gōng / rén / xiān / guān / chá / shù / mù / de / nián / lún / ， / zài / pàn / duàn / xīn / cái / de / zhì / liàng / 。

工人先观察树木的年轮，再判断心材的质量。

The workers first examine the tree rings and then assess the quality of the heartwood.