Abstract: This article investigates the relationships between soil characteristics (physical and chemical) and wood properties of Persian oak in three different elevation sites. For this purpose, 27 trees were randomly chosen and cut in Zagros forests in western Iran. The test samples were prepared at the stem (breast height) to examine physical and biometrical properties. For each elevation site, four soil samples were obtained at a 0-20 cm soil depth under the canopy of each tree to measure soil properties, including clay, silt soil, sand soil, electrical conductivity, pH, nitrogen, phosphorus, potassium, and organic matter content. Then, the relationship of soil and wood properties was determined by principal component analysis. Results specified that there are a positive correlation between wood density and volumetric swelling with clay and available potassium. Moreover, the results revealed a positive correlation between fiber length, cell wall thickness, and fiber diameter with electrical conductivity, sand percentage, and total nitrogen content, respectively.

ABSTRACT Wood plastic composite was fabricated using high density polyethylene and pine wood fiber. The effect of addition of TiO2 nanoparticles at different weight fractions (0%, 1%, 3%, and 5%) on some properties of the composite was examined. The experimental composites were tested for bending strength, tensile strength, Izod impact strength, thickness swelling, and contact angle. Field emission scanning electron microscopy was also investigated to study the distribution of TiO2 nanoparticles in the composites. The results showed that using TiO2 nanoparticles as a reinforcing agent in wood plastic composites resulted in an increase in the tensile and bending strengths and a decrease the thickness swelling of the composites. The effect of TiO2 nanoparticles on the Izod impact strength of composites was not significant. The results also showed that the contact angle of wood plastic composites was improved by using TiO2 nanoparticles.