Modeling distribution of oriental beech (Fagus orientalis Lipsky) trees in riparian forest by HOF model

We modeled the distribution of oriental beech (FagusorientalisLipsky) stands to determine optimum ecological amplitude range along riparian forests of RamsarSafaroud riverside in Mazandaran province. Data were collected on transects which were perpendicular to the water flow on both river sides. Each transect was 200 m in length, with a 200 m distance between transects. On each transect five 400 m2 quadrats were laid in 50 m intervals. At each sampling location the number of beech individuals with a diameter at breast height (DBH) > 7.5 cm were recorded. In addition three soil samples per plot were taken from the upper 30 cm depth. Totally 44 transects and 220 quadrats were sampled. An extended HOF model implemented in eHOF package in R was applied to assess the response of beech to soil variables, and the corrected Akaike's information criterion (AICc) was used for model selection based on models associated with the lowest AICc values. The results showed that only 27.5% of the models obtained a symmetric normal response curve (model IV), whereas 72.5% of models showed linear and asymmetric (i.e. I to V) curves. However, the VI and VII models were observed in none of the results. We assessed the HOF models to be of high potentials to be further employed in similarly-structured riparian forests

Relationship of soil physical and chemical properties with ecological species groups in Pinus taeda plantation in northern Iran

Abstract. Adel MN, Daryaei MG, Pashaki MS, JalaliJ, KuhestaniJS, Jiroudnezhad R. 2017. Relationship of soil physical and chemical properties with ecological species groups in Pinus taeda plantation in northern Iran. Biodiversitas 18: 422-426. The aim of this study was to investigate the relationship of physical and chemical properties of soils with ecological species groups in Pinus taeda plantation forests in Guilan province, Iran. For this purpose, a random systematic 100 m × 200 m grid sampling plan was used to establish 75 sampling plots. In each plot, soil factors and percent cover of each herbaceous species were recorded. Sub-plots of 32 m2 were used for herbaceous species measurements. At each sampling plot, soil samples were collected in depth of 0-30cm. The result of TWINSPAN analysis revealed five dictinct groups. Multivariate analysis was performed through CANOCO 4.5 to explore the relationship between soil factors and plant community. Results showed that the most important soil factors in these communities were N, P, K, OC, Ca, Mg, TNV, pH, SP, soil texture (clay, sand, silt) and EC. The results indicated that the physical and chemical soil characteristics have a significant role in the growth and distribution of plant communities in the study area. Keywords: Pinus taeda, plantation, soil properties, vegetatio