  We study the Fibered Isomorphism conjecture of Farrell and Jones for groups
acting on trees. We show that under certain conditions the conjecture is true
for groups acting on trees when the stabilizers satisfy the conjecture. These
conditions are satisfied in several cases of the conjecture. We prove some
general results on the conjecture for the pseudoisotopy theory for groups
acting on trees with residually finite vertex stabilizers. In particular, we
study situations when the stabilizers belong to the following classes of
groups: polycyclic groups, finitely generated nilpotent groups, closed surface
groups, finitely generated abelian groups and virtually cyclic groups.
  Finally, we provide explicit examples of groups for which we have proved the
conjecture in this article and show that these groups were not considered
before. Furthermore, we deduce that these groups are neither hyperbolic nor
CAT(0).
