Our rails, brackets, posts and post caps are made from either cast or extruded aluminum. Both the casting and extruding design and manufacturing process make the aluminum extremely durable. However, Curb Allure’s tree guard and garden fencing side panels and certain accessories cannot be manufactured in the same way because of their thickness and design. Therefore, these components are made of steel in order to withstand the rigors of an urban environment. Our landscape fencing products have a protective undercoating and are finished with the highest rated DuPont powder coating available for outdoor applications in order to minimize the effects of long-term exposure to the urban elements. Our manufacturers and Curb Allure designers, along with our structural engineering firm, have carefully chosen the perfect metals and alloys for our different components that strike a balance between strength, environmental friendliness, design, and cost in order to make this outstanding line of tree & garden guard products.Click here to see the structural engineering firm's (Blue Sky Design, Inc. Consulting Engineers) summary report of Curb Allure’s Tree Guards.