  In recent years, Imaging Atmospheric Cherenkov Telescopes (IACTs) have
discovered a rich diversity of very high energy (VHE, > 100 GeV) gamma-ray
emitters in the sky. These instruments image Cherenkov light emitted by
gamma-ray induced particle cascades in the atmosphere. Background from the much
more numerous cosmic-ray cascades is efficiently reduced by considering the
shape of the shower images, and the capability to reduce this background is one
of the key aspects that determine the sensitivity of a IACT. In this work we
apply a tree classification method to data from the High Energy Stereoscopic
System (H.E.S.S.). We show the stability of the method and its capabilities to
yield an improved background reduction compared to the H.E.S.S. Standard
Analysis.
