In 2005, trees outnumbered people 61 to 1. In 2015, it's 422 to 1. Here's what changed.

Trees are some of the most helpful organisms on earth.

One large tree can supply a day's worth of oxygen for four people. They also absorb carbon dioxide, provide homes for animals, and make the nitrogen cycle happen, not to mention the whole "food and goods for human consumption" thing. No doubt about it, trees are pretty good at what they do.

Trees also make for excellent organic chairs. Photo by iStock.

And a new study revealed there are even more trees on Earth than we thought. A whole lot more.

The researchers found that there are over 3 TRILLION trees on Earth. That works out to be around 422 trees per person. Congrats, you just got yourself a tiny forest.

This is a huge deal, considering the previous tree tally, conducted in 2005 by Evergreen State College in Washington, only used NASA satellite imagery and found just 400 billion trees, which averaged out to a scant 61 trees a person.

Just some of Earth's 3,000,000,000,000 trees. And yes, I had to think long and hard about just how many zeroes that number required. Photo by iStock.

To arrive at that number, an international team of scientists combined two common methods: satellites and manually counting tree trunks.

You read that right. One of the most accurate ways for scientists to count trees is to actually go trunk-by-trunk and count them.

In this 2011 photo, a team from the Regional Office for Woodlands and Forestry in Germany count and catalog a selected section of forest. Photo by Johannes Simon/Getty Images.

The team, led by Dr. Thomas Crowther, an ecologist at the Netherlands Institute of Ecology who conducted the research while working at Yale University, first gathered the results of on the ground tree counts from every continent except Antarctica.

The various counts covered about 430,000 hectares (1,062 acres) worldwide, which may not sound like much, but when combined with satellite imagery, it gave the team a better estimate about the density of the forests and allowed them to make a more accurate count of the total number of trees on the planet.

Why is the tree count so important? It all comes back to conservation.

"It's not like we've discovered a load of new trees; it's not like we've discovered a load of new carbon," Crowther told BBC's "Science in Action."

"We're simply describing the state of the global forest system in numbers that people can understand and that scientists can use, and that environmental practitioners or policymakers can understand and use."

And hopefully, they will.

Trees on the island of Borneo are clear-cut to build a palm oil plantation. Photo by Bay Ismoyo/AFP/Getty Images.

Between poor forest management practices, deforestation, and land-use policies, humans have had a majorly negative impact on tree populations around the globe.

Crowther's team estimates the number of trees has decreased 46% since the dawn of human civilization.

While a more accurate count is great news, we're also not out of the woods yet.

As much as we all love trees, paper still makes up the largest percentage of municipal solid waste.

On average, the world uses an estimated 27,000 trees each day in toilet paper alone. And we're not much better when it comes to paper towels. They make up an estimated 20 to 40% of waste from dorms and office buildings.

Left: Trees are clear-cut to make way for a pulp and paper plantation in Indonesia. Photo by Ulet Ifansasti/Getty Images. Right: Paper towels, anyone? Photo by Mike Mozart/Flickr.

Knowing and understanding the tree count is the first step to saving these rapidly diminishing resources and developing sustainable solutions.

But there are still plenty of things you can do to help Earth's tree population grow and thrive.

And you don't have to replant billions of trees to do your part.

Start by choosing paper made from recycled material or from sustainable forests. Say no to paper and plastic at the store and bring a reusable bag. Even reducing your font one size before printing is a small change that can have a big impact.

#TreeFriendlyRelationshipGoals. Photo by iStock.

Making smart choices about the products we use and our personal habits may help spare our forests.

Because we may have 3 trillion trees on Earth, but we need every last one.

You can hear from Crowther himself, as he shares his method and findings in this short video from Yale University's School of Forestry and Environmental Studies: