Mapping the canopy: What NASA’s forest lasers tell us about the planet’s lungs

This article is based on our podcast episode released on the 23rd of April 2025. [Listen to the full episode here.]

In this episode of Foresting Tomorrow, we explored a space-age perspective on forest health—how NASA’s LiDAR system, orbiting aboard the International Space Station, is giving us unprecedented insight into tropical canopies around the world.

But as we looked skyward, we asked: What does this new layer of data actually change on the ground?

Forests from above: Tracking the canopy with lasers

NASA’s GEDI (Global Ecosystem Dynamics Investigation) mission is using high-resolution LiDAR to scan forest canopies from space. The system, mounted on the International Space Station, emits laser pulses that can accurately measure tree height and vertical forest structure.

The implications? Big.

According to the Harvard-led study, canopy height is one of the strongest indicators of forest health, carbon storage, and ecosystem productivity. Taller trees = greater biomass, stronger microclimates, and more resilient systems.

In the southern Amazon, however, the story looks different. Increasingly long dry seasons are already showing signs of weakening forest structure. And with climate models predicting even more intense droughts, it’s clear that not all forests are coping equally.

When data leads to decisions

By combining GEDI’s precise canopy data with topography, soil, and climate models, researchers can now identify which forests are most at risk—and where conservation resources will matter most.

“Almost 75% of the variation in canopy height can be explained by environmental conditions,” the study found.

For countries or organisations working with limited budgets, this is transformative. Conservation strategies can now be guided not only by maps and satellite images—but by real, vertically informed data that reveals forest function, not just coverage.

As Benjamin noted on the podcast:

“Tree height is something we already use in forest management—especially when paired with age data. It tells us a lot about site quality and long-term growth potential.”

In tropical forests, where species are diverse and the canopy is dense, laser-based precision can break through the limitations of traditional methods.

Bringing the laser home?

Could this kind of technology help in the forests of Northern Europe?

In Denmark, for example, airborne LiDAR flights are already conducted every five years and are publicly available. But that’s still a long cycle, especially when compared to the continuous coverage from space-based systems.

Rasmus pointed out that canopy penetration, density estimation, and even annual updates could soon become possible—particularly if LiDAR is integrated with satellite imagery.

“In the north, tree growth is slow—so a five-year update might be enough. But imagine the benefits of annual monitoring for detecting damage, canopy loss, or illegal activity.”

And this leads us to an important point...

Forest data, forest justice

One of the episode’s other stories touched on illegal timber flows from the Amazon to Europe and the U.S.—often disguised as legal wood through fraudulent paperwork. Here, canopy height and forest density data could become part of enforcement and traceability systems.

But we must be cautious.

As stated on the show, enforcement is a human issue as much as a technological one. Satellites can show where change is happening—but not always why. And in regions with weak governance, corruption, or informal markets, data alone is not enough.

Still, as Rasmus put it:

“Even in a place like Denmark, EUDR enforcement will be hard. So if we’re serious about traceability, combining satellite imagery, canopy data, and supply chain tracking is a must.”

A new layer in forest thinking

What GEDI offers is not just height measurements—it’s a shift in how we see forests. From static patches of green to dynamic, layered ecosystems whose vertical structure reveals their health, stress, and potential.

It also opens up a broader mindset:

• Where is our forest data weakest?
• Can global tech inform local action?
• What new tools do forest managers need as climate signals intensify?

As we continue exploring digital tools, sustainable forestry, and ecological resilience, NASA’s space-based forest mapping reminds us of the power of perspective—and the promise of data that actually touches the treetops.

Because the future of forestry isn’t just about planting more.

It’s about seeing deeper.