Exploring the lungs of Asia

Much of Asia has a tropical climate, and our vegetation has long adapted to these sweltering conditions.

In fact, forests thrive here. How could they not? Enjoying constant sunlight throughout the year as well as consistent rainfall and moisture from sun-warmed air and ocean winds, these trees have set their roots in prime real estate.

Unsurprisingly, the tropical climate harbours around half of the world’s forests—but they aren’t all the same. Asia’s tropical forests have their own quirks thanks to the different environments they grow in. There are three types: tropical rainforests, tropical mangroves, and tropical dry forests. These are known as “biomes”—collections of wildlife with similar characteristics due to the environments they live in.

This was probably the biome you thought of when you first read “tropical forests” in this piece—and you’d be right!

Tropical rainforests have survived more than 70 million years on Earth, and their impact on our planet’s ecosystem and human survival is monumental. They are immensely biodiverse, supporting more than half of the wildlife species that we know exist. They provide many of the best foods, medicines, and forestry products for our everyday use. They’re even crucial for the Earth’s weather, creating and absorbing rainfall and regulating the gases in our atmosphere. About 20 percent of the world’s tropical rainforests lie in Asia and the Pacific.

In fact, there’s a great one near us in Southeast Asia. The Leuser Ecosystem stretches across Aceh and Northern Sumatra in Indonesia, and it’s recognised as one of the region’s richest expanses of tropical rainforest. It’s 35 times the size of Singapore—a staggering 2.6 million hectares of trees.

Orangutans, rhinoceroses, elephants, and tigers all live here. That might not seem too impressive, but nowhere else on Earth is there a landscape vast or rich enough to support these critically endangered, highly territorial animals. This makes it among the world’s most irreplaceable areas; in 2004, the Leuser Ecosystem and its surrounding forests were inscribed as a World Heritage Site.

Next up, we have mangroves. This ecosystem lives on the edge—specifically the coastal, riverine, and estuary edges, areas where freshwater and seawater meet.

Mangroves are the hardier cousins of tropical rainforests. Sometimes considered rainforests too, mangroves tolerate far tougher conditions, such as water almost a hundred times saltier, waterlogged soils with extremely low oxygen levels, as well as rising and fading tides all day.

And boy, have they adapted. From leaves with salt glands to “breathing” roots that take in oxygen and nutrients above ground, mangrove trees have outdone themselves evolutionarily.

The Sundarbans mangrove forest, stretching across parts of India and Bangladesh, is Asia’s largest. It sits at the edges of the region’s largest delta— a piece of wetland formed when rivers deposit their sediments into another body of water, usually the sea. Right where the Ganges, Brahmaputra, and Meghna rivers enter the Bay of Bengal, the Sundarbans enjoy an environment so nourishing, it supports the biggest remaining continuous mangrove forest on Earth—all 10,000km² of it.

The Sundarbans provide a terrestrial, freshwater, and marine habitat all at once, making it a prime location for an insane variety of wild fauna and earning it a spot on the World Heritage List. It protects several globally endangered species, including the Royal Bengal Tiger, and is the only mangrove forest on Earth where tigers live.

Tropical dry forests aren’t nearly as popular as rainforests, but they sure go through a lot. Their tough dry season each year translates to around four to seven months without rain!

How is it that parts of the tropics have such dry periods? This is mostly caused by geographical location. Moist winds from the oceans are often blocked by mountains, and the dry winds from the northeast monsoon during winter surely don’t help.

Sadly, even though dry forests are the most threatened of tropical forests, people often think that rainforests are, instead. The former’s extremely dry period makes it easy for wildfires to start, which both destroys vegetation and prevents quick regrowth. As always, human involvement worsens things—clearing land for agriculture and carelessly throwing away burning materials have led to even more of such fires, razing hectares of woodland.

The tropical dry forests have become our most overlooked woodlands. It’s a shame, as they’re one of the most beautiful land types in our region.

One can simply look to Central Indochina for an example—even the massive Leuser Ecosystem is dwarfed by the sheer size of the Central Indochina Dry Forests. These dry forests cover a bigger area in Southeast Asia than any other forest type, extending through most of Thailand to central and southern Laos, northern and eastern Cambodia, and even parts of Vietnam.

Most trees in the dry forest are deciduous—they shed their leaves during the tough dry period to prevent too much water loss. Over here, fires low to the forest floor occur frequently. This vegetation area is thus sometimes known as the “fire climax community”.

The conditions here aren’t ideal, but that doesn’t stop plenty of wildlife from making it their homeground. The Central Indochina Dry Forests house around 167 mammal species, including many threatened large mammals and at least 500 different bird species.

In Asia, Japan, the Korean Peninsula, Mongolia, and most parts of China have a temperate climate. Over here, drastic changes in temperature and rainfall give rise to four distinct seasons.

Forests here have adapted to these conditions and, as a result, their seasonal changes are exceptionally beautiful. The deciduous tree species in these forests have leaves that glow a healthy green during the spring, change into orange and red during the autumn, before finally falling off during the winter—only to grow back again when the next spring arrives.

Beautiful as they are, temperate forests are still especially cold in winter, and the animals here need to know how to survive it. Few fauna can hibernate or migrate to warmer places, which means the biodiversity here isn’t comparable to that of tropical forests.

In Asia, they are mainly sorted into temperate deciduous forests and temperate steppes biomes.

Temperate deciduous forests are the most common biome in this climatic zone. Often, they’re the stars of that Korean drama you can’t seem to stop watching, setting a gorgeous backdrop for a dramatic confession or two.

In the Korean Peninsula, the Central Korean Deciduous Forests are among the world’s most extensive.

This woodland extends over most of the Peninsula’s varied terrain: plains and low hills which can sometimes be rugged and steep. Still, it supports a vast forest area that includes maple, oak, and hornbeam trees.

Interestingly, the wildlife residing here are said to be related to those living in southern Manchuria, central China, and Japan. In the past, fearsome predators such as the Siberian tiger, Amur leopard, and Mongolian wolf roamed the place, but they are nearly all gone today.

Now, smaller predators are more abundant here, and they share the forest with several important migratory bird species such as the red-crowned crane, an important species widely recognised as a symbol of good fortune, loyalty, and longevity.

Like rainforests and mangroves, the temperate steppes are more like siblings than cousins to the temperate deciduous biome. Steppes have deciduous trees, but they are dominated by vast plains of grassland, with trees only growing near water sources such as rivers and lakes. These areas have adapted well to the changing seasons, and they often support large wild populations of hoofed animals.

While visually less abundant, the steppes are no less beautiful. They show up in dramas and movies too, with armies of men on horses thundering through. The Mongolian-Manchurian grassland, or the Mongolian-Manchurian steppe is an incredibly vast area that occupies around 887,329km2 of land, stretching from the inland portion of Manchuria’s coastal mountain ranges and river basins to the Greater Khingan Mountains.

While the fauna are less abundant than in the tropics, most are still very threatened. The biome is the prime breeding ground for many migratory birds. In fact, the brown-eared pheasant is the only endemic bird—which means this species is native to nowhere else.

Mammals here suffer a tougher fate. Large hooved mammals like the Bactrian camel, Przewalski’s gazelle, and Przewalski’s horse used to be abundant on these lands, but they are now almost gone—mainly due to hunting. Smaller mammals are more frequent now, but even those populations are fragmented.

Finally, further upwards from the temperate zone, we reach the boreal climatic zone. It’s strange to imagine that there are forests on Earth that can be cold all year—but that’s exactly what happens here.

Boreal forests are generally cold all year round, but their winters are especially unforgiving. Wildlife that live here must withstand these extreme temperatures, and many of them hibernate or migrate away when the harsh winters hit.

Boreal forests aren’t very common in Asia, as most of them are in Canada, Alaska, and Russia. That said, some parts of China do have them; their main biome is the boreal coniferous forests.

Conifer trees are probably the most recognisable trees in the world—they’re Christmas trees! But while we’re used to domesticated conifers by now, these incredible species have actually evolved over millions of years to become the perfect specimens for weathering cold conditions.

Look at what they have:

• An especially thick bark for cold protection
• Thin needle-like leaves with small surface area prevent water loss in a dry and cold climate
• A cone shape ensures heavy snowfall slides right off
• Pine cones protect precious seeds during the harsh winters

To add to all that, conifers are green trees throughout the year—despite often being portrayed as a landscape covered in a white blanket of snow. This ensures that their leaves can photosynthesise whenever they get some sunlight.

In Asia, these trees are mainly found in China, and even then they’re a rare sight—most of them are restricted to the northernmost portion of northeast China, within the Greater Khingan mountain range. These are known as the Da Hinggan-Dzhagdy Mountains conifer forests.

While harsh weather prevents the region from having high biodiversity, it is still home to many endangered and rare animals such as the wolverine, the northern lynx, and the Amur moose.

Moreover, the Hanma Biosphere Reserve, which contains well-preserved conifer forests and over 2000km2 of wetland habitats, is an important breeding site for migratory birds within the Da Hinggan-Dzhagdy Mountains.

This is hardly news to most of us. Each year, we lose forests to deforestation and degradation. Deforestation tends to be more serious—it’s the complete and permanent removal of trees to convert the forest to another land use, meaning these trees will not regrow. On the other hand, degradation refers to forest density loss, with no changes in land use; with degradation, the trees are expected to regrow.

Such deforestation and degradation occurs for many reasons, but most of them are caused by humans. There are five main human causes of forest loss: commodity-driven deforestation, urbanisation, shifting agriculture, forestry production, and wildfires.

Especially in Southeast Asia, palm oil is a major driver of deforestation. Despite the global supply encompassing 44 countries in total, Indonesia and Malaysia make up more than 85 percent of it. Borneo, especially, faces a particularly high threat from slash-and-burn forest clearance methods, with 39 percent of the island’s forests destroyed from 2000 to 2018.

The demand for palm oil is high, simply because it’s a versatile oil used in all sorts of products—from food to toothpaste to cosmetics.

But these products come at the cost of wiping out millions of hectares of habitats, as well as emitting tonnes of carbon dioxide into the atmosphere. Unlike forest degradation, these are permanent changes, and the acres of land with the same species of oil palm hurt local biodiversity.

In response, the Roundtable of Sustainable Palm Oil (RSPO) was created in 2004 to ensure sustainable production of palm oil. While there are replacements such as vegetable oil, palm oil is simply much more versatile than its alternatives. More land has to be cleared to grow the alternatives, which just shifts the problem.

In terms of broader forest protection, organisations such as the World Wildlife Fund are putting in their work, creating and enforcing innovative solutions for conservation, pushing businesses to use products from forests that are sustainably managed, and collaborating with governments to prevent illegal logging, among other efforts. Governments have also been pushed to increase the amount of protected land over the years.

Another way of looking at global forest protection efforts is to review national policies that support Sustainable Forest Management (SFM), defined by the United Nations. SFM seeks to “maintain and enhance the economic, social, and environmental values of all types of forests, for the benefit of present and future generations”.

Globally, we have made great progress towards forest protection. Many countries’ national policies generally support SFM, but on-the-ground enforcement remains a problem. The Food and Agriculture Organization of the United Nations (FAO) supports and advises nations on moving towards more sustainable land use methods.

The forests of Asia may be vast, but they’re not so big that only large organisations can help. It may be a cliché to say this, but individual efforts do matter. Thankfully, people are taking an interest in understanding and conserving our natural areas—including you, if you’ve read this far.

The younger generations are now pushing to make change happen on their own. We’re seeing evidence of this from the growing numbers of students who choose to study in environment-related fields, where they will learn skills and knowledge that they can apply in various fields.

Apart from learning about the forests, there is still a lot we can do. We can use products made with RSPO certified palm oil or that show the Forest Stewardship Council label—which means that the forest the product came from was responsibly managed.

All of these actions count; every little bit goes a long way. The fate of the forests depends on us as individuals and organisations, but the inverse is true, too. Regardless of whether you’re able to see the beauty of these natural woodlands, it is undeniable that human beings have relied on forests since time immemorial, from the food we eat and the products we use, to the water we drink and the air we breathe.

If human beings don’t change our resource use, both we and the environment will ultimately bear the brunt of what comes next. But here’s the difference: humans can’t live without the forests, whereas forests, having adapted to the harshest conditions the planet has to offer, will regrow and carry on just fine without us.