Sturdy trees are an important part of the natural environment, providing shelter and food for many species. Two examples of sturdy trees are OAKS and elms. OAKS (4 letters) are deciduous trees that can live for hundreds of years and are known for their strong wood. Elms (4 letters) are also deciduous trees that can live for hundreds of years and are known for their tall, straight trunks. Both OAKS and elms are considered to be very sturdy trees.