  A method of reducing the problem of the calculation of tree multiparticle
cross sections in $\phi^4$ theory to the solution of a singular classical
Euclidean boundary value problem is introduced. The solutions are obtained
numerically in terms of the decomposition in spherical harmonics, and the
corresponding estimates of the tree cross sections at arbitrary energies are
found. Numerical analysis agrees with analytical results obtained earlier in
the limiting cases of large and small energies.
