Sunday, August 11, 2013

ASH TREES: Chalara Ash Dieback

Tragically, these wonderful, graceful native trees are severely threatened in the UK, where our landscape- which includes 92 million Ash trees- could be changed as it was by the onslaught of Dutch Elm disease in the late 60's.  This time, it is by a deadly fungus- Chalara fraxinea- which especially affects the Common Ash,  Fraxinea excelsior (so named for its height- rising to the Heavens, sometimes to 40m!).

The disease has spread from Northern Europe- where 90% of Ashes in Denmark have been infected-  first reaching the UK in February 2012, and now being found in 17 Counties.

Before going into more details, I would like to celebrate the Ash trees as they now are, starting with photos of skeletal Winter ones in the London region:

 I love the fluid curves at the extremities of the branches, described by Gerald Manly Hopkins as "contradictory supple curvings" (he also makes a comparison between a Bluebell and an Ash:"Its inscape is mixed of strength and grace, like an ash-tree.")   

Purple Ash flower clusters appear before the leaves...

Photo by Donar Reiskoffer
 I find the animal hoof-like black buds strangely magical...

And the compound leaves make endless wonderful patterns

The patterns are enriched by the large bunches of winged seed Keys

As a child, I believed these "keys" were really functional keys for locks, which added to their magic!

Younger trees have smooth bark...

Here are some older ones:

And here you can see the diamond shape formation of the mature tree's bark

 Ash trees are very much part of Folklore- they are embedded in our consciousness.  The very words "The Ash Grove" conjure up a romantic image, based on remembrances of the old Welsh lyrics to the song, of which there are many versions.  Here is a link to one by Benjamin Britten and Peter Pears.

Ashes have long been credited with both magic and healing powers in many countries.  To heal them in Britain, sick children would be passed through the cleft of a tree- and subsequently their health would be related to that of this particular tree.

The Ash is also vital in Viking mythology.  The World Tree, Yggdrasil, was depicted as an Ash.  This tree formed the world's scaffold or Cosmic Axis.  Growing on an island in the ocean, the World Serpent lay in its roots which reached down to the underworld while its trunk reached up to the Heavens and its branches spread over the Earth.  An Eagle sat in the canopy and a squirrel conveyed messages between him and the Serpent, while deer fed on the leaves and the World's rivers poured from their antlers and a Goat dispensed mead (a honey-like substance can in fact be obtained from ash bark and leaves) to the god Odin's Great Hall and the gods gathered under this guardian tree.  

Below is an illustration of this concept, by Friedrich Wilhelm Heine:

"The Ash Yggdrasil" (1886)
We are all familiar with rhymes associated with Ash trees- such as "The Ash before the Oak and we shall have a soak- The Oak before the Ash and we shall have a splash".  One I did not know of is: "Beware the ash, it courts a flash, beware the Oak, it courts a stroke".   Now this last one is interesting as it refers to the fact that these two trees attract lightening more than any others.   Lightening was seen by the ancients as a fertilizing power from the heavens down to earth.  The word "ash" derives from the Icelandic aske, which means "a great fire blaze" while the botanical name for the Ash, Fraxinus, means "Great Fire Light".  Consequently, the Ash is often thought of as the Father of mankind and in Scandinavian myths the first man Askr was made from Ash, and they called themselves Aeslings, men of Ash.

There are countless other magical myths associated with the tree- from Druids wands to Witches broomsticks.  You can read about some of them on the Trees for Life site.

Apart from all this Ash timber has very practical properties.  Having a tight grain and being very flexible, it has great strength and load-bearing uses which has long made it indispensable.   In the past it was used for chariots and weapons, while ash has been traditionally the choice for the handles of tools.  Also in woodlands- Ashes  having light foliage which does not block out sunlight-  wild flowers and other plants are able to flourish beneath them.

 I have written about all this at some length to emphasize what a loss it would be to us in so very many ways if this invaluable, historical and miraculous tree was lost from our landscape- let alone for the fact that we can ill-afford to lose our 92 million Ash tree canopy.  

So, to return to this horrible fungus, Chalara fraxinia, what is being done to halt its progress?

As the main spread of the disease seemed to be through the importing of infected saplings to nurseries in Britain, it was finally decided to ban this trade- but not until far to late.  The first cases in this country were noted in February 2012- from a Dutch consignment, when the Netherlands already had confirmed cases in 2010- but the law was not enforced until October 2012.

The Government has set up a Chalara Management Plan, the four key objectives being:
  • Reducing the rate of spread of the disease
  • Developing resistance to the disease in the native ash tree population
  • Encouraging  landowner, citizen and industry engagement in surveillance, monitoring and action in tackling the problem
  • Building economic and environmental resilience in woodlands and in associated industries
 Scientists have unravelled the genetic code of the fungus, hoping in the long term to stop the epidemic- see BBC link

The Forestry Commission have set up a site, which includes showing how citizens can help by reporting cases.  Below, are five examples of what to look out for:

The above diamond shape is significant

 The Forestry Commission regularly updates this information and map showing the Distribution and progress of Chalara :

  Confirmed findings at 12 August 2013:

Nursery sites - 24
Recently planted sites - 336
Wider environment, e.g. established woodland - 194
Total: 554

Outbreak map.

 Well, the immediate prospects of our beloved Ash trees do not look optimistic.  We can only hope that scientists are successful in finding a breakthrough or that Nature comes to our rescue.  Let's just hope that future children don't grow up knowing the graceful Ash tree only through Mythology.



Thursday, July 25, 2013

Silk Floss Tree

I am shocked to see how long it is since I have posted anything here.  It is odd, because Treeaware is always on my mind and I have constantly been taking photos for the blog but not actually posting them.  I think this is largely caused by the fact that I have been adjusting to having two delightful Granddaughters instead of just one- and helping look after two very young girls is certainly more demanding than one!  Don't misunderstand me, I feel incredibly lucky to have the experience and enjoy it immensely- I just need to push myself to make use of the ample time I have for my own work.  I have just got out of the habit.
That said, I am restarting by writing a long post about one of my very, very favourite Los Angeles' trees- the Silk Floss tree, or Ceiba speciosa, a drought tolerant native from the tropical and sub-tropical forests of South America. 

I love it because everything about it is- to me- extraordinary and totally unexpected as you watch it through the seasons. 

What first excited me on seeing one of these trees in Santa Monica was these amazingly sharp conical spikes, giving the tree the appearance of some scaly prehistoric animal:

 Apparently, one of the uses of these spikes is to store water...

           Whereas older trees turn grey, young trees have green trunks due to a high chlorophyll content  to enable photosynthesis when the leaves fall off (they are deciduous).
           Below, are some examples of smoother bark, but still having a very animal-like structure:

   Even the roots sometimes perpetuate this animal-like formation!

Here below is a Silk Floss in the Los Angeles Arboretum and Botanical Gardens in Arcadia.  This, and the following one, show how the older trees are often bottle shaped, bulging out in the lower trunk- caused by water collecting there:

  I also love the patterns of green lines you often find between the spikes, as above and below.  These are in fact "stretch marks" caused by the expansion of the bark as the tree becomes bloated with water.

 But this possibly younger tree- also in the Arboretum- has no bulge and is immensely tall.  They can grow rapidly up to as much as 80ft:

                And here is another tall one, but this time with a good collection of spikes:

The next thing that excited and surprized me about this most surprizing tree, was the flowers that usually appear after the leaves have fallen.  Who would believe that this extraordinary spiky barked tree would produce these delicate, pink (or sometimes white or dark pink) orchid-like flowers?  I find this unexpected juxtaposition fascinating.

And then this tree has yet another surprize, gradually evolving into a sci-fi tree, as the flowers die and morph into mysterious avocado-like "pods", covering the trees...

Now for the last excitement: if you have wondered why it is called a Silk Floss tree, here is your answer.  The pods begin to split, exposing some white fluff:


The hard sections of the pods fall away leaving the "silk floss" exposed:

At this stage the floss can be very reminiscent of cauliflowers!

But after a time it breaks up and becomes silky.  If you look carefully you can spot the bean-like seeds nestling inside:

Finally, the wind blows the floss off the branches onto the ground- a fluffy mass of silk, one seed in each piece:

So this is explains why the Silk Floss belongs to the same family as the Kapok tree, whose fluff was traditionally used as stuffing for toys and cushions.   As a child, before the days of synthetic wadding, I used this constantly.  Now, of course, the value of using organic materials is recognized.  The Silk Floss tree's fluff has sometimes been used in this way too, but sadly it's uses are limited as it is so much more delicate and insubstantial than kapok.


The last things we see- scattered on the ground below the tree - are the fallen sections of the pods...