Behind the A Rating: Sabah Rainforest Project in Malaysia

For over three decades, deep in the tropical rainforests of Sabah, Malaysia, an extraordinary restoration effort has been unfolding quietly, diligently, and with notable scientific rigor. Today, the Sabah Rainforest Rehabilitation Project stands out as one of the most robustly monitored nature-based removal projects we have seen. Its newly rated A score from BeZero* makes it one of the highest‑quality Improved Forest Management (IFM) projects globally. In fact, there are no other higher rated IFM projects. This is the story behind Sabah’s score and why these credits represent some of the most high‑integrity nature-based removals available today. 

*Note: BeZero's review was done pre-issuance, so the score is officially A-pre, and applies to the credits now issued and available for sale.  

A Project Defined by Scientific Rigor 

The Sabah project’s strength begins with its location. It has restored over 25,000 hectares of logged‑over dipterocarp rainforest, one of the most biodiverse forest types on Earth. For context, this project area is larger than Washington, D.C. at over 250 square kilometers. Next, what makes this project truly exceptional is its scientific evidence base: nearly 400 permanent monitoring plots. Rather than relying on theoretical modelled growth curves alone or generic regional defaults, Sabah’s carbon calculations are underpinned by these permanent measurement plots, established in the project’s early years and maintained through successive verification cycles.  

These permanent monitoring plots have allowed researchers, auditors, and our own technical specialists to observe the natural growth cycle of dipterocarp forests, the dominant native rainforest type in Borneo: 

• In the first 10 years after enrichment planting, fast‑growing pioneer species dominate. 

• Both project and baseline areas experience similar rapid gains, masking the benefits of project interventions.  

• After about a decade, the long-living and impressively tall dipterocarps trees overtop and outcompete pioneers, becoming climax tree species that store massive amounts of carbon. 

• The climate dipterocarp trees drive a surge in biomass accumulation that is restricted almost entirely to the restored areas.  

Observing Sabah’s monitoring plots has produced one of the clearest demonstrations of carbon removals from project interventions versus a comparable baseline in tropical IFM projects. Further, across the entire monitoring period, there have been no recorded reversals.  

The previously logged forest has matured and been rehabilitated, earning BeZero’s high confidence in the project’s durability. The rating body highlighted its very low exposure to reversal risk, long operational history, and alignment between measured carbon gains and peer‑reviewed ecological research. The result: an A‑pre overall grade and AA permanence score, placing Sabah at the top of global IFM projects. 

Scientific Rigor in Action: The 2024–2025 Monitoring Campaign 

In 2024, the Sabah project launched one of the largest field measurement efforts undertaken in the region in over a decade. The team had to clear roads and camp deep within the rainforest to reach monitoring plots. Highlights from the monitoring campaign included: 

• Many months of fieldwork 

• Three trained field teams  

• 24,000 individual trees measured 

• Nearly 400 permanent monitoring plots 

• Covering both project and baseline areas with equal rigor 

Climate Impact Partners’ NBS Technical Lead, Stanley Nokes, joined the March 2025 field visit, alongside our own local forester and Southeast Asia Carbon Project Manager, Glad Aben, observing plot measurements conducted under the supervision of an accredited Validation and Verification Body (VVB). The results were decisive: the restored forest significantly outperformed the baseline, with strong, quantifiable gains in biomass accumulation directly attributable to earlier rehabilitation interventions.  

The data collected through this comprehensive monitoring campaign forms the backbone of the 2013-2024 carbon credit issuance calculations, which were validated by a third-party VVB. Unlike some projects that undergo annual monitoring and issue credits with annual vintages, Sabah’s large-scale approach to monitoring meant that it was only worthwhile to issue credits after the forest’s most productive biological growth window was complete.   

Worth the Wait: A Decade of Restoration and Protection 

Monitoring a large-scale rainforest rehabilitation project is not cheap. Monitoring costs paired with the natural growth cycle of dipterocarp forests already mentioned, meant that it made sense for the project to wait to issue carbon removal credits.  

But while carbon removal issuances were paused between 2013 and 2024, the forest was anything but inactive. The Sabah project continued its restoration and stewardship work relentlessly, ensuring that the ecosystem remained healthy, protected, and scientifically monitored. Across the decade, teams on the ground: 

• Maintained all rehabilitated areas, including climber cutting, health checks, and targeted enrichment planting. 

• Conducted monthly forest patrols to prevent fire and encroachment, both critical to the project’s exemplary permanence record. 

• Provided seedlings to other restoration efforts across Sabah, amplifying ecological benefits beyond project boundaries. 

• Supported extensive scientific research, including LiDAR‑based structural surveys, ethnobotanical studies, and biodiversity monitoring. 

• Hosted training programs and restoration tourism, welcoming practitioners from other tropical IFM projects and even receiving high‑profile visitors, including the Prince and Princess of Wales. 

• Supplied infrastructure for the Global Atmospheric Watch Station, contributing to global climate science. 

While Sabah’s A‑pre score from BeZero is relatively new, the work behind this score began nearly 30 years ago with a commitment to patient, evidence‑based monitoring, and these 2013-2024 credits reflect that.  

For buyers seeking high‑quality removals, Sabah is one of the most credible opportunities available.