Earth is home to 3 trillion trees, according to one of the most comprehensive assessments of global tree populations ever completed, recently published in the journal Nature. The new estimates were arrived at by using extensive satellite imagery combined with ground-based tree density estimates, a method more comprehensive than that used in the past. Because the number was so much higher than the previous estimate of 400 billion trees, the new findings are a small cause for celebration.

The bad news, though, is that the world suffers a net loss of 10 billion trees per year. Even schoolchildren can do the math to figure out how many years it will take at 10 billion a year to reach 3 trillion. The survey estimated that the total number of trees on Earth has fallen by nearly half since the start of human civilization. Of particular concern are forests in sub-Arctic regions, home to about 43 percent of the global tree total, mainly in Russia, Scandinavia and North America.

Conversion of land for agriculture has been the most devastating force on global forests, but industrial and urban development is taking an increasingly large toll. Japan is in some ways the exception, though not entirely. Japan ranks third for percentage of total land area being forested, after Finland and Sweden. Two-thirds of Japan is still covered by forest, double the world average.

That would sound promising, except that Japan’s forests have not been sufficiently managed to ensure maximum re-growth and sustainability. Managing forests through research, planning and replanting, especially with an eye on the effects of global warming, is crucial. Japan’s forests are particularly vulnerable since the country spans subtropical and temperate zones, each with its own unique trees. However, many of Japan’s forested areas have been more or less abandoned as most of the nation’s lumber is imported from abroad.

Japan can also help slow the destruction of the world’s forests by ensuring that its imports of lumber are not harming other countries’ forests. Japan should continue to support and strengthen the United Nations Forum on Forests, which seeks to implement forest-related agreements and enhance sustainable forest management, as well as to protect biological diversity.

Japan also needs to better manage its own forests and continue its contributions, which have been considerable, to researching and monitoring world forests.

Plenty of options exist other than harvesting trees as building materials. Japan should develop eco-tourism, a natural outgrowth of the current city-based tourist booms in Kyoto, Osaka and Tokyo, especially with so many abundant, and unique, forests in place. Such tourism also helps everyone understand the value and importance of forests. That understanding is vital because there are currently fewer trees now than at any point since human civilization began.