SPECIES DIVERSITY AND PHENOLOGY OF VASCULAR GROUND FLORA ALONG MAE MON STEAM AT 475 TO 575 MITOR FROM MEAN SEA LEVEL IN CHAE SON NATIONAL PARK, LAMPANG PROVINCE

Abstract

A survey of the vascular ground flora along Mae Mon Stream at Chae Son National Park, Lampang Province was conducted from April 1996 to March 1997. The survey area extended from the headquarters at 475 m to a reservoir at 575 m, the total length of the study area being c. 2.6 km. Collecting data was done twice per month and an effort was made to collect herbarium specimens both flowering and fruiting material of all species there. The specimens were collected. proper detailed notes taken. pressed and preserved by drying at the CMU herbarium building, where identifications, specimen processing, distribution, and filing were carried out. A total of 172 plant specimens were collected, of 45 families, 99 genera, 128 vascular plants species including some cpilithic species along the water fall and outcrops along the stream. Detailed descriptions of 81 species were made. The forests has been severely degraded by timber (mostly teak) extraction, fire, and now considered a degraded. deciduous, seasonal, mostly primary mixed deciduous forest with much bamboo. There are areas, especially in relative undisturbed parts of the stream valley that can be considered as being of a primary seasonal evergreen with mixed deciduous facies. The stream flows throughout the year, however there is a distinct dry period from November to May and rainy period from about June to October. The dicotyledon family represented by the most species diversity was Leguminosae, (Papilionoideae) (13 species), and the monocotyledon family represented by the most species diversity was Zingiberaceae (15 species). Various phenological notes were recorded, including seasonality of flowering. fruiting and leaf production of all species. Habitat preferences, abundance, and other notes were included for each species.