Tuesday, April 22, 2014

Spring Emergence - A SLOW Process In 2014

April 18, 2014
Spring Emergence In Duffield Valley
Lower Elevations of High Knob Landform
Large-Flowered Trillium ( Trillium grandiflorum )
Photograph by Bill Harris - © All Rights Reserved.

The emergence of Trilliums are a certain sign 
that the spring season has arrived, and are often coincident with the return of species like the Wood Thrush ( Hylocichla mustelina ) and appearance of butterflies such as the West Virginia White.

Pieris virginiensis )
West Virginia White Butterfly 
Photograph by Bill Harris - © All Rights Reserved.

The West Virginia White is a woodland butterfly that is in trouble due to the invasive spread of an introduced plant species called Garlic Mustard ( Alliaria petiolata ).

April 18, 2014
High Knob Landform
North Fork of Clinch River Watershed
West Virginia White Butterfly ( Pieris virginiensis )
Photograph by Bill Harris - © All Rights Reserved.

Large patches of Trilliums are now blooming in many lower to middle elevation sites across the Upper Tennessee & Upper Cumberland river basins of the High Knob Landform and adjoining basins like that of the Russell Fork River.

April 18, 2014
Upper Tennessee River Basin
Classic Patch of Large-Flowered Trilliums
 Photograph by Bill Harris - © All Rights Reserved.

These are among a vast array of ephemeral wildflower beauties which emerge every spring while mountain forests remain mostly devoid 
of leaves, allowing critical sunlight to reach the forest floor where chemical triggers react to increasing day length & warmer temperatures.

Glorious Spring Renewal - Rhythms Of Life

April 18, 2014
High Knob Landform
Dependent Upon Forest Floor Sunlight
 Photograph by Bill Harris - © All Rights Reserved.

That certainly has been the case this April with mostly bare trees on display across mid-upper elevations and cooler, lower elevation valleys during Easter Weekend.

Elevation 3149 feet
Easter Sunday - April 20, 2014
Morning View From Birch Knob of Pine Mountain
 Photograph by Roddy Addington - © All Rights Reserved.

Emergence of vegetation can vary by up to a month during any given spring, being a couple weeks or more early like in 2012 or a couple weeks late like during 2013 and 2014.

It often depends upon the weather character 
of the first month of meteorological spring.

The Month of March!

( The Warmest March On Record )
Early Spring - Wet & Warm March 2012

Late Spring - Cold & Snowy March 2013

March 2013 - Colder & Snowier Than Average

March 2014 Statistics & Winter 2013-14

Many more examples could be cited from climatology, but these are the most recently observed for differences driven by synoptic-scale weather patterns across the USA.

Local variations in spring emergence during any spring, regardless of the synoptic-scale pattern, are driven by both elevation and latitude differences along the High Knob Landform.

HKL Spring Differences: Elevation + Latitude

A U.S. Forest Service photograph taken this week of the High Knob Lookout construction site illustrates the still dormant nature of upper elevation trees.

Week of April 20-26, 2014
Looking East-Southeast Across Massif Crest
Aerial View Of High Knob Lookout Construction
U.S. Forest Service - Clinch Ranger District Photograph

April 20, 2014
Birch Knob of Pine Mountain
Spectacular Easter Sunday Sunrise
 Photograph by Roddy Addington - © All Rights Reserved.

Regardless of vegetation emergence, my friend and photographer Roddy Addington captured another simply spectacular sunrise from Birch Knob on Easter Sunday.

Rod Addington Photography

April 20, 2014
Cumberland Overthrust Block
Spectacular Easter Sunday Sunrise
Photograph by Roddy Addington - © All Rights Reserved.

Chilly Mountain Valley Nights
April 1-25, 2014 Period

A much drier than average April 1-25 period supported many chilly nights, especially amid mountain valleys via cold air drainage, 
to help slow vegetation emergence.

( Northern Base of High Knob Massif )
City of Norton - Elevation 2141 feet
Average Daily MAX: 65.0 degrees
Average Daily MIN: 33.8 degrees
April 1-25 MEAN: 49.4 degrees

The morning of April 24 was a prime example with widespread mountain valley frost and sub-freezing temperatures.  A total of 5.5 hours was at or below freezing in the City of Norton where the MIN reached 29.7 degrees ( * ).

*Minimums in mid-upper 20s were widespread in mid-upper elevation mountain valleys from the City of Norton and High Knob Massif to Burkes Garden ( official MIN of 25 degrees at 3068 feet ).  One could literally drive for miles through frosty countryside on this morning if on valley roadways ( like Alt. 58 from Norton to Coeburn or around Pound & Clintwood ).

Difference Between Ridges & Valleys
Drop Rates April 23-24 Period

April 23, 2014
                           CN      LR        HV  
04:00 PM    60       57         58
07:00 PM    56       55         47
09:00 PM    48       49         42
10:00 PM    44       48         39
11:00 PM    40       48         35

April 24, 2014
                        CN      LR        HV
  Midnight    38       47         32
01:00 AM    35       47         30
03:00 AM    32       45         28
07:00 AM    30       44         26

CN = City of Norton
LR = Long Ridge at Nora 4 SSE
HV = Colder high valleys above 2700 feet

This was a typical but excellent example of the temperature contrasts that pioneers learned to recognize, even without keeping detailed weather records, such that thermal belt locations like Long Ridge and exposed sections of the Wise Plateau were chosen for the best growing conditions with respect to escaping late and early season freezes 
in the mountains. 

Minimums in the 30s were widespread amid mountain valleys on mornings of April 26-27, with frost in coldest locations ( from the High Knob Massif north into hollows of the Russell Fork Basin ).

The Arrival Of Spring
Mountain Measurements

Head of Powell Valley in Wise County, Virginia
Great Calcareous Cliffs Ring High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved.

( Tribute To Addison M. Stallard )
Special Edition: The Man & The Mountain

My friend Addison Stallard, who happens to be the youngest ( at heart ) resident of the Head of Powell Valley in Wise County, Va., reported that the first visible green made the leap across this great band of calcareous cliffs above his home on April 24.

For many years the "official" arrival of spring in 
the High Knob Massif has been declared upon this occasion, with variations in Green Jumps to top of this cliff line varying between March 23 in 2012 
( warmest March on record ) to April 24 of this year ( the mean date since 2000 being around April 13-14 ).

Once "green" spreads over these great cliffs it typically remains a long time before the sprawling high country above fully greens up, as suggested most recently by the U.S. Forest Service aerial photo, such that it can be early June in some years before tree leaves reach summer maturity at highest or coldest elevations.

Wood Thrush ( Hylocichla mustelina )
Photograph by Richard Kretz - © All Rights Reserved.

( Includes Tab For The Gorgeous Songs & Calls )
Life History of Wood Thrush - The Cornell Lab

Another Spring season arrival measure in the mountains, at least for lower elevations, is the annual return of beautiful Wood Thrush songs 
( typically how I first know they are back ).

Annual Return Dates
Wood Thrush To Russell Fork Basin

April 15

April 15

April 12

April 15

April 19

April 19

April 24

April 18

( Missing )

April 11

April 17

April 15

April 19

April 16

April 17

April 17

15-Year Mean: April 16-17

*Returned to Powell Valley On April 19

In many ways this part of the Natural Calendar 
is amazingly consistent, regardless of weather conditions, with differences between the warmest spring on record ( 2012 ) and these past two slow starting spring's ( 2013-2014 ) being merely 1 day!

Veery Thrush ( Catharus fuscescens )
Photograph by Richard Kretz - © All Rights Reserved.

( Includes Tab For The Wondrous Songs & Calls )
Life History of Veery Thrush - The Cornell Lab

My favorite thrush for listening is the Veery, which is an abundant summer breeder in upper elevations of the High Knob Massif, with its wondrous songs that all should hear in the wild.