Three Ancient Trees

It's 1600 years old now, which means it may have been seen by the famous poet Bai Juyi in the Tang Dynasty and my favorite poet Su Shi in the Song Dynasty.

The remaining two are Cryptomeria trees (Liushan)柳杉.

I saw three ancient trees in the town on topthe summit of Mount Lu.

"Summit" is a slightly more specific word than "top" that also matches what you said (顶上), and is more mountain-themed, but what you wrote is perfectly fine.

Actually, theThe direct translation of the Chinese name is Three Treasure Trees.

I'm not sure yet if it's a Chinese thing to use 其实 and 实际上 more liberally than in English, but in English I usually wouldn't say "actually" unless there were a misconception or mistake I were trying to correct. In isolation you can say "actually" if you think someone might have an assumption about something (example: "actually, the food was quite good"), but when just stating a fact by itself I wouldn't add "actually".

The remainingother two are Liushan柳杉.

"Remaining" implies that one of the trees is no longer there (or is dead), and the other two are still there/alive. My dictionary says 柳杉 = "Japanese cedar".

The oldest one is a ginkgoGinko tree.

It's 1600 years old now, which means it may have seen the famous poet Bai Juyi inof the Tang Dynasty and my favorite poet Su Shi inof the Song Dynasty.

They stand together as a scenic spotThe scene is picturesque.

The grammar is correct but the sentence sounds a bit unnatural

It's 1600 years old now, which means it may haveprobably has seen the famous poet Bai Juyi in the Tang Dynasty and my favorite poet Su Shi in the Song Dynasty.