtDbh (R2</sup>adj</sub> = 0. 956). Also, the best 展开更多
A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）...A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）, large （242-332 m^2） and very large （333-550 m^2） gaps, as well as under closed stands were studied eight years after-the gap creation. Soil samples were taken from three depths, 0-10, 10-20 and 20-30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters： Mg^＋2 concentration of 0-10 cm at medium gap size, bulk density of 10-20 cm at very large gap size as well as K^＋ and Ca^＋2 concentrations at 20-30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent （Sp %） at 0-10cm as well as P and Mg^＋2 at 20--30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca^＋2 at depth 0--10 cm and 10-20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.展开更多
文摘Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter （DBH） to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter （age） typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%-64.3%, 15 cm-75 cm, and 2.0-19.5 m, respectively. With increasing trunk diameter, the propor- tion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological charac- teristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter 〉1 m do not provide valu- able round wood for industries and cause to raise wood production costs. We recommend that these trees 〉1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.
文摘Despite the importance of Hyrcanian forests for biodiversity conservation, a few studies with biomass destruction has been done to predict biomass and carbon pools from this forest and there is a lack of knowledge in our country. Biomass and leaf area index (LAI) are important variables in many ecological and environmental applications and forest management. In this paper, allometric biomass and leaf area equations were developed for three common Hyrcanian tree species, Oriental Beech (Fagus orientalis Lipsky), Hornbeam (Carpinus Betulus Lipsky) and Chestnut- leaved Oak (Quercus castaneifolia C. A. Mey). To evaluate and estimate the leaf biomass and leaf area index of Oriental Beech, Horbeam and Chestnut-leaved Oak, 21, 27 and 17 individuals were selected and felled down, respectively. Tree characteristics such as diameter at breast height, total height, crown length and perpendicular diameters were measured. Destructive sampling was applied for determination of leaf biomass and LAI. Allometric equations were calculated for estimation of leaf biomass and LAI using simple linear regression and nonlinear regression analysis. The equations were compared based on several modelling parameters. Model comparison and selection were based on R2, Akaike’s information criterion (AIC), prediction error sums of squares, model standard error estimate (SEE), ΔAIC, and a correction factor. Based on the results, the mean values of leaf area, leaf biomass and LAI for Oriental Beech were 53.05 cm<sup>2</sup>, 0.176 gr, 2.16, for Hornbeam were 27.2 cm<sup>2</sup>, 0.128 gr, 1.13 and for Chestnut-leaved Oak were 62.419 cm<sup>2</sup>, 0.401 gr, 2.26, respectively. The highest significant correlation for Oriental Beech was found between LAI and total height (R2</sup>adj</sub>= 0. 931), the highest significant correlation for Hornbeam was found between LAI and Dbh (R<sup>2</sup><sub>adj</sub> = 0. 956) and the highest significance for Chestnut-leaved Oak was found between LAI and SqrtDbh (R2</sup>adj</sub> = 0. 956). Also, the best
文摘A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand. Changes of soil properties in small （60-150 mE）, medium （151-241 mE）, large （242-332 m^2） and very large （333-550 m^2） gaps, as well as under closed stands were studied eight years after-the gap creation. Soil samples were taken from three depths, 0-10, 10-20 and 20-30 cm. The gaps were different from their around undisturbed stands in terms of the following soil parameters： Mg^＋2 concentration of 0-10 cm at medium gap size, bulk density of 10-20 cm at very large gap size as well as K^＋ and Ca^＋2 concentrations at 20-30 cm at small and large gap sizes, respectively. Furthermore, the size of the gaps had no effect on soil characteristics through the whole profile. Water saturation percent （Sp %） at 0-10cm as well as P and Mg^＋2 at 20--30 cm was different amongst undisturbed stands around different gap sizes. The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm. Significant differences were observed between gaps and closed canopy regarding P and Ca^＋2 at depth 0--10 cm and 10-20 cm, respectively. It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.
