The Pine's Coldest Winter

For the last decade and more, the pine trees in Taiwan's plains have been ravaged by a deadly disease. Recently, this pine plague has spread to Taiwan's native red pine. A tiny organism less than a millimeter long and almost invisible to the naked eye may cause the collapse of one of Taiwan's ecosystems, bringing ecological disaster to the island.

Driving through Puli in early winter, all the way up the mountain the Chinese sweetgum (Liquidambar formosanum) and the maple species Acer serrulatum vie with each other in shades of red and yellow, while the ridges are crowned with majestic pines. Our destination is the mantle which clothes Mount Nengkao in Taiwan's Central Mountain Range: the Auwanta forest.

Auwanta by day is a world of reds, yellows, blues and greens. Under an azure sky, the morning sun and drifting clouds caress the mountain peaks. The dancing leaves of maple and sweetgum turn shades of yellow and red; green is the color of the pines and cypresses. By night, as we stroll along a mountain path by Wanta Creek, the moonlight slips through the gaps in the pine needles to stalk among the trees, reminding us of the Tang-dynasty painter-poet Wang Wei's lines, "The bright moon slants between the pines/ A clear brook babbles o'er the stones." The Auwanta Forest Recreation Area has been open for three years, and has become a popular destination for people from Taiwan's subtropical plains, who come up the mountain in search of a climate with four distinctly defined seasons.

But in the autumn of last year, as tourists poured into Auwanta and roamed between Pine Wind Wood and Maple Leaf Grove, one after another more than 1000 diseased mature Taiwan red pines on the mountain slopes succumbed to the winter's cold and were cut down.

In recent years pine wilt disease, which had formerly affected only the lowlands of northern Taiwan, has finally crossed the Central Mountain Range to Hualien County in eastern Taiwan, and spread across the Tachia River towards central and southern Taiwan. Cases have been reported at Auwanta, Wuling Farm, Techi Reservoir, Kukuan, Tungshih Forestry Center, Huisun Forestry Center, the Fushan Forest Research Station, and other well-known tourist spots in Taiwan. Even mighty pine trees with trunks so thick that it takes three people to join hands around them have one by one turned yellow, withered and died.

For many people this comes as a great surprise, for the Taiwan red pine to which the infection has recently spread, has long been seen as one of Taiwan's toughest wild plants.

Green through the cold of winter

Shade-loving tree species often need plenty of water, but wherever pine seeds are blown by the wind, on cliffs and steep slopes where other plants cannot easily take root, no matter how loose the ground or how thin the soil, if only there is sunshine the pines will grow tall, fast and strong, claiming the land as their own.

The youthful energy of Taiwan's geology is still pushing the land upwards, constantly sending boulders rolling and scree sliding. Especially in the mountains, which cover two-thirds of the island's area, there is "infertile" land everywhere. But is there anywhere where pines do not grow? According to Taiwan Forestry Bureau figures, of Taiwan's more that 100,000 hectares of forest, 8% is covered by trees of the pine family, the Pinaceae.

Taiwan has four native pine species. Driving south along the freeway, you leave behind moist northern Taiwan and reach the Huoyan Mountains of Miaoli County. This dry, barren land presents a scene of nothing but landslip-scarred brown earth. But the cold windward upper slopes of the mountains are the lonely stronghold of the "minority people" among Taiwan's pines-the masson pine (Pinus massoniana). If you put on a rucksack and trek up into Taiwan's high mountains, although the areas above 2000 meters are cold all the year round, the five-needled Pinus morrisonicola and the Armand pine (Pinus armandii var. masteriana) are there to greet you with outstretched branches.

But these three pines are not nearly as familiar as the two-needled Taiwan red pine (Pinus taiwanensis). In the countryside south of Hsinchu, at elevations from 200 to 2500 meters above sea level, Taiwan red pines are everywhere. Leave the freeway at any exit and drive up to any of the recreation areas at which busy Taiwanese like to rest and recuperate, and you can see how the Taiwan red pines are just as feisty as the people of Taiwan themselves, and are everywhere trying to expand their territory.

In December 1991, nature photographer Hsu Jen-hsiu set out from Lishan on the Central Cross-Island Highway to photograph Mt. Hehuan in winter. When he reached the 2300-meter-high Songchuankang (Pine Spring Ridge), snow was falling in huge flakes all around him. He stayed the night at Luoying Hostel. In the silent, snowy night, all that could be heard was the occasional muffled thud as the branches of the Taiwan red pines bent to release their heavy loads of snow.

Next day, the thick snow on the ground made the going difficult, and to take the weight of his rucksack off his body Hsu gathered some red pine branches, which had been broken off by the weight of snow and were still covered in pine needles, and fashioned them into a makeshift sledge. That night, he camped in the snow. Deep in the night a strong wind began to blow down the valley from the mountain tops, and the sound of ice and snow falling from the trees came from all around the woods. Now and then, a succession of powerful gusts would set the pines soughing. Before dawn the wind died down and the snow stopped, and Hsu slept. When he awoke and crawled out of his tent, he saw that the sun was well up in the sky. The sunshine warmed his tent, and he cooked breakfast and brewed tea with snow which was fragrant with the scent of pines. In Taiwan, a journey through the high mountains may also be a journey of the pines.

Protectors of the land

When the million or so hikers who climb Taiwan's mountains each year tramp out of the dark cypress forests onto the open ridges, what meets their eyes is always verdant pines. "In shady, damp places, pine trees cannot compete with the tall cypresses, but where there is ample sunlight, it is the pines which thrive. The pine woods have their own special scenery which puts you in a more cheerful mood," describes one mountaineer. The Taiwan red pine, along with the close-grained, dense-timbered Formosan cypress (Chamaecyparis formosensis) and Hinoki cypress (Chamaecyparis obtusa var. formosana) which account for most of Taiwan's gigantic ancient trees, together make up the typical Taiwanese scenery which leaves such a deep impression in people's memories. "The sweetgum leaves are red, red/ The pine and cypress green, green"; the seeds of the Taiwan red pine and the Chinese sweetgum are light and are spread by the wind, and these are the most commonly seen trees in Taiwan's most popular spots for enjoying autumn color.

Meanwhile, in the eyes of botanists and forestry researchers, the Taiwan red pine and the Formosan alder (Alnus formosana), both of which are "pioneer plants," form a superb team under Taiwan's most adverse geological conditions, for they are usually the first green plants to appear on landslip scars or on land which has been scorched by fire. With the help of the hyphae (growth tubes) of the symbiotic bacteria in their root nodules, the pines strike a deep and extensive root system. Even in extremely dry and infertile soils, they can grow into a single-species forest. By fixing nitrogen from the air they increase the fertility of the barren soil, giving other plants the opportunity to grow under their shade and protection, to eventually form a dense mountain forest with a rich diversity of plant and animal species. Taiwan red pines cover and protect Taiwan's poor land, spreading a skin and features over Taiwan's fragile rocks and bringing a richness of life.

After forest fires, the Taiwan red pine is the first to recolonize the empty patches of charred ground. At Huisun Forestry Center, which belongs to Taichung's National Chunghsing University, an area of burnt forest ground has deliberately been left bare instead of being artificially replanted, and on it naturally seeded pine shoots are just reappearing. Beneath pine trees which grow in dry areas, the ground is thick with pine needles, and pine seeds are unable to reach the ground to take root. But whenever there is a big fire, it burns away the pine needles, leaving the ground clear for seeds which fall on it to germinate in spring. This is why one lecturer at Chunghsing University's forestry department says that from the pines' point of view forest fires are not a disaster, because they help the trees to grow.

Thus the Taiwan red pine is a natural survivor. During the Japanese era, when large-scale logging began throughout Taiwan of the island's high-grade timbers-Formosan cypress and Hinoki cypress-few people were interested in Taiwan's quick-growing native pines. Their wood being neither dense nor finely grained, they were regarded as second-grade timber, so there was no need to fear that the trees would become rare species.

But although the Taiwan red pine does not fear forest fires and has escaped the ravages of man's axes, it may be no match for the onslaught of a tiny nematode worm.

Waiting for the storm to pass

In 1985, Professor Tseng Hsien-hsiung of NTU's Plant Pathology and Entomology Department isolated pine wood nematodes (Bursaphelenchus xylophilus) from a dead Luchu pine (Pinus luchuensis) in Taipei County's Shihmen Rural Township, confirming the cause of the continued death of pine trees at lower elevations in northern Taiwan.

When a pine tree is attacked by pine wood nematodes, it begins to wither quickly. This was first noticed early this century in Japan. Today, in Japan's two million hectares of pine forest, one quarter of the pines are diseased. Since 1990 an average of three million mature pines have died every year. In mainland China, pine wilt disease has also spread to six provinces.

The pine wood nematode is related to the roundworms which parasitize humans. Once, they only lived in the soil and had a very limited range, but at some time or other they evolved a symbiotic relationship with pine sawyer beetles (long-horned beetles of the genus Monochamus in the Cerambycidae family; their larvae are called sawyers because of the noise they make while feeding in a log or stem). The nematodes hitch a ride in the sawyer beetles' breathing spiracles, and when the beetles feed or lay their eggs on pine trees, the nematodes take the opportunity to invade the trees, where they infest the xylem tubes, which transport sap, and the resin canals, which secrete pine resin.

With the help of the flying sawyer beetles, the pine wood nematodes can spread far and wide; and with the help of the nematodes, when the sawyers bore through the wood of the pine trunks, they have much less sticky, indigestible pine resin to worry about, and can munch away to their hearts' content. But because the nematode infestation disrupts the flow of sap in the pine trees, the trees quickly wither. Once a pine tree's needles begin to turn yellow, the tree may wither and die within the space of two weeks. "It spreads so fast that where this year you see a few spots of brown, next year all the pines in the area will be dead," says Bruce Hua of Yangmingshan National Park's conservation and research section, who has watched the pines of Yangmingshan die before his own eyes.

For researchers, nematodes, which mostly live in the soil, have always been among the most difficult plant pests to study. Furthermore, research into tree diseases does not fit easily into the brief timeframe of a postgraduate degree project, and as a result, understanding of the diseases of forest trees is very limited compared to those which affect horticulture and cash crops. Since pine wilt disease first appeared in Taiwan, there have been many reports of diseased trees being drip-fed with drugs just like human patients. But the experience of more than a decade has shown that none of the pesticides used is effective with one dose, and with so many trees to treat, with limited funds, and because the chemicals are highly toxic and have many environmental side-effects, people have given up the idea of treating every pine tree individually.

In one area in Japan, aerial spraying was kept up for three years, but was then stopped because it was causing water pollution. In the fourth year, most of the pine trees died. The Japanese tried to breed a resistant hybrid pine by crossing masson pine with Japanese black pine (Pinus thunbergii). But the cultivar's ability to withstand wind and its resistance to disease were both very poor, seemingly only going to show that humans cannot get the better of nature. In mainland China, foresters tried cutting wide buffer zones around areas of diseased pine forest in the hope that the pine sawyer beetles would not be able to fly across them, but the beetles advanced inland just the same. Although researchers in affected countries have been constantly trying to develop new pesticides to control the nematodes and the sawyer beetles, to date no lasting cure has been found.

Today, the populations of Luchu pines and Japanese black pine in northern Taiwan have been decimated by the nematodes. Whether taking the Taipei-to-Ilan Highway, the Northern Cross-Island Highway or the North Coast Highway, everywhere the pines are dead or dying. "The red withered trees are all pines, and not one infected tree has survived," says Tseng Hsien-hsiung.

"Red and green" vs. "white and black"

But at a time when local cultural consciousness is flourishing, and with the associated preference for local plant and animal species, the sudden epidemic of disease among lowland pine trees has been greeted with no great concern by many in forestry and botanical circles. This is because the pine trees in Taiwan's plains are all introduced species brought by immigrant settlers and colonists, who planted them out of nostalgia for their old homes. After the native coastal forests had been cleared, the immigrants brought Japanese black pine-with its sharply defined, dense shape and resistance to wind and salt-from mainland China and Japan. Planted as windbreak trees, these became second only to beefwood trees (Casuarina spp.) as defenders of Taiwan's coasts. Taiwan's high mountains have their scenery of "red maple and green pine" created by nature, but competing with it on the coasts are the "white sands and black pines" lovingly created by the efforts of humans.

After Taiwan's return from Japanese to Chinese rule, many slash pines (Pinus elliottii) imported from America were planted along Yangte Avenue in the area of Yangmingshan where many European and American residents live. These trees have now grown to form the tallest and most striking trees lining any of Yangmingshan's roads. And because the evergreen pine and cypress are seen as representing the revolutionary spirit, pines were planted at Chungshan Hall, at military installations and in all Taiwan's parks.

In the 1960s, the Taiwan Chung Hsing Paper Corporation also widely planted Luchu pines in Taipei and Ilan counties as raw material for woodpulp production. Northern Taiwan became a great center of pine planting, and the Luchu pine, although an introduced species, was even chosen as Taipei County's county tree.

Chung Hsing Paper and the plantation owners thought that by quickly planting large numbers of introduced pine trees, they would be able to reap a profitable harvest. But in fact after 20 years of planting they found it had all been for nothing. Pine resin makes pine wood harder to process, and this raised the cost of pulp making, quickly eating up their profits. Thus many plantation owners could only leave their Luchu pine plantations untended, and this allowed northern Taiwan's forests to become a prime breeding ground for the pine wood nematode.

Actually, plants may be affected by disease just as often as humans. But except in cases of fire or logging, it is very unusual for a whole forest to quickly wither and die. Organisms in nature often reach a "dynamic equilibrium" in which they do not destroy each other. In North America, native pine trees have developed resistance to nematodes, and so are only sporadically affected by pine wilt disease-it does not strike whole swathes of forest at one time. But the sudden death of large patches of pine forest and the explosion of nematode populations in Asian countries leads researchers to conclude that the worms must have arrived from abroad. With an increasing flow of goods and people around the world in the 20th century, the pine wood nematode must have come from North America to Japan and from there to Taiwan.

In the face of this new invader, Asian pine trees do not know how to respond. Furthermore, artificially introduced species are often propagated from only a few individuals, and this inbreeding leads to a restricted gene pool. This has favored the swift growth of the nematode population in Asia. Widespread planting in Japan in the 20th century of pines, Formosan cypress and Japanese red cedar (Cryptomeria japonica) has also assisted the rapid advance of nematode disease in Japan's pine forests.

Although the death of pine trees in Taiwan has been greeted with regret, Taiwan's plains have abundant rainfall and a warm climate, and in the opinion of many forestry workers, if the introduced pine species are lost, they can very quickly be replaced by native broad-leaved trees. Furthermore, the pine sawyer beetles' distribution was thought not to extend above 2000 meters, where there is heavy snowfall in winter. Without the beetles as a vector, forestry workers assumed, the nematodes would only attack genetically weak introduced pines in the plains, and the native Armand pines and Pinus morrisonicola of Taiwan's high mountains were sure to be safe. Furthermore the Taiwan red pine, the most important and most widely distributed of Taiwan's native pines, was considered such a robust tree that few people worried about it.

But people had both overestimated Taiwan's native red pine, and underestimated the microscopic pine wood nematode.

Late countermeasures

"Biologists cannot control the ecology," is Tseng Hsien-hsiung's comment on the nematodes' southward and upward "migration" in recent years. Although past laboratory experiments led people to conclude that the nematodes would not attack the Taiwan red pine, nematodes breed prolifically and have short reproductive cycles. They may pass through several generations in one summer, so they can mutate rapidly. Thus, says Tseng, no-one could have said with certainty that these little creatures could not quickly adapt to the cold of high altitudes, and thus be able to attack pine trees at high elevations.

In the plains, where temperatures are high, the pine sawyer beetle does not hibernate, and has a short breeding cycle-"so they spread very quickly," says Dr. Chang Ruey-jang, an assistant research scientist with the Taiwan Forestry Research Institute (TFRI). Because Taiwan's area is small, the impact is even greater. Although sawyer beetles are not strong fliers, Nobuo Enda, a retired tree disease prevention and treatment expert formerly with the forestry department of the Japanese agriculture ministry, says that the beetles are light enough to be carried up to higher elevations by air currents. "This may be a reason for the pine wood nematode's spreading into Taiwan's high mountains," he speculates.

Judging from experience in the USA, pine family species in Taiwan which are at risk of infection include the fir species Abies kawakamii, the Taiwan spruce (Picea morrisonicola), the Douglas fir species Pseudotsuga wilsoniana, the Chinese hemlock (Tsuga chinensis), and even the rare Taiwan keteleeria (Keteleeria davidiana var. formosana). The rare masson pine, which is protected under the Cultural Assets Preservation Law, has also been shown by the TFRI to have no resistance to nematodes.

The way the pine wood nematode epidemic has spread in Taiwan is reminiscent of fires in Taipei: people round about have shown little concern, and neglected the task of removing diseased trees, thus allowing the infection to spread. The "flames" are now finally licking their way into central and southern Taiwan and up into the mountains, to consume the native pine populations.

The nematodes' quiet migration into Taiwan's mountains is thus far confined to a small number of areas. But the pine wilt disease epidemic in northern Taiwan also began with sporadic cases. In late 1984 the rate of nematode disease in pine trees was 5%; today it has risen to more than 50%.

"Seven years ago only pines in a small numbers of areas of a few hectares each along the north coast were infected. If the trees had been removed then, perhaps the infection would not have spread to Taiwan red pines today. But sadly when I came back to Taiwan after seven years overseas, the pine wilt disease was even worse." Yan Chih-heng, a nematologist who went abroad to study for his doctorate, says that prevention is now impossible. The infection has reached Wuling, Huisun and Kukuan, and he fears that at this speed, in only a few years the mountain forests in central and southern Taiwan will have been devastated.

Carrying away the corpses

With the previous occurrence of pine tree disease in Japan to serve as a warning, "we cannot say that this is something that has happened suddenly in Taiwan," says TFRI forest conservation division director Chao Jung-tai frankly. Chao has recently been asked to organize a prevention and treatment team. But he says that although the Council of Agriculture has begun to officially "declare war" on the pine wood nematode over the last two years, in fact it is "already too late to put out the fire"-all they can do is "watch the flames spread."

A compensation scheme has been set up as the main means of encouraging plantation owners to assist by cutting down diseased trees in private plantations, and in December 1996 Taipei County Government allocated over NT$400 million for compensation payments. Huang Jui-hsiang, a section chief at Taipei City Government's Bureau of Reconstruction, which is responsible for dealing with pine disease in Taipei City, says that what the city government spends on removing diseased trees is a pittance compared with other areas of expenditure, "but this money is just spent on carting away the corpses, not on solving the basic problem."

Lee Yuan-chin, chief of the Forest Division at the Council of Agriculture's Forestry Department, says that last July the Council designated the pine wood nematode a quarantinable pest, and announced that imported timber would in future be subject to more stringent inspections, to prevent the unintentional introduction of diseases into Taiwan. But because of the nature of the terrain in some areas where disease is already present, such as along the Central Cross-Island Highway or the banks of the Tachia River, it would be "very difficult" to cut down pine trees growing on the cliffs in order to reduce the rate of infection.

"We need a national policy with different measures for different situations," says Chao Jung-tai. For instance, although in Japan people have gradually given up treating infected forest trees, in important coastal windbreak forests they are still planting large numbers of replacement pines, and they are making a great effort to treat and save individual pines of cultural value around Shinto shrines, temples and elsewhere. Old and valued trees in Taiwan's parks, gardens and elsewhere would take a century to replace, so even though the cost may be high, people in here too should keep watch on them and try to prevent their becoming diseased.

How did the pine wood nematode first come to Taiwan, and how did this American nematode team up with Taiwan's native pine sawyer beetles? How were the nematodes able to spread from low to high elevations? Which species of sawyer beetles act as vectors for infestation? What factors limit the spread of the nematodes? All these questions require monitoring and research before effective countermeasures can be devised. "By just relying on guesswork, we oversimplified the problem, and mistakenly believed that native species would not be affected. This is why people were unprepared when the disease advanced into the mountains," says Chao Jung-tai, who believes this also partly explains the lack of preventive strategies.

In the eyes of researchers, the government's former policy on forest planting was a major factor promoting the spread of pine wilt disease. Plantation owners are not willing to clear away the diseased pines from the woods unless they can profit by it, so some people worry that now that the government is starting to encourage the removal of diseased pines, if it does not also enforce compulsory measures to replant with native tree species, then the pine woods may be replaced with betel nut or tea plantations. In the past, people rushed to plant trees as short-term cash crops, but did not develop the economic potential of native trees, nor was there any long term plan for nursery raising and planting of native tree species. Today we must work hard to make up for this lacuna, otherwise if non-native species are planted as cash crops, the final result may be the same as with pine wilt disease: that we will benefit from neither the introduced nor our native species.

Reshuffling the cards

Will this epidemic, which at the moment there is no way of controlling, cause the extinction of the Taiwan red pine?

Because most Taiwan red pines grow in natural forests, they have a high degree of genetic diversity, and researchers are optimistic that "a small number of disease-resistant genes should emerge," as Chang Ruey-jang puts it. But how long will it take for resistant trees to appear?

When large numbers of pine trees began dying in Japan, the Japanese began replanting with pine immediately, determined to wage a long war against the nematodes. They spent *12 billion a year on replanting, in the hope that in the long term, resistant trees would survive. But today, "people in Japan have given up hope of saving the pines," says Nobuo Enda. Now a technical adviser with Pfizer Pharmaceuticals Inc. of Japan, he is in Taiwan promoting the company's anti-nematode chemicals.

In view of the resilient and healthy constitution which our native conifers have developed over millions of years, most forestry experts are not worried that the present nematode epidemic will cause the pine trees to completely disappear. But one thing which is certain is that it will be more than just a few years before large numbers of nematode-resistant pine saplings can be seen growing throughout Taiwan.

Although the Taiwan red pine will not completely disappear from Taiwan, the loss of large numbers of the trees will set off a chain reaction which will reshuffle all the cards in Taiwan's ecological deck. "Everyone who has grown up in this land will have to pay a price," says Professor Kuo Shing-rong of NTU's forestry department.

Aside from the direct economic loss to the human race of the trees as a source of timber, many people believe that if large numbers of Taiwan red pine exit Taiwan's biological stage, it would be overoptimistic to think that in many areas of rugged terrain where native pines now grow, the original vegetation could be restored by voluntary tree planting campaigns. These areas are also sources of drinking water, and the potential cost in terms of the effects of soil erosion on reservoirs is incalculable. Many conservationists worry that if the water catchment area of Techi Reservoir becomes denuded of trees, the supply of drinking water to Taichung will be at risk.

The restructuring of the ecology of a large area of forest involves a transitional period of a hundred years or more. Are there any other plants which can replace the Taiwan red pines on the poor land on which they grow? Even if they are replaced by broad expanses of grassland in the short term, can this type of vegetation take over the Taiwan red pine's role of maintaining soil stability? And how much wildlife could it support? Moreover, if tens of thousands of hectares of Taiwan red pine disappear, what will be the damage to education and tourism? "These losses are all impossible to calculate," says Kuo Shing-rong.

The chain reaction which would be caused by the Taiwan red pine's being struck down by disease "leaves no room for optimism," says Chao Jung-tai, adding that if the forests die, the temperature of water in the rivers will rise, and this may even affect the rare and treasured Taiwan trout in the Chichiawan Creek, an upper tributary of the Tachia River.

The clatter of falling pine cones

Not only the Taiwan red pine, but also the introduced Japanese black pine and Luchu pine--the immigrants of a century ago--have made great contributions as wind-breaks on the coasts, and in protecting soil from erosion. Already over the last two years, the quality of the water in the Feitsui Reservoir--currently the best in all Taiwan--has been affected by pine wilt disease in the catchment areas which feed it.

And if the masson pine, which is only found on the Huoyan Mountains, a designated nature conservation area, is infected, the mountains "will be eroded flat sooner than they would have been otherwise." TFRI biology division head Pan Fuh-jiunn reminds us that the downstream areas may be swamped by the resulting silt, because the earthen Huoyan Mountains rely heavily on the masson pines, which cover two-thirds of their area, for protection from erosion.

Perhaps for many people the introduced pines of the plains are of no great consequence, but in the grounds of Shihtung Elementary School, one of the oldest schools in Taipei City's Shihlin area, the pupils often sing the school song "The lingering music of the qin drifts out from the pines. . . ."

Sixty years ago when Shihtung Elementary School was founded, 10 Japanese black pines were already growing in the school's grounds. These became the models for the children's sketches in art classes year by year, and part of the shared memories which pupils all take away with them. Five years ago, two of the trees began to turn yellow. Although the two diseased pines died, with the help of the TFRI the disease was kept from spreading to the other trees. The school hopes the other eight old pine trees, which seem to have been saved from the brink of disaster, will be able to survive, for "they are the school's landmark." If the pines die, the school song will have to be rewritten and the school magazine renamed. And Taiwan's plains will have lost a few more of their last remaining old pines.

High in the mountains, amid the white clouds, everywhere there are red-trunked, green-needled pines. The bright moon between the pines and the pine scent in the woods have always been there for everyone. When we go into Taiwan's mountain forests, we can enjoy a marvelous communion with the pines.

"There is no way forward/ Ahead are only the heavens/ The great pines below like grass/ The white clouds around like a pool/ You could live here forever by fishing it/ We will always remember the difficult road we have traveled. . . ." In his youth, before he went to live in the USA, poet Cheng Chou-yu climbed Tapa Peak in Hsinchu County. Looking down at the enormous pines below his feet, he wrote his "Impressions on Tapa."

Meanwhile the little forest animals at the Huisun Forestry Center in Nantou County have their own impressions of the color, fragrance and taste of the pine trees. Along the tracks, the ground is strewn with shredded remnants of pine cones. Squatting down to pick them up, tourists find that the cones are sticky and fragrant with resin. Among the fallen pine needles there are also the yellow cores of pine cones. Putting two and two together, we realize that a banquet of pine cones has taken place here not long ago. Formosan rock monkeys, squirrels and crows all are guests at this feast. In those pine species which rely on the wind to spread their seeds, the scales on the seeds form a pair of thin wings to help them fly. But the seeds of Taiwan's masson pine do not have these wings. To attract small animals, the cones grow horizontally. The little creatures can take as much as they want, as long as they spread the seeds far and wide.

A journey among the disappearing pines

Ten years from now: They say the broad-leaved native trees Michelia compressa and Chinese sweetgum planted by the Taiwan Forestry Bureau to replace the dead pines will create a new style of scenery, and there will finally no longer be the sight of black and brown withered pines to remind people of a mistaken policy of afforestation using introduced species.

But on the mountains? If the Taiwan red pines are lost, will Taiwan's many mountain hikers be able to enjoy a merry walk among the pines? Will there still be green to set off the reds of Auwanta's autumn colors? And will the little wild animals of the mountains still be able to indulge in a pine-cone banquet?

[Picture Caption]

How will the spread of nematode disease to Taiwan's native pines affect the island's ecology? Will the tall, straight Taiwan red pines of Auwanta disappear?

Only when infestation of native pines was reported did people begin to take seriously the work of protecting pines from infection. In Taiwan's plains it is difficult to find a single area of healthy pine forest. (ph oto by Hsiao Chi-hui)

Research in the laboratories of the Taiwan Forestry Research Institute h as shown that the masson pines of the Huoyan Mountains lack resistance to pine wood nemato des.

For well over a decade, NTU's plant pathology department and the Taiwan Forestry Bureau have been inoculating pesticides into diseased pines, but sadly this has not been enough to save the trees from danger. (photo by Diago Chiu)

As part of a plan to introduce non-toxic pesticides from Japan to combat pine wilt disease, late last year the Council of Agriculture invited Japanese experts to experiment with injecting them into pine trees in Taiwan. However, the new chemicals do not effect a la sting cure with a single dose, so it is necessary to treat pine trees once every two years.

With the pine sawyer beetles as a vector, the nematodes invade the pine trees. A sawyer beetle lays eggs under the bark of a pine, and these hatch into larvae, which bore through the wood. After a larva (left, top ) pupates into an adult, it emerges through a hole (left, center) and fl ies away. The new adult, carrying nematodes in its body, feeds on another pi ne tree (left, bottom; photo by Chang Ruey-jang). Through wounds such as these (right), the microscopic nematodes enter a healthy tree. A perfect symbiotic strategy is played out by these two tiny creatures.

In 1985, Professor Tseng Hsien-hsiung of NTU's department of plant pathology and entomology found nematodes in a withered pine tree in Taipei County's Shihmen Rural Township, confirming the cause of the tree's death. For more than a decade since then, pine trees have been wilting all over Taiwan. To date, no effective treatment has been found.

Birds feast on the cones of Pinus morrisonicola high in the mountains of Taiwan. Is this pine species, which is only found at high elevations, s afe from infection? In view of the pine wood nematode's short reproductive c ycle and fast mutation, people today cannot afford to be complacent.

Research in the laboratories of the Taiwan Forestry Research Institute h as shown that the masson pines of the Huoyan Mountains lack resistance to pine wood nemato des.

For well over a decade, NTU's plant pathology department and the Taiwan Forestry Bureau have been inoculating pesticides into diseased pines, but sadly this has not been enough to save the trees from danger. （photo by Diago Chiu）

As part of a plan to introduce non-toxic pesticides from Japan to combat pine wilt disease, late last year the Council of Agriculture invited Japanese experts to experiment with injecting them into pine trees in Taiwan. However, the new chemicals do not effect a la sting cure with a single dose, so it is necessary to treat pine trees once every two years.

With the pine sawyer beetles as a vector, the nematodes invade the pine trees. A sawyer beetle lays eggs under the bark of a pine, and these hatch into larvae, which bore through the wood. After a larva (left, top ) pupates into an adult, it emerges through a hole (left, center) and fl ies away. The new adult, carrying nematodes in its body, feeds on another pi ne tree (left, bottom; photo by Chang Ruey-jang). Through wounds such as these (right), the microscopic nematodes enter a healthy tree. A perfect symbiotic strategy is played out by these two tiny creatures.

In 1985, Professor Tseng Hsien-hsiung of NTU's department of plant pathology and entomology found nematodes in a withered pine tree in Taipei County's Shihmen Rural Township, confirming the cause of the tree's death. For more than a decade since then, pine trees have been wilting all over Taiwan. To date, no effective treatment has been found.

Birds feast on the cones of Pinus morrisonicola high in the mountains of Taiwan. Is this pine species, which is only found at high elevations, s afe from infection? In view of the pine wood nematode's short reproductive c ycle and fast mutation, people today cannot afford to be complacent.

The pine trees at Shihtung Elementary School in Taipei City are part of the collective memories of the school's alumni, and also serve as models for the children's art classes.