Tuesday, April 8, 2014

Do Cold Winters Impact Hemlock Wooly Adelgid Populations?



Sarah Johnson from The Nature Conservancy's High Allegheny Hemlock Project shared some encouraging news about overwinter mortality of hemlock wooly adelgid (HWA).  This information was initially provided by Rick Turcotte, Entomologist, US Forest Service, and Tim Frontz, DCNR Forest Pest Management.


Rick shared his analysis of 2 samples of HWA:
~93% mortality of HWA in Clarion River sample
~95% mortality of HWA in Allegheny river sample

Tim Frontz shared the below data about samples from Cook Forest State Park and one Elk County infestation from DCNR lands.  HWA mortality assessments were made on foliage collected on Jan. 15 and Feb. 9, 2014 at Cook Forest State Park, PA.  You can see, the mortality rates were 97% or higher with most at 100%.  That is good news for the hemlocks of the high Allegheny Plateau.

HWA density County Live HWA Dead HWA % Mortality
HIGH Elk/ Cameron 9 306 97
LOW Forest (CF State Park) 0 47 100
LOW Forest (CF State Park) 0 94 100
LOW Forest (CF State Park) 0 60 100
LOW Forest (CF State Park) 1 106 >99

Because of the high fecundity of HWA, an overwinter mortality rate of 91% is necessary to keep the population from increasing.  So mortality rates at 91% mean the infestation will not get any larger, above 91% means a temporary decrease in the infestation size.  The entomologists have also shared a caveat – with such high reproductive rates of HWA, this winter kill would need to be repeated maybe several years in a row, or happen more often (rather than just once every 10 years) to have significant overall impact in the grand scheme of things.

PA DCNR also provided an overview in a recent news release shared below.

DCNR gauging past frigid winter’s effect on forest insect pests
The past winter of seemingly unending snowstorms and frigid temperatures has proved to be a strong ally for state woodland managers battling the No. 1 enemy of Pennsylvania hemlocks, but the reprieve could be short-lived, Department of Conservation and Natural Resources officials said recently.  To read the full story click here.

Wednesday, March 26, 2014

More on Emerald Ash Borer



Emerald Ash Borer larvae

I had a phone call this morning from someone who thought they may have emerald ash borer (EAB) infesting a number of ash trees on their property.  They owned a 45 acre woodlot as well as a few ash trees around their house in the yard.  They noticed the bark being knocked off by woodpeckers trying to get at the larva.  I thought it would be beneficial to share a quick update with my readers as well as the below article which makes for an interesting read.

Woodpecker damage as they search for larvae under the bark 

From www.emeraldashborer.info
1.  Discovered in southeastern Michigan near Detroit in the summer of 2002
2.  Probably arrived in the United States on solid wood packing material
3.  Larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients
4.  In 2013 new infestations were found in New Hampshire, North Carolina, Georgia, and Colorado
5.  Has killed tens of millions of ash trees across 22 states and two Canadian provinces
6.  Now found from Colorado to Quebec and south to Georgia.

What about the cold weather this winter?  Did that have an effect on EAB populations?
The prolonged sub-zero temperatures experienced this winter in North America have raised hopes that pests like EAB will freeze to death.  Though studies suggest that this may happen to some of the EAB larvae, it looks like it may not be enough to make a big impact on the EAB population.  Click here to read what some of the experts are saying. 

For more on EAB click here to go to a series of fact sheets from Penn State Extension.
Feeding galleries made by the emerald ash borer larvae

by Dan Stiles, originally published in the Morgan Messenger
Come to find out, lots of people were aware that emerald ash borers were here in Morgan County.  It was, however, a great surprise to me.  As I look closely at my ash trees I can find some sort of emerald ash borer damage on just about all of them.

I’m reminded of an old friend that remarked about people looking, but not seeing.  I should have seen the EAB damage months ago.  EAB is now considered the most destructive forest pest ever seen in North America.  Billions of lost dollars are involved.  EAB is an invasive, exotic insect that is native to Russia, China, Japan and Korea, and was first discovered in our country eleven years ago. 

As of this week, emerald ash borers have been detected in 29 West Virginia Counties, according to the WV Department of Agriculture.  This year it was detected in Colorado, so now ash borers have spread to 22 States.  To read the rest of the article click here.

Friday, March 21, 2014

Are Deer Changing the Look of US Forests?

Interesting reading......I was sent the below news release by a botanist from the US Forest Service out of the Durham, NH, Northeastern Area State & Private Forestry office.  This news release is the result of two recently published studies, one from Cornell University researchers entitled "Deer Browsing Delays Succession by Altering Aboveground Vegetation and Belowground Seed Banks" and another from University of Pittsburgh researchers entitled "In a long-term experimental demography study, excluding ungulates reversed invader's explosive population growth rate and restored natives." I wanted to share this information with my readers.  Much of what these scientists are documenting, with rigorous scientific research, reinforces what I have been seeing in the field.  Is deer impact reduction the only way to address invasive plants at a landscape scale, while also allowing forests to once again grow new trees?  Good question, read on....

Overgrazing by deer is changing the face of U.S. forests
by: EarthSky March 18, 2014

Scientists in the U.S. Northeast published two studies examining the impact of deer overpopulation on natural ecosystems in early March 2014. Biologists at Cornell University investigated disruptions by large numbers of deer to natural growth in developing forests. University of Pittsburgh researchers showed how large deer populations are causing an increase in garlic mustard, an exotic invasive plant, in forest understory fauna. In both instances, the root problem is overgrazing of native plants by deer that open up more growing space for invasive exotic plants that deer find unpalatable.

These studies were conducted in Ithaca, New York and Pittsburgh, Pennsylvania. But the problem of deer proliferation is widespread across the U.S. and Canada. Their numbers have increased dramatically for several reasons. Since the arrival of European settlers more than 300 years ago, the deers’ natural predators, wolves, have been exterminated. And, as human populations have increased, deer forest habitat has shrunk drastically, mostly giving way to suburban lawns, gardens and farms that can also provide a deer’s food sources. Compared to historical population estimates prior to European settlement, deer populations today have increased, depending on location, by four to 10 times.  Click here to read the rest of the news release.

Wednesday, March 12, 2014

Pennsylvania Game Commission Releases Deer Harvest Estimates for 2013-14 Season


The Pennsylvania Game Commission recently reported that hunters harvested an estimated 352,920 deer during the 2013-14 seasons, an increase of about 3 percent compared to the previous seasons’ harvest of 343,110.  To read the full release click here.

Some of the highlights include the following:
1.  Hunters harvested 134,280 antlered deer (similar to last year) and 218,640 antlerless deer (a 4% increase over last year)
2.  The antlered deer age structure was 47 percent 1½-year-old bucks and 53 percent 2½ year olds or older
3.   The antlerless harvest was nearly 62 percent adult females, about 21 percent button bucks,  and almost 18 percent doe fawns (similar to long term averages)
4.   The antlerless success rate remained approximately 1 in 4 for licenses issued

I have been tracking the Pennsylvania deer harvest trends for a number of years now and thought I would share these along with a few interesting facts that pertain to season changes, antler restrictions, and antlerless permit allocations, etc.

Many of the changes in deer harvest numbers can be attributed to many sweeping changes that have occurred within the Game Commission deer management program.  Below I provided a list of changes by year.  These changes can be useful in explaining current trends as we see deer numbers begin to shift back upwards.

PA Deer Season Changes
2002 - Concurrent buck & doe season
         - Early firearms and muzzleloader antlerless seasons
         - Antler restrictions
         - Increased antlerless tag allocation
2003 - Deer Management Assistance Program (DMAP)
         - Wildlife Management Units
         - Mentored Youth Program
2008 - 4 WMU’s reduced to split 5/7 season
2010 - Additional 4 WMU’s added to split 5/7 season
         - Reduced DMAP allocations
2011 - Additional 3 WMU’s added to split 5/7 season
2013 - Mentors can transfer DMAP permit to mentored youth

Many of these programs were instituted under the direction of Dr. Gary Alt.  Dr. Alt has since retired and now the deer management program is under the direction of Dr Chris Rosenberry.  Many of these changes were made in an attempt to balance the deer herd with the available habitat and implement more a quality deer management approach.
When antler restrictions were implemented in 2002, in an attempt to protect young buck and regain a more natural breeding ecology, approximately 40,000 bucks were protected from harvest.  In addition, about 70,000 more antlerless deer were harvested in 2002 than in 2001.  Pennsylvania had historically harvested around 200,000 antlered deer
In the late 1990’s buck and doe harvest rates were very similar.  In the 2000's the state began harvesting more antlerless deer than antlered deer.  This was a huge change compared to the traditional deer management that had been practiced in the past where does were heavily protected. 
At the highest peak of harvest, seen in 2002-03,  there were 973,000 antlerless permits allocated.  That number has since been reduced.  When the Deer Management Assistance Program (DMAP) was first made available in 2003 there were 176 properties enrolled for a total of 31,784 antlerless coupons.  The coupons were made available for distribution by landowners.  DMAP was the first program that was ever available to landowners who owned nothing but wooded property to assist in harvesting additional deer from their property. 
Beginning in 2008 the Game Commission has been removing Wildlife Management Units from the 2 week concurrent buck and doe seasons that was adopted in 2002 and been going more towards the split 5 days buck only and 7 days buck or doe.  There are now a total of 12 units with split 5/7 seasons.

To read more about deer management in Pennsylvania be sure to visit the Pennsylvania Game Commission's White-tailed Deer page.  There is a host of very good information that has been made available about deer and deer management.