Paulownia trees have been popular in Asia for centuries. They are now attracting more interest for their wide variety of benefits, including potential for sustainable agroforestry systems.
Paulownia trees have attracted great interest, and
the genus has developed a substantial “following” in the US over
the past few decades. As highlighted in this communication, they have been
popular in Asia for a great many centuries. We have invited the
author, who has a commercial agroforestry and tree plantation services company,
to share some of his passion for this plant which clearly has substantial
potential for sustainable agroforestry systems in many areas of the world.
The Paulownia tree has been grown in China for at
least 2600 years. It may well hold the record for history’s oldest plantation
tree. In ancient times (221-207 BC), a book entitled On Qin Dynasty
reported that thousands of Paulownias were planted around Arfang City in China
Paulownia wood, a light-colored hardwood, has been
revered for centuries by Japanese craftsmen because of its workability and
beauty. In the Japanese tradition, Paulownia was used to build kotos
(Japanese harps) because of the wood’s superior acoustical quality.
Paulownia species probably first came to the United
States sometime during the mid-1800s, although researchers have also discovered
evidence that the genus Paulownia grew in the northwestern United States in
prehistoric times (2). Because the seeds are very tiny and light in weight
(1.75 million per pound), the Chinese immigrants often used the seed to cushion
their dishes and other breakables when shipping from the Orient. Some seeds
undoubtedly escaped and took root. About 1970, a group of Japanese wood buyers,
while driving through Virginia, noticed the trees growing wild. The Japanese
began buying up these old-growth (P. tomentosa) Paulownia logs. By 1979,
U.S. growers established a commercial plot with three acres of P. elongata
planted in Polk County, North Carolina.
The genus Paulownia is found in the family Scrophulariaceae,
and is composed of nine major species. All originate in China except P. fortunei,
which is found in Vietnam and Laos. P. tomentosa also grows in Korea and
Japan. Some common names for Paulownia include Empress Tree, Royal Paulownia,
Royal Princess Tree, and Kiri (Japanese). After China opened its doors
to the West following their Cultural Revolution, an Australian was able to
travel to China and return with several varieties of Paulownia. In early 1992,
a California joint venture was formed to market two of these varieties in the
West: P. fortunei and P. kawakamii. Today we find Paulownia
growing on every continent except Antarctica.
Let me begin by sharing with you a little about my
background in agriculture and silviculture, specifically as it relates to Paulownia.
As a teenager, I spent my summers in the mountains of Central
California working on a large cattle ranch, riding the range, growing alfalfa,
and planting apple orchards. I could feel my life changing, and that is when I
discovered the intrinsic value associated with farming—hard work, but very
I studied agriculture in school, completed two tours
of duty in Vietnam, and then in 1970 was asked to participate in the
development of subtropical commercial fruit plantations in the Sonoran Desert
of Northern Mexico. I became a partner in a large ranch, developing a 100,000
tree nursery and working as a farm advisor. During a part of each year, I
worked as a sub-tropical fruit researcher in the Central Valley of California,
and co-authored a booklet for the University of California Extension Service.
In the 1980s, I worked in Mexico to promote the commercial establishment of
Amaranth, a native grain of Mexico.
I first read about Paulownia in the early 1990s. In
1992, a group of Australian and American investors arranged a joint venture to
market the Paulownia in the United States. Their company, known as Sapphire
Dragon Corp., established a nursery in Santa Paula, California. As far as I
know, this was the first commercial production of Paulownia in the Western U.S.
By early 1995, after some unsuccessful attempts to market the Paulownia in Mexico,
Sapphire Dragon called upon me to market two Paulownia species (P. kawakamii
and P. fortunei) in Mexico. By this time, I had married a woman from Mexico
City and our three children had been born in Mexico.
I read all the technical information about Paulownia I
could get my hands on. I was truly impressed, but I still had doubts about the
various incredible assertions made about the wood. I soon set about to see for
myself what the wood was capable of doing. I obtained several 3-year-old logs,
and eventually ordered some milled 12 year-old P. tomentosa from a
fellow member of the American Paulownia Association, Bob Davis. My brother (a
home builder who has a cabinet-making shop) and I began testing the wood. We
cross-cut the wood, stained it, air dried the logs, and varnished it. We milled
it, hammered nails into it, and planed the wood. We also had musical
instruments, wood carvings and molding made from it.
We were eventually convinced of the stories told about
Paulownia wood. Both the juvenile wood of P. fortunei and the
older P. tomentosa performed well. The wood had lived up to the
claims, and then some.
During this time, I took a trip to Mexico where
friends in the agricultural community—both private and government—received Paulownia
with overwhelming enthusiasm. By mid-1995, my brother and I formed Eco Ranchos
(a California partnership) to market Paulownia. By mid-1996, we became members
of the Paulownia Association and formed a Mexican corporation, Eco Ranchos,
S.A. de C.V., whose focus from the beginning has been large reforestation
We soon generated tremendous interest in nearly a
dozen states in Mexico. Sapphire Dragon Corp. proved incapable of filling our
orders, which created a challenge. We were, by necessity, forced into the
propagation and cultivation of Paulownia.
Now that we were getting into the business of growing
the tree, we were anxious to see how well the plant would perform under
different conditions. Would it really do all it was reported to do?
We worked with three species of the genus Paulownia.
We propagated plants using both seeds and root cuttings and experimented with
cloned plants. We also tried using many combinations of planting mixes, in
different sized containers and at different stages of propagation. We planted
trees with different exposures to heat, light, and humidity. We subjected our
plants to various amounts of water and lack thereof. We also tried
transplanting early and late. We exposed the plant to freezing temperatures and
desert highs of 115 degrees F and higher. We also had plants growing from about
19° N latitude to about 40° N.
Not only have we pruned in various ways, but we have
also coppiced in every season, and allowed insects to have at it. We have made
intentional mistakes in every way possible, and the plant has been pushed to
its limits. After all of our testing, we ended up producing Paulownia in both Mexico
Benefits of Paulownia
The plant itself can be used in many beneficial ways.
Just to name a few, the plant has capabilities for ornamental living posts, as
livestock fodder and in honey production. It would also create a barrier for
forest erosion and of course would be excellent for wood production.
I will highlight a few specific ways in which Paulownia
can have a positive effect on the water, the land and the air.
Let’s first look at a few ways Paulownia can be used
to reduce water pollution. Paulownia can be used to help alleviate the problem
of livestock effluent. This liquid run-off can be a big problem, especially for
dairy and pig farmers. A Paulownia plantation surrounding such a farm—in any
configuration—can help consume much of the run-off, while producing shade,
honey and wood at the same time.
Effluent from food processing plants (such as fish and
shrimp processing) can be piped to Paulownia plantations where it can enhance
the growth of trees, and the trees in turn can provide industry with carbon
credits. Paulownia will also flourish from the use of gray water and sewage
run-off. A friend planted a Paulownia directly above the end of a leach line to
his ranch sewer system. He never irrigated it, but it grew to well over 20 feet
tall in its first full growing season and is one of the healthiest Paulownias
I’ve seen. This tree (P. fortuneii) is now more than 60 feet high and
attracts much attention, especially when in blossom (mid-March to mid-April).
To benefit the land, Paulownia can be used to reclaim
mined areas, to prevent erosion, and can be planted on moderately toxic land
sites. However, I think intercropping with Paulownia is by far the most
land-benevolent use of this cultivar. Millions of acres around the world have
been used—or should I say “over-used and abused?”—for centuries by planting the
same annual crop (e.g. corn, cotton, wheat, rice, etc.). The topsoil, the root
zone for these annuals, is often exhausted. When you intercrop with Paulownia,
its roots reach down into soil perhaps never accessed by plant roots.
Paulownia roots—with the help of mycorrhizal
fungi—probe deep into the soil, drawing up untapped nutrients through the stem
or trunk, and eventually into the leaves where they are incorporated into
organic material until, like clockwork, this precious organic material is
broadcast in the large circle of the trees’ leaf litter. Because of the partial
shade, increased moisture, and this rich, high quality leaf-drop, the soil
begins the miraculous process of regeneration. Depleted soil that has been
over-fertilized, fumigated and often chemically choked is transformed and
restored. A life-giving humus begins to form, and with it both flora and fauna
microorganisms begin to thrive.
These microorganisms, the basis of almost every
healthy ecosystem, begin to multiply on a non-stop, 24-hour basis. The soil is
on its way back to a dynamically alive micro-universe, where just a handful of
soil may contain millions of microbes.
You might be saying, “Why sure, all trees perform this
function in nature.” However, the quality of the Paulownia leaf-drop is unlike
that of many other tree and shrub species. Let’s take for an example the
eucalyptus tree. The eucalyptus is an invasive species that completely
dominates the area around it. In order to prevent competition from other
plants, the eucalyptus drops a toxic resin, making the soil uninviting to other
plants (a process called allelopathy).
Many plants develop a beneficial or symbiotic
relationship with a type of microscopic root fungus called “mycorrhizae,” to
help gather moisture and nutrients from the soil. It is known from fossil
records and genetic evidence that soil fungi were present at the time when
plants first colonized land. These fungi have co-evolved with plants to the
present state. The fungi form a symbiotic association with the cells of roots.
The host plant benefits from the presence of its fungal partner, in that mycorrhizal
roots are more efficient than non-mycorrhizal roots. With the help of these
fungi, plants can take-up far more of certain minerals than they otherwise
By inoculating our Paulownia roots with mycorrhizae
fungi at the nursery stage, we can reduce disease, increase growth, improve
stress resistance, and decrease transplant mortality. The result is a stronger
plant, and of course stronger plants are much less likely to be bothered by
pests and diseases. This research is based, in large part, on the work of Dr. Robert Linderman, a world-renowned USDA pathologist, whom
I have had the pleasure of getting to know personally.
When it comes to improving air quality, Paulownia is a
star! It is an excellent plant for the sequestration of carbon and giving off
of oxygen. As noted earlier, the plant is a fast grower, and the faster it
produces wood (where carbon is stored) the more carbon will be taken up.
Selected Uses of the Wood
There are hundreds of established uses of Paulownia
wood, and most likely an equal number of as yet undiscovered uses. In Table 1 I
have provided a list, which is by no means exhaustive, of ways Paulownia has
been used and is being used.
Uses for Paulownia wood
Interior framing, including door and window frames
Wall paneling and folding partitions
Plywood, particleboard, and flake-board
Furniture, especially with doors and drawers
Automobile and yacht interiors
Paneling and partitions in airplanes and ships
Boat construction and paddles
Beehive construction (resistant to cracking and
warping, good insulation qualities, lightweight)
Decorative containers (pails, jewelry boxes, bowls,
Humidors and cigar boxes
Lining for safe deposit boxes
Pallets, boxes and crates (lightweight airfreight
crating minimizes shipping costs)
Packing material (natural insulation, biodegradable
packing, no odor or taste)
Food and gift packing (cuts thin, light and strong,
free from odor or flavor: could pack specialty foods such as cheese, fruit,
Arts and crafts: small stock (from crown of tree)
used for paint brush handles, pencils, charcoal bars for sketching, etc.
Shoe and sandal manufacturing
Filtration material for evaporation coolers
A friend of mine who lives in Arizona is a master
flautist. I shared some small-diameter branches with him so he might test the
wood. I thought the characteristic hole down the middle would help the process.
He later wrote back to me, and I quote: “I have worked on my Bass Paulownia
until it has become the pride of my collection. Without reservation, the Paulownia
instruments are superior to any materials I’ve ever used. I recently played a
gig where the acoustics were very live. People reacted as though it were a
‘creature’ sublime. I think it has been a turning point in my flute making
journey/experience.” Maybe Paulownia could be just as successful in the
construction of guitars and other musical instruments.
With all of the wonderful properties and uses of Paulownia—those
known throughout the centuries and those recently discovered—this tree
definitely merits further examination and experimentation. Its potential
benefits in agriculture, environment, and industry have only just begun to be
explored and utilized. Who knows how many other areas of human society and our
world may benefit in the future from this “agroforestry gem.”
(Click to enlarge)
Figure 1: Paulownia fortunei in Santa Paula, California,
approximately 5 years old
(Click to enlarge)
Figure 2: This Paulownia fortunei “mother tree”
resulted from a breeding program to produce a strain well-suited for lumber.
Selected from 1700 trees started mostly from seed and grown for seven years,
its trunk is 60 feet tall and has very little taper, making it valuable for
lumber production. This tree is being reproduced through tissue culture cloning
and root cuttings.
(Click to enlarge)
Figure 3: Paulownia kawakamii propogated from root
cuttings, at three months old. This species is usually used for landscaping
(Click to enlarge)
Figure 4: Paulownia kawakamii blossoms
(Click to enlarge)
Figure 5: Paulownia elongata in Georgia,
approximately 10 years old
Academy of Forestry Staff (1986) Paulownia in China:
Cultivation and Utilization, Asian Network for Biological Sciences.
CJ (1961) A Record of Paulownia in the Tertiary of North America, American
Journal of Botany 48(2): 175-179