ability to improve the soil and its tolerance and adaptability to grow
in poor soil conditions made it the ideal tree for remediation and
reclamation of spoil heap sites. With its quick growing and deep rooting
nature, Paulownia has also been found to be extremely beneficial in
areas of soil erosion. Paulownia is also grown on salt affected areas
where other trees would not survive, to quickly lower the water table
and provide protection to the fragile soil
which would otherwise be lost. Because of Paulownia’s deciduous nature,
its leaf fall also helps to regenerate an otherwise barren earth by
building up a natural humus which in a short time can provide a suitable
environment for the re-growth of native grasses and sages.
large hairy leaves of Paulownia play a very helpful role in purifying
dust and smoke. Paulownia has become the main tree species for
afforestation in many industrial center’s in mainland China, Singapore and the United States where
dust and smoke pollution are comparatively serious. By comparison, the
airborne sulfur dioxide content in clean areas where Paulownia has been
extensively grown and the polluted districts, were 0.169% and 1.410%
respectively. Paulownia still grows naturally in the polluted areas of
these countries whereas many other trees drop their leaves or fail to
grow under the same conditions.
natural deep rooting characteristic, which absorbs large amounts of
water and nitrates and the natural filtering effect through
transpiration of its leaves make it an ideal crop for use in areas where
large amounts of manures have to be spread.
Paulownia tree makes a delightful, quick growing addition to any medium
to large garden or landscape. Its abundant flowers in spring, which
range in colour from mauve to cream, depending on variety, are very
fragrant and attract bees and the honey from this crop is a
connoisseur’s choice. In addition the large leaves of this tree, up to
75cms across, make it an ideal quick growing tree where shade is
some countries intercropping is practiced either to produce an
agricultural crop between the trees that are more widely spaced for
timber production or by sowing clover or other legumes between those
grown for biomass. The legume would provide a valuable source of
nitrogen, a nutrient to which this crop is particularly responsive.
Paulownia trees create a microclimate. In the dry season, Paulownia
absorbs underground water from greater depths than other crops and
humidifies the air by transpiration, which is beneficial to the growth
of the food crops. In summer, in the inter-copped land, the temperature
has been shown to be reduced by 0.2-1.2° C during the day.
This also helps to guard against natural disasters such as drought, sandstorms, dry hot winds and early and late frosts.
addition to increasing the crop yield, the Paulownia is also a valuable
asset to the farmer. Besides the timber produced the leaves and flowers
are rich in nitrogen (4%) which is returned to the soil. Thus, the vast
area of farmland will be used for producing both food crops and timber.
Paulownia leaves have a similar food value to Lucerne and
are suitable for combining with wheat straw or hay for feeding out to
cattle, sheep or goats. If planted at 540 trees per ha (180 per acre)
Paulownia will produce 1220 kg DM per ha with a protein level of 20% and
digestibility of 60%. Although any trimmings obtained through the years
can be used for fodder, leaves should not be harvested in the spring
and summer as it inhibits timber growth.
The world’s current and future shortage of timber is offered a lifeline with investment in the Paulownia tree.This
has been recognised by the Chinese who have a huge demand for timber
and to help satisfy this have planted some 2.5 million hectares of
Paulownia. The rapid growth of this hardwood tree makes it an ideal
candidate for governments, corporations and private investors alike.
With the tree able to reach a harvestable size in 8 to 15 years,
depending on growing conditions, a rapid return on investment is
possible. Furthermore the tree will re-grow from the stump, so
replanting is unnecessary. It is just a matter of pruning to encourage
re-growth by the favored stem. The wood has many and varied uses.
homes constructed from Paulownia offer very comfortable homes or
offices with a high insulation value. The timber has a high resistance
to rot, can be milled to a high standard and takes a wide range of
external finishes. The lightweight materials used in the construction of
these homes means that delivery and erection costs are low.
timber and plywood offers the marine, surfboard, caravanning, and other
industries substantial advantages in terms of high strength with
lightness in weight. With the timbers’ resistance to cupping, warping
and splitting, manufacturers find this an ideal material for the
reliable construction of high quality,
durable, lightweight equipment. In addition Paulownia plywood can be
prepared with a wide range of decorative finishes and can be
manufactured to marine standard.
The biomass can be used in several forms as it can be:
- burnt for the direct generation of heat for an individual home or for a community heating scheme
- burnt for the generation of steam for the production of electricity
- as a feedstock for the process of pyrolysis for the generation of gas and liquid fuels.