Scientists count the world's tree species

Context: Based on global ground-sourced data, a multinational team of scientists has estimated the total tree species richness at global, continental, and biome levels are 73,000 tree species in the world. 

• Of these only 64,000 is known to humans.

Key Importance

• Tree diversity is fundamental for forest ecosystem stability and services. 
• However, because of limited available data, estimates of tree diversity at large geographic domains still rely heavily on published lists of species descriptions that are geographically uneven in coverage. 

Key Findings

• 43% of the tree species in the world occur in South America. 22% occur in Eurasia. 16% occur in Africa. 15% occur in North America. 11% occur in Oceania.

Study about South America

• 40% of the undiscovered tree species are in South America. Also, South America has the largest number of rare tree species. It has 8,200 rare tree species. South America has the highest number of endemic species. Endemics species are those tree species that occurs only in that region and nowhere else in the world.
• Most of the undiscovered tree species in South America were found in tropical and sub-tropical moist forest of the continent. These forests are in the Amazon River basin. Some of these rare species are also found in Andean forest at altitudes between 1000 metres and 3500 metres.

How were the tree species counted?

• The Global Forest Biodiversity Initiative (GFBI) data base was used. The GFBI has records of 38 million trees. This includes more than 28,192 species. The scientists also used the data from TREE CHANGE. The combined data sets provided information about 64,100 tree species.

Significance

• The study will help in establishing a quantitative benchmark. It could contribute to forest conservation efforts. Also, the study will help in future discovery of new trees.
• Losing regions of forest that contain these rare species will have direct and potentially long-lasting impacts on the global species diversity and their provisioning of ecosystem services.

Inference

• The forests of South America should be protected largely. The forests here are threatened by fires, climate change, deforestation and other anthropogenic activities.

About Global Forest Biodiversity Initiative 

• It is a multi – stakeholder research collaboration. 
• It works around forest sciences. 
• It is platform for international forest education and research dissemination.

Road Ahead

• Species surveys are very time-consuming and present many challenges, including lack of access to certain areas and consistency of identification, and several botanists may characterise the same species slightly differently.
• Noting that “tree species are going extinct due to deforestation and climate change, and understanding the value of that diversity requires us to know what is there in the first place before we lose it.