Douglas Falls hemlocks question (NC)   James Smith
  Jan 15, 2007 11:51 PST 

I finally made the hike off the Blue Ridge Parkway down to Douglas
Falls. We started along the Mountains to Sea Trail at the Graybeard
Overlook, took that down to the intersection with the Douglas Falls
Trail, and hiked down to the falls, walking through the old growth
hemlock forest, and then made the round trip back to our vehicle.

I noticed that almost all of the hemlocks we encountered looked pretty
darned healthy. Not in perfect health, but pretty good. I did notice
adelgid sign, but only in some of the trees.

A friend of mine who is an avid hiker in that area of NC told me that a
couple of years ago the hemlocks looked much worse than they do now. He
also told me that predator beetles had been released there, and he's
convinced these have had an effect. I told him that you guys here
completely discount the use of predator beetles, but he contends that
the beetles have been the cause of the rebound in the health that he has
witnessed over the past two years in that grove of hemlocks.

What do you guys think? Have the beetles helped the hemlock grove at
(and above) Douglas Falls? Or has someone gone in there and treated that
grove with adelgicide? Or is there some other reason (high rainfalls
totals) that has improved the health of the trees. He is totally
convinced the health of that grove has improved in the past couple of
Re: Douglas Falls hemlocks question.   Jess Riddle
  Jan 15, 2007 13:09 PST 


Glad to hear you finally made it to Douglas Falls. I agree with you
that the hemlocks in that area generally look healthier than the
hemlocks in many other parts of western NC, but I'm not sure that your
friend's theory completely accounts for their current health. I
haven't seen the marked improvement in their health that your friend
has observed, but I've only been looking at that area for about a
year, not two years. To me, the adelgid populations appeared to have
only recently peaked, so I would be surprised to hear that they have
already caused extensive damage two years ago. The explanation that
immediately jumps to my mind is that the color of infested hemlocks
changes with the seasons. They tend to be most green in winter and
most gray in summer or fall. I would guess that your friend's first
visit was in summer or fall and the more recent visit was in winter.
If both visits were in winter, then that theory certainly isn't
correct. The beetles also seem like an unlikely explanation because
of the homogeneity of hemlock health in that area. If the beetles
were responsible for the improved health, it seems like the hemlocks
around the falls would be the healthiest. I did not see any great
variation in hemlock health along the length of the trail, and
hemlocks on the ridge on the opposite side of Waterfall Creek are just
as healthy. This line of reasoning also makes chemical treatments an
unlikely explanation. Other than Sasajiscymnus, I still have some
hope for the beetles, but they don't seem to account for the hemlock
health at Douglas Falls; it would be nice to be wrong on this one
though, because that is a wonderful tract of forest.

Jess Riddle
RE: Douglas Falls hemlocks question.   Will Blozan
  Jan 15, 2007 13:11 PST 

Personally, I think it is the favorable weather the hemlocks have had in the
past few years compared to the previous drought stricken years. Hemlocks in
general look better- in groves still free or lightly infested with HWA. I
agree, they look great, but I bet he won't be saying that in two years.