Tuesday, March 28, 2017

More predators in action!

Just last week we were collecting data for some ongoing research we are doing measuring the impact that predator beetles are having on hemlock woolly adelgid.  We saw evidence of predators on all of our trees, but I was able to capture this satisfying footage of a Laricobius nigrinus larvae feasting on adelgids...


Just how much of an impact are these predators having?  Not sure just yet, but we are part of a regional study hoping to figure that out.  Stay tuned...

Tuesday, February 28, 2017

Visiting The Smoky Mountains...

At the beginning of the month, Bud and I visited Great Smoky Mountains National Park to talk about a research project we would like to do there and look at some potential sites.  Driving through Gatlinburg, we were astounded at the damage caused by the wildfires this past fall on the park lands, but even more so the damage in downtown Gatlinburg itself! 


Like so many others, I followed the news stories as the fires were ongoing, but it is very different to visit.  People all around town are actively picking up the pieces and rebuilding.  These were devastating fires, a tragic reminder that we must be vigilant stewards of the environment we live in and ever aware of local climate conditions.

 Only the foundation and chimney remain of a house near downtown Gatlinburg.

  Fire damage in some of the hemlock forest on park land.

Our trip was productive and despite the damage caused by wildfires, there are still good sites with surviving hemlock where we can do the proposed research. We also got to see some of the largest living hemlock trees that I have personally had the pleasure of seeing.  These beauties were over 100 feet tall!  The foresters at GSMNP have treated over 250,000 hemlock trees!  Obviously, they are working hard to preserve this vital tree species. 

A mature hemlock stand at GSMNP.

On the way back to Asheville we had this view of the park.  Yes folks, despite the warm temperatures, it is still winter.  The lighter color along the mountaintops is indeed ice.

 A view of GSMNP from the Foothills Parkway.

Monday, February 6, 2017

Coming soon ...

I recently had the distinct pleasure of introducing the Untamed Science film crew to some of our hemlock sites and research.  You may remember a fire video I shared on a previous post.  That was them.  Most recently, Untamed Science did this excellent short on the USFS Hydrological Lab at Coweeta.  Now, Rob and Trenton are making a film about invasive pests of southern forests and will be relating the loathsome tale of how hemlock woolly adelgid is reshaping our forests.

 Trenton mounting a Gopro camera to one of the vehicles.

Our first stop was to meet Dr. Pat Parkman who runs the beneficial insects laboratory at UT-Knoxville.  I showed the guys some hemlock habitat on our way through the mountains to TN, then we got the full tour of his facility including a primer on beetle life cycles.

Dr. Parkman sketches out the Laricobius life cycle for Rob.

We only had 2 full days with the crew and oh so much to show and tell.  Our cooperators from CAMCORE, Dr. Robert Jetton and Andy Whittier, met up with us at Dupont S.F. where we talked about cone collection and seed conservation.  I am especially hoping the tree climbing shots make it into the film.  You will also see gripping interviews with Forest Service scientists including our very own Dr. Bud Mayfield, who will educate us on hemlock conservation efforts.

Trust me you are not going to want to miss this...


Thursday, November 17, 2016

Fall Fires of 2016

Since September, we have been watching the woods gradually dry up.  There has been an audible change trekking to and from our sites throughout the mountains this fall.  The gentle shuffling sounds of walking on leaves and sticks has become a loud crunch, crunch and thud, thud on an increasingly dry and dusty forest floor.  When we started seeing this happen, we knew the drought was on.

The curling leaves of a Rhodendron maximum shrub in TN.

When you start seeing the leaves curl up on these big Rhododendron bushes you know they are conserving their resources and stressing out a little.  We have research sites stretching from the piedmont of South Carolina to the mountains of North Georgia and Western North Carolina all the way over to the Cumberland Plateau of Tennessee.  We have been visiting these sites all summer and fall watching drought take hold and the subsequent fires start.  Here is a video from a site in TN.


I realize you may not be impressed by the quality of that video, but please notice 2 things.  1) The loud crunching of leaves as I walk.  2) The complete lack of water coming over that large cliff.  This is what is usually going on at Upper Piney Falls.

Photo of Piney Falls borrowed from American Travel Journal Blog.

Thankfully, none of our research sites are in danger of burning...yet.

And here is the problem.

We are in a drought y'all! These dry forest conditions are perfect for ignition of wildfires and boy are we having our share of wildfires. 

An aerial image of fires in the Southern Appalachians compliments of NASA's Aqua Satellite.

Remember that in our Southeastern forests there are beneficial, non-threatening fires.  You can learn about those here.   The wildfires we are experiencing now are not of that amiable variety.  So in these treacherous conditions please take Smokey's advice:

Tuesday, November 1, 2016

Hungry, Hungry Lari!

This is a very satisfying part of my job...


A young, healthy Laricobius nigrinus beetle digging into an Adelges tsugae ovisac.  I just finished releasing these predators out at some of our hemlock restoration plots.  What a great way to spend a day! 


Wednesday, October 26, 2016

The Mystery of Dying Rhododendron

One of the most recognizable plants along the Blue Ridge Parkway is Rhododendron maximum, especially this time of year.  While the leaves of surrounding trees make there seasonal change from dull green to bright yellows, oranges and reds, Rhododendron sits underneath just as green as an evergreen should be.

  Healthy Rhododenron shrubs along a section of the Blue Ridge Parkway.

But something strange is afoot in Floyd County, Virginia.  We were just investigating large swaths of dead and dying Rhododendron along the Blue Ridge Parkway near Mabry Mill.  If you are enjoying a drive this time of year in Floyd County you may have spotted this phenomenon.

Dead and dying Rhododendron shrubs along the Blue Ridge Parkway.

Dead Rhododendron shrubs under forest canopy.
We were alerted to this mortality event by retired forest pathologist Dr. Ed Barnard who, in his fashion, assembled a small team of experts that included a pathologist from VA Tech, a forest historian, along with a county forester and us.  Ed and the crew all did their homework and we found that this event is not without precedent.  Dr. Richard Baird of Mississippi State University researched similar Rhododendron mortality in the Great Smoky Mountains National Park a few years back.  A forest pathologist from the U.S. Forest Service (Dr. Steve Oak) also investigated this issue several years ago.  Rhodo samples have ended up in diagnostic labs from landowners with shrubs from their yards, but in all this no single culprit has been found.

Cross-section of healthy Rhododendron stem.

Here is a quick rundown of what we found on our short field visit.  Above is a stem from a healthy Rhodo shrub lacking any evidence of decay, disease, infection, or impairment.  Below are stems from shrubs showing various symptoms of decline, decay, and death.

 Cross-section from unhealthy Rhododendron stem.

 Cross-section from unhealthy Rhododendron stem.

Cross-section from unhealthy Rhododendron stem.

Can you see the difference?  This staining indicates that something just ain't right.

A section of Rhododendron root with staining.

We have successfully eliminated the possibility of  an abiotic cause such as windthrow, voles, or moles.  There doesn't seem to be an insect chomping away at leaves, stems, or roots. What seems most likely is that a root rot is hard at work in these areas. 

But, there are still other organisms that could be to blame.  Nematodes (microscopic soil worms) have been reported at high numbers in some of the affected areas.  Could the Rhodo simply be aging out?  Are environmental stresses to blame?  The area in question has experienced periods of flooding then drought in rapid succession over the past couple years.

The bad news, there is an awful lot of dead Rhododendron and we don't know exactly why.  There is some good news though.  This "decline" is only affecting R. maximum and not other important relatives such as Catawba Rhododendron, Mountain Laurel, and Blueberry.  The mortality is fairly limited in its range and doesn't seem to be spreading. 

A root/stem sample with fungal growth.  (Photo:S. Fraedrich)

We bagged up some samples form the field and sent them along to several pathologists to pore over.  Our hope is  to start unraveling this mystery and figure out an answer in case a similar "decline" event happens somewhere else.

Monday, October 3, 2016

Fire in The South Explained

I am excited about this!  Our SRS Center for Disturbance Science recently partnered with Untamed Science to produce a video that helps explain the complexities of forest fires in the Southern U.S.