The destruction of healthy forest systems causes so many different problems. Trees provide a habitat for animals, purify water sources, control flooding and erosion and help to replenish the soil with nutrients needed for farming. When farmers can’t grow anything their farms fail and they have no option but to move to the overcrowded cities looking for work. Often they have to resort to selling themselves or their families into slavery just to survive.

The Problem America’s forests are facing a perfect storm of threats. Infestations of diseases and invasive pests like the Emerald Ash Borer are killing tens of thousands of acres of trees nationally. Increased development is splitting once-vast forests into small fragments, and a history of suppressing natural fires has created unhealthy stands of forests. Additionally, climate change is altering the size and growth patterns of forests. Without these forests, 50 percent of the nation’s water supply will go unfiltered and 12 percent of U.S. carbon emissions won’t be absorbed. Iconic and important plant and animal species will lose their home, and more than $14.5 billion generated on Forest Service lands – money that goes back to local communities – will be lost.

How You Can Help The Plant a Billion projects in the United States are rejuvenating iconic forests in key locations throughout the country. The Nature Conservancy is making sure each dollar donated can have the most effect on creating healthy forest habitat by using two methods: planting tree seedlings in areas that have been highly degraded, and assisting the natural regeneration of the forest by removing barriers to the forest’s ability to heal itself. One project in the Brazilian Amazon is using a new technique for planting trees that results in more, stronger plants–and hopes to cover 70,000 acres in new forests. “If the world is to hit the 1.2°C or 2°C [degrees of warming] target that we all agreed to in Paris, then protecting tropical forests in particular has to be a big part of that,” M. Sanjayan, CEO of Conservation International, tells Fast Company. “It’s not just the trees that matter, but what kind of trees. If you’re really thinking about getting carbon dioxide out of atmosphere, then tropical forests are the ones that end up mattering the most.” He’s right: Simply stopping deforestation could allow existing forests to absorb up to 37% of our annual carbon emissions; replenishing degraded areas could do significantly more for the planet. “This is not a stunt,” Sanjayan says. “It is a carefully controlled experiment to literally figure out how to do tropical restoration at scale, so that people can replicate it and we can drive the costs down dramatically.”

Over the past 40 years, about 20% of the Amazon has been cut down or destroyed, and scientists worry that another 20% of the rainforest will be lost in the next couple of decades. So, instead of following precedent and planting saplings, which are labor and resource intensive to manage (and, depending on the selected species, may not be best-suited for the territory, resulting in less than ideal survival rates), the organizing coalition is trying something different. Developed in Brazil only a few years ago, the new planting technique is called muvuca. “In Portuguese, it means a lot of people in a very small place,” says Rodrigo Medeiros, Conservation International’s vice president of the Brazil program and the lead on the ground. The muvuca strategy demands that seeds from more than 200 native forest species are spread over every square meter of burnt and mismanaged land. The seeds are purchased from the Xingu Seed Network, which since 2007 has acted as a native seed supply for more than 30 organizations, thanks a collection of more than 400 seed collectors–many of whom are indigenous women and local youths. Of course, even in nitrogen- and phosphorus-rich soil, only some of these seeds will survive–but that bit of natural selection is key to the muvuca magic. Several seeds germinate, compete between themselves for nutrients and sunlight, and the strongest ultimately become big trees. According to a 2014 study by the Food and Agriculture Organization and Bioversity International, more than 90% of native tree species planted with this strategy germinate, and they’re especially resilient, able to survive drought conditions for up to six months without irrigation. 83 projects you can support for reforestation: