October 26, 2021 By John Brandt, Jessica Ertel and Will Anderson
“We can’t see the forest for the trees.” The popular saying calls on us to remember the big picture problems as we identify individual solutions. It turns out that it’s accurate for real forests and trees, too.

For years, researchers have produced accurate techniques to track where people are damaging, protecting and restoring the world’s 1.03 billion hectares of primary tropical forests, which are vital tools to store carbon and protect biodiversity.

But current monitoring systems fall short: They simply aren’t detecting trees outside of these closed-canopy forests.

The billions of trees living in “mosaic landscapes” — where people use the land in multiple ways — are also important. In agricultural landscapes, people use them to protect their crops. In cities, they rely on them to clean the air and lower temperatures. And in drylands, they are a vital source of income and timber. In Latin America, for example, restoring trees to a hectare of land can add $1,140 in value.

Fortunately, a solution is here. Preliminary tree cover data developed by WRI shows where billions of these trees — previously invisible to governments, investors and the public — are growing across 1.4 billion hectares of Africa and Latin America (an area 40% larger than the entire United States). Most importantly, this “trees in mosaic landscapes” data gives credit to the undervalued and underfunded local communities who work to protect and restore these ecosystems.

Why We Need More Data On Trees Outside Dense Forests

Existing global tree cover datasets on platforms like Global Forest Watch rely on medium-resolution satellite data. That makes them accurate enough, in 30 meter by 30 meter squares, to capture where trees are living and dying in dense forests. However, they are not detailed enough to detect trees growing outside them. This new, less expensive method is nine times more detailed, at a 10 meter by 10 meter resolution, and allows us to see trees that are young or growing far apart.

This information is especially useful for government officials looking to track where young trees and sparse forests are contributing to their land restoration pledges to the global Bonn Challenge, AFR100 and the Great Green Wall in Africa, and Initiative 20x20 in Latin America and the Caribbean.

It’s also important for community-based organizations and local enterprises working to grow trees the right way and their investors and donors. They could all use it to detect trees more accurately in mosaic landscapes and identify which areas could be restored.

4 Reasons Why Monitoring Trees Outside Dense Forests Is Important

While this dataset is still under development, it is already revealing important insights about the billions of trees central to urban and rural life.
1. Trees Help Millions of Farmers Grow Food

Millions of farmers grow trees on and around their land. Agroforestry systems, for example, which grow trees on croplands, underpin the livelihoods of more than 900 million people. Think of shade-grown coffee in the tropics, where canopies of native trees shelter the berry-producing bushes from the harsh sun.

Farmers typically plant trees on their land far apart so that sunlight can still reach their crops. That makes it difficult for less detailed satellite monitoring systems to detect them. This gap is especially important in Central America, where millions of farmers use agroforestry to produce commodity crops like bananas. Our data, however, reveals that 75% of the region’s farms — around 4 million hectares — have more than 10% tree cover. This is a testament to the work of local communities planting and protecting trees.
Drylands are a diverse set of landscapes that cover more than 40% of the world's surface and are home to about 2 billion people. They are also full of trees that store carbon and protect soil health.

While local communities know how to manage these trees to provide energy, grow food and keep the soil healthy, most satellite datasets have trouble detecting them in a consistent way. The lack of data also furthers the misperception that drylands are treeless wastelands “degraded” by local communities. In contrast, the land next to communities in the Sahel is often full of trees whose shade protects residents and animals from extreme heat that can reach 49 degrees C (120 degrees F).

Innovative past studies, which have found that trees extend across an area of dryland larger than the Amazon forest, use sampling methods that don’t count tree cover for every point in the landscape. This makes it impossible to show precisely where these trees benefit biodiversity and help communities adapt to the effects of climate change, like extreme (and increasingly commonplace) droughts.

READ Further from the source above