In 2015, trees covered only 1.9% of these drylands in Ethiopia; Nine years later, helping ancient roots grow increased forest cover to more than 22%.

In 2015, trees covered only 1.9% of these drylands in Ethiopia; After nine years, helping the old roots grow increased forest cover to more than 22%.A comprehensive land restoration assessment study in the Kembata Timbaru region of central Ethiopia has shown that protecting wild growth and planting new trees has significantly reduced severe topsoil loss across dry and hilly areas.The research was published in the scientific journal Scientific Reports by lead author Meles Wondater Ceesay. The investigation assessed the real-world impact of the REDD+ investment programme, an environmental initiative launched in 2015 with funding support from the Norwegian government. By examining high-detail satellite images provided by the International Climate and Forest Initiative in Norway along with ground elevation maps and historical rainfall records, the research team mapped land changes and soil movement between 2015 and 2024 across six experimental test sites covering more than 107 square kilometres.Three test sites were restored using supported natural regeneration, a management strategy that focuses on protecting existing root systems and managing the surrounding land so native shrubs and trees can grow naturally without the need for expensive nursery planting. At these sites, forest cover grew from 1.9% in 2015 to 22.18% in 2024. As a result, annual soil loss decreased from 13.19 tons per hectare to 9.49 tons per hectare over the nine-year assessment period.

Planting trees leads to a sharp reduction in topsoil loss

Direct tree planting programs have achieved greater increases in forest canopy along with significant reductions in washed away topsoil. Across three trial tree planting sites, where new seedlings were actively added to bare or deforested land, forest cover expanded from 8.5% in 2015 to 34.92% by 2024.Because these active farming sites suffered significant land damage when the project began, the initial topsoil loss was very high, reaching 43.37 tons per hectare per year in 2015.

By 2024, protective tree cover helped reduce that loss to 31.29 tons per hectare per year.The results provide important data for Ethiopia’s National Forest Development Strategy and climate-resilient green economy policy frameworks. In the country’s dry highlands, rapid population growth, unpredictable rainfall, and heavy agriculture often cause steep slopes to lose between 20 and 100 tons of topsoil per hectare each year.

This ongoing erosion washes away nutrient-rich soil, directly compromising farm productivity, harming agricultural productivity, and threatening the food supply of local communities.

Satellite tracking reveals restored landscape

To accurately track these environmental changes over time, the researchers analyzed 4.77-meter-resolution satellite images within Google’s cloud mapping software. They classified regional landscapes into seven basic cover types: dense forest, open forest, brushland, cropland, grassland, bare dirt, and urban.Satellite maps have proven highly reliable when checked against 356 real ground locations verified through detailed aerial photographs. The mapping achieved an overall accuracy of 81.4% for the 2015 baseline data, and reached an accuracy of 86.79% for the 2024 map.To estimate how much dirt was actually saved from erosion, the researchers built a computer formula that combined long-term average rainfall from 1990 to 2024, local land slopes, soil types, and vegetation.

Known as the Revised Global Soil Loss Equation Model, this standard calculation explains how different weather and terrestrial factors work together to cause or prevent land erosion. When tested using standard statistical reliability tests, the model demonstrated strong predictive power, scoring 0.823 out of a maximum score of 1.0.

Local geography and climatic conditions

The local geography of the Kembata Timbaru district is characterized by a diverse topography of high flatlands, deep valleys and undulating hills, ranging in elevation from 800 meters to 2,600 meters above sea level.

This wide elevation range creates distinct microclimatic zones. However, almost all of the test areas (95%) lie within the hot, dry lowlands known locally as the Kula District, and lie at an elevation of less than 1,500 metres, with smaller parts extending into mid-elevation ridges known as Wena Digha.The REDD+ investment program has established large-scale community forestry programs across 54 districts in Ethiopia, covering four major administrative regions including Amhara, Central Ethiopia, Sidama, and Oromia.

The Kembata Timbaru area was selected for this study through targeted sampling to reflect a realistic range of physical slope conditions and land types across the area.

Guide future forest restoration strategies

While planting new nursery seedlings remains necessary on completely bare land, protecting living root systems and allowing native trees to sprout on their own provides a less expensive and highly effective way to remediate damaged community land.The research team notes that these findings provide clear real-world evidence that combining natural regrowth methods with active tree planting can successfully protect farmland, halt topsoil loss, and rebuild resilient forests in dry areas facing extreme environmental stresses.