Reforestation
One study estimates that 15 billion trees are cut down each year, on top of the impact on our atmosphere, this can cause many other devastating effects. (4) One such effect is increasing amounts of diseases spread through animals due to this consequential lack of separation of forest between animals and humans. In addition to storing carbon dioxide to help reduce greenhouse gasses, replanting trees helps to avoid the land becoming less able to support plant and tree life. It also reduces the chances of soil erosion and flooding.
As global warming is largely caused by CO2 in the atmosphere, it follows that planting trees to undergo photosynthesis would prove an effective global warming prevention technique. This has been researched extensively and there are many methods of replanting and even creating new forests. Whilst the projections as to how reforestation will affect climate change are quite varied and likely won’t be able to fully mitigate climate change it can still prove an essential part of the mitigation and provides many benefits alongside it.
Key ideas in drone seeding
Drone seeding is exactly what it sounds like, unmanned aerial vehicles that can be used to plant seeds. It is a rapid, safe, cost-effective method of reforestation that also allows lots of what would ordinarily be inaccessible terrains to become relatively easy to plant in. There are multiple projects with drones and reforestation, BioCarbon Engineering performs the planting by having the drones initially report the potentiality of the area for restoration. They carry seed pods to provide the appropriate nutrients as well as growing the seeds out before planting (germinating them), which significantly increases the chance of successful growth. These pods are then released by a pressurised system to provide enough force to go into the soil and grow appropriately. This system allows for a 6 to 10 times faster approach than other alternatives and has already been used in areas like mangroves, deserts and areas affected by wildfires. Optimising locations to grow seeds and monitoring the survival of the seeds can supplement the drones to provide better outcomes. (1)
Factors needing considering
The approach to tackling such a feat varies largely depending on the soil, weather, species in the area, method of planting seeds and many other factors. Planted forests will also have a reduced resilience to disease and pests due to their lack of diversity in comparison to naturally grown forests. Direct seeding or planting sprouted seeds achieves very different results. Direct seeding is much cheaper and time-efficient but has less than a 20% chance of growth which can be even lower if the land is affected by certain conditions. There are however practical constraints as to allow the seeds to sprout as there is a lag time in how soon they can be produced if there are demand spikes and whether there are seeds available. It is extremely important to consider the benefits of each and whether to include monitoring of growth and soil erosion afterwards. There are also several rules on drones that vary largely depending on the country and a huge amount of data processing is required
Benefits and Issues
Surprisingly, planting forests in certain areas can sometimes end up increasing the overall temperature of the earth due to the reflectivity of snow (90% of light) in comparison to dark forests (10% of light) meaning that radiation is less likely to be reflected into the atmosphere. The effect of the plants on absorbing water means that less cloud cover will be there and thus there will be fewer clouds to reflect radiation. In arid climates, most of the rainfall, 90% or more, may be lost through evaporation and transpiration. There is likely a limit as to how much warming and CO2 level differences that trees can take whilst still efficiently reducing the amount of CO2 in the atmosphere.(3)
Further areas to research and alternatives
This method of reforestation has many areas in which it could improve from using AI which could help improve precision efficiency, analysis mapping and planting. There are efforts to make it more environmentally friendly using solar panels or rechargeable pads. Implementing thermal sensors is also being considered to detect forest fires possibly autonomously and scan for areas that require reforestation.
[2]Sonntag, S., J. Pongratz, C. H. Reick, and H. Schmidt (2016), Reforestation in a high-CO2 world—Higher mitigation potential than expected, lower adaptation potential than hoped for, Geophys. Res. Lett., 43, 6546–6553, doi:10.1002/2016GL068824
[3] Jing, S. J. (2019). Reforestation is Not a Mitigation of Climate Change in All Situations – A Literature Review. Asian Journal of Environment & Ecology, 10(2), 1-8. https://doi.org/10.9734/ajee/2019/v10i230113
[4] Crowther, T., Glick, H., Covey, K. et al. Mapping tree density at a global scale. Nature 525, 201–205 (2015). https://doi.org/10.1038/nature14967