EN
We compute the Coxeter polynomial of a family of Salem trees, and also the limit of the spectral radii of their Coxeter transformations as the number of their vertices tends to infinity. We also prove that if z is a root of multiplicities $m₁,..., m_{k}$ for the Coxeter polynomials of the trees $𝓣₁,..., 𝓣_{k}$ respectively, then z is a root for the Coxeter polynomial of their join, of multiplicity at least $min{m-m₁,..., m-m_{k}}$ where $m = m₁+ ⋯ +m_{k}$.