Can we protect old trees by planting new ones?

Aerial view of the Managalas Conservation Area. Photo by Dean Arek / CIFOR-ICRAF

An interesting case in point is the Managalas Conservation Area (MCA), which spans the 214,696-hectare Managalas Plateau in Papua New Guinea’s (PNG)’s Oro Province. Far from an uninhabited wilderness, it’s populated by over 22,000 people—most of whom draw the bulk of their sustenance and livelihoods from the landscape. 

There—after 30 years of negotiation, education and consensus-building facilitated by Port Moresby-based NGO Partners with Melanesians (PwM) and funded by the Rainforest Foundation Norway (RFN)—the 152 clans that own the area have agreed to protect their biodiversity-rich land from large-scale logging, mining, industrial agriculture and other destructive land uses.

But this hard-won agreement is also just the start of a new and nuanced conversation. Most people signed up to the agreement on the understanding that they would be tangibly ‘better off’ by pursuing conservation—that it would enable other kinds of development that could improve their living conditions and sustain them long-term.

Now, the work of the local organisation charged with managing the MCA and its international partners—namely, the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF), with funding from the European Union—is to help its communities find ways to make that happen.

And trees will almost certainly play a role.

One species, the okari (Terminalia kaernbachii), has spurred conversations about sustainable livelihoods from the outset of PwM’s engagement. A large rainforest tree that’s native to the surrounding lowlands—and likely introduced to the Plateau by locals many years ago—it yields large, creamy nuts that taste similar to almonds and for which there is a considerable domestic market. In the 1990s, PwM staff assisted Managalas’ communities to export the nuts for sale in Port Moresby, tangibly demonstrating the value of leaving rainforest trees standing rather than felling them for a one-time profit. 

There’s also the poponda tree (Alstonia scholaris)—the namesake of the nearest town, Popondetta, which grows in the lower reaches of the Plateau. “People use the sap for medicinal purposes,” explained Nalau Bingeding, a Moresby-based botanist who contracts to the MCA project on forestry issues. “It’s used for asthma and skin diseases… and supposedly for sorcery, as well! Mastwood (Calophyllum inophyllum) and balsa (Ochroma pyramidale) could also feature as sustainable timber sources,” said Bingeding.

Another species with lucrative potential is the massoia tree (Cryptocarya massoia), the bark of which has been used for centuries to make a high-value, caramel-coconut scented essential oil that features globally in perfumes, flavouring and medicine. It’s native to the Plateau, and managing harvest is important because the tree is cut down to a stump when harvest time comes, and the bark is peeled off and dried—though the tree can then regrow to maturity from the stump in about ten years.

Eaglewood—a fragrant, resinous wood that forms in the heart of some Aquilaria trees as an immune response to fungus—is another extremely high-value product, which has been traded for use in perfumes and incense, as well as medicines, for millennia. Most of the Plateau’s wild eaglewood has already been extracted, but cultivation may be an option. 

“If you shift to doing things like making small woodlots of massoia, where you get a lot of money out of it,  […] you stop cutting down new areas of forest, and the forest grows back. That’s how we do conservation indirectly.” 

With high-value, multi-purpose crops like this in the mix, Bingeding hopes that people will see fit to practice less shifting cultivation in secondary forests. That practice—cutting down small areas of trees to plant food gardens, then moving on to a new area when the fertility drops—is common in Managalas, but could become unsustainable as populations grow.

“If you shift to doing things like making small woodlots of massoia, where you get a lot of money out of it, you don’t go back to making huge gardens of [lower-value crops like] banana and taro,” said Bingeding. “You stop cutting down new areas of forest, and the forest grows back.”

“That’s how we do conservation indirectly.” 

Planting trees and managing harvests carefully can also help meet local demand for firewood and timber whilst reducing forest extraction and increasing carbon sequestration,” said Will Unsworth, PNG project manager at CIFOR-ICRAF. “Such demand is significant in Managalas, as most cooking is done on fires and almost all houses are built from local timbers.”

“We can also look at improved fallow systems with tree planting to develop new products, and/or enhance soil recovery after gardening to reduce the land/time needed between rotations,” Unsworth said.