Thijs Biersteker
Awarness artist to create sustainable digital work on topics of climate change, pollution and nature
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Forestate

Forestate is a monumental, real-time data-driven art installation by ecological artist Thijs Biersteker, unveiled at the World Economic Forum Davos 2026 in collaboration with UNESCO. Using live satellite data from Global Forest Watch, the five-metre-high canopy visualises global deforestation and reforestation as it happens. Each disappearing or reappearing leaf represents 100 square metres of forest lost or regained, confronting world leaders with the urgency, scale and asymmetry of forest loss and recovery at the heart of global decision-making.

Forestate

Showing in real time how forests reappear and
disappear across our planet.

 

Satellites monitor how much forest is disappearing and reappearing at every moment of the day. It’s unimaginable. To help change this, we created Forestate.

The digital forest sculpture visualises the disappearance and reappearance of forests on our planet through the disappearing and reappearing of leaves in the work.

Each leaf becoming transparent represents 100 m² of forest being lost in real time, while each leaf reappearing represents 100 m² of forest being gained.

 

Forestate

Forestate is a real-time, data-driven artwork that translates the state of the world’s forests into a tangible, physical experience.

 

Forestate shows the real-time state of the world’s forests. The title combines “forest” and “state” to signal that the work visualises the measured data of forests’ conditions as they are right now. 

Through appearing and disappearing leaves, the artwork brings alive the data of deforestation, regeneration and recovery. Providing a sense of loss and hope at the same time.

The leaves in the artwork respond continuously to live satellite data from Global Forest Watch datasets that are validated by the series partner UNESCO. Visualising forest loss and recovery happening at this moment. What is normally abstract, distant, and statistical becomes immediate and unavoidable.

Weekly GLAD alerts detect new forest disturbances as they occur. Because forests regenerate over decades rather than days, regrowth is visualised using the scientifically accepted twenty-year average rate of tree cover gain, based on the standard thirty percent canopy threshold used in satellite analysis.

By turning live environmental data into a physical presence, Forestate makes forest loss and recovery perceptible at human scale. Not as an image of nature, but as a measured, ongoing process that is still unfolding.

This creates a constant imbalance in the work. Loss moves fast. Recovery moves slowly. The gap between the two is not symbolic. It is measured, calculated, and visible.

Forestate was commissioned by the
World Economic Forum’s Arts and Culture programme, and developed in collaboration with UNESCO. The artwork is deliberately placed at the centre of one of the world’s most data-driven decision-making environments.

Every leaf disappearing is 100 square meters of forest lost at this moment.

Every leaf reappearing is 100 square meters of forest gained.

Surrounded by reports, dashboards, and projections, the artwork functions as a shared reference point. A reminder of the scale, speed, and consequences of choices being discussed inside the Forum.

Rather than illustrating a future scenario, Forestate shows the present. It does not speculate. It reflects what is happening now, using the same datasets relied upon by scientists, institutions, and policymakers.

Commissioned by
World Economic Forum

Curator
Joseph Fowler

Data partner
UNESCO

Artist
Thijs Biersteker

Sustainably produced at
Woven Studio 

Communication and education  
Woven Foundation 

Studio Director
Sophie de Krom

Software and Data processing
Denisa Půbalová, Thijs Biersteker 

Lead Technician
Tomáš Potůček 

Construction  
Daan van der Sman, Tom Bekkers, Lara Rodrigues Ris, Marie Colombeen,
Yoana Elazarova, Theo Rekelhof 
 
Notable Collaborators 
Meriem Bouamrane, Paulo Massoca, Marjolein van Zanten

©WEF_CMcCrickard

 

Estimating Global Tree Cover Gain and Loss Using Satellite-Derived Forest Change Data

The data

Forestate transforms live environmental data into a real-time portrait of the world’s forests. Using UNESCO validated Global Forest Watch data, the work turns complex satellite measurements into a visible choreography of leaves appearing and fading. Each disappearing leaf marks an amount of square meters of forest loss right now, while each returning leaf reflects the long-term average rate of forest regrowth, since real-time measurement of recovery is not possible. 

By placing rapid loss alongside slow return, Forestate reveals the imbalance shaping our planet’s forests and offers a quiet reminder that restoring this balance is essential for a nature-positive future.

Calculation Abstract
This calculation establishes a consistent method for estimating global tree cover gain and loss using publicly available satellite datasets from Global Forest Watch and the University of Maryland Global Forest Change products.

Tree cover loss and gain represent two different measurement systems. Loss is updated annually and supported by near-real-time GLAD alerts, making it suitable for near-real-time indicators of current disturbance. Gain is only available as a cumulative 20 year dataset and does not provide annual or near real time values. The gain layer captures the establishment of tree cover in areas without tree cover in 2000 but does not distinguish natural forest regrowth from plantations, assisted restoration, or post harvest recovery. For ecological interpretation, plantation areas must be masked and gain must be restricted to natural forest domains.

Forest estimates are sensitive to the canopy threshold used to define forest. Typical thresholds are 10 percent, 30 percent, and 50 percent canopy cover. Because global indicators often adopt the 30 percent threshold to align with FAO definitions, this analysis uses it as the central case and applies a plus or minus twenty percent sensitivity band to approximate 10 percent and 50 percent thresholds.

Using the Global Forest Review value of 130.9 million hectares of tree cover gain from 2000 to 2020, the cumulative gain converts to 1.309 x 10^12 square meters. Dividing by the 20-year period yields an annual average of 6.545 x 10^10 square meters per year. Converted to a per-second rate, this equals approximately 2080 square meters per second for the 30 percent canopy threshold. Applying the sensitivity range produces gain estimates of roughly 2490 square meters per second at 10 percent canopy and 1660 square meters per second at 50 percent canopy.

Global deforestation reported by FAO for 2015 to 2020 averages 10 million hectares per year, which is equivalent to 1.0 x 10^11 square meters per year or approximately 3170 square meters per second. This represents deforestation specifically and is lower than total tree cover loss reported by Global Forest Watch, but provides a stable, policy-relevant reference value.

Across all canopy thresholds, the estimated loss rate exceeds the gain rate. This result reflects both the faster detectability of forest loss compared with forest gain in satellite data and the underlying imbalance between global deforestation and long term forest regrowth.

Development of Forestate at Woven Studio