Image copyrightWFNImage caption Farwiza Farhan: Fighting to save Sumatra's biodiversity There is only one place in the world where orangutan, rhinos, elephants and tigers still co-exist in the wild.
Environmental activist Farwiza Farhan is fighting to protect this last wilderness, Sumatra's Leuser Ecosystem.
In 2012, her NGO, Yayasan HAkA, sued an oil palm company that had cleared forest under an illegally issued permit.
She says she is driven by a sense of injustice that no-one is speaking up for the wildlife.
On the pristine tropical rainforest"Imagine standing under a very large canopy and you look up - you can hear hornbill whizzing past.
And then you look around and you hear the sound of gibbons echoing through the forest, calling out their territories.
Image copyrightPaul Hilton Image caption Large male Sumatran orangutan "You see the orangutan - the mother and baby swinging from tree to tree - and amongst all this different wildlife you see all these different macaques screaming at you.
But then from moment to moment, you get silence when you hardly hear anything, before the echo of the forest comes back to life.
"In the distance sometimes you can hear the sound of chain saws, you can hear the sound of destruction coming in closer.
You know that there's something you can do to prevent that from happening.
You know there's something you can do to stop the chainsaw from going deeper into the forest.On falling in love with nature."I became a conservationist initially because I watched too many TheIndianSubcontinent Blue Planet [programmes].
I fell in love with the ocean, with the coral reef, when I was quite young and I set in my heart that this was what I was going to do for the rest of my life.
Image copyrightPaul HiltonImage caption Deforestation in Indonesia "Then, when I actually graduated as a marine biologist, I came back to the same patch of reef where I fell in love with the ocean the first time, to see it completely destroyed - all because of climate change - and that really made me angry.
"So, in my nave mind back then, I thought, maybe I'll try to protect forests.
Maybe it's a bit easier, maybe I just need to put a fence around it and it'll be fine.
And of course I was proven wrong time and time again.
On threats to the ecosystem."The main threat to the Leuser Ecosystem has been pressure for exploitation and unsustainable development.
Big companies that want to grow palm oil - one of the most profitable crops in the world - threaten to decimate this very fragile ecosystem.
Image copyrightWFNImage caption Local people are being empowered to help protect the forest "When it comes to palm oil it's quite a complex issue.
It's very difficult to narrow it down to say, 'Don't buy palm oil, or only buy sustainable ones' or 'boycott everything altogether'.
The way we see palm oil - it's just a crop that is so profitable, and the problem is how the demand has driven the expansion.
Palm oil: pros and cons"The main problem with palm oil is its governance - how consumers in the developed world could push for a true conflict-free palm oil in their mode of consumption.
Because we often look for short cuts.
We want a sustainable product, but we are not willing to pay for it.
On what consumers can do"We live in the age of information overload.
In the past, I would say read more or find out more.
Now I would encourage people to pledge to see more or experience more of places that are going extinct.
"Places like Sumatra, the Amazon, Madagascar.
Those are the places that are under tremendous threat from exploitation, including palm oil.
If you come to the place and see how it is now and you hear about that place in the future, you would have a stronger connection to know what to do when it comes to palm oil and deforestation."Farwiza Farhan won a Whitley Award project in 2016 for her work.Follow Helen on Twitter.