Invasive Aliens and Alien UFO

A splendid late summer view of my preserve's meadows

A former member of my land stewardship staff, Mike, moved on five years ago to become the land manager at a preserve owned by another land conservancy in our area.  I consider Mike a colleague, and I contacted him when Temple University (where I am an adjunct faculty member) needed an individual to teach a class on invasive organisms.  It was a match made in heaven (both for Mike and Temple), and Mike is now teaching the class for a second year.

Mike (second from right) holding forth on restoration strategies

On Thursday, September 17, Mike brought his students to my preserve to examine invasive plants (no shortage of them here, unfortunately) and our organization's restoration projects.  I spent the morning outside (a rarity for me) accompanying the class as we walked about three miles through the preserve.

Handling (carefully!) an American chestnut burr

One of our stops was a reforestation area planted in 1994.  We incorporated pure American chestnut trees into the reforestation project, and now the trees are 30 feet tall and producing fruits (more appropriately called burrs).  The trees are all infected with the non-native chestnut blight fungus, but they are pumping out burrs like crazy nonetheless.  The burrs are really prickly and painful to hold; I don't know how squirrels manage to get them open.

Preparing for liftoff

After the walk, Mike brought out his drone to show the students how these devices can be useful for examining the landscape from the air.  He flew the drone about one mile away and returned it to the launch site, a tour that took 9 minutes.  The drone has the capacity to fly for about 18 minutes on one battery charge.

UFO spotted over the preserve

Mike remotely piloted the drone to fly over the meadows and woodlands of the preserve, and then to circle the tower on the right (one mile distant) in the image above.  All the while, the drone was sending back remarkably clear video that Mike recorded on his iPad.  He promised to share the video with me; if he does so, I will post it later.

Forest Restoration Setback

In 2003, our organization expanded a forest restoration project originally begun in 1990.  In the expanded planting of 200 trees, we included a dozen pure American chestnuts (Castanea dentata) that we obtained from a nursery in Oregon.  The Oregon nursery said it believed its seedlings were resistant to the chestnut blight fungus (Cryphonectria parasitica), a pathogen introduced into the United States in the 1920s via imported Chinese chestnut trees.

For those who don't know the story of chestnut blight, the fungus quickly spread from the point of introduction (New York City) throughout the eastern United States.  By the time the pandemic had subsided, one quarter of all trees in the eastern deciduous forest had died, and what had been a major component of the forest became, for all intents and purposes, ecologically extinct in only a few decades.  (Not all chestnut trees died outright; the roots of some of the trees remain alive and continue to produce sprouts.  Once the sprouts reach about 20 feet in height, they are attacked by the fungus again [the fungus remains in the environment] and die back to the ground.  Some saplings even survive long enough to flower and set seed.)

With regard to our planting, the chestnuts have grown tall and beautiful over the last decade; perhaps, I hoped, they really were resistant to the fungus as the nursery suggested.  Then, two weeks ago while on a walk, I noticed that one of the trees had a wound located right a the top of the tree shelter we use to protect all trees from deer damage.  Maybe the tree shelter had rubbed the bark and caused the wound...  But, you probably already know where this is going.  On closer inspection and upon comparison with references, the wound turned out to be a canker caused by the blight fungus.  In fact, there are tiny tell-tale red fungal fruiting bodies on the bark surrounding the canker as well, visible above the canker if you look closely at the image accompanying this post.

I contacted the American Chestnut Foundation (which is trying to develop a resistant chestnut strain) to determine if I should destroy the tree to prevent or delay the fungus from spreading to the other chestnuts.  The Foundation's representative told me that my story was all too familiar and that destroying the tree would only delay spreading the fungus by a very short time.  Better, the person said, would be to let nature takes it course and, hopefully, the roots will re-sprout once the above-ground portion of the tree dies back.