Trees have become an iconic image of environmentalism, but that doesn’t necessarily mean we should plant millions of them.
While scale is important for landscape restoration, we need to reconsider quality and not just quantity. When does the presence of a tree really make a difference, and when is it neither an environmental or economical solution to a host of complex issues? What are the implications for food security, biodiversity and landscape protection?
First, we need to take a step back — why shouldn’t we count the trees? Planting hundreds or even millions of trees does not automatically translate into an increase in the overall long-term tree population. To increase population levels, survival and planting rates have to outweigh losses from tree mortality and removal.
Challenges in China, Nigeria and Haiti
Traditional Chinese approaches to restoration have focused on afforestation (establishing forest on land not previously forested) as an important tool to control desertification.
However, over the long-term, tree planting projects have actually increased environmental degradation. In arid and semi-arid regions of China, the fast-growing trees draw moisture from the soil, causing many trees to die in water-stressed regions with low annual precipitation. Since 1949, the overall survival rate of trees planted for afforestation projects has been only 15 percent across northern China. Rather than focusing solely on afforestation, re-creating natural ecosystems would provide a better chance of fighting desertification.
In Nigeria, among the 11 northern states worst-hit by desertification nearly four out of every five seedlings — 37.5 million out of the 50 million planted each year — wither and die within two months. In these dry areas, water is more valuable than a standing forest.
“You can’t plant a tree in the desert without a water source and expect people who are struggling for water for their human needs to shoulder the extra burden of watering it,” says Kabiru Yammama from the National Forest Conservation Council of Nigeria. Furthermore, since 70 percent of rural Nigerians depend on wood for fuel, there’s little incentive to protect the trees that are left standing.
Haiti, one of the most deforested nations on Earth, could definitely benefit from increased tree cover and could ecologically sustain it too.
Before European occupation, Haiti was almost entirely covered with forests. Tree cover now stands at 3 percent. Although the World Bank spent $4.2 million to plant 20 million trees — of which 60 percent died — over seven years in the 1980s, they estimated that 10 times as many trees would need to be planted to result in net restoration. In fact, in the 2000-2005 period the deforestation rate in Haiti accelerated by over 20 percent from the 1990s. Although forest-friendly policies exist, demand for energy and markets that encourage deforestation undercuts these policies.
Tree planting 2.0
In Africa’s Sahel region, even an individual tree’s value has been demonstrated. Adding single trees to agricultural land across this drought-scarred land creates shade, regenerates soils, fertilizes the ground and fundamentally leads to greater food security. The process of agroforestry has helped the area come back from the brink of severe desertification, starting in the mid-1980s.
Driving this restoration was a locally driven practice called farmer-managed natural regeneration, under which farmers allow native trees and shrubs to regrow from remnant underground root systems and/or plant new ones amidst crop fields. Since 1985, more than a million rural households in Niger have protected and managed trees in agroforestry landscapes across approximately 5 million hectares.
Green corridors in fragmented landscapes
In forests, trees can make a difference by connecting fragmented landscapes.
Most of the Atlantic forest in Brazil has been converted into agricultural land, with only 2 percent of the original forest remaining, dispersed in small patches surrounded by open fields. This kind of habitat loss affects tree species, their pollinators and animal dispersers — animals that consume seeds and excrete them across environments.
Researchers from the journal Nature have called for a new paradigm for forest restoration, and discourage exclusively prioritizing the expansion of existing medium-to-large size forest fragments. Instead, they suggest focusing on planting forest bridges, connecting otherwise disparate clumps of woods to form one large ecosystem.
The recently approved Brazilian Forest Law could help make this a reality. The law requires all rural properties in Brazil to maintain Forest Legal Reserves — to protect natural vegetation on 20 to 80 percent of land according to the vegetation and geography. However, there is a 16-30 million hectare gap between what should be set aside and what actually is. With an estimated 4 million properties not meeting their requirement, BVRio created a Forest Reserve Credits (market which allows landowners to buy and trade restored areas. Now, large landowning companies can pay smallholders to regenerate their own land. This trade-off of small, scattered clumps of restored land for larger, aggregated landscapes on large landowners’ properties could benefit ecosystems in the long-run.
To an economist, the law requires a total amount of land that must be restored, so trading permits for which land is restored creates no net gain. However, environmentalists might ask what the difference is between the two landscapes that could be restored. Trading has the potential to not only incentivize compliance with laws but to connect landscapes. Connectivity has been demonstrated in Puerto Rico by smallholders restoring even small fragments of land.
So before setting out on another billion-tree campaign, let’s put down our spades and ensure that standing trees won’t compete for resources — with local populations, economics or politics — but instead establish where and how a tree can benefit a landscape as well as provide for human needs.