The Transfiguration spell Temran Madera was taught by Transfiguration Professor Preston Kingsley during Term 26. It is used to change leaves (or similar objects) into lumber and is ideal for creating a shelter out of objects found in the wild.
The wand motion is a small horizontal line over the object being transfigured. The size and green quality of the leaf will not impact the size and thickness of the lumber; rather, the intention of the caster has a much greater impact. There are some limits to the size of the lumber based on the leaf and skill of the caster.
Note that because the spell is not permanent, it isn't advisable to build anything lasting from the lumber.