- Press Release
- Nov 27, 2022
In Search of Moon Trees – NASA Science News
Hundreds of trees have been to the Moon. How they got there and back again
is a curious tale.
August 13, 2002: Scattered around our planet are hundreds of creatures that
have been to the Moon and back again. None of them are human. They outnumber
active astronauts 3:1. And most are missing.
They’re trees. "Moon Trees."
NASA scientist Dave Williams has found 40 of them and he’s looking for more.
"They were just seeds when they left Earth in 1971 onboard Apollo 14,"
explains Williams. "Now they’re fully grown. They look like ordinary
trees–but they’re special because they’ve been to the Moon."
How they got there and back is a curious tale.
It begins in 1953 when Stuart Roosa parachuted into an Oregon forest fire.
He had just taken a summer job as a US Forest Service "smoke jumper,"
parachuting into wildfires in order to put them out. It was probably
adventure that first attracted Roosa to the job, but he soon grew to love
the forests, too. "My father had an affinity for the outdoors," recalls Air
Force Lt. Col. Jack Roosa, Stuart’s son. "He often reminisced about the tall
Ponderosa pine trees from his smoke jumping days."
Thirteen years later, NASA invited Roosa, who had since become an Air Force
test pilot, to join the astronaut program. He accepted. Roosa, Ed Mitchell
and Al Shepard eventually formed the prime crew for Apollo 14, slated for
launch in 1971.
"Each Apollo astronaut was allowed to take a small number of personal items
to the Moon," continued Jack. Their PPKs, or Personal Preference Kits, were
often filled with trinkets–coins, stamps or mission patches. Al Shepard
took golf balls. On Gemini 3, John Young brought a corned beef sandwich. "My
father chose trees," says Jack. "It was his way of paying tribute to the US
The Forest Service was delighted.
"It was part science, part publicity stunt," laughs Stan Krugman, who was
the US Forest Service’s staff director for forest genetics research in 1971.
"The scientists wanted to find out what would happen to these seeds if they
took a ride to the Moon. Would they sprout? Would the trees look normal?" In
those days biologists had done few experiments in space; this would be one
of the first. "We also wanted to give them away as part of the Bicentennial
celebration in 1976."
Krugman himself selected the varieties: Redwood, Loblolly pine, Sycamore,
Douglas Fir and Sweetgum. "I picked redwoods because they were well-known,
and the others because they would grow well in many parts of the United
States," he explained. "The seeds came from two Forest Service genetics
institutes. In most cases we knew their parents (a key requirement for any
post-flight genetic studies)."
On January 31, 1971, Apollo 14 blasted off. Only Shepard and Mitchell
actually walked on Moon. On Feb. 5th they landed the lunar module Antares in
Fra Mauro–a hilly area where Shepard famously launched his golf balls using
a geology tool as a makeshift driver. Roosa remained in orbit as pilot of
the mission’s command module Kitty Hawk. Inside his PPK was a metal
cylinder, 6 inches long and 3 inches wide, filled with seeds. Together they
circled the Moon 34 times.
Apollo 14 was a success. Scientists were delighted with the mission’s
geology experiments and they were eager to study the 43 kg of Moon rocks
collected by Shepard and Mitchell. Krugman was just as eager to study the
"We had a bit of a scare," Krugman recalls. During decontamination
procedures, the seed canister was exposed to vacuum and it burst. The seeds
were scattered and traumatized. "We weren’t sure if they were still viable,"
he says. Working by hand, Krugman carefully separated the seeds by species
and sent them to Forest Service labs in Mississippi and California. Despite
the accident, nearly all of them germinated. "We had [hundreds of] seedlings
that had been to the Moon!" Thirty-one years later, Krugman still sounds
During the years that followed, the trees thrived as scientists watched.
"The trees grew normally," he continued. "They reproduced with Earth trees
and their offspring, called half-Moon trees, were normal, too." (He notes,
however, that DNA analysis wasn’t routinely done in the early ’70’s, and so
the Moon trees weren’t tested in that way. There might be subtle differences
yet to be discovered.)
Finally, in 1975, they were ready to leave the lab. "That’s when things got
out of hand," he says.
Everyone wanted a Moon tree. In 1975 and ’76, trees were sent to the White
House, to Independence Square in Philadelphia, to Valley Forge. "One tree
went to the Emperor of Japan. Senators wanted trees to dedicate buildings.
We even did some plantings in New Orleans because the mayor there, Mayor
Moon, wanted some," says Krugman. There were so many requests that "we had
to produce additional seedlings from rooted cuttings of the original trees."
No one kept systematic records, notes Dave Williams. That’s why the
whereabouts of the trees today are mostly unknown.
One of the them went to a Girl Scout camp in Cannelton, Indiana, where 3rd
grade teacher Joan Goble found it in 1996. (She knew it was a Moon Tree
because a sign said so. Most Moon trees were planted with ceremony; there’s
usually a sign or plaque nearby that identifies them.) "My students love
it," she says. "It looks like an ordinary tree, but they feel it’s special
anyway because of its trip to the Moon." Jack Roosa has since become a pen
pal of Goble’s class, encouraging the students to explore and learn as his
When Goble contacted Dave Williams to ask for more information about Moon
trees, "I was clueless," Williams admits. Like many people who were young in
the 1970’s, Williams had never heard of such trees, but he soon became an
enthusiast. "I found one Moon tree right here at Goddard near my office," he
laughs. "I had no idea it was there."
Often that’s how they’re encountered–by accident. Williams now maintains a
web site listing all known Moon trees. If you stumble across one, contact
Dave. He’ll investigate the find and add it to the collection if it’s
Moon trees are long-lived, adds Krugman. The redwoods could last thousands
of years, and the pines have a life expectancy of centuries. Indeed, they’ve
already outlived Stuart Roosa and Al Shepard–two of the humans who took
them to the Moon.
Says Jack, "I think my father always knew that these trees would serve as a
long-lasting, living reminder of mankind’s greatest achievement–the manned
missions to the Moon." Of course, if humans don’t return soon, Moon trees
could become the only living things on our planet that have been to the
Moon. That’s probably not what Stuart had in mind.
Jack, however, is optimistic: "These trees will be here 100 years from now,"
he says. "By then I believe we’ll be planting Mars trees right beside them."
Editor’s Note: Stuart Roosa is not the best known Apollo astronaut, but he
is remarkably influential. Even after his death he continues to inspire
young people to become explorers–witness the students in Joan Goble’s
class. Sometimes great explorers neglect their own families in pursuit of
the unknown. Not Roosa, as this anecdote from son Jack illustrates: "Not
long ago I was attending the Army Command and General Staff College at Fort
Leavenworth, Kansas," says Jack. "It was a brisk fall afternoon and I
decided to take my two daughters up to Atchison (the home of Amelia Earhart)
for a day-trip. We stopped at a park just outside of town, and as we were
walking around, I noticed a path leading to a tree surrounded by a circle of
bricks. I stopped and read the placard. It was a Moon tree! Tears welled in
my eyes as I stood there looking at the tree and thinking of my father. He
had died a few years before and the tree brought forth a flood of family
memories. I missed him then and still miss him dearly."