The section of the Old Hohuan Trail from Tayuling to Sungyuan has not been disturbed by human feet for over 40 years, and is covered in layer upon layer of fallen pine needles from Formosa pine (Pinus taiwanensis) and David's pine (Pinus armandii var.
在合歡越古道的大禹嶺到松苑段，古道在歷經近一甲子無人侵擾的時空下，步道上堆積一層又一層由台灣二葉松及台灣華山松鋪成的松針軟墊。