February 2013 seems to many to have gotten off to a fine start with very low air pollution reported for the northern provinces, unlike that in Bangkok or Beijing.  So we can unashamedly welcome the many Chinese tourists who have appeared after seeing a film about Chiang Mai.


But if it’s a healthy vacation they are seeking one place to avoid is Nimmanhaemin Rd. If the pot holes and still snarled traffic do not deter the cycling or pedestrian visitor, the place to avoid is the exercise ground at the Chiang Mai University Convention Center (CMUCC). The reason is weeds and their deadly effect.

Perhaps you have heard of Water Lettuce , Pistia stratioides , จอก .

The northern end of the gardens around CMUCC has exercise equipment and a jogging track around a pond and winding canal which is mostly dry.

As the picture here shows the pond is almost completely covered with Water Lettuce. A closer inspection however reveals the floating bodies of large Nile Perch (Pla Nin). I counted 24 this afternoon and was told more were around the bank early today.

CMU Deadly Pond 1
CMU Deadly Pond 3 fish

My former fish farming friend said the deaths were due to lack of oxygenation of the pond caused by the floating mas of weed.  Formerly the old gardener, now retired, at CMUCC would remove the weed which can be used as fertilizer and thereby allowing more oxygen into the water.

It is hard to find examples of good management of the open spaces at CMU but perhaps if the great expanses of public land they are responsible for were co-managed together with students, staff and the wider Chiang Mai community we would not have to report on distasteful stories such as this or the recent hacking of giant Dipterocarpus trees near Huai Kaew Rd.

Should any of our Chinese visitors chance to stray into the CMUCC park a nosegay of marigolds may be in order.

CMUCC flowers

CMU Deadly Pond 2 fish