This study will compare three reforestation interventions, each designed to test the impact of soil and microbial amendments on the growth and survival of native tree species in a degraded forest landscape:

Control Group: Standard planting of saplings without any soil amendment or microbial inoculation. This treatment will represent baseline reforestation practices typically employed in Kenyan afforestation programs.

Mycorrhizal Treatment: Saplings will be inoculated with arbuscular mycorrhizal fungi (Rhizophagus irregularis), a well-researched species known to establish symbiotic relationships with a wide range of native trees. It improves phosphorus uptake, drought resistance, and root biomass—key factors in early-stage sapling survival in degraded soils. Commercial inoculum of Rhizophagus irregularis will be sourced from certified Nairobi-based suppliers (e.g. Mycorrhizal Africa Ltd). For consistency, 10 grams of granular inoculum will be applied directly into each planting hole at the root zone during sapling transplantation.

Biochar Treatment: Soil at the planting site will be amended with biochar produced onsite from agricultural residues (primarily maize cobs and dry pruned branches) using a flame cap kiln. This method is chosen for its low-cost, low-emission efficiency. Biochar is applied at a rate of 0.25 kg per planting hole, thoroughly mixed with the topsoil to enhance nutrient retention and water holding capacity.

Each treatment will be applied to 200 saplings, following a randomised block design across multiple plots to account for site variability.

These 3 native tree species were chosen for planting due to their ecological suitability, availability, and importance to local communities:

Juniperus procera – drought tolerant, culturally significant

Prunus africana – endangered, medicinal value

Croton megalocarpus – fast-growing, nitrogen-fixing

Kereita Forest, a montane ecosystem located within Kenya’s Aberdare Range, is facing increasing degradation due to deforestation and habitat loss. This project aims to enhance native tree regeneration by testing the effectiveness of mycorrhizal fungi inoculation and biochar soil amendment in improving sapling survival and growth. Through a scientifically designed field experiment, the project will generate data-driven insights into affordable, scalable restoration methods suitable for degraded tropical forests. The long-term vision is to establish a cost-effective model for ecological restoration that can be replicated across Kenya and other regions facing similar challenges.

enhanced ecosystem resilience to climate change

The project, led by Kijabe Environmental Volunteers (KENVO), will share findings with local communities, conservation organizations, and policymakers to support evidence-based afforestation strategies. Ultimately, the initiative contributes to biodiversity conservation, climate mitigation, and sustainable forest management in Kenya.

How does mycorrhizal fungi inoculation affect the survival and growth rates of native tree saplings in Kereita Forest?

What impact does biochar application have on the survival and growth of saplings in degraded forest areas?

How do these interventions compare to conventional reforestation methods in terms of cost-effectiveness and sapling performance?

Baseline measurements will be taken immediately after planting in September 2025. Follow-up monitoring will occur at 3 months (December 2025), 6 months (March 2026), and 12  months (June 2026) post-planting. Final analysis and reporting will take place in July 2026.

The project budget of £6,100 covers staffing, saplings, biochar, mycorrhizal inoculum, equipment, training and logistics. 

Mycorrhizal and Biochar-Based Reforestation