Influence of habitats on the physical and mechanical properties of Iron bamboo (Ferrocalamus strictus) and its optimal habitats

Abstract

The structures and the physical and mechanical properties of Ferrocalamus strictus culms were differently affected by the environment in different habitats. Correlation analysis, random forest and cluster analysis were used to investigate the effects of environmental factors in five habitats on the structure and physical and mechanical properties of bamboo poles or stalks of F. strictus. The air-dry density of F. strictus stalks ranged from 0.66 to 0.91 g/cm³. Data showed that the average annual temperature, soil water content and available potassium content were important factors affecting air-dry density the bamboo stalks. The compressive strength of F. strictus stalks varied from 60.62 to 126.16 MPa and was positively correlated with mean annual sunshine hour. The modulus of rupture (MOR) ranged from 57.95 to 252.09 MPa and the soil available phosphorus content limited the MOR of F. strictus. The modulus of elasticity (MOE) ranged from 6.04 to 12.89 GPa. The outer hardness ranged from 66.75 to 94.83 HD (Shore D hardness) and the inner hardness ranged from 28.42 to 58.42 HD. Soil silicon content affected the structures and mechanical tissue strength of F. strictus culms. The principal component analysis indicated that the Yuanyang was the optimal habitat of F. strictus with highest composite scores of 14.07, the F. strictus of Yuanyang had the highest bending strength in the world, suggested that selecting a habitat site as breeding materials be reasonable. The regulation of hydrothermal conditions, i.e. soil pH, silicon (Si), phosphorus (P) and potassium (K) elements, was essential for the growth rate and physical and mechanical properties of F. strictus stalks. Further research will work on regulating the growth conditions of F. strictus at Yuanyang according to the information found from this paper and evaluating the impact of regulation.