Evaluation of environmental factors on Lonicera nummulariifolia Jaub. & Spach in Chaharmahal and Bakhtiari Province

Background and Objectives: Understanding the site demands and characteristics of various plant species is essential for effective forest protection and restoration.Consequently, determining soil properties is one of the most critical steps in assessing the site requirements of different plant species.This research was conducted to investigate the site demands of Lonicera nummulariifolia in Chaharmahal and Bakhtiari Province.Additionally, it aims to identify the most significant soil factors influencing the distribution of L. nummulariifolia.Materials and methods: Four sites were selected in Chaharmahal and Bakhtiari Province: Gazestan (1792 m above sea level), Samsami (2210 m a.s.l.), Kohrang (2215 m a.s.l.), and Ardal (1531 m a.s.l.).Soil samples were collected from a depth of 0-30 cm.The physicochemical properties of the soil, including nitrogen content, available potassium, organic carbon, pH, and electrical conductivity, were analyzed.Additionally, quantitative characteristics of the trees, such as diameter, height, and crown diameter, were measured.Soil properties were evaluated using one-way ANOVA.Furthermore, principal component analysis was employed to identify the most significant soil variables influencing the distribution of L. nummulariifolia. Results:The results of this study indicated that the tallest and shortest trees had average heights of 2.26 meters and 1.57 meters, respectively, and belonged to the Kograng and Gazestan sites.Additionally, the tree origin at the Samsami site was coppice, while the other three sites featured high stands.The physicochemical properties of the soil revealed that electrical conductivity, nitrogen content, and organic matter levels showed no significant differences among the studied sites.Furthermore, soil pH was nearly neutral across all sites and did not exhibit significant variations.However, Koohrang and Gazestan recorded the highest significant levels of potassium.Also, Gazestan exhibited the lowest percentage of sand in the soil compared to the other studied sites.Conical correspondence analysis indicated that the most significant factors influencing the distribution of L. nummulariifolia are soil organic matter, nitrogen, potassium, electrical conductivity, clay content, slope, and aspect, in that order. Conclusion:L. nummulariifolia requires sites with higher soil nutrient levels and organic carbon content.Additionally, it prefers a neutral soil pH.In other words, the physicochemical properties of the soil play a crucial role in the distribution of L. nummulariifolia.Understanding the site requirements of this species could aid in identifying suitable locations for reforestation efforts aimed at enriching the Zagros forests.