The area is the source of water of Nan River and Sirikit Dam, and consists of productive forest, such as mixed deciduous forest, deciduous forest and hill evergreen forest, which has economically valuable plants, and many kinds of animals.
The area is in the area of monsoon climate which is damply hot and sultrily hot, the hottest is on daytime. The rains is from May to October, approximately 1,440 mm. of rain per year. The winter is very cold on the top of the mountains and mountain range which are suitable for traveling.
Flora and Fauna
Forest areas are where you should set foot in most. There are mixed forests, semi-evergreen forests, and deciduous dipterocarp forests.
About semi-evergreen forests, they are around brooks and also connect those 3 provinces: Uttaradit, Phrae, and Nan.
Mixed forests can be found within the national park, especially around Sirikit Dam. There are bunches of valuable and rare tree species in those forests, mixed deciduous forest, deciduous forest and grass forest.
At last but not least, deciduous dipterocarp forests. Those forests can be found on the left side of Lam Nam Nan Lake. There are economically valuable plants such as teak wood, Makhaa Mong, Burmese ebony, rosewood, ironwood, Siamese sal, ingyin etc.
The animals found are mammal, reptile and bird, such as, deer, mountain goat, wild boar, Asiatic black bear, Malayan bear, palm civet, monkey, porcupine, fishing cat, pheasant, jungle fowl, mountain turtle, many kinds of snake and more than 200 kinds of bird.
Of course, there are many animals in those forests, mostly medium-size ones to small-size ones. You may see them during your trip.