Thuja occidentalis trees naturally turn brown in the fall as the temperatures drop. The old needles in the inner portion of the branches fall on the ground. The rest of the needles stay on the trees and return to green by the end of the winter. If the Thuja occidentalis is still brown by the beginning of summer, then the tree is dead and needs to be removed.
About this Author
Karen Carter has spent the last three years working as a technology specialist in the public school system. This position included hardware/software installation, customer support, and writing training manuals. She also spent four years as a newspaper editor/reporter at the Willapa Harbor Herald.