Giant rees crossing borders

In the world of trees, David Milarch is a rock star.

In 2013, The Man Who Planted Trees — a book that reached the New York Times bestseller list — chronicled Milarch's transformation from a lumberjack living in Michigan to an international crusader who clones giant trees to restore old-growth forests around the globe. A documentary about Milarch's efforts is now in the works.

I had interviewed Milarch following the wave of media coverage, intending to write an article about whether it was feasible for Germany to restore its forests by importing large trees such as redwoods, when Milarch asked me: "Could I send you some baby trees to plant?"

I had flashbacks to my childhood family vacation to California's Muir Woods National Monument, a place that quickly reminds one of humanity's insignificance. The two species of redwoods, giant sequoias and coastal redwoods, can grow beyond 115 meters tall and 8 meters in diameter! But Muir Woods is also an indication of humanity's might: more than a century of logging has left the northern hemisphere with only five percent of these giant trees.

There are Websites that track where giant trees have been planted globally, and a quick search at one such site, monumentaltrees.com, shows users have uploaded photographs and the location of more than eight dozen non-native giant trees planted in Europe during the last two centuries.

After agreeing to have Milarch’s baby redwoods shipped to my address, I still wanted to understand more about these giants and talked to someone who would know.

Planting redwoods globally in spite of a changing climate

"We're fascinated in knowing where redwood trees are planted around the world," says Emily Burns, director for science at the Save the Redwoods League, who added that the timber industry in New Zealand has planted California redwoods for decades.

Although a tree stops sequestering carbon the moment it's cut down—and additional carbon is released in the transportation of cut trees—redwoods are able to hang on to a bulk of their carbon in the final wood product.

"Once we know where enough of them are, then we'd actually be able to do a climate analysis and start expanding our knowledge of the possible range of climate conditions redwoods can live in," Burns told me. "That could help us to make decisions on where redwoods can be planted as climate changes."

Anthony Ambrose, a researcher at the University of California, Berkeley, who also studies these trees, says that storing a lot of carbon does not, however, make redwoods particularly special when it comes to climate change and overall resilience. His research shows that California's coastal redwood forest, where trees are two to three thousand years old, have the greatest carbon biomass on Earth. That doesn't mean these trees remove carbon from the atmosphere at a rapid rate to influence the warming of our planet.

"It's not that they're sucking up carbon out of the atmosphere faster than other trees, it's that they store it for longer periods of time," Ambrose said.

Climate zones are changing due to climate change, which adds another challenge to figuring out what species of trees to plant where. This may come down to the value judgements of society.

And then there is politics.

The European Parliament approved a resolution in April 2014 that has initially restricted 50 invasive plant and animal species from entering Europe, although it's suggested that the number is a baseline and might turn into hundreds or thousands of restrictions. It is not clear if large trees are on that initial list, according to Frank Krumm, a senior researcher at the European Forest Institute. So, if I were to deposit my baby redwoods in a public park I might be in for trouble. It is illegal without the appropriate documents and permissions to import live plants, as detailed in the International Plant Protection Convention (https://www.ippc.int/). It sometimes takes laboratories years to gain the approval of government bodies to import species for research.

Such rules, however, appear in contradiction with the realities facing Europe's forests, where centuries of deforestation forced farmers to plant non-native tree varieties to restore their lands.

"Natural dynamics are usually suppressed," Krumm said. "Forest management in Europe differs from the United States, because Europe lacks the kind of space necessary for large tracks of conservation."

Even native trees, such as the European beech, can have an invasive character, he added, demonstrating an ongoing tension between what should be planted and where.

"You needed proof these species would not be invasive and getting that proof might take generations," he said.

Neither time nor the law were clearly on my side, as I found out since the tree saplings were delivered to me from Michigan.

They have, sadly, since withered away on my Berlin patio.