Arboreal excursion along Chiang Mai’s City moats

Chiang Mai’s moats, walls and fortifications are believed to have been built at the end of the thirteenth century, when the ‘New City’ was founded by King Mangrai. It soon became the largest and most important city of the Lan Na Kingdom. Following endemic warfare, it was deserted for some decades, but in the nineteenth century regained its position as the cultural capital and largest city of the North.
During Chiang Mai’s hectic history, the moat and wall have been subject to many changes, even in the twentieth century when they had lost their importance as defense works. According to scholars, a lot of symbolism is incorporated in the plan of the wiang (walled city) — it may represent the human body, the northern gate being the head, the two southern gates the legs.

Under the flag of preservation of historical sites, the gates and walls were renovated or torn down and rebuilt. Felling the trees lining the moat and planting young trees were part and parcel of these projects, or simply aimed at beautifying the old city. During the past 25 years, I have witnessed many such changes, but failed to distinguish a vision behind the choice of selected tree species. Whatever the case, at present an amazing variety of trees species can be found along the moat, contributing to the popularity of the four sides of the moat as picnic site among the locals. This profusion also makes the botanical six kilometre circumambulation worthwhile.


Talipot palms

Young talipot palms at Chaeng Hua Lin.

Starting from the bastion at Hua Lin Corner in the northwest, let’s set off going clockwise and concentrate on a dozen specimens, the more interesting ones all growing on the inner bank. At Hua Lin Corner, and lining a recently restored ‘ruined wall’ that faces Computer City at the other side of the moat, a row of talipot palms have been planted.

These palms (Corypha umbraculifera), not yet fully grown, look similar to the sugar palm, which is a common sight in the countryside. However, the way it blooms is completely different. Unlike most other palm species, the talipot palm will not do this for decades. But then, it produces a cluster of tens of thousands of tiny white flowers — the largest inflorescence known in the plant kingdom.

This phenomenon is known as ‘big bang flowering’, since the tree will not survive its delayed burst of procreation. While thousands of plum-like fruits develop at the top, the palm sheds its leaves and begins to die. As the fruits are edible, men may climb the palm and cut the main stalks. Only a dead trunk is left of the once majestic palm, and, for some years, may remind us of the transiency of all life.

Golden shower.

Golden shower along the northern moat at Wat Khun Kha Ma.

flowers golden shower

A flowering golden shower tree.

Much of the northern moat is dominated by small to medium-sized golden shower trees (Cassia fistula). These are rather inconspicuous during most of the year, but easy to recognize by the long pods that look like drumsticks. From March to May they produce showers of magnificent bright yellow blossoms. As this tree is a native of Thailand, where it is called chaiyaphruek (‘Plant of Victory’), it is obvious why its blossom is chosen as the kingdom’s ‘national flower’.

In amongst their abundance, two other representatives of the Leguminosae are scattered — rain trees and flamboyants. As the former (Samania saman) are such a common feature of the Southeast Asian landscape, few realize that they are not native — though in fact they originated in tropical America. In relatively few years, they grow to form excellent shade trees, their impressive trunks and main branches often covered with epiphytes. In the North they are also grown for the shellac produced by an insect beneath the tree’s bark. Just harvested trees, with most branches cut off, are a common sight along highways and around villages. Three beautiful rain trees, their trunks arcing over the moat, stand on the stretch between Wat Khun Kha Ma and Chang Phuak Gate.

Nor is the flamboyant tree (Delonix regia), or Poinciana, native to Thailand — its home is Madagascar. As one of the most beautiful flowering trees, it has been planted widely throughout the tropics. From April to June, it bursts into scarlet orange blossems, which may completely cover the by then mostly leafless tree. Each flower is a splendid creation in itself, reminding the Thai of a peacock spreading its tail feathers — hence the name ton hang nok yung,  ‘peacock’s tail tree’.
When not in bloom, its gnarled trunk and main branches and fine pinnate foliage still make it a beautiful tree. Many of the flat, dark pods remain hanging from the branches throughout the year. A drawback of this otherwise impeccable ornamental tree is the sturdy root system that constantly breaks up the sidewalks. A number of flamboyants, spectacular when in full bloom, stand near the Chang Phuak Gate.


teak tree

A teak tree at Chaeng Si Phum.

bodhi Chaeng Si Phum

Leafless bodhi trees at Chaeng Si Phum.

The northern moat is also the place to see teak (Tectona grandis). These trees are universally known for their excellent timber, and helped shape Thailand’s and Burma’s history. When Europe’s oak stocks became depleted in the 1880s, the demand for teak resulted in a ‘teak rush’. Yet few visitors from Europe know what a teak tree looks like.

Well, look for some trees with large ellipsoid leaves and numerous clusters of round desiccated fruits resembling witches’ brooms in the top of their crowns  — these are teak. That’s their appearance most of the year — not that spectacular. However, in the rainy season, they lavishly produce lovely clusters of hundreds of tiny, white flowers. Numerous small, round fruits develop from these flowers. During the cool season, teak trees shed most of their leaves. (More about teak trees in the article Teak, which is in English, in the category Planten en bomen.)

A few teak trees grow on the ramparts of Chaeng Si Phum (Si Phum Corner), but this historical landmark is dominated by two bodhi trees (Ficus religiosa) and the large spirit house erected behind them. This bastion is considered an ancient, auspicious site — according to one source the construction of the ciry wall began from here —  while Chiang Mai’s spirit mediums annually gather at the site to dance in honour of their tutelary spirits, a ritual that is also to ensure their protection of the city.
The bodhi tree, of course, is well-known as a sacred tree in Buddhism — it is believed that Prince Siddharta reached enlightenment while meditating under such a tree in Bodhgaya, India. It is only one of the hundreds of known fig tree species, but is identifiable by the slim elongated tips of its leaves. Though not native to Thailand, it is planted in or near virtually all Buddhist temple compounds. More about bodhi trees in the article Ficus (category Planten en bomen) and Boeddha’s verlichting (Category: Boeddhisme en vereringen), both in Dutch.


The casuarina trees along Mun Muang Road.

Walking southwards past a number of flamboyants, you come across many Queen of Flowers (or Pride of India, Lagerstroemia spec.), probably the most numerous tree along the inner bank of the moat — there are also a number of specimens on the eastern section of the northern moat you have just past.
Many are still young and low, but from February until September they produce a wealth of beautiful, light violet flowers. There are a few different species and varieties, but in the most common the flowers appear in terminal branched clusters. When not in bloom, the tree has little charm, but is recognizable by its countless small, dark, desiccated, split fruits — not unlike star anise.

South of Somphet Market, the Queen of Flowers cedes place to a dozen casuarina trees (Casuarina equisetifolia, also called ‘sea oak’), their line of gnarled, pock-marked trunks stretching until Tha Phae Gate. (Below the trees the bank is overgrown with bougainvillea shrubs.) The Thai call the casuarina ton son thale (‘sea pine’), as both its needle-like leaves and cone-like fruits look similar to the pine’s. Actually it is not related at all, as anatomical characteristics indicate that it is a true flowering tree, the reduced leaves and fruits representing an example of ‘parallel evolution’.

These trees are native to the coastal areas of Southeast Asia, where they belong to the pioneer vegetation of sandy beaches. That’s why The Casuarina Tree is the title of Somerset Maughum’s collection of stories on European ‘settlers’ in the colonial East. Casuarinas are widely planted as ornamental trees, but also grown for their straight trunks that make excellent poles for construction works. The preface to Somerset Maugham’s book relates that people in the East believe that ‘if you stand in the casuarinas’ shadow by the light of full moon, you will hear, whispered mysteriously in its dark ramage, the secrets of the future.’ I don’t know if this belief was the reason, but until not so long ago, the casuarina-lined pavement of Mun Muang Road was a popular night promenade. A visitor was likely to be approached by one of the many “night butterflies”, who, as virtually all were transvestites, indeed had some secret in store.


A flowering pradu pa tree behind Tha Phae Gate.


The Oueens of Flowers (Lagerstroemia).

Along both ends of the walls extending from Tha Phae Gate, you ‘ll notice another member of the Leguminosae, the tree Pterocarpus macrocarpus, which the Thai call pradu pa. Unlike most Leguminosae — that produce pods — its fruits consist of single seeds hidden in a thin, round membrane. After the first rains in the hot season, the trees burst into brilliant yellow blossoms that attract large amounts of bees and other insects, but, unfortunately, they blossom only briefly. These specimens escaped the onslaught of bulldozers in 1986 — when a small city park was transformed into the present tiled plaza in front of the gate — but their size is still a far cry from the many impressive angsana trees (a closely related species) that make Georgetown (Penang, Malaysia) one of the arboreal capitals of the East.


Many phikun trees adorn both sides of the moat south of Tha Phae Gate.

tin paet

Tin paet trees with their layered crown.

Again, the stretch some few hundred metres south of Tha Phae Gate is dominated by Lagerstroemia, but you may notice some trees with layered crowns of regular whorls of half a dozen leaves, which look like the feet of ducks — at least ton tin paet (‘duck’s feet tree’) is the Thai name of this tree, Alstonia scholaris.

It is distantly related to the frangipani — which is conspicuously absent beside the moat, but common in temple compounds all over the city.

Alstonia scholaris is a native from South and Southeast Asia, and its timber has traditionally been used for such different items as coffins and classroom blackboards.
According to A Field Guide to the Forest Trees of Northern Thailand (Gardner et al.), the latter use inspired the second half of its scientific name. In autumn this tree blooms prolificly, its little white flowers pruducing a very fragnant smell during the night. The pods are very long (up to 60 cm) and thin and bunches of these filaments hang from the branches throughout the year.

South of Tha Phae Gate, you will also find many bullet wood trees (Mimusops elengi), small shade trees called phikun in Thai.  They have a dense foliage of elliptic leaves, and their trunks are dark. They produce tiny, very fragnant white flowers from which develop the bullet-shaped orange fruits. This tree species is predominant along various stretches of the outer bank of the moat.

On your way to Katam Corner in the Southeast, see will also see two old bodhi trees, their gnarled trunks wrapped in colourful sashes. A little further to the south, near Mandalay Nightclub, a few impressive raintrees line the moat. During the hot season, children turn the moat here into their private swimming pool, dropping into the moat from swings hanging from the rain trees’ branches.

Rain trees

Rain trees near Chaeng Katam...

Chaeng Katam

...also used as aswing.

Turning westwards, the southern moat offers golden showers, Alstonia, and flamboyants, until you arrive at the giant Ficus elastica with an impressive trunk and hundreds of aerial roots drooping down from the branches.

This member of the Ficus genus is a common indoor plant in the West. With its relatively large leaves it makes an excellent shade tree in the tropics.

A spirit house has been erected in front of it, but citizens also ‘deposit’ their old ‘Chinese’ home altars near the tree. Once the whole area is covered with such bright red altars, they are all removed.


Magnificent flamboyants at Chaeng Katam.

From here, you pass some flamboyants and sugar palms before arriving at the majestic Ficus altissima at Chiang Mai Gate.

This fig tree, that looks similar to the Indian banyan, is a true beauty, producing thousands of bright orange figs as big as cherries.

Many of such revered ancient trees keep their secrets.
Over ten years ago, a local newspaper showed a picture of this tree, with a young man hanging from one of the branches.
The caption incorrectly referred to the tree as a ton pho (bodhi), while the statement that victim had hanged himself was contradicted by his bent legs.
Only the ‘banyan’ knows what happened.

In the evening, a little tiled square at Chiang Mai Gate transforms into a lively site for simple alfresco dining, amidst a number of copper pod trees (Peltophorum pterocarpum). These trees, like many others, are member of the Leguminosae family, producing an abundance of little yellow flowers in April. Gradually they transform into reddish brown pods. The Thai call this species nonsi; its is a native tree from the south, but is widely planted in the north.

West of Chiang Mai Gate Market grow a few small trees with drooping branches have numerous knobs. These Radermachera ignea (Indian cork tree) are rather inconspicuous, but in February and March steal the show when their branches are densely covered with lovely, bright orange, trumpet-like flowers, sprouting in clusters from the knobs. During these months their blossoms can also be spotted in the forests of the north.

Ficus elastica along the southern moat.

Ficus elastica along the southern moat.

Ficus altissima.

A majestic Ficus altissima at Chiang Mai Gate.

The stretch from Chiang Mai Gate until Suan Prung Gate offers — beside Radermachera, golden showers, flamboyants, Queen of Flowers and sugar palms — also a few Singapore (or Bengal) almond trees (Terminalia catappa).

These are also, confusingly, called ‘umbrella tree’, and are excellent shade trees, since their characteristic leaves — Thai call the tree ton hu kwang, ‘deer’s ear tree’ — spread in dense layers.

Its tiny white flowers appear on inconspicuous spikes, but before the tree sheds part of its foliage in January and February, it appears to flower, since many of its leaves turn bright red.

The green fruit look like almonds. A few mango trees (Mangifera indica) also stand along this stretch of the moat, opposite the fire station.

Indian cork tree

The lovely orange flowers of the Indian cork tree sprout from the branches. A few trees stand near Chiang Mai Gate.

The tallest tree you will come across towers beside Suan Prung Gate, a handsome yang (Dipterocarpus alatus), the same species as the trees lining the road to Lamphun. The members of the Dipterocarpaceae family are a major, and often dominant, element in tropical forests.

Their scientific name derives from their two-winged seeds, which in some species look similar to those of maples. In March this tree is adorned with thousands of these reddish seeds.

Beside supplying excellent timber, many yang trees are important for their valued resins — in Thai, yang means ‘resin’. In South-East Asia they have been widely planted as ornamental tree. The majestic yang trees aligning to (old) road to Lamphun are all Dipterocarpus alatus. More about these trees in the article Dipterocarps (in English) or Dipterocarpen (in Dutch) in the category Planten en bomen.

West of Suan Prung Gate the pink poui or Cuban pink trumpet tree (Tabebouia paleida) reigns, especially during the hottest months (March-April) when it bursts into eye-catching pink blossoms of trumpet-like flowers.

Many of these drop to form a pink carpet floating on the moat. The outer bank especially, where the pink poui blossoms alternate with the soft violet ones of the Queen of Flowers, is a brilliant sight.

Pink poui trees are native to tropical America, and a related species is the national tree of Salvador.

On the outer bank from Buak Hat Park, large, orange-red flowers adorn the crowns of the numerous African tulip trees (Spathodea campanulata), their flowering peak coming at the end of February. A few of these trees are also scattered along the inner moat.

Dipterocarpus alatus.

The yang tree at Suan Prung Gate.

Turning northwards at Ku Huang Corner in the southwest, we come across a hotchpotch of tree species. A bodhi, almond trees, golden showers, flamboyants, Queen of Flowers, and raintrees are all present.
I even spotted two small Chinese gooseberry trees (Phyllanthis acidus, in Thai mayon), their branches covered with clusters of very sour, yellow fruit.

A majestic raintree stands just before Suan Dok Gate, while two beautiful bodhi trees adorn the southern wall of this gate. North of it, another yang tree towers — albeit a less impressive specimen than the one at Suan Prung Gate.

Past this tree you will spot a number of flamboyants, golden showers, African tulip trees, Radermachera, and the only two Eucalyptus along the moat. Then you will be back at Hua Lin Corner, where you started the excursion.