this is the largest known living tree on the planet.

這是地球上已知最大的活樹。

Nicknamed General Sherman,

綽號謝爾曼將軍。

this giant sequoia has sequestered roughly 1,400 tons of atmospheric carbon

這棵巨大的水杉已經固存了大約1400噸的大氣碳。

over its estimated 2,500 years on earth.

在地球上估計2500年的時間裡。

Very few trees can compete with this carbon impact,

很少有樹木能與這種碳影響相媲美。

but today, humanity produces more than 1,400 tons of carbon every minute.

但今天，人類每分鐘產生1400多噸碳。

To combat climate change,

應對氣候變化；

we need to steeply reduce fossil fuel emissions,

我們需要急劇減少化石燃料的排放。

and draw down excess CO2 to restore our atmosphere's balance

並吸走多餘的二氧化碳，以恢復大氣的平衡。

of greenhouse gases.

溫室氣體的影響。

But what can trees do to help in this fight?

但是，在這場鬥爭中，樹木能做些什麼呢？

And how do they sequester carbon in the first place?

他們又是如何首先固碳的呢？

Like all plants, trees consume atmospheric carbon

和所有植物一樣，樹木也會消耗大氣中的碳。

through a chemical reaction called photosynthesis.

通過一種叫做光合作用的化學反應。

This process uses energy from sunlight

這個過程利用太陽光的能量

to convert water and carbon dioxide into oxygen

將水和二氧化碳轉化為氧氣

and energy-storing carbohydrates.

和儲能碳水化合物。

Plants then consume these carbohydrates in a reverse process

然後，植物以反向過程消耗這些碳水化合物。

called respiration, converting them to energy

稱為呼吸作用，將它們轉化為能量。

and releasing carbon back into the atmosphere.

並將碳釋放回大氣中。

In trees, however, a large portion of that carbon isn't released,

然而，在樹木中，這些碳有很大一部分並沒有釋放出來。

and instead, is stored as newly formed wood tissue.

而以新形成的木質組織形式儲存。

During their lifetimes, trees act as carbon vaults,

在它們的一生中，樹木充當了碳庫的角色。

and they continue to draw down carbon for as long as they grow.

而且只要它們生長，就會不斷地吸取碳。

However, when a tree dies and decays,

然而，當一棵樹死亡和腐爛時。

some of its carbon will be released back into the air.

其部分碳將被釋放回空氣中。

A significant amount of CO2 is stored in the soil,

大量的二氧化碳被儲存在土壤中。

where it can remain for thousands of years.

在那裡它可以保持數千年。

But eventually, that carbon also seeps back into the atmosphere.

但最終，這些碳也會滲回大氣中。

So if trees are going to help fight a long-term problem

所以，如果樹木要幫助解決一個長期的問題

like climate change,

如氣候變化。

they need to survive to sequester their carbon

它們需要生存來封存它們的碳。

for the longest period possible, while also reproducing quickly.

儘可能長的時間，同時也能快速繁殖。

Is there one type of tree we could plant that meets these criteria?

有沒有一種樹我們可以種植，符合這些標準？

Some fast growing, long-lived, super sequestering species

一些生長速度快、壽命長、超強封存能力的物種。

we could scatter worldwide?

我們可以分散到世界各地？

Not that we know of.

據我們所知，沒有。

But even if such a tree existed,

但即使有這樣一棵樹存在。

it wouldn't be a good long-term solution.

這不是一個好的長期解決方案。

Forests are complex networks of living organisms,

森林是複雜的生物體網絡。

and there's no one species that can thrive in every ecosystem.

沒有一個物種可以在每個生態系統中茁壯成長。

The most sustainable trees to plant are always native ones;

最可持續發展的種植樹木永遠是在地的樹木。

species that already play a role in their local environment.

已經在當地環境中發揮作用的物種。

Preliminary research shows that ecosystems

初步研究表明，生態系統

with a naturally occurring diversity of trees have less competition

樹木的自然多樣性，競爭較少。

for resources and better resist climate change.

資源，更好地抵禦氣候變化。

This means we can't just plant trees to draw down carbon;

這意味著我們不能只靠種樹來吸碳。

we need to restore depleted ecosystems.

我們需要恢復枯竭的生態系統。

There are numerous regions that have been clear cut

有許多地區已經明確

or developed that are ripe for restoring.

或開發的，已經成熟，可以恢復。

In 2019, a study led by Zurich's Crowtherlab

2019年，蘇黎世Crowtherlab上司的一項研究。

analyzed satellite imagery of the world's existing tree cover.

分析了世界現有樹木覆蓋率的衛星影像。

By combining it with climate and soil data

通過與氣候和土壤數據相結合

and excluding areas necessary for human use,

而不包括人類使用的必要區域。

they determined Earth could support

他們認定地球可以支持

nearly one billion hectares of additional forest.

新增森林面積近10億公頃；

That's roughly 1.2 trillion trees.

這大概是1.2萬億棵樹。

This staggering number surprised the scientific community,

這個驚人的數字讓科學界感到驚訝。

prompting additional research.

促使進行更多的研究。

Scientists now cite a more conservative but still remarkable figure.

科學家們現在引用了一個更保守但仍然了不起的數字。

By their revised estimates, these restored ecosystems

根據他們的訂正估計，這些恢復的生態系統

could capture anywhere from 100 to 200 billion tons of carbon,

可以捕獲1000億到2000億噸的碳。

accounting for over one-sixth of humanity's carbon emissions.

占人類碳排放量的六分之一以上。

More than half of the potential forest canopy

一半以上的潛在森林樹冠

for new restoration efforts can be found in just six countries.

僅在6個國家就能找到新的恢復工作。

And the study can also provide insight into existing restoration projects,

而且該研究還可以為現有的修復項目提供深入的瞭解。

like The Bonn Challenge,

如波昂挑戰賽。

which aims to restore 350 million hectares of forest by 2030.

該計劃的目標是到2030年恢復3.5億公頃的森林。

But this is where it gets complicated.

但這是它變得複雜的地方。

Ecosystems are incredibly complex,

生態系統是非常複雜的。

and it's unclear whether they're best restored by human intervention.

而目前還不清楚它們是否最好通過人工干預來恢復。

It's possible the right thing to do for certain areas

對某些領域來說，有可能是正確的做法。

is to simply leave them alone.

就是乾脆不要管他們。

Additionally, some researchers worry that restoring forests

此外，一些研究人員擔心，恢復森林

on this scale may have unintended consequences,

在這個規模上，可能會產生意想不到的後果。

like producing natural bio-chemicals

像生產天然的生物化學物質

at a pace that could actually accelerate climate change.

以實際上可能加速氣候變化的速度。

And even if we succeed in restoring these areas,

即使我們成功地恢復了這些地區。

future generations would need to protect them

子孫後代需要保護他們

from the natural and economic forces that previously depleted them.

從以前消耗它們的自然和經濟力量。

Taken together, these challenges have damaged confidence

綜上所述，這些挑戰損害了信心

in restoration projects worldwide.

在世界各地的修復項目中。

And the complexity of rebuilding ecosystems

以及重建生態系統的複雜性

demonstrates how important it is to protect our existing forests.

顯示了保護我們現有森林的重要性。

But hopefully, restoring some of these depleted regions

但希望能恢復這些枯竭地區的一些功能。

will give us the data and conviction necessary to combat climate change

將為我們提供應對氣候變化所需的數據和信念。

on a larger scale.

在更大的範圍內。

If we get it right, maybe these modern trees will have time to grow

如果我們把它弄好了，也許這些現代樹就有時間生長了。

into carbon carrying titans.

變成了帶碳的泰坦。