Native vs. Non-Native Species: How are they different?

Native tree species are deeply rooted in the ecosystems they naturally belong to. They have evolved alongside local flora and fauna, which all depend upon one another symbiotically, contributing to a balanced and resilient environment. Due to these interdependent relationships, native trees are crucial for supporting biodiversity, improving soil health and water retention, and maintaining the delicate relationships between species in the area. Moreover, native trees are often more adapted to local climatic conditions, making them better suited for long-term survival, growth, and carbon sequestration.

Non-native species have also found a place in large-scale afforestation projects, as these trees can grow faster and be more resistant to certain pests or diseases, allowing for quick carbon capture in the short term. Non-native species have been a go-to in many countries, especially where rapid reforestation is needed to support environmental efforts. However, the introduction of non-native species can also result in problems, such as changes to wildlife habitats and outcompeting native species due to invasive behaviours. As such, ecologists and forestry experts are now encouraging the re-introduction of native tree species to improve the ecological balance and provide enhanced resilience as our climate changes. 

If the conditions are right, native species can capture high rates of carbon over the long term. While the initial carbon absorption rates may be slower than fast-growing non-native species, native trees are better suited for the long haul. Their deep roots and well-adapted growth patterns mean they have the potential to store carbon for decades, or even centuries, as they mature.

The Challenge: Measuring Carbon Sequestration in Native Trees

One of our biggest challenges is the difficulty of accurately measuring how much carbon native tree species are capturing. In contrast, the carbon sequestration rates of some popular non-native species are often more easily estimated, thanks to the wealth of research and data available worldwide. 

Unfortunately, there is a significant gap in understanding the carbon storage capacity of native species. This is partly because the science around native trees is still emerging, and, in many regions, planting native species in large-scale projects is a relatively recent initiative. With limited data, we often rely on models or extrapolations from other areas, which may not always be fully applicable to local conditions. This increases the margin of uncertainty.

Overcoming the Data Deficit: The Path Forward

As we look to expand native tree planting in our projects, it is crucial that we address this data gap. To do so, OCW has partnered with local universities, research institutions, and forestry organisations, for example in Kenya and Uganda. By working together, we have started conducting localised field studies and creating reliable data sets for native species. This data will help us understand growth rates, carbon sequestration potential, and broader ecological impacts. 

Furthermore, adopting a mixed-species approach—combining both native and non-native trees—can also offer a pragmatic solution in some cases. While native species are crucial for long-term sustainability, non-native trees can help in the short term, acting as carbon sinks until native forests mature and achieve their full potential.

A Comprehensive Approach to Afforestation

In the end, the goal of afforestation is not simply to plant and grow trees but to restore ecosystems and soils, protect biodiversity, and bring food security and sustainable development to local communities. While native species should be prioritised for their long-term and co-benefits, non-native trees may still have a role to play in some cases, especially in addressing immediate carbon sequestration needs.

As we continue to grow more native trees, we want to collaborate to develop a more robust understanding of their specific role in carbon sequestration. We would encourage any entity measuring native tree planting, growth or sequestration to join the conversation with us. By sharing data, we can build models that will help others in the future measure more swiftly and accurately.  We are also following closely the debate on how to measure and acknowledge the value of biodiversity and woodland. By embracing a comprehensive approach, we can support thriving ecosystems that benefit both people and the planet.

As the Chinese proverb says, the best time to plant a tree was 20 years ago. The second best time is now.

Learn more about our work here.