In Rt△AFG, ∠ AFG = ∠ FAG = 45,

∴AG=GF=x，

In Rt△ADG, tan ∠ adg = tan 30 = agdg = xx+9 = 33.

∴x≈ 12.9, that is, AG≈ 12.9 (m)

∴ab = ag+GB = 12.9+ 1.5≈ 14(m)。

Answer: The height of this tree AB is 14 meter.