Eighteen of us assembled at the Arboretum and there were enough cars available to carry us all to the Ob Khan National Park where we were waved in without the need for registration. Unusually both checkpoints were manned. It was un unhurried walk along the stream (Nam Mae Khan) following the Nature Trail with pauses for photos, water and opportunities to revel in the beauty of nature. At Nature Trail point 10 we continued alongside the stream having rediscovered the longer track that would have taken us at higher level. This higher track proved too overgrown to be a viable option. Alongside the stream we passed some activity which appeared to be the construction of a bridge across the stream. We heard that this was part of a film set. We reached a point where further progress alongside the stream was not possible and had a long break to enjoy the scene. We retraced our steps back to Nature Trail point ten where we turned left and followed the trail markings along the wide track through the forest until we reached our starting point. Many of us had lunch at the restaurant before returning to Chiang Mai. It proved to be a relaxing and worthwhile day out.