  Given any two forests with the same degree sequence, we show in an
algorithmic way that one can be transformed into the other by a sequence of
2-switches in such a way that all the intermediate graphs of the transformation
are forests. We also prove that the 2-switch operation perturbs minimally some
well-known integer parameters in families of graphs with the same degree
sequence. Then, we apply these results to conclude that the studied parameters
have the interval property on those families.
