Wednesday, November 9, 2016

Paulownia

A few years ago our neighbors brought us several gigantic leaves from a tree up on top of our hillside.  They wore them draped over their heads like huge sun hats.  This was our introduction to Paulownia, an Asian invasive species.  Barb isn't smiling, that is actually a grimace.

This is the Princess Tree or Empress Tree, Paulownia tomentosa, a tree that you can love and hate at the same time.  Let's start with the love.  It is planted as an ornamental in gardens and parks.  It was even awarded the Royal Horticultural Society Award of Garden Merit in England.  It has large, colorful and fragrant flowers.

Paulownia flowers - Wikimedia
It is rapid growing, a pioneer plant adept at growing on barren ground.  Its massive leaves can enrich the soil and while it grows tall (35-80 feet) rapidly, it doesn't tolerate shade of the taller trees that in China will grow more slowly and eventually replace it.

There is now a growing market for Paulownia as a rapid growing soft wood that carves easily and can be used in plywood.  It is said to be strong and lightweight, "ideal" for surf boards and wooden boats.  It is also being touted as rapid growing carbon dioxide sink.  The sites selling it talk about the ease of the trees spreading and the fact that stakes cut from the stems readily root.  Can you spell invasive?

One year growth - click to enlarge

"Rapid growing" is like calling Moby Dick a big fish.  I cut the three trunks of our specimen last fall and was amazed to return this year and watch the growth.  The young trunks are flexible and hang in a curve with the weight of the leaves.  Richard Herman joined us and was able to pull the 12 foot high plant down for pictures.  The picture on the right is one of the trunks after we cut it off at ground level without spraying the stump last fall.  You can just make me out in the hat in the lower right hand corner.


The first few years Barb and I battled on the fate of the tree.  I wanted to leave it alone at least until we saw blossoms and fruit.  Barb wanted it cut and killed immediately.  We compromised on cutting it when it blossomed, while she told every visitor that saw the tree that when she died they had a sacred responsibility to come to our tree farm and cut it down in her memory.

This year in the spring the tree produced buds and she called in her debt.  With a heavy heart, I cut down the trunks and photographed the results.  The poor buds died before fulfilling their biological mission to "go forth and multiply."

Paulownia stems
Paulownia trunk












This did give me the opportunity to study the wood, which demonstrated how it can grow so rapidly.  In addition to being very soft and light weight, the young trunks are hollow in the center!  As you might expect, this rapid growth is at the expense of strength.  Two strokes of a hand held Silkey Saw halfway through the trunk and it broke off.  




The final question was how did this get into the middle of our timber stand, several miles from the nearest residential yard.  The answer lies in the tiny light weight winged seeds,  These can easily be spread by wind and water.  So are Paulownia trees good or bad?  As usual, the answer is "it depends."

5-14-2017  6 month update
We stored several of the cut 2" trunks in the garage for future use.  Last week one sprouted several sets of leaves.  As Bill Bryson* said, "Life just wants to be; but it doesn't want to be much."

* A Short History of Nearly Everything - Bill Bryson

1 comment:

  1. So are Paulownia trees good or bad?
    If you are in North America the answer is: BAD

    ReplyDelete