The mishnah says that in the afternoon, two gezirei etzim are part of the process of the tamid. (The gemara will explain why you need two cohanim, unlike the morning where one cohen brings both.)
But the mishnah doesn't say that in the morning we count one cohen for the gezirei eitzim, it leaves it off the list entirely.
I'd guess the reason is obvious: Rashi says our lists start from the aivarim of the tamid and onward; in the morning the sh'nei gezirei eitzim are much earlier in the process (see 33a for the list).
The gemara 34a will say that there is a change in the order of korbonos from morning to afternoon in terms of when the ketores is brought. But it doesn't mention this change; maybe there are many of them.
I know that the Rambam makes a simple blanket statement that we do in the afternoon what we did in the morning, and the mefarshim point out that we know already of exceptions.
R' Shlomo Wiener gave a chaburah on whether you divide the neiros of the afternoon into five and two as you do in the morning; it seems to be a machlokes rishonim. According to the gemara 33b, we know of two reasons in the morning: (1) "to get the whole azarah excited", and (2) because of a verse בבקר בבקר. The second reason at least might not apply in the afternoon.
But the mishnah doesn't say that in the morning we count one cohen for the gezirei eitzim, it leaves it off the list entirely.
I'd guess the reason is obvious: Rashi says our lists start from the aivarim of the tamid and onward; in the morning the sh'nei gezirei eitzim are much earlier in the process (see 33a for the list).
The gemara 34a will say that there is a change in the order of korbonos from morning to afternoon in terms of when the ketores is brought. But it doesn't mention this change; maybe there are many of them.
I know that the Rambam makes a simple blanket statement that we do in the afternoon what we did in the morning, and the mefarshim point out that we know already of exceptions.
R' Shlomo Wiener gave a chaburah on whether you divide the neiros of the afternoon into five and two as you do in the morning; it seems to be a machlokes rishonim. According to the gemara 33b, we know of two reasons in the morning: (1) "to get the whole azarah excited", and (2) because of a verse בבקר בבקר. The second reason at least might not apply in the afternoon.