Orangutans are sometimes referred to as ‘gardeners of the forest’ because of their role in seed-dispersal (they spread seeds in their dung). Seed dispersal is vital for the health of rainforests, so as much as orangutans need forests, the forests need them too.
New research shows that the loss of large animals such as orangutans and elephants from ecosystems has a huge impact on plants’ ability to respond to climate change. Larger animals transport seeds further than smaller ones, which helps mitigate the effects of the changing climate on plant species by enabling them to migrate. Losing this function by losing orangutans and other large seed-dispersing animals threatens not only the plants themselves, but the things we rely on them for, such as carbon storage and food production.
Thankfully, the rewilding methods used by our partners in Sumatra enable orangutans and elephants to return quite quickly to the sites they work on and resume their role as gardeners of the forest. Of course, we must also ensure that we work to keep animal populations stable by connecting forest patches and understanding what other threats face them, and we are continuously analysing data to keep ahead of these trends.
At the sites being rewilded in Sumatra, staff and volunteers use eco-polybags to house seeds and seedlings as they grow in the tree nurseries. In the past, they used plastic polybags, which protected the seedlings but created a lot of waste, which of course was not biodegradabale.
While eco-polybags made from banana trunk fibres are biodegradable and enable the new trees' roots to breathe, humidity and heat at the planting sites makes the eco-polybags start to break down much quicker than the team would ideally want. For fast-growing seedlings, it's not too much of a problem, as within a few months the seedlings can be moved out of the nursery environment and planted out in the site, where the eco-polybag degrading won't cause their roots to rot. However, it's important to grow a mix of species - including slow-growing trees, which stay in the nursery for much longer. If the eco-polybags start breaking down while in the nursery when the roots are not surrounded by the complex soil of the larger site, it can be disastrous for the delicate seedlings.
To address this problem, staff are now replacing the eco-polybags for slow-growing seedlings every three months while they're in the tree nursery. This has the added bonus of providing more work for the women's groups who are paid to make the eco-polybags. Many of the women are now using eco-polybags in their own vegetable gardens as well.
The restoration teams in Sumatra always prepare a contingency of extra seedlings when stocking the tree nurseries, and the photo above shows one of the reasons for doing this. The seedlings in the foreground are all squashed because an elephant stood on them, so are now unlikely to survive if planted out in the site. On the plus side, it's always good to know there are amazing mammals like that so nearby and that they will benefit from the restoration process!
Thank you for continuing to support this work. Your donations ensure the team have all the tools and time they need to keep seedlings growing healthy and strong to create new rainforest.
The reforestation projects SOS supports in Sumatra all use assisted natural regeneration to restore areas of land that have been degraded. But how does this look in practice, and what are the benefits?
Fully natural regeneration is often suggested as an alternative to more labour-intensive restoration methods. For example, if we decided to use this method, after buying any piece of land we would simply fund some fences or patrols to protect it but otherwise leave it alone to recover over time. While this would undoubtedly cost less money than assisted natural regeneration, the reality is that nature cannot be separated from people, and so involvement of and benefit to local communities is vital in ensuring that a restored forest remains protected long-term. Additionally, a lot of seed dispersal relies on animals and birds which may have long ago disappeared from a degraded area, so natural regeneration doesn’t always happen as quickly as it would if these species were present.
The aim of restoring forest is to restore a complex ecosystem with diverse plants and animals and natural ecological processes. Simply planting a large number of fast-growing trees to quickly turn an area green does not achieve this aim, and there have been cases where tree-planting is used as a ‘quick fix’ for carbon-offsetting without consideration of long-term sustainability or even the effectiveness of this method of carbon-offsetting.
A recent study by Philipson et al looked at carbon storage over a twenty year period – in areas where tropical forest in Malaysia was left to regenerate naturally, and in adjacent areas that had been restored with assisted natural regeneration. The results for carbon storage were stark – the forest restored with assisted natural regeneration was storing carbon 50% faster than the forest left to regenerate naturally.
Additionally, as mentioned above, leaving land to regenerate naturally can have negative social consequences. For example, if land that was previously used for agriculture is simply protected with fences and left to regenerate naturally, there is likely to be a loss of employment opportunities and income for people who previously made a living from agriculture. This would be an unacceptable cost:benefit ratio, while assisted natural regeneration creates jobs and involves people, rather than alienating them.
Thank you for continuing to donate and allowing this vital work to continue.
Cinta Raja III is one of the restoration sites we support in Sumatra's Leuser Ecosystem. It has been under the care of the restoration team since 2018 and is flourishing. Just a few years ago, Cinta Raja was bare and quiet, with a few stumps of oil palm trees and some tough grasses pushing through the depleted soil, but recently, Restoration Manager Rio Ardi spotted a female orangutan and her baby at the site, enjoying some fruit in one of the trees above him as he walked through one of the replanted areas.
The arrival of these orangutans is testament to the amazing work the restoration team does to restore orangutan habitat. It is also testament to the incredible support we get from donors like you, without whom we couldn’t keep these projects running.
I hope the video at the link below makes you as happy as it made us!
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