The Hike

The Sunday, September 12th hike went to the Dtaat Krok Waterfall and then up to a small lake. The start of the hike was on the southern part of the Samoeng loop, about halfway between the turnoff from the Canal road and the turnoff to Samoeng. There wasn’t much elevation gain on the hike, starting at 470 meters and ending at the lake at 627 meters. We mostly followed an old road cut, which leads up to the lake.

During the first part of the hike, we turned off the road cut and dropped down to the stream and waterfall. Krok means grinding bowl, which refers to the waterfall pool’s shape. The riverine habitat includes many species that require high moisture levels such as ferns, as well as gingers and beans, a few of which were flowering.

After this, we followed the road cut up to the lake, where we had a nice break for lunch along the edge of the lake. There were some interesting plants and invertebrates around the lake (described below). After lunch we walked around the lake and then back down the road cut. The total hike length was a fairly level 10 kilometers, one of the easiest hikes we’ve had for some time. We returned around 2 p.m.

There was quite a large turnout for the hike, 23 people, from about 10 different countries, including a Belgian “from everywhere”, quite a few Germans, 1 and ½ from Thailand, several from the United Kingdom which I’ve been told is not a country but a state, plus one person from another state, Louisiana, and a Korean cook who told me about the wonders of kimchi.

The Forest

(N.B., after a year studying the forest, I’m still learning, so some of my identifications aren’t always right, though usually pretty close).

Although often we pass through more than one forest type because of the small elevation gain on this trip, the hike stayed in a single forest type. Though on the ‘wet side’ of Doi Pui, the forest we saw was a disturbed lowland secondary growth forest, typical of what we see around Chiang Mai. Most trees were about 5-8 meters in height (15-25’) and had a girth of about a foot or less. My guess is that this forest is about 20-25 years old.

Dipterocarp seeds - as with any picture on this site click to enlarge

This type of forest is characterized by dipterocarp species, the most common species of which is Dipterocarpus obtusifolius, which has round, slightly flattened seeds. The dipterocarp family includes about 500 species, almost all of which are found here in Southeast Asia. The name means ‘two-winged seed’ in Latin and they are named for the modified leaves that help the seed to glide to the ground. We saw a lot of these seeds on the trail. There was some bamboo, which grows very fast, so it’s common in disturbed forests.

Quercus kerrii

We also saw oak trees, esp. Quercus kerrii. There are about 700 species of oaks worldwide, so no, these are not the oaks that grow in England. There are about 50 species of oaks (including the chestnuts, which are in the same family) in Northern Thailand growing at pretty much all elevations and almost all forest habitats.

We also saw a couple of Casuarina trees growing on the far side of the lake. This is an introduced species. Casuarina equisetifolia trees look like pines, with needle shaped leaves and even have small, pinecone like fruits, but are actually a flowering plant species. Although native to Australasia, this is a coastal species not originally from Northern Thailand. It’s planted in many places because it is salt tolerant, can grow in sandy soils and prevents erosion.

Ground Cover

I saw many interesting plants during the hike, mostly ground cover. I didn’t notice many epiphytes, climbers or lianas, but there were some in the moister areas we hiked through, such as the “sea bean” species, Entada rheedii, whose large, shiny brown beans could be seen on the ground near the lake.

Costus speciosus -Crape ginger

As always, there were a number of wild ginger species, such as the Crape ginger, Costus speciosus, which grows in a spiral to a height of over a meter and has a large white flowers. Another flowering ginger was Boesenbergia larsenii, which has a pink and white bell-shaped flower that grows close to the ground.

Boesenbergia larsenii with Selaginella wildenovii

We also saw many of Globba gingers, with their small yellow flowers, including Globba schumburghkiii and Globba wintii. These grow to about half a meter.

Impatiens flower

I saw a couple of other flowers near the stream, which I think were Impatiens (the small purple ones) and white Thunbergia fragrans and the purple Thunbergia laurifolia flowers.

Thubergia fragrans sweet clock-vine


I’ve been trying to understand the ferns and fern allies for the last few months. On this hike, there were lots of Maidenhair ferns (genus Adiantum) whose leaflets are more or less rectangular and connected by black midribs and stalks. Another kind of fern I saw a lot of were what could be called “hand ferns” (Lygodium), whose fronds look more or less hand-shaped, and grow in pairs.

Lygodium and Adiantum ferns

Along with the ferns, there are some fern allies that we see hiking. The most common is Selaginella. These go by the common name “spikemosses”. In spite of the name, they are not mosses and are easily mistaken for ferns. One species that is very common is Selaginella willdenovii. This species usually grows flat along the ground and is often is easily identified because the younger fronds are blue-colored.

Lycopodium clavatum - Clubmoss

We also saw a cousin of Selaginella growing by the lake edge; the “clubmoss” Lycopodium clavatum (also not a moss). This species is sometimes called “ground pine” and looks a bit like a Norfolk pine. It is found naturally all over the world. Lepidodendron, a fossil clubmoss, were the dominant trees in Carboniferous forests, about 300 million years ago, along with tree ferns and tree-sized horsetail ferns. They grew to about 30 meters in height.


I missed the turnoff to the waterfall. While I was standing around waiting for the rest of the group to return, a family of White-crested laughing thrushes flew through the forest nearby. These noisy birds are communal breeders and are seen in groups of a half dozen or so. They have a pleasant call and handsome colors, with chestnut brown below, white above with a crest and a black beak and eye stripe. They are pretty common in the lower forest elevations, although you can hear them more often than you can see them.

We saw a lot of insects on the hike, including grasshoppers, butterflies.

Horned Shield Bug

Perhaps the most interesting ones were the bugs (Order Hemiptera). On the trail we came across an adult Horned Shield bug, Amissus testaceus, which I incorrectly identified as it’s cousin, the Lychee stink bug. Too bad, because I couldn’t find much on the Horned Shield bug.

Scale insects

Mark Crittenden pointed out some scale insects (Superfamily Coccoidea) on the underside of a plant growing next to the lake. These insects look rather like plant “barnacles”, they have a covering for protection and camouflage that makes them look very uninsect-like and they generally stay in one spot sucking out the juices of the plants they are on. Scale insects are a big group with about 8000 species worldwide and the source of many interesting natural products such as Shellac, the red Cochineal dye. Many are also crop pests. The ones we saw were sort of furry and white and about 3/8” in diameter (6-8 mm).

Junonia lemonias - Lemon Pansy

The butterflies we saw included the medium-sized Lemon Pansy, Junonia lemonias, which is brown and white with three pairs of orange and black eyespots. This is perhaps the most common butterfly we see hiking. We also saw some the Pierid (“yellows and whites” family) butterfly, called a Grass Yellow.

A number of butterflies at the lake landed on our bodies and tried to suck off the sweat, which is high in salt, including a “Great Nawab” (Polyura eudamippus), and the small Ciliate Blue (Anthene emolus), whose larvae are attended to by weaver ants.

Polyura eudamippus -Great Nawab attracted to the sweat on one hikers forehead

Ciliate blue (Anthene emolus) on sandwich

We also an adult female spider, Nephila maculata (aka Nephila pilipes) at the lake. This is a species we commonly see on our hikes, but to me a pretty amazing one. The females are quite large, about 6” across (legtip to legtip). They are “orb weavers”, among the largest in the world, and weave a web that is generally well over a meter in diameter. The trip lines of these webs are very strong. While we were examining it, Mark described it as almost “like fishing line”. This species is sexually dimorphic, but unlike mammals and birds where the mammals are usually the large sex, in spiders, it’s the females. Female N. maculata are more than 5 times as large the males. In human terms, that would be like pairing with a woman who was about 10 meters tall.

Nephila maculata female

Author : Gene Mesher, Chiang Mai, Sept. 13, 2010