Reforesting can help us remove carbon. But should it cover the land? Or could it go vertically in a city?


Reforesting, or the planting of millions (and billions) of trees, seems to be the go-to climate crisis policy for governments everywhere (we have covered foresting and trees extensively on this site).

New Zealand’s government has just announced its ambition - backed by $240m dollars - to plant 1 billion trees across the country (according to Global Citizen). They also report that in Pakistan,  newly elected Prime Minister Imran Khan has announced a plan to plant 10 billion trees and India has backed similarly ambitious projects.

As the Citizen article summarises, their climate benefits seem to be obvious:

Trees fight climate change by pulling greenhouse gas emissions from the atmosphere. They also help to protect landscapes from some of the more extreme consequences of climate change like flooding and storms. That’s on top of the many other benefits of trees — cleaning the air, soil, and water; providing food and shelter; and much more.

However, each tree-planting programme needs to be judged on its specifics. From the Yale Environment 360 site, veteran eco-writer Fred Pearce blogs that

The good news is that, even as deforestation continues in many countries, reforestation is under way in many others. From India to Ethiopia, and China to Costa Rica, there are more trees today than there were 30 years ago, saving species, recycling rain, and sucking carbon dioxide from the air.

The Bonn Challenge, an international agreement struck eight years ago to add 1.35 million square miles of forests (an area slightly larger than India) to the planet’s land surface by 2030, is on track.

But what kind of forests are they? 

damning assessment published earlier this month in the journal Nature brought bad news. Forest researchers analyzed the small print of government declarations about what kind of forests they planned to create.

They discovered that 45 percent of promised new forests will be monoculture plantations of fast-growing trees like acacia and eucalyptus, usually destined for harvesting in double-quick time to make pulp for paper. 

Such forests would often decrease biodiversity rather than increase it, and would only ever hold a small fraction of the carbon that could be captured by giving space for natural forests.

Another 21 percent of the “reforestation” would plant fruit and other trees on farms as part of agroforestry programs; just 34 percent would be natural forests.

“Policymakers are misinterpreting the term forest restoration [and] misleading the public,” the study’s two main authors, geographer Simon Lewis of Leeds University and tropical forest researcher Charlotte Wheeler of Edinburgh University, commented in a blog. It is, they say, a “scandal.”

Worth the watching (and inquiring) - and more from Fred here. The conclusion of the piece is that we must resist deforestation of natural forests, as much as we attempt to restore them.

However, it might be that no matter how arbitrary our new forests are, they may be a lot better than our techno-dreams of “vertical” forests, parks and farms in the heart of our cities, as a way to both decarbonise and localise food production.

We’ve been excited about this stuff before, but we noticed this tweet from a great inspiration to the D.A., sustainability designer John Thackera (see left).

He’s responding to Milan’s proposed Vertical Forest (which we blogged on here). The point seems to be that there is no way that such “greenwrapping” of buildings (as it’s described here) can sustain the kind of deep ecological systems which actual forests provide.

What kind of health will these trees be in, over ten, twenty years? Where will their root networks be able to extend themselves?

This greening of the urban is a growing theme in sustainability and architecture talk. The Dutch master-architect, Rem Koolhaas, is preparing a massive exhibition at the Guggenheim in New York, scheduled for Feb 2020, titled Countryside: Future of the World. From the blurb:

Countryside: Future of the World will present speculations about tomorrow through insights into the countryside of today. The exhibition will explore artificial intelligence and automation, the effects of genetic experimentation, political radicalization, mass and micro migration, large-scale territorial management, human-animal ecosystems, subsidies and tax incentives, the impact of the digital on the physical world, and other developments that are altering landscapes across the globe…


Following decades of urban triumphalism, in which much of architectural production and thinking has focused on development and audiences in metropolitan areas, Countryside: Future of the World posits that rural territories are undergoing more radical reorganizations. The exhibition will explore this frontier, which has largely remained unexamined by city-focused architects.

“The fact that more than 50 percent of the world’s population now lives in cities has become an excuse to ignore the countryside,” said Koolhaas. “I have long been fascinated by the transformation of the city, but since looking at the countryside more closely in recent years, I have been surprised by the intensity of change taking place there. The story of this transformation is largely untold, and it is particularly meaningful to present it in one of the world’s great museums in one of the world’s densest cities.”

More here. Thackera suggests in another tweet: “it's surely desirable to foster dialogue between the design singularity juggernaut and those who really know how forests think”. We agree!