Monday, June 13, 2016

Aerial tree seeding for landscape forest restoration in East Africa.

 Recommendations and Research Needs

Preface: After 5 or so years of reading about aerial tree seeding and it's potential for low cost landscape scale reafforestation of degraded woodlands and forests, we have started this blog to aggregate as much information about this as we can for use by forestry industry professionals and enthusiasts in East Africa. 

First Kenyan trials of dryland aerial tree seeding Timau - 2016

Aerial tree and pasture seeding presents many challenges and opportunities, especially in Tropical countries. While technology and techniques are developed and available, they are yet to be tested and adapted for use in Tropical areas now suffering devastating deforestation. Because experience with aerial seeding of forests in humid and dry land tropics is limited, little is known about the methodologies for achieving meaningfull seeding success rates.
We are focusing on the more desirable endemic timber, fuelwood, charcoal,  fodder and pioneer species growing naturally in their area,  that are currently being over harvested such as the acacia species.
Initially, these trials have not required the use of aircraft. It is necessary only to broadcast a small amount of seed (pelletized vs. controls) on a small patch of the area being tested with conventional tree-planting methods. However, to evaluate fully the potential of aerial seeding in a given area, we must consider:

· The characteristics of species, especially the ability of its seed to germinate.

· The choice of site and site preparation;

· Effect of season and weather on best time for sowing;

· Seed acquisition;

· Seed handling (storage, transport, care in the field);

. Seed preparation (stratification, coating with animal repellents, inoculation, testing the

coatings for toxicity to seeds or seedlings); and

· Major predators.

Biochar seedballs - a Chardust Ltd. - Cookswell Jikos collaboration!

Appx 40% germination of acacia xanthophloea at 12 days. 

Existing plantations and natural stands can sometimes demonstrate how successful direct seeding is likely to be. They indicate the best season to sow the seeds and can generally foretell the seed predation and the success of natural germination (care must be taken that the natural germination being observed is occurring in conditions that approximate those on sites to be sown). The silvics ( the study of the life history and characteristics of forest tree) of the species in question should be studied to determine its suitability for direct seeding.

Direct-seeding trials should first be implemented at sites favorable for seeding, and then, with experience, should move to the more difficult sites.
Along with all direct-seeding trials should be some seedling-planting trials. The relative costs and successes of the two techniques can be better judged when they are done in tandem.

Before aerial seeding, sites should be chosen and inspected, if possible, at least 8 months in advance. Factors to be considered include:

. Extent of grazing by livestock and wildlife;

· Infestations of ants, rodents, and seed-eating birds;

· Areas where trees are adequately reproducing naturally;

· Conditions of seedbed and need for burning the site; and

· Advantageous ridges from which aircraft can be guided.


With this information plans can be made for site preparation, seed procurement, and any seed coatings.

Researchers wishing to improve the technology and techniques of aerial seeding might pursue the following challenging research projects:

. Aerial reforestation of regions covered with local forbs and other vigorous tropical grass species;

· Development of seed coatings for use in dry sites that absorb and hold water and yet do not disintegrate rapidly;

· Improvement of seeding equipment to provide greater control over seedling density and spacing;

. Development of less hazardous chemicals for protecting seeds from rodents, insects, and birds (some examples worth considering are wood vinegar, neem oil, chillies, clay, copper sulfate.) 

. Development of seed coatings containing spores of mycorrhizal fungi.

The existing knowledge on seed coating and pelleting should be reviewed. Successes and failures are reported in different situations.

Seed can be targeted accurately (often within a meter or two). Thus aerial seeding might prove feasible for filling in the widely scattered breaks in the forest left by slash-and-burn farmers or charcoal makers with useful species that best protect the vulnerable soil.

Examples of degraded and erosion prone areas in Southern Kenya that could potentially use aerial seeding.

Here are some links to information about seed coatings and aerial seeding;

Germination trials of the biochar acacia tree seedballs

Some historical clips of post-war aerial seeding after WWII.

Examples of aerial seeding trials from around the world.

Rare shots of UH-1B helicopters of Vietnam People Air Force in the aerial seeding configuration.
Following the conclusion of the Vietnam War, the Air Force devoted many of its American-made assets to improve agriculture production across the country.'

Alternative seed distribution methods are also under R&D in Kenya :) 

Here is a short video of one of our most recent tests.

Thanks for reading and please dont hesitate to contact us at for more information. 

tree seeding kenya

After all - hundreds of species trees have spent millions of years perfecting aerial tree seeding - with a bit of help, perhaps with technology and information transfer, we can find a way to make planting and growing billions of trees more cost effective! 


  1. Wow beautiful and interesting!

  2. Hi,

    I love your concept! Do you have any information on the success rate of tree seedling establishment and survival on old pasture, disused agricultural fields and cleared areas? I am from South Africa and would love to explore the efficiency of seedballs in habitat restoration in the Cape of South Africa.

    Looking forward to hear your advise.

    Kind regards,

  3. Hi apologies for the delay in corresponding. Beyond Google I am afraid I do not but it would be very interesting to trial!