Saturday, December 21, 2013

Yggdrasil


During my last course I wrote a paper on ash tree genetics and resistance to Emerald ash borer. (Don't get your hopes up. North American species don't appear to be very resistant).  While I was looking through assorted scientific papers I came across the term Yggdrasil - which is a name from Norse mythology for a giant world tree. By all accounts Yggdrasil was an ash tree!

  The Ash Yggdrasil by Friedrich Wilhelm Heine (1886)

I really wanted to work old Yggy into my paper, but I couldn't find a proper way to do it. I have been thinking about this mythological ash tree ever since then. Here on Earth a variety of ash tree species populate the entire northern hemisphere, and it happens that European ashes (Fraxinus excelsior) are also vulnerable to a serious invasive fungus species, ash dieback. Between these assorted pathogens ash trees globally are truly a genus that is on the ropes.

Yggdrasil (possibly) occupying a Viking age tapestry

It seems to me that in our culture if we associate any mythological meaning to any tree it's oaks, or maybe maples, that immediately jump to mind. Around these parts White ashes are valued for their fall color, but otherwise these trees were seen as solid, utilitarian native citizens - but that's about it. Not very mythological as trees go! Seeing how ashes were once elevated to such a status was a surprise to me.

Ash tree. Cook County IL :: 2013

Today my solstice hike led me out to the edge of Phantom Prairie at Crabtree Nature Center where I saw this ash tree hanging on - for now.  Along the trail through the woods I spotted some canoe paddle shaped ash seeds here and there. Once a very common sight these too will be soon be rare. Only time will tell if North American ashes have any natural resistance to Emerald ash borer and it will be interesting to see what trees will fill ultimately fill the environmental voids left by infested ash trees.  

 Ash seeds.

Perhaps we should get a good look at our local ash trees while they're still here. They're rapidly on their way to folkloric, if not mythological status.

4 comments:

troutbirder said...

No signs in our immediate locale but I'm very apprehensive. Between this and all the invasive species in our waters it's a gloomy prospect, for sure....
Chins up though, Happy Holidays, Dave...:)

Dave Coulter said...

troutbirder - HAppy Holidays to you too! :)

You may have seen this map already:

http://www.aphis.usda.gov/plant_health/plant_pest_info/emerald_ash_b/downloads/eab_quarantine_map.pdf

Up north you may get a break. I saw one paper that suggested the extreme cold in MN & the Dakotas (etc) may keep the insect away. I'll keep my fingers crossed!



Nook Naturalists said...

Dave I hope you have (or will) submit this post to Berry-go-round today! I'd love to see it in this month's carnival.

Dave Coulter said...

Hey Nook,

Thanks for the reminder - just sent it in :)

Happy Holidays!