Which of the following wood types is considered natural timber?

The choice of pine as the correct answer stems from its classification as natural timber. Natural timber refers to wood harvested directly from trees, which maintains its natural structure and grain. Pine, specifically, is a type of softwood that is commonly used in construction and furniture making, notable for its workability, strength, and aesthetic appeal.

In contrast, the other options represent engineered wood products. Medium Density Fibreboard (MDF) is made from wood fibers that are bonded together using adhesives and compressed to form panels. Plywood consists of layers of thin wood veneers glued together, and particle board is formed from wood chips, sawmill shavings, or wood shavings that are pressed and glued together. These engineered woods have unique properties and applications, but they do not classify as natural timber since they undergo significant processing and do not retain the inherent characteristics of solid wood from trees.