The American Chestnut is Going

Extinct?

A disproved myth.

2016 Annual Meeting of the Mid-Atlantic

Chapter of the Ecological Society of

America

April 2016

Richard Gardner

Heather Cuthbert

rtgardner3@yahoo.com

410.726.3045

A copy of this presentation along with other research

can be found at:

http://www.slideshare.net/rtgardner3

Abstract:

During the summer of 2015 in reaction to the inherently flawed concept about how hybridization of the American Chestnut (Castanea dentata) with non-native chestnuts is the only way to prevent its extinction, I decided to do a census of the American Chestnut near home, northern Berks County, PA. In 38 days of walking a census was performed using a GPS equipped camera. Two local areas were walked; Blue Mountain from the Rausch Gap to the Lehigh Gap and sections of trails in the Hay Creek/French Creek area. Over 7500 trees were found from seedlings to mature trees producing seeds. The limiting factor in tree reproductive success was not the Chestnut Blight (Cryphonectria parasitica), but rather access to direct sunlight on the apical ends of branches. With present diseases and pests such as Bacterial Leaf Scorch (Xylella fastidiosa), Emerald Ash Borer (Agrilus planipennis), Gypsy Moth (Lymantria dispar dispar) the Hemlock Wooly Adelgid (Adelges tsugae) and the Elongate Hemlock Scale (Fiorinia externa) opening up the canopy, the American Chestnut may soon again become the dominant tree in our eastern hardwood forests. My conclusion is that attempts to hybridize the American Chestnut with non-native “blight resistant” trees are unnecessary tinkering which is harmful to the Appalachian ecosystems.

Introduction

This study was conducted throughout the spring,

summer and fall of 2015.

The American Chestnut Federation: proudly

tinkering since 1989. Still clueless.

Me: walking for one year. Issue resolved.

The American Chestnut is not a problem to be

solved but rather a fascinating study in a human

mediated ecological disaster and the biological

response.

My issues with the American Chestnut Federation

are based on their:

• lack of study and understanding of the Eastern

Forests,

• inherently flawed paradigms about how natural

systems function and how human interference

can cause them to function “better” and

• common human almost demonic drive to tinker.

As an ecologist I continually see where

introductions of magic bullet plants to solve

non-existent ecological problems cause

problems: Sawtooth Oak, Russian/Autumn

Olive, Multiflora Rose, Chinese Lespedeza … .

In Invasive Plant Ecology we have the Enemy

Release Hypothesis.

In part, this states that an overwhelming

number of native organisms cannot use

introduced non-native plants because they did

not coevolve together.

Hybridizing a native plant with another native or

especially a non-native creates a non-native

plant of little or no ecological utility.

Therefore, changing the gene structure of a

native plant by hybridizing with a non-native in

hopes of improving/saving the plant from

introduced diseases or pests is doomed to be an

ecological failure because few if any native

organisms using the native plant will be adapted

or adapt to use this hybrid due to changes in the

physical and chemical properties of the plant.

In other words, we do not want to hybridize

plants in ecology because it destroys the plant’s

ecological utility as a food source, etc.

Simply put:

No matter how successful the hybridization appears

to be it is an ecological failure.

“The operation was a success, but the patient died.”

And, it is hard to conceive how hybridizing one

plant with disease susceptibility with another

plant susceptible to the same disease makes a

disease resistant hybrid.

It is better to patiently study the system to

understand what is happening and determine if

the apparent crisis is a real crisis.

If the crisis is real, then develop strategies which

have minimal or no ecological impact such as

looking for resisting/resistant plants.

In the case of the American Chestnut, the

answer was always there, but those with power

never looked for it.

7,551* American Chestnuts total were found in the

spring, summer and fall 2015 on two sets of trails

separated by @ 25 miles at their closest.

*If there was more than 6” or 8 “ between stems in a cluster unless obviously a clone, the stems were counted as separate

trees. This is in line with the concept that animals such as squirrels and corvids made non-recovered caches of seeds which

produced multiple trunks in the same location.

Appalachian Trail

Rausch Gap

Lehigh Gap

Birdsboro Reservoirs and

French Creek State Park

7,251 American Chestnut trees found on the

Appalachian Trail and related trails from Rausch Gap

to Lehigh Gap, @ 80 miles linear distance.

Non-native Chestnut

Lehigh

Gap

Rausch

Gap

Blue Mountain: Rausch Gap to Lehigh Gap

2015 chestnut survey

Hamburg

Reservoir

Dan’s Pulpit

Allentown Shelter

Roundhead

yellow indicates C. dentata

groves

Lehigh

Valley

Nature

Center

One of the two most interesting discoveries is that the

Appalachian Trail is a corridor for the spread of the

American Chestnut tree.

Local large groves associated with the Appalachian

Trail during this study:

1.) Hamburg Reservoir,

2.) south of Roundhead Overlook and the old

Appalachian Trail at that location (halfway between

Rt. 183 and Rt. 501),

3.) Hawk Mountain south of Dan’s Pulpit,

4.) Allentown Shelter.

Other trails in Pennsylvania such as the Mason Dixon,

Conestoga, Mid State, Brandywine and Laurel

Highlands probably serve the same purpose. I will be

exploring sections of these this summer.

Based on what I found at the Hamburg reservoir early

in the study I looked at a connected pair of reservoirs

near Birdsboro, to see if it was chestnut refuge due to

long term protection from logging.

The Hamburg Reservoir has not been logged for about

127 years.

The Birdsboro Reservoirs have not been logged for

about 133 years.

1,749 American Chestnut trees found on trails in the

Hamburg Reservoir area in a thorough survey. (It is a

subset of the Appalachian Trail survey.)

119 American Chestnut trees found on trails in the

Birdsboro Reservoirs area in a quick incomplete

survey to confirm data from the Hamburg Reservoir.

(181 trees found at French Creek, a related trail set,

but unrelated study.)

Hamburg Reservoir area 2015

chestnut survey

Pocahontas Spring

Appalachian Trail

Pinnacle

Pulpit

parking lot

spur trail

Appalachian Trail

side trails

Birdsboro Reservoirs

French Creek State Park

The concept of American Chestnuts thriving in

refuges from logging such as reservoirs will be

explored more in the next couple field seasons.

Another apparent correlation is that wider parts of

the AT and other trails serve as corridors for the local

spread of the trees in that they provide an easy

“friction free” route for birds such as blue jays to fly

along, turkeys to run down and small mammals to

use.

When exploring trails in the Hamburg Reservoir

area, small single track trails did not have nearly

the chestnut density as the wider trails did and the

further from a trail the fewer apparent trees.

This needs more work as it was not an absolute

correlation, but an apparent one.

Extrapolating from a reference*, crows during the fall

migration may be spreading seeds along the ridgeline

the AT uses locally.

*American crow http://bna.birds.cornell.edu/bna/species/647/articles/migration

Fall migration

Over the length of the AT, the probable southward

spread of seeds during the fall crow migration and

northward spread of pollen during the spring

pollinator migration are two of the most important

ways for the American Chestnut to maintain its

genetic heterogeneity (diversity). As part of this

process disease resistance genes spread between

groves and widely spaced trees.

This is part of the process of basic Darwinian

evolution – the more resistant trees reproduce at a

higher rate because they are healthier than the less

resistant. (Eventually, the less resistant tree lineages

go extinct by continually losing the competition for

sunlight and other resources.)

Pollinators and crows – maintaining

genetic heterogeneity and spreading

disease resistance along Blue

Mountain

Pollinators move pollen north

during spring migration as the

trees bloom

Crows move seeds south

during fall migration

tree

nut

Within a set location, the seeds are spread by

rodents such as red squirrels, gray squirrels and

corvids such as blue jays and crows.*

*Heinrich, B. 2014. American Chestnut Seed Dispersal and Regeneration. Northeastern Naturalist 21(4):619-628.

*Heinrich, B. 2014. American Chestnut by Red Squirrels. Northeastern Naturalist 22(4):N19-N23.

tree

Seed spread by blue jays with red and gray squirrels

squirrels

blue jays

Trees

Seedlings

AT north of Auburn Overlook

tree from AT north of Auburn

Overlook transplanted at home

Sand Spring trail near Shartlesville

AT south of Lehigh Gap

Disease

The Chestnut blight was found in Brooklyn, NY in

1904. It spread to Pennsylvania a few years later.

The Pennsylvania Chestnut Blight Conference was

February 20 and 21, 1912.

Basic Science was rejected in favor of proud

machismo based actions which almost resulted in the

extinction of the tree they were trying to save.

When a tree becomes infected and a trunk dies it

fights back by coppicing, sending up new shoots from

the root crown.

(Multiple trunks appear to be a common growth habit

among some trees in our area such as silver maple.

This may be a common defense against disease and

other injuries.)

Another apparent discovery I found is that trees show

varying disease resistance in all age classes.

Flowers

The second important discovery this past summer is

that the limiting factor in tree reproductive success

was not the Chestnut Blight (Cryphonectria

parasitica), but rather access to direct sunlight on the

apical ends of branches.

All mature trees which received direct

sunlight had flowers, burrs and nuts.

Diseases and pests such as;

• Bacterial Leaf Scorch (Xylella fastidiosa),

• Emerald Ash Borer (Agrilus planipennis),

• Gypsy Moth (Lymantria dispar dispar),

• Hemlock Wooly Adelgid (Adelges tsugae) and

• Elongate Hemlock Scale (Fiorinia externa)

are opening up the forest canopy.

Which means more mature reproducing trees as the

American Chestnut begins to reassert itself in the

Appalachian forest. This leads to the strong

probability that the American Chestnut will soon

again become a dominant, if not the dominant, tree

in our eastern hardwood forests.

As an aside, American Chestnut flowers are a good

source of nectar and pollen for insects such as bees,

moths and butterflies at a time before many non-tree

flowers bloom. This gives pollinators early season

flowers to feed on as part of a continuous food supply

from mid-spring to frost.

Burrs and Nuts

• 46 trees have burrs in several distinct locations along Blue Mountain.

• 40 of these trees are between Rt. 183 and Port Clinton

• 1 is on the Appalachian Trail on the top of the ridge at the northern edge of the Hamburg reservoir watershed

@ 200 yards left of Gold Spring,

• 1 is on the trail to the Berks County highest point,

• 3 are near Round Head and the old AT and

• 1 is on the south side of the Lehigh Gap just north of the AT.

Two trees which

produced burrs in 2015.

Left

Berks County highest

point

Lat: 40 31 15.624

Long: -76 14 47.514

Right

Hamburg Reservoir,

Appalachian Trail

Lat: 40 36 20.562

Long: -75 56 51.846

40 trees with burrs Rt. 183

north to near Port Clinton

Port Clinton

Rt. 183

Burrs appear to open just after rain because the rain

causes the burrs to swell.

Burrs appear to open on both the tree and the

ground. Open burrs on trees can become food for

crows, blue jays and squirrels. On the ground they

can be food for mice, chipmunks, squirrels and

turkeys.

Wet soil makes it easier for corvids and rodents such

as squirrels to cache nuts in the ground which

enhances germination success.

The inner parts of swelled burrs decompose easily

and swiftly due to being soft from the absorbed

moisture which makes them a good food source for

bacteria, fungi, protists and insects – moist,

nutritious, easy to burrow in and easily digestible.

This allows the nutrients in the burr to be quickly

recycled into the soil while creating a community of

organisms which benefit from the tree while giving

benefit to the tree.

Benefits to the tree may include increasing disease

resistance, lowering the load of pathogens and

predators near the tree, adding nutrients around the

base of the tree, moving nutrients into the soil close

to the tree, encouraging plants to grow which work

with the chestnut tree for mutual enhancement, etc.

Nut dispersal

Nuts in burrs had 3 basic shapes: spoon shaped

(spatulate), egg shaped (ovate) and house

shaped (truncate).

Most burrs had 3 nuts, often 1 ovate with 1

spatulate on both sides or a mixture of spatulate

and truncate shape.

wt. (g)

height

(cm)

width

(cm)

thickness

(cm)

3.7 2.2 2.0 1.4

Average dimensions of seeds dehisced on their own

wt. (g)

height

(cm)

width

(cm)

thickness

(cm)

3.5 2.1 1.8 1.5

Average dimensions of seeds manually dehisced

The following is measurements of the egg shaped

(ovate) seeds.

*No measurements were taken for the other shapes.

Path forward:

2016

1. finish survey in the Birdsboro/French Creek areas

2. extend the ends of the survey to the Susquehanna River and the Delaware River

3. survey other relevant trails within 90 minutes of home

4. start looking at reservoirs to find fruiting trees as they should have more open areas than trails

5. continue looking for seedlings in danger from trail maintainers and hikers to transplant at home

6. continue collecting nuts to grow at home

7. identify and document pollinators and other nectarivores on American chestnut flowers.

I plan to use a quadcopter (drone) with camera this

year to better understand and document what I see.

Our ultimate goalTo grow 2 successive generations (F2 generation) of

burr bearing American Chestnuts from seeds in our

yard.

Anyone who wants to join me is welcome to grab a

camera, their shoes, a day pack and do so.

Walk more

Tinker less

Richard Gardner

rtgardner3@yahoo.com

410.726.3045

http://www.slideshare.net/rtgardner3

Addendum

www.google.com/maps

Mar. 9, 2016

Appalachian Trail on Blue Mountain

Birdsboro Reservoirs and French

Creek State Park

@ 25 miles between points

our home

Molasses HillLake Ontelaunee

Middle Creek Wildlife Management Area

Mt. Penn

Expected locations of American Chestnut trees

Hamburg

Reservoir

Known grove of American Chestnut trees

Second and Sharps Mountains

Copied from Google Maps on Mar. 2, 2016

Topographical map showing distance between Blue Mountain and the Birdsboro Reservoirs/French Creek State Park with

other relevant information

Miscellaneous thoughts on how American Chestnut

seeds are spread.

tree

squirrels, chipmunks and other small mammals – distance nuts

are moved from tree depends on size of mammal, the larger the

mammal the further the nuts are moved

Small animals such as mice

Medium sized mammals such as squirrels

Larger mammals such as raccoons

tree

physical factors – steepness of slope, texture of ground (smooth, rough,

boulders, duff, trail), proximity to and type of water way (ephemeral,

intermittent and perennial streams), wind, other trees, density and size

of understory plants

ephemeral/seasonal/intermittent stream

perennial stream

smooth trail

rough ground –

boulders and logs

trees and shrubs

tree

birds – distance nuts are moved

depends on size of bird, primary type

of movement, migration patterns, …

Crows depend on

whether migrating

or in home territory

Turkeys on trails and

through the woods,

primarily on foot

Blue jays through

the forest to

roosts and

perches

Merged trees from several seeds producing

several trunks are not uncommon. Determining

which trunks are from the same seed and which

are from a cache of seeds is a question which

affects the census of the American Chestnut I

have been doing. This is especially important

when dealing with trees coppicing due to

disease. I do not yet have that answer.

Castanea dentata

Tsuga canadensis

Betula lenta

Quercus alba

Gypsy moth, Elongate Hemlock scale and

Hemlock Wooly Adelgid.

Diagrams of how I think the American

Chestnut and how its genes are being

spread.

gypsy moth

larva

gypsy moth laying eggs

elongate

hemlock scale hemlock

wooly

adelgid

Disease on other trees in a way similar to

chestnut blight on American chestnut

disease on

American

chestnut, Castanea

dentata, near the

Eagle’s Nest

Overlook cutoff

trail

disease on red oak trees, Quercus rubra,

on Blue Mountain near Shartlesville

disease on black birch tree, Betula lenta,

Hamburg Reservoir

disease on choke cherry,

Prunus virginiana

disease on choke cherry,

Prunus virginiana

disease on Betula papyrifera

disease on Acer saccharinum

Coppicing on non-chestnuts

Acer saccharinum

Acer saccharinum

Acer saccharinum

Non-native Chestnut

non-native chestnut traits:

lower crown,

thicker leaves

darker green on leaves