This is the tale of two ancient cities and the trees that determined their destinies.
这是两个古老城市的故事，而树木决定了它们的命运。
In 3,000 BC Uruk was more densely populated than modern day New York City.
在公元前3000年，乌鲁克的人口密度已经超过了现代纽约市。
This crowded capital had to continually expand their irrigation system to feed its growing population.
拥挤的首都只能不断扩大灌溉系统，以养活其不断增长的人口。
2,500 years later in Sri Lanka, the city of Anuradhapura had a similar problem.
2500年后，斯里兰卡的阿努拉德普勒市也遇到了类似的问题。
They were also growing constantly, and like Uruk, their city relied heavily on an elaborate irrigation system.
这里的人口也在不断增加，就像乌鲁克一样，城市这座城市也严重地依赖于精心设计的灌溉系统。
As Uruk grew, its farmers began chopping down trees to make space for more crops.
随着乌鲁克的扩张，其农民开始砍伐树木以腾出空间种植更多农作物。
In Anuradhapura, however, trees were sacred.
然而，在阿努拉德普勒，树木是神圣的。
Their city housed an offshoot of the Bodhi tree under which Buddha himself was said to have attained enlightenment.
他们的城市安置了菩提树的一棵分支，据说，佛陀本人在菩提树下得到了启迪。
Religious reverence slowed farmer's axes and even led the city to plant additional trees in urban parks.
宗教敬虔放慢了农民挥动斧头的速度，甚至导致该城市在城市公园种下了另外的树木。
Initially, Uruk's expansion worked well.
最初，乌鲁克的扩张运作良好。
But without trees to filter their water supply, Uruk's irrigation system became contaminated.
但是，由于没有树木来过滤供水，乌鲁克的灌溉系统受到了污染。
Evaporating water left mineral deposits, which rendered the soil too salty for agriculture.
蒸发的水留下了矿物质沉积，使土壤变得太咸，无法用于农业耕种。
Conversely, Anuradhapura's irrigation system was designed to work in concert with the surrounding forest.
相反，阿努拉德普勒的灌溉系统旨在与周围的森林协调工作。
Their city eventually grew to more than twice Uruk's population,
他们的城市人口最终达到了乌鲁克的两倍多，
and today, Anuradhapura still cares for a tree planted over 2,000 years ago.
如今，阿努拉德普勒仍然在呵护2000年前种植的树木。
We may think of nature as being unconnected to our urban spaces, but trees have always been an essential part of successful cities.
我们可能会认为自然与我们的城市空间无关，但是树木一直是成功城市背后的重要组成部分。
Trees act like a natural sponge, absorbing storm water runoff before releasing it back into the atmosphere.
树木就像天然海绵一样，吸收雨水径流，然后释放回大气中。
The webs of their roots protect against mudslides while allowing soil to retain water and filter out toxins.
其根部的网状结构可防止泥石流，同时使土壤保持水分并滤出毒素。
Roots help prevent floods, while reducing the need for storm drains and water treatment plants.
根部有助于防止洪水泛滥，同时减少对雨水渠和水处理厂的需求。
Their porous leaves purify the air by trapping carbon and other pollutants, making them essential in the fight against climate change.
它们那多孔的叶子可通过捕获碳和其他污染物来净化空气，从而使其在应对气候变化时起到了至关重要的作用。
Humanity has been uncovering these arboreal benefits for centuries.
几个世纪以来，人类一直都在不断发现这些树木的好处。
But trees aren't just crucial to the health of a city's infrastructure; they play a vital role in the health of its citizens as well.
但是，树木不仅对于城市基础设施的健康至关重要，它们在公民的健康方面也起着不可忽视的作用。
In the 1870's, Manhattan had few trees outside the island's parks.
在19世纪70年代，曼哈顿岛在公园以外的地方几乎没有树木。

Without trees to provide shade, buildings absorbed up to nine times more solar radiation during deadly summer heat waves.
没有树木遮荫，建筑物在致命的夏季热浪中吸收的太阳辐射比平时多了近9倍。
Combined with the period's poor sanitation standards, the oppressive heat made the city a breeding ground for bacteria like cholera.
加上该时期恶劣的卫生条件，酷热使这座城市成为霍乱等细菌的温床。
In modern day Hong Kong, tall skyscrapers and underground infrastructure make it difficult for trees to grow.
在当今的香港，高大的摩天大楼和地下基础设施使得树木难以生长。
This contributes to the city's dangerously poor air quality, which can cause bronchitis and diminished lung function.
这加剧了该城市本就恶劣的空气质量，还会导致支气管炎和肺功能下降。
Trees affect our mental health as well.
树木也会影响我们的心理健康。
Research indicates that the presence of green foliage increases attention spans and decreases stress levels.
研究表明，绿叶的存在增加了注意力跨度，并降低了压力水平。
It's even been shown that hospital patients with views of brick walls recover more slowly than those with views of trees.
甚至有证据表明，在窗外只能看到砖墙的医院，患者的康复速度要比在窗外有自然风景的医院的患者康复得更慢。
Fortunately, many cities are full of views like this -- and that's no accident.
幸运的是，许多城市的窗外都是这样的一番风景--这绝非偶然。
As early as the 18th century, city planners began to embrace the importance of urban trees.
早在18世纪，城市规划者就开始重视城市树木的重要性。
In 1733, Colonel James Oglethorpe planned the city of Savannah, Georgia
1733年，詹姆斯·奥格索普上校对佐治亚州萨凡纳市进行了规划，
to ensure that no neighborhood was more than a 2-minute walk from a park.
以确保每个社区距离公园的步行路程不超过2分钟。
After World War II, Copenhagen directed all new development along five arteries— each sandwiched between a park.
第二次世界大战后，丹麦哥本哈根市将所有新的开发项目布局在五条城市要道周边，彼此间有公园相隔。
This layout increased the city's resilience to pollution and natural disasters.
这种布局提高了城市抵御污染和自然灾害的能力。
And urban trees don't just benefit people.
另外，城市树木不仅使人类受益。
Portland's Forest Park preserves the region's natural biodiversity,
美国俄勒冈州波特兰市的森林公园保留了该地区的自然生物多样性，
making the city home to various local plants, 112 bird species, and 62 species of mammals.
使该市拥有各种当地植物，112种鸟类和62种哺乳动物。
No city is more committed to trees than Singapore.
没有哪个城市比新加坡更致力于植树造林了。
Since 1967, Singapore's government has planted over 1.2 million trees,
自1967年以来，新加坡政府已种植了超过120万棵树，
including those within 50-meter tall vertical gardens called supertrees.
其中包括50米高，被称为“超级树”的垂直花园。
These structures sustain themselves and nearby conservatories with solar energy and collected rainwater.
这些建筑物利用太阳能和收集的雨水来维持自身和附近温室的运转。
Trees and vegetation currently cover over 50% of Singapore's landmass,
目前，树木和植被覆盖了新加坡50%以上的陆地，
reducing the need for air conditioning and encouraging low-pollution transportation.
减少了对空调的需求，并鼓励了低污染的交通运输方式。
By 2050, it's estimated that over 65% of the world will be living in cities.
据估计，到2050年，全球将有超过65%的人居住在城市中。
City planners can lay an eco-friendly foundation,
城市规划人员可以打下生态友好的基础，
but it's up to the people who live in these urban forests to make them homes for more than humans.
但居住在这些城市森林中的人们可以决定是否为人类以外的生物提供生存空间。