6. The Tree

If our goal is capturing and storing carbon therefore we plan to use the fastest growing tree the world has to offer.

What we want is a tree with big leaves like this. (First year Paulownia)

leave paulownia

Paulownia features

Paulownia is not just another exotic tree. It is difficult to list without missing some areas where different parts of it are used. Wood, leaves, blossoms – each of them have usable properties.

The whole plant with its remarkably fast growing feature is a little treasure to environmentalists. They have found, that paulownia, with its rapidly developing root system, is extremely suitable to forest plots at risk of erosion. Because of the considerable quantity of foliage, it provides natural fertilization of the areas after the fall of the leaves.

There is no need to mention what a big amount of green (and photosynthetic) mass these leaves contain and how much carbon dioxide they are able to process. If there really is a tree to call the “lungs of the earth”- it is paulownia.

The leaves are about 75 cm in diameter and are suitable to prepare food for the grazing stock, they contain about 20% protein and their features are close to the lucerne. The accessibility and the big yield provide low cost (one of the most important benchmarks for the selection of feed in the cattle industry). But this is not the only thing that paulownia leaves are appreciated for. It is known that they contain some substances which influence beneficially the activity of the liver, kidneys and gallbladder. These properties of them have been known for a long time in China; the Chinese pharmaceutical industry produces medicines based on paulownia.  Only recently have extracts of paulownia leaves been included in the formula of creams and perfumes. The same applies to the blossoms; the aroma of paulownia blossom is defined as vanilla and lightly almond. It was revealed that it is due to the heliotropin it contains. This is a substance, well known in perfumery present in other aromas (Tahitian vanilla for example).

Comparative characteristics by growing speed of the first 7 species of fast growing trees of the planet.

Common Name Growth Rate per Yr. Height in 3 Yrs Mature Height
Paulownia, Empress Tree(Paulownia spp.) 3 – 5 m 10,5 – 15,5 m 15 – 20 m
Willow Hybrid(Salix spp. hybrid) 1,5 – 4 m 7,5 – 12 m 15 – 25 m
Lombardy Poplar(Populus nigra) 2,5 – 3,5 m 9 – 12 m 20 – 25 m
Hybrid Poplar(Populus deltoides) 2,5 – 3,5 m 9 – 12 m 20 – 30 m
Nuttall oak(Quercus texana, Quercus nuttalli) 2 – 2,5 m 7,5 – 9 m 15 – 20 m
Eucalyptus Tree(Eucalyptus polyanthemos) 2 – 2,5 m 6 – 9 m 10 – 15 m
Weeping Willow(Salix babylonica) 1,5 – 2,5 m 4,5 – 9 m 15 – 20 m

*This data is taken from research done on the territory of the USA

From all of these species, the Paulownia is the least pretentious regarding the soil quality. It easily adapts to different types of soil and the only specific requirement is the presence of enough moisture during the first years of its growth. The tree has a long lifespan – from 70 to 100 years, which makes it an exception among the other fast growing species.

Climate – Paulownia is a deciduous tree, indigenous to south and east China, paulownia has been grown successfully around the world in plantations in a wide range of climatic zones. Naturally it occurs between latitudes 20 degrees and 30 degrees mostly in the warm temperate to tropical zones. The temperature range in its natural distribution is –10°C to 40°C with an annual rainfall of 500 to 1200mm mostly during spring and summer.

The fast growth of the tree is extremely suitable for obtaining large quantities of biomass for a short time. Many growers of Paulownia have already introduced this practice at their farms. The whole tree is used – stem, leaf mass, etc. The biomass of paulownia is suitable for silage (therefore as food for animals), and for other purposes like the use as energy source.

One of the most perspective applications is bio charcoal easily to produce and use, without any harm done to the environment. The tree is used to produce the current nowadays pellets, used as fuel for boilers, heating single homes or entire buildings and for industrial purpose.

The cheap and easy obtaining of biomass is possible because the following features of paulownia:

– It does not require replanting; even at low cutting. The young tree grows from the log and it will grow even faster because the root system of the tree is already developed.

– The stem may be cut at any time – not caught up with seasons and limits to harvest.

Nothing is really lost from paulownia; nothing pollutes or changes the environment. In this sense it is not an exaggeration to call it the “Tree of the future”.

Paulownia Biomas Plantation

Paulownia after harvest

Paulownia after harvest

Six Weeks Later

Six Weeks Later

8 weeks later

8 weeks later

After 10 weeks

After 10 weeks

15 weeks old

15 weeks old

Harvest after 25 weeks

Harvest after 25 weeks

to the power plant

to the power plant

Almost ready for next cycle

Almost ready for next cycle

Bio-mass or Bio-charcoal will create income  after one year maximum two years.  After a few rotations the tree can grow for it’s timber (7/10 years)

One of the interesting features of paulownia tree is the wonderful properties of its wood. When compare its cost to its features, it is seen that we are not too far from the ideal wood.

Lightweight
Paulownia is about 2/3 the weight of the lightest commercial wood grown in the US. It weighs an average of 14 to 19 lbs per cubic foot. Paulownia is almost 1/3 the weight of Oak (44 lbs p/cubic ft) and half the weight of Pine (30 lbs p/cubic ft).

The specific gravity of Paulownia ranges between 0.23 to 0.30 (23 to 30% of the density of water).

Strength
Paulownia has one of the highest strength to weight ratios of any wood.
Strength modus of rupture MOR (psi) of Paulownia is 5740.

Paulownia holds nails and screws well and does not require pilot holes to be drilled. In fact both yellow poplar and white pine have proven to split before Paulownia. Flat head screws can be driven flush with the surface.

Plantation grown Paulownia is mostly knot free, making it very consistent.

Workability
The paulownia tree has been widely used in the orient for fine furniture, musical instruments, carvings and decorative finishes for over 1000 years. It can be peeled for veneer in 1/16 inch thickness and has even been sliced at 1/32 inch.

Stability
Air-drying takes as little as 30 days. Boards can be kiln dried at high temperatures in as little as 24 hours to 10% to 12% moisture content with no warping. Reported shrinkage from green to oven-dry is only 2.2% radial and 4.0% tangential.

Paulownia remains stable during changes in humidity and experiences little shrinkage or expansion compared to most other woods. It is highly durable and resists decay under non-ground contact conditions. The wood is insect resistant.

Conductivity
Paulownia is a very good insulator. Paulownia log homes are said to have twice the R factor as pine or oak logs. This temperature resistance serves to give the wood a high fire resistance. Ignition temperature is approximately 400 deg. C. which is almost twice many conventional American hard and soft woods.

Attractiveness
Paulownia has a light blond appearance and resembles White Ash. It stains well with a variety of colors and can be made to mimic other woods. Once planed a silky luster is revealed. The feel is also very silky.

Source(s):

http://paulowniapanama.org/index_archivos/Page1881.htm

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