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How does your garden grow?  By Eric Danell, Dokmai Garden


The Dragon Orchid

The dragon orchid (Dendrobium draconis, Orchidaceae) is currently in blossom at Dokmai Garden in Chiang Mai in northern Thailand. It is native to eastern India and Southeast Asia including Thailand. Being a native to deciduous and evergreen forests (500-2000 m) it s quite common and I have seen it in the wild on Shorea roxburghii in Chiang Rai.

The dragon orchid is currently blooming at Dokmai Garden and said to be fragrant, although ours doesn’t seem to be.

The dragon orchid may resemble another common orchid (Dendrobium infundibulum), which is a characteristic of Doi Inthanon national park.  The dragon orchid has an orange-red blotch on its lip and quite slender petals, while D. infundibulum usually has a yellow blotch and strikingly broad petals. Although the dragon orchid is said to be fragrant, I can not feel any fragrance at all (a very subjective and unreliable character which also vary between strains). A striking feature of the dragon orchid is the long and slender mentum, a spur-like structure which is more sac-like in another similar species, D. formosum.

In spite of the past few days heat (34-36C) we have had a steady stream of tourists – we thank you for that. Today’s afternoon rain shower (8 mm) was a refreshing reminder of the upcoming rainy season. Rains here are erratic and so it was still dry 8 km north of us. On one of the hottest days we saw a barn owl standing in the shade under some bushes (Murraya paniculata, orange jessamine). That is a new bird record for Dokmai Garden! I am sure it has been around all the time, but a bird with no typical call and with nocturnal behaviour is easily overlooked until politely posing in full day light. It showed us its elegance in flight and I have seen similarly large shapes with pointed wings before. Other nocturnal birds at Dokmai Garden is the white-tailed nightjar, the collared scops-owl and the Asian barred owlet. [email protected]

Air pollution in the North

The other day we had thunder and a few drops of rain, but less than what could be measured (<0.5 mm). Rumours have circulated that governmental cloud seeding is in progress, i.e. the spraying of clouds with chemicals to induce rain. That in turn is due to the illegal and man-made fires of farmlands and national parks. The wind yesterday was southwestern, the direction of the monsoon, and so this could have been an early natural rain, nothing remarkable.

Although fire is a natural part of the dry forest ecosystems of northern Thailand, the burning of the same spot year after year for decades is not natural. Many native trees around Dokmai Garden do not regenerate because although mature trees are strong enough to stand a fire, a seedling is not.

If you are fed up with the fires and smoke simply sign the petition on air pollution. If you hesitate, consider the following:

These are some common answers from northern Thai farmers on why they like to burn up northern Thailand:

1. We have always done so.

2. Fire will remove cobras, fire ants and other pests. (True, but fire will remove everything else too, such as orchids and butterflies. In a thriving and biodiversity-rich garden, village or forest pests are scarce).

3. Fire will remove weeds. (Weeds always come back. Mowing or grazing will do the same job).

4. Fire will promote the formation of the Thai truffle , Astraeus hygrometricus, an important cash crop for forest dwellers. (Ongoing research will resolve the question. It is likely fire simply removes the vegetation so that the cracks revealing the growing truffle is easier to spot. Dogs can be used instead of fire).

5. A gentle fire each year will reduce the amount of accumulated fuel and so prevent dangerous fire storms. (This is the only intelligent answer in my ears. However, fire storms are not likely in arable lands and urban areas where fuel can and should be removed by other means).

6. A fire releases ashes rich in nutrients which benefits agriculture. (True, but such nutrients easily wash out with the rains. Fire removes the organic matter too, which is important for binding water and as a food for worms which keep the soil aerated. The leaf litter is needed as a root and soil insulation against heat. Traditional slash and burn meant moving to new land while the small burnt patch recovered. Due to overpopulation there is no virgin land to move to, the same spot is burnt repeatedly. Thai agronomists do not consider fire as a proper land management method and Thai farmers from other regions say fire worsens the growing conditions. ).

7. A fire opens up a landscape and promotes grasses which is good for cattle. (True, but keeping cattle inside national parks is illegal. Many illiterate cowboys also burn land which belong to other private people and let their cattle graze there without asking for permission. Wild grazing mammals such as water buffaloes and deer were adapted to forest foraging, while modern zebu cows need soft grass).

These are the reasons for not burning up northern Thailand:

1. Starting a fire on a dusty and dry day, at 37 C, and simply walk away is a hazard, not a prevention.

2. Annual fire on the same spot for decades leads to biodiversity decline, i.e. less plant and animal species can survive.

3. The haze and the breathing problems affect the long term human health. Asthma and other respiratory diseases, as well as lung cancer and nasopharyngeal carcinoma have a high incidence in Southeast Asia (Laos, Burma and Indonesia are burning too).

4. The haze scares away tourists and foreign settlers go abroad, which has a bad effect on the legal economy of northern Thailand.

5. Fire ruins the agricultural conditions by turning the soils into concrete, speeding up mineral nutrient leakage and depriving the soils of water holding organic matter.

6. If the carbon dioxide hypothesis is a correct explanation for global warming, then we need to store carbon, not release it. About 80 000 square kilometers are affected by burning in northern Thailand. However, in the short run it seems the temperature cools down 1-5 degrees due to the haze, just like after a volcano eruption. Smog and haze was once very common in industrial areas of the world possibly resulting in an unnaturally cold climate. One estimate claims that 200 million farmers on Earth are involved in slash and burn agriculture.

7. Forests, and healthy forests with logs and leaf litters in particular, reduce landslides and flooding. Slash and burn affects many people downhill.

If the Thai law forbids fires, and if most provinces in Thailand obey the law, how come it still goes on in a gigantic scale in northern Thailand?

The people who burn up their national heritage (the national parks) are poor and uneducated, but this fact is only part of the answer, because the equally poor region Esan is not pyromanic. The lawless attitude, or attitude of independence from Bangkok, is an important part of the answer. Northern Thailand, Lanna, used to be a kingdom separate from Siam until 1899. The northern Thai language and the many hill tribe languages are different from Central Thai language. Many people in northern Thailand have never traveled outside their village, and so a Bangkokian is almost as exotic as a Swede. Being told what to do from the central government arouses ridicule. I have had a report of a village head telling his villagers over the morning loudspeakers that although Bangkok says fires are illegal, the village head will not interfere with their traditions. Illegal burning is sanctioned by the local low-level authorities, and so is other crime (illegal logging, illegal trade with endangered organisms, land encroachment, voting fraud etc). It also seems that the detrimental habits of many uneducated locals are encouraged by the numerous savagists operating here, sabotaging the Thai government’s pedagogic efforts.

Education and taxation of land will continue reducing the numbers of uneducated small scale farmers. Education in combination with a gradual ban of fires and a strict law enforcement will change the methods of those who remain. Teachers and police from other Thai regions may contribute in making a difference in the former Golden Triangle. Signing the petition above may remind the central government of the problem. [email protected]

It is getting hot

A new blossom of the Lilavadee family at Dokmai Garden is a plant identified as Strophanthus perakensis.

Here in Chiang Mai in northern Thailand the hot season begins in mid February when the afternoon temperatures surpass 32 C. Night temperatures are perfect, although grandma Nived put on a sweater for grandchild Mika when the temperature dropped to 26.6C. The bird chorus at night is impressive and at daytime we admire the fluffy pink clouds of the pink shower tree (Cassia bakeriana, Fabaceae).

Yesterday Dokmai Garden received another group of enthusiastic Nordic tourists (TEMA resor). Unfortunately this was the last one in a while since the tourist season is deemed ‘over’ by the experts. I regret that, since the flora becomes more spectacular for every day now, and later in the green season May-October you can enjoy a fresh landscape with gingers, mushrooms and butterflies. Many of the guide books are responsible for declaring when the best time is to come, but that depends on what you like. If you love heat and plants like me, and if you want to stay away from crowds and save money, this is a good time. The guidebooks describe the current haze due to the man-made forest fires as a problem, and it is for locals who must live with it forever, but it is hardly a problem for a short-term visitor. I am more concerned about the fires’ destructive impact on flora and wildlife than on the impact on my own health.

March is the time for many Dendrobium orchid blossom, and also for many wild members of the lilavadee (Apocynaceae) family such as Holarrhena. A new blossom of this family at Dokmai Garden is a plant I have identified as Strophanthus perakensis. The Flora of Thailand key on this family is most pedagogic and handy, but since this is presumably quite a rare plant, fruits are undescribed and pictures scarce. I ask our readers if they agree or disagree with my ID?

Scrambly woody growth, opposite leaves with a milky latex, no punctuation beneath the leaves, no spines, corolla lobes overlap to the right in the bud, corona present as in the picture, no long corolla lobes as in the other two native Strophanthus species. The diameter of the flower is around 6 cm. The plant should be grown in full sun. It should be considered very poisonous. New English name: Hydra’s Hug.

Photographers – please help!

This is aimed straight at photographers active in Thailand, or photographers willing to come and visit Thailand:

The jungle vanilla (Vanilla siamensis) is a huge but rare and endangered orchid with white flowers, probably pollinated at night. It is only found in northern Thailand and Laos (where it will probably go extinct soon). To save it we need to know more about its reproduction. The Orchid Ark knows about a natural site where natural pollination and fruit formation still occurs.

Recently I contacted Dr Andr Schuiteman at Kew Gardens in Richmond, London. He is a world authority on Southeast Asian orchids. I asked if there is any source about what insects pollinate Thai orchids. He said there is none. We need to establish a database about this knowledge in order to restore defunct ecosystems. An orchid growing in a tree without its natural pollinating insect is genetically dead, because that orchid cannot reproduce. If we know what insect, we can grow the food plant of that insect larva, and we can save the orchid species.

This is my request:

Instead of keeping taking pictures of the photographer’s favourite flower lilavadee (Plumeria or frangipani), why not take pictures of something unknown to mankind, and which may help saving the Southeast Asian orchids? To mee, taking a billionth picture of a Plumeria, not even native to the Asian content, is like taking another picture of a coke can while you could take pictures of wine bottles of the Roman Empire, hitherto unearthed.

This is a very difficult job. To start with, we need to catch the insect in action and then take pictures of it, collect it and hand over the insect to an entomologist for identification or species description if new to science. Another group of people will then have to search for the insect in the vicinity of the orchid to try to find its food source. Luckily many native orchids grow and pollinates naturally at Dokmai Garden, which will somewhat facilitate the job for some orchid species.

Some 400 species of orchids are known in northern Thailand, Laos and Burma, which implies we need to document some 400 different pollinators or more, many of which could be nocturnal, so this project will last beyond my lifetime. To get started, simply send me an e-mail that you are interested and whether you are good at macro photography, insect photography and/or night photography. Please include references (links to published pictures).

If you know of such a photographer, kindly forward this request to that person. [email protected].