  In this paper, we are concerned with the symmetric simple exclusion process
on the regula tree $\mathbb{T}^d$ for $d\geq 2$. Our main result gives moderate
deviation principles of occupation times of the process starting from an
invariant product measure. Two replacement lemmas play key roles in the proof
of our main result. To obtain these replacement lemmas, we utilize duality
relationships between the symmetric exclusion process and two types of random
walks on $\mathbb{T}^d$ and $\left(\mathbb{T}^d\right)^2$ respectively.
