فهرست مطالب gh. zahedi amiri

Forest ecosystems are one of the principal sources of carbon storage. The Lirehsar forest in Tonekabon was studied to assess the carbon sequestration capacity of underground biomass, soil, and roots of beech and hornbeam mixed stands. Thirty samples of uprooted beech and hornbeam trees were unintentionally selected. Soil sampling was carried out at three depths (0-10, 10-30, 30-50 cm), and root diameter sampling was conducted in six classes (50 mm) from distinct parts of the root. Soil samples were passed through a 2 mm sieve, and root samples were dried and pulverized with a grinder. The carbon storage value in beech and hornbeam roots was 8404 kg.ha-1 and 6235 kg.ha-1, respectively. The total amount of carbon deposited in soil mineral layers from 0-10 cm to 30-50 cm depth on beech and hornbeam was calculated 121 and 161 t.ha, respectively. Furthermore, the study results on soil carbon sequestration in beech and hornbeam revealed that the amount of soil carbon sequestration in all layers was 56.9, 72.5, and 62.3 t.ha for hornbeam, while its value for beech in all layers was 42, 43.6, and 35.7 t.ha. The independent t-test results showed no significant difference between carbon stored in diverse root diameters in beech and hornbeam. Findings showed that the amount of soil carbon sequestration on hornbeam was higher than on beech in all layers, revealing the influence of species diversity on soil carbon sequestration. It is expected that a variety of different tree species can be employed for reforestation in suitable areas as a result of the species diversity effect on carbon storage and carbon sequestration compared to pure beech species. It is supposed that hornbeam is a mitigated species for decomposition of soil elements and carbon sequestration in forest soil due to the developed distribution of the studied species in Hyrcanian forests.

The aim of this research was to study the plant associations in Baharbon district of Kheyroud Forest (north of Iran) and their relationship to physiographical factors. Determination of plant associations and sub associations were done, using Braun - Blanquet School. For this purpose, 51 releves consisting of 100 m2 area, were located at different sites. The phytosociological data was analyzed by the Factorial Correspondences (AFC) and Classification Ascendant Hierarchique (CAH) methods, using the Anaphyto software. Nine associations consisting of Querco macrantherae-Carpinetum orientalis, Fraxino excelsioris-Aceretum velutini, Parrotio persicae-Quercetum castaneifoliae, Parrotio persicae-Carpinetum betuli, Pterocaryo fraxinifoliae-Alnetum subcordatae, Aceri velutini - Fagetum orientalis, Carpino betuli-Fagetum orientalis, Rusco hyrcani-Fagetum orientalis and Fagetum orientalis were distinguished in this forest. Then relationships between the associations and the landform features were investigated, applying the DCA method and CANOCO 4.5 software. The results showed that although there were significant relationships between the associations and the altitude and the geographical aspects; but there was not significant relationship with the slope gradient.

In order to achieve a sustainable management of land resources and to improve land quality, quantitative ssessment of effective factors and environmental indicators are required. Environmental apability valuation regulates the relationship between socio-economic impacts and land use changes to monitor the sustainable development. The aim of this study was to evaluate environmental capability of the Saman-e-Orfie-Cham-Haji of Kakareza forest in Lorestan province for ecotourism management. Digital topographic map, classified tree crown cover density map, some soil properties and socio-economic data have been prepared to appropriate different management practices such as recreational and conservational zoning using GIS application. Results indicated that 6%, 68% and 26% of total areas in the study site were specified as appropriate zone for intensive recreation, extensive recreation and conservation, respectively. The evaluation of environmental capability and the ranking of the suitable zones for intensive recreation (in order to choose the best zone for physical development planning) were performedby considering the socio-economic criteria such as recreational demand, distance from rivers, accessibility and the present land use. The results showed that the most important factors affecting the process of environmental capability evaluation in the study site for ecotourism zoning are altitude, land use and recreational demand.