| Tree planting now dominates political and popular agendas |
| and is often presented as an easy answer to the climate crisis, |
| as well as a way for business corporations to offset their carbon emissions. |
| But unfortunately, tree planting isn't as straightforward as some people think. |
| When the wrong trees are planted in the wrong place, |
| it can do considerably more damage than good, |
| failing to help either people or the environment. |
| Reforestation projects are currently being undertaken on a huge scale in many countries |
| and it's crucial that the right trees are selected. |
| A mix of species should always be planted, |
| typical of the local natural forest ecosystem |
| and including rare and endangered species in order to create a rich ecosystem. |
| It's important to avoid non-native species that could become invasive. |
| Invasive species are a significant contributor to the current global biodiversity crisis |
| and are often in competition with native species |
| and may threaten their long-term survival. |
| Restoring biodiversity that will maximise carbon capture is key when reforesting an area, |
| but ideally any reforestation project should have several goals. |
| These could include selecting trees that can contribute to wildlife conservation, |
| improve the availability of food for the local community |
| and maintain the stability of soil systems. |
| Meeting as many of these goals as possible, |
| whilst doing no harm to local communities, native ecosystems and vulnerable species, |
| is the sign of a highly successful tree-planting scheme. |
| To ensure the survival and resilience of a planted forest, |
| it's vital to use tree seeds with appropriate levels of genetic diversity: |
| the amount of genetic variation found within a species essential for their survival. |
| Using seeds with low genetic diversity generally lowers the resilience of restored forests, |
| which can make them vulnerable to disease and unable to adapt to climate change. |
| Choosing the right location for reforestation projects is as important as choosing the right trees. |
| Ultimately, the best area for planting trees would be in formerly forested areas that are in poor condition. |
| It's better to avoid non-forested landscapes such as natural grasslands, savannas or wetlands |
| as these ecosystems already contribute greatly to capturing carbon. |
| It would also be advantageous to choose an area where trees could provide other benefits, |
| such as recreational spaces. |
| Reforesting areas which are currently exploited for agriculture should be avoided |
| as this often leads to other areas being deforested. |
| Large-scale reforestation projects require careful planning. |
| Making the right decisions about where to plant trees depends on having the right information. |
| Having detailed and up-to-date maps identifying high-priority areas for intervention is essential. |
| Drone technology is a useful tool in helping to prioritise and monitor areas of degraded forest for restoration. |
| In Brazil, it's being used to identify and quantify how parts of the Amazon are being devastated by human activities |
| such as rearing cattle and illegal logging. |
| A good example of where the right trees were picked to achieve a restored forest |
| is in Lampang Province in Northern Thailand. |
| A previously forested site which had been degraded through mining |
| was reforested by a cement company together with Chiang Mai University. |
| After spreading 60 cm of topsoil, |
| they planted 14 different native tree species |
| which included several species of fig. |
| Figs are a keystone species |
| because of the critical role they play in maintaining wildlife populations. |
| They are central to tropical reforestation projects |
| as they accelerate the speed of the recovery process |
| by attracting animals and birds which act as natural seed dispersers. |
| This helps to promote diversity through the healthy regrowth of a wide range of plant species. |
| Unlike the majority of fruit trees, |
| figs bear fruit all year round, providing a reliable food source for many species. |
| At this site, for example, after only three rainy seasons, |
| monkeys started visiting to eat the fig fruits, |
| naturally dispersing seeds through defecation. |
| Reforestation projects should always aim to make sure that... |
| local communities are consulted and involved in the decision-making process. |
| The restoration of mangrove forests in Madagascar |
| is an example of a project which has succeeded in creating real benefits for the community. |
| Destruction of the mangrove forests had a terrible impact on plant and animal life, |
| and also badly affected the fishing industry, |
| which was a major source of employment for local people living in coastal areas. |
| The reforestation project involved hiring local people to plant and care for the new mangrove trees. |
| Millions of mangrove trees have now been planted |
| which has resulted in the return of a healthy aquatic ecosystem. |
| The mangroves also act as a defence against the increased threat of flooding caused by climate change. |
| What's more, the local economy is more stable |
| and thousands more Madagascans are now able to send their children to school. |
| One other important point... |