ORCHID HABITATS OF NORTHERN THAILAND

By Ken Jones

Several members of the Species Orchid Society recently travelled to Thailand on a trip arranged by Tony, in conjunction with Peter Williams who lives in Chiang Mai. This was our third trip with Peter, and this time we visited several National Parks and Wildlife Reserves in Northern and North Eastern Thailand. While the we saw a reasonable number of orchids in flower (20-25 species), what really amazed me was the habitat in which these orchids lived.

Our first visit was to a Phu Hin Rongkla National Park in the Phitsanulok province, approx 300 km south east from Chiang Mai.

To get there, after loading all our luggage into a van, we travelled by railcar from Chaing Mai to Uttaradit. We were then picked then up by five vans that Peter Williams had hired for the tour - five for us (including two orchid enthusiasts from UK, and two from the Netherlands) and one for luggage. The first night we stayed in Sukothai before visiting the Sukothai Historic Park, and after lunch, travelled to the Rain Forest Resort. While some members found the steps up and down a little frustrating, the surroundings were very pleasant (although well away from any sizable town and shopping).

The next morning, we travelled to Phu Hin Rongkla National Park for the first of our expeditions. After visiting a small on-site museum which had many exhibits dating from the time of the Communist occupation of the region, we watched film showing more of the history of the area. The park, which covers 307 sq kilometres was designated in 1984 and lies in the Phitsanulok and Loei provinces. In addition to orchids, there were many Rhododendrons in the mixed deciduous, dry evergreen and hill evergreen forest.
After watching the film, we walked to an area known as the Lan Hin Taek (the Broken Rock Field). This area was a mix of rocky outcrops, crevasses of varying depth and occasional small patches of scrubby forest.

As the following photographs illustrate, the orchids were growing in a dry, evergreen low scrub area with frequent large rock outcrops. In some instances, these rocky areas were literally covered in orchids including Epigeneium amplum, Eria pannea, Doritis pulcherrima, Otochilus fuscus (sausage orchid), Thunia alba (or marshalliana), with many Bulbophyllum, Coelogyne, Eria and Luisia species that were not readily identifiable.

We did see one solitary 'Bulbophyllum' that Peter Williams had not seen before (this might be a Rhytionanthos species growing on an exposed rock face, with small, somewhat desiccated round bulbs. Peter collected a flower to send to Kew for identification.

We also observed the effect of the drought that is presently affecting Northern Thailand. Some species growing in full sun were very red in colour, and very desiccated, particularly the small botanical species shown in the next photo which was living in the thin lichen layer on top of a large rock. This diminutive species had recently flowered and some we saw were carrying seed pods. We saw several plants of Doritis pulcherrima in similar positions looking extremely desiccated

Numerous leafless canes of Thunia alba (or marshalliana) that had flowered and were carrying up 3-5 large seed pods. These plants were growing in leaf litter and humus, but it was very noticeable that those in the open were less robust that those growing in shaded areas that probably retained some moisture or dew runoff.

A thicket of Thunia alba

In some cases, the canes of these latter plants were up to one metre tall and up to 4cm in diameter. Many had started to make new growth, even though there was little if any moisture available

Another interesting habitat observation was one that stood to reason, that is that species growing out in the open were generally quite different from those growing down in the ravines (that were often several metres deep and according to Peter Williams, sometimes held small streams even in the middle of the dry season). Looking down into these ravines, we were able to see large mats of orchids, principally Bulbophyllum, Drymoda, Rhytionanthos and Trias. Unfortunately, because we were not able to sight any of these plants in flower , it was impossible to positively identify any species.

Coelogyne species

Another species that we saw in flower was either Coelogyne cummingii or viscose. This species was growing in a bed of leaf litter under a small evergreen shrub.

Some of the group made their way to a lookout over a high cliff, while most of worked our way through the rock field.
Eventually, after about three hours, Peter Williams rounded up the stragglers and we returned to the Ranger Station area for lunch.

After a late lunch, we headed back to the vans and drove back to Rain Forest Resort. After a shower, several of us walked up to the nearby waterfall and across a very rickety suspension bridge, made all the more existing by the motor bikes being ridden across by locals (who probably wondered what we were doing there), and then wandered up for dinner at about 7.00pm.

The pathway to our room.

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Part Two of this article covers the last few days of our orchid tour in Northern Thailand. As I mentioned in part 1, Northern Thailand is in drought and the in situ orchids species that we observed were shrivelled and often quite blackened, but is many cases were flowering despite this adverse treatment. On Sunday 21 March, we left the Rainforest Resort and drove for a few hours to the lowland Namnao National Park

I recall thinking that we would probably see different orchids given the altitude, and the number of orchid plants in flower at the park headquarters. However, the trek itself was disappointing with relatively few orchids sighted and even less in flower. The forest was heavily invaded by bamboo, and there were few large trees- these often had orchid plants on horizontal limbs but even with binoculars, it was difficult to identify orchid plants.

After leaving this park, we stopped briefly at dry stream bed where Peter Williams had previously seen Paphiopedilum concolor growing in an overhanging earth bank.

After a short walk to the steam, we walked up the bed and Peter pointed out a solitary plant (which was not in flower). While walking along this stream bed, we saw numerous bamboo stems that had been cut at an angle on one end that are used to remove orchids, including the rest of the Paphiopedilum concolor that Peter had seen some years earlier.

This particular plant appeared to be a more difficult position to remove and so was still in-situ, although it was difficult to be confident that if we went back, it would still be there. There is an active trade in wild-collected plants.

We saw several species in this immediate vicinity, and spent some time trying to identify them. Ultimately, I thought that the species pictured below could be an albinistic form of Dendrobium draconis, although there is an albinistic form of Dendrobium lituiflorum but cannot be sure.

We also saw plants of Chilochista that had fallen from its place on a tree branch, Pomatocalpa spiccata (the flowers had been pollinated and were forming seed pods), and several other botanical species, none of which were in flower.

After spending a hour or so walking up the stream bed, we returned to the vans and headed for our next destination, Loei. Loei is a large town, located in North-eastern Thailand, approximately 40 km from the border of Laos.

We stayed at three star hotel, which while comfortable, principally catered for local business travellers. Consequently, it lacked some of the facilities which we might normally expect, for example, the restaurant which was located off the entry foyer was not part of the hotel, but a separate business. They had difficulty coping with the influx of some 34 guests on the first night after Loei was drenched by a sudden thunder storm not long after we arrived. Naturally, most were less than enthusiastic about heading out for dinner (in fact some had to cope with rain coming through the roof into their rooms!)

The following day, we set out for a highland wildlife sanctuary that Peter has been visiting for several years. During this time, he has developed a relationship with one of senior rangers who has a good knowledge of where the best orchids are located. As this park does not have any food stalls (other than for its workers) we stopped to buy something for lunch on the way. While the choice was limited, none of us starved!

After travelling for about 45 minutes, we arrived at the park entry and after Peter negotiated the fee, we travelled for another 45 minutes up a steep, winding road through primary forest to the Ranger station on a high plateau (1,450m above sea level).

As had been carried out at the previous park, many orchids had been attached to trees around the ranger station. Peter mentioned that probably some of these were plants that had been seized from people who had removed them to sell at the local markets.

In this area alone, we saw many species in flower including Bulbophyllum, Coelogyne, Cymbidium, Dendrobium, Eria, Sunipia and Vanda.

The habitat on the plateau consisted of occasional large trees, but was primarily low evergreen scrub containing large stands of tropical Rhododendron.

While the habitat was dry (even though it had rained the previous evening) we saw the effect of the drought as many of the orchids were shrivelled and showing signs of stress. We also saw many orchids with seed pods indicating the pollinator population is active and in good health.

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Part three of this article covers the two days that we spent at a high elevation, remote Phulang wildlife sanctuary and hour and half drive from Loei (as mentioned in last month's article.). I have already listed some of the species that we saw in flower around the ranger station, and while we saw more of the same in the forest, we were able to view them in their natural habitat.
In term of flowering species, the most frequently sighted was Dendrobium unicum. The flowers ranged from pale to intense orange, often on small, shrivelled plants on twigs. These often leafless, sometimes blackened plants carried up to 4 flowers per raceme. As you can see from the photo below, they were growing on branches covered with lichen

In recent discussions with orchid-growing friends, they have often remarked about the difficulty in growing this species so that it continues to be vigorous. I have imported several Dendrobium unicum (and I recall that the Species Orchid Society once had it as monthly plant), but have not found it easy to grow.

We set out along a narrow trail with the ranger in the lead, and three young men from a local high school who had come along as volunteers. They were very enthusiastic and quite happy to discuss the orchid plants that we saw, telling us the local names.

As we walked along (straggled might be a better word) I took the opportunity to observe the habitat. I have attempted to grow Bulbophyllum dayanum without much success to date, but here it was growing in large masses, often on the lower side of large rocks in moss/lichen beds. This unusual species was another that was in flower as the preceding photo shows. I also noted that leaves were often quite red indicating that the plant receives a lot of light.
In this same area we saw Aerides, Bulbophyllum, Chilochista, Cleisostoma, Coelogyne, Cymbidium, Dendrobium, Eria, Gastrochilus, Hygrochilus, Luisia, Paphiopedilum, Vanda and various botanical species in flower. Thankfully, this sanctuary showed much less impact from collecting than most of the others that we visited, and demonstrated the value of having a tour leader who had developed a relationship that permitted access to such locations.

Observing these plants growing in their natural habitat constantly challenged my assumptions and the accepted wisdom about these species. For example, we saw many Dendrobium species growing as lithophytes as the preceding and following photograph shows. However, when speaking to other experienced growers about whether it was practical to attempt to replicate these conditions, generally their advice was a firm no!

It appears however, that many of the species that we regard as epiphytes are quite opportunistic when it comes to making the most of the available habitat.
This assumption was further reinforced while on another trek the following day, we were privileged to see a large colony of Paphiopedilum villosum growing part way up a large tree, with many small seedlings scattered down the trunk. As noted earlier, we saw few Paphiopedilum species as these are one of the prime targets for wild collecting. While it proved difficult to photograph these plants as we were looking into the sun Tony has done a great job with the following photos.

The trail on the second day finished up at a lookout that showed that we were on a high plateau which receives strong air movement, and presumably (from the abundant lichens and mosses), good rainfall in the wet season. From the lookout, we were able to see large tracts of primary forest which appears to be protected by virtue of its inaccessibility.
As I have remarked earlier, there were relatively few large trees, however generally those that did exist in the areas we trekked through were festooned in orchids, ferns and similar plants competing for the limited space and sunlight.
While walking in these forests, you need to look up and down, left and right - firstly to make sure that you don't trip and fall, but most importantly to see the orchids and other flowing plants. On our way back to the ranger station down a dirt road, I saw a orange coloured flower in the undergrowth- we tentatively identified it as Bulbophyllum siamense.

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In Part 4 I will take this opportunity to show a few more photos from our Thailand Trip from the excellent CD that Tony has produced. As I did in the earlier parts of this article, I will focus on habitat and what it can teach us about growing our species orchids better.
While some of the following photos show 'rescued' or transplanted orchids, others are in their natural habitat.

Firstly, in Thung Salaengluang National Park, we saw many large clumps of Cymbidium aloifolium on trees. The very floriferous species was both vigorous and abundant. However, I was surprised that small plantlets around these large clumps were rare, even though there were many signs of previous year's seed pods.

As you can see, the roots which are anchoring the plant to the tree are fully exposed to the sun, and wrap around the tree holding the plan firmly in place. In the first of these photos, it shares its host with a Dieffenbachia or Pothos.

You may also recall that in an earlier part of this article, I mentioned Doritis pulcherrima that we observed doing it very tough growing on exposed rocks in full sun. However, Tony found some growing in a habitat much more to their liking - a live moss bed. Clearly the plants in the first of these two photos look much healthier, however in both locations they were flowering and setting seed. This tells us that orchids are really adaptable, and in fact are well able to cope with extremes including long periods without water.

In Nam Nao National Park (the very rocky area that I wrote about in the April newsletter, we found the unusual species, Eria pannea shown in the following photographs.

While not prolific like some of the other species, we observed two of three places where quite large mats of plants were living, often in a leaf mulch-filled crack in the rocks. Perhaps this traps moisture from dew. The silvery leaves were covered with fine fuzzy hairs (similar to some of the arid succulent plants where the leaf colour and hairy surface act to minimise the effects of an adverse climate).

Another species in this same habitat was Luisia filiformis. This botanical species was growing in full sun with roots running along the top of the rocky outcrop, although was benefiting from some shelter provided by a nearby low broad-leafed shrub, and leaf litter on the rocky surface.

On closer examination, some of the roots had made their way into small cracks in the rocks where presumably like the Eria pannea, they benefited from being cooler and accessing moisture. However, most of the active roots (ie those with green tips) were purely aerial, while those on exposed rock were anchoring the plant. With its terete leaves, this species is well adapted to living in high exposure locations.

Another species that we saw was Phalaenopsis cornu cervi, commonly grown by several club members. This species was growing on rough-barked tree near to the visitor centre in Thung Salaengluang National Park.

As you will see in the photo, the roots are firmly locating the plants - in the second photo, they are encircling the tree branch. The extended flower racemes show that these plants have been flowering for a long time - perhaps several years. While not as vigorous as those grown by members like Tony, Peter and Maxine, clearly these plants are getting enough nutrient to grow and flower. Their choice of habitat suggests that they would be quite happy on mounts.

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As a finale to this article, I will take a final look at some more of Tony's photos from the recent Thailand trip, and some from our visit to Vietnam in 2008.

Firstly to Thailand - when visiting one of the many temples, I noted a number of trees with vandaceous species orchids mounted on them. The roots ran up and down the tree over a span of more than two metres. What this tells us that when mounting many of our species orchids, we need to use a mount that will be suitable for several years, and it's probably much larger than we first imagine. While not as large, if you look at the roots in the following photo of Vanda lilacina that we saw in a car park along the Mekong River, you will note that way the roots run along the trunks and tree branches firmly locating the plant and absorbing every bit of nutrient that is available.

We also saw, by way of contrast, semi-cultivated orchid species (obviously receiving more water than those in the wild) in the Ancient City of Sukothai that were multi-planted along with birdsnest ferns and some succulent species.

This form of multi-planting is desirable as it provides a more constant display of flowers and is generally used in developed gardens.

In the Phuluang Wildlife Park, we saw many plants of Bulbophyllum capillipes. This diminutive, single flowered species gradually forms large colonies.

The photo above shows a clump of this species that had been transplanted to a tree near the headquarters. The next photo shows a close up of a flower in the wild (note the size of the photographer's the fingers!)

The following photo shows the same species in company with a variety of other orchid and non-orchid species, in a considerably darker area of the forest - shown by the darker green colour of the leaves, and the abundant ferns and lichens.

We also observed Taeniophyllum obtusum (a leafless orchid) growing on a rough-barked tree, and carrying several seed pods. Most often, leafless orchids grow as twig epiphytes (eg Chilochista usneoides), often dangling in the air and secured by one or two roots. In this instance, the plant is firmly anchored to the rough bark surface. Perhaps this indicates that this species ought to do well on natural cork or perhaps a large piece of pine bark that retains little or no moisture.

In our trip to Vietnam in 2008, we did a part day trek in a pine forest (planted by the French) in a high area outside Da Lat. All of us were struck by the successful colonisation of these pine trees by Dendrobium bellatulum. The plants were almost always solitary, with perhaps only 3-6 plants per tree. While this species is particularly difficult to grow in our conditions, in Da Lat they were out in the open, exposed to any extremes in the weather. The canopy was sparse and the plants were exposed to high light , generous air movement, and as is obvious by the mosses and lichens, reasonably high humidity. The first photo shows the roots actively clinging to the pine bark, ready to capture any water and fertiliser available.

A little further along the track, we found a small branch that had broken and fallen to the ground, on which was growing a juvenile plant (unflowered). This photos shows just how diminutive this species is, and yet in many cases the plants were on the weather (sunny) side of the tree.

What was more surprising however was while some plants carried seed pods, we saw few juvenile plants on the same tree as the parents. Similarly, not every tree carried plants of Dendrobium bellatulum, although in some cases there were also large mats of Bulbophyllum species.

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