Mass swing set retailers use low-quality, thin lumber from abroad, but Tree Frogs manufactures our own line of swing sets out of the finest woods available. Tree Frogs swing sets are built with chemically free, thick, premium lumber that comes from certified mills and is sustainably harvested. Both redwood and cedar are naturally resistant to insects and decay and are unlikely to warp or twist. Because our lumber is chemical free and from sustainable forests, it is not only healthy for families but the world in which they play.