by Rémy Ghalayini

20 May 2022

UNCCD Monitors Tree Growth Along the Great Green Wall with High-Resolution Earth Observation Data

GLOBHE's mission is to create a more sustainable future with earth observational data. By partnering with The United Nations Convention to Combat Deforestation, UNCCD, we assist satellite data in verifying the health of baobab trees in Northern Ghana through drone imagery.


The UNCCD was established in 1994 to protect and restore our land and ensure a safer, just, and more sustainable future.  The Convention – based on the principles of participation, partnership, and decentralization – is a multilateral commitment to mitigate the impact of land degradation and protect our land so we can provide food, water, shelter, and economic opportunity to all people. It unites governments, scientists, policymakers, the private sector, and communities around a shared vision to restore and manage the world’s land. This work is crucial to ensure the sustainability of the planet and the prosperity of future generations.

The Great Green Wall (GGW) is an African-led movement with an epic ambition to grow an 8,000km natural wonder of the world across the entire width of Africa. A decade in and roughly 15% underway, the initiative brings life back to Africa’s degraded landscapes unprecedentedly, providing food security, jobs, and a reason to stay for the millions who live along its path. This African-led movement aims to restore 100 million hectares of currently degraded land, sequester 250 million tons of carbon and create 10 million green jobs by 2030.

Restoration efforts

The UNCCD is actively engaged in land restoration efforts, classified as active or passive. Functional restoration includes tree planting, agroforestry, and soil conservation practices such as sand-dune stabilization or terracing. Passive restoration involves setting aside land by enclosing an area for a time to allow the soil and vegetation to recover naturally. 

Since several active restoration projects involve a tree planting component, it is imperative to closely follow the survival rates in the five to 10 years following the planting. A plantation with a low survival rate will disappear completely, with the project efforts and funding wasted. Complementary to monitoring survival rates, maintaining the plantation in the initial stages is essential to ensure a sufficient vegetation cover that can become sustainable in the long term. 

It is vital to set up a follow-up or monitoring system for GGW projects that last at least five to ten years and includes an exit and sustainability strategy. One needs to consider project lifetimes and related crediting periods for delivering environmental services such as carbon sequestration for several decades. All this is to ensure the actual viability of the projects beyond the implementation period.

Why Crowddroning makes all the difference

GLOBHE assists the UNCCD and its partners, such as the FAO, in a joint project to combine macro satellite data with high-resolution microdata from drones to accelerate the verification of tree species in Northern Ghana supporting the implementation of the GGW. The aim is to monitor the growth of the Baobab trees and make sure that they are growing as planned.

Baobab is the icon of the African landscape, revered as the tree of life that provides essential shelter, produces nutrient-dense fruits, and stores water from the rainy season for the dry season. They can live up to 5000 years, growing to 50 meters in circumference and reaching up to 30 meters high. 

Before Crowddroning, the UNCCD monitored tree growth using high-resolution satellite images to assess tree-cover density and land use. This method, however, was limited by the low spatial resolution of the satellite images. Private satellite imagery can provide 30 cm of the resolution at its best, which comes at a high financial cost. It is challenging to detect tree species and monitor tree growth even using that resolution level. On the other hand, drone imagery provides a spatial resolution of about 1 cm, making it ideal for detecting small leaf details and quickly recognizing tree species and their growth. The UNCCD uses an AI model, specifically trained to detect tree species, to analyze the orthomosaic imagery submitted by GLOBHE. 

high resolution earth observation data with drones to the left compared with low resolution satellite images to the right

The details observed from drone data (left) allow AI models to precisely detect the baobab tree and quantify its rates. The satellite data (right) does not automatically provide enough resolution to detect the tree species.

"GLOBHE provided incredibly fast, high-quality service and products. The imagery collected will be extremely useful for measuring and monitoring individual trees in an environment critical to both large-scale resource management and local-scale livelihoods and wellbeing. The data collected are already being used to scale up the detection and characterization of trees and tree species across a larger area of the Sahel, which, for sure, will be very important for conservation, restoration, and nature-based climate change activities," said Eric Lindquist from FAO.

GLOBHE captures data quickly through local drone operators and automatically provides it to the UNCDD and the FAO via the Crowddroning platform. The geospatial engineers then feed this data to the AI model that analyzes it quickly to provide insights at record speed and incredible detail, which was challenging to achieve with the old traditional method. With GLOBHE working together with the UNCCD partners in this project, we can scale up this technology globally to monitor land restoration. Today, local communities benefit from this work by employing local drone operators, thus empowering the local economy.