A total of 316 herb species has been recorded in bamboo/deciduous forest, of which 294 are ground herbs. Of those, 65% are perennial.
Deciduous dipterocarp-oak seasonal forest
In seasonally dry or degraded areas, from the lowlands up to about 800-900 m elevation, deciduous dipterocarp-oak forest replaces bamboo/deciduous forest. It is a secondary, fire climax forest which merges with bamboo/deciduous forest, but is never replaced with mixed evergreen/deciduous forest.
It contains less biodiversity with only 99 tree species, of which 24 are common or abundant.
47 of the recorded vascular plant species live as epiphytes. Some of the most characteristic are evergreen, succulent, vines and creepers in the Asclepiadaceae, such as:
Dischidia major (has two kinds of leaves, i.e. normal and bladder-like ones which have a symbiotic relationship with ants)
Robust, deciduous Poaceae (grasses) dominate and are all very combustible during the hot dry season from March to May. Some of the more common species are:
From about 800 m elevation (600 m near permanent streams) to about 1000 m, there is a mixture of deciduous and evergreen trees.
217 tree species have been recorded, with only about 43% of them being deciduous trees. The tree flora is similar to that of the bamboo/deciduous forest.
The characteristic tall, emergent, evergreen, dipterocarps, which have large gray trunks, small leaves, and open, broad crowns, are:
The ground flora is diverse and includes both annual, perennial, deciduous and evergreen species. Of the 278 ground herbs recorded, 25% are annual. Common deciduous herbs include:
The upper part of the mixed evergreen/deciduous forest usually merges with the lower part of the evergreen forest at c. 900-950 m elevation.
Evergreen forest supports more tree species than any of the other forest types. 250 species have been recorded, of which only 67 (27%) are deciduous.
The evergreen forest has a wide variety of trees, with no dominant species or genera. Trees belong to diverse families, such as Lauraceae, Fagaceae, Theaceae, Moraceae, Magnoliaceae, and other families.
Other deciduous trees more typical of deciduous forest types sometimes spread up into evergreen forest due to fires or human disturbance. Common tree species shared with other forest types include:
The herbaceous ground flora (321 recorded species) is very diverse and includes numerous species of dicots, monocots, and ferns. Some of the most characteristic ferns in open, fire-damaged place are:
On fire-prone, exposed ridges at elevations of about 950–1,800 m, Pinus kesiya grows together with other evergreen forest tree species. In some areas, it is the dominant tree.
Some species more commonly found with Pinus kesiya than elsewhere, mostly due to the acidic lower pH of the soil, include:
Where fires are particularly frequent, plants of deciduous dipterocarp-oak forest spread up into the pine forests at much higher elevations than is typical, including:
Epiphytes (86 recorded species) are especially conspicuous and include both evergreen species (68%) and annual or deciduous ones (32%). Epiphytic, hemi-parasitic Loranthaceae, all evergreen shrubs, are common:
The summit flora has been significantly altered, especially after the original primary evergreen forest was cleared and replaced with cultivated trees on the summit of Doi Pui in 1955. The soil has also become much more acidic.
Some of the original epiphytic flora has returned to the summit of Doi Pui, such as:
9 plant species, all of which are rare or down to a few individuals, are entirely restricted to summit areas between 1620 and 1685 m above sea level. They are:
Mountains in Thailand that more or less preserve the original vegetation at above 1650 m are Doi Inthanon (2565 m), Doi Chang (1975 m), and Doi Lang Ka (2031 m).
Disturbed areas and secondary growth
A total of 288 species of ground herbs survives in disturbed areas or secondary growth. 144 species are annuals, and 144 species are perennials. There are numerous annual tertiary growth herbaceous weeds, all of which require exposure to sunlight for germination and growth. Some of the more common species found at all elevations include:
Robust perennial grasses are especially common in upland areas. They are robust, evergreen, and very persistent weeds in open, fire-damaged, upland areas, and include:
Secondary growth treelets (36 species) and trees (81 species) are common seen. If left undisturbed, they are replaced by primary forest trees. Some typical examples are:
^Yarnvudhi, Arerut, Sarawood Sungkaew, Sutheera Hermhuk, Pasuta Sunthornhao, Surin Onprom (2016). Plant Diversity and Utilization on Ethnobotany of Local People at Hmong Doi Pui Village in Doi Suthep-Pui National Park, Chiang Mai Province. Thai J. For. 35(3): 136-146 (2016).
^ abcdefghijklmnSungkajanttranon, Oraphan; Marod, Dokrak; Petchsri, Sahanat; Kongsatree, Kritsiam; Peankonchong, Anothai; Chotpiseksit, Thunthicha; Supnuam, Benjawan (2019-01-28). "Altitudinal Effect on Diversity and Distribution of Araceae in Doi Suthep-Pui National Park, Chiang Mai Province in Thailand". J. Of Agr. Sci. And Tech. B. 9 (1).
^Gardner, Simon; Sidisunthorn, Pindar & Anusarnsunthorn, Vilaiwan (2007). A Field Guide to Forest Trees of Northern Thailand. Bangkok: Kobfai Publishing Project. ISBN978-974-8367-29-3
