one stand at a time silvicultural options for stand...

Dr. Jim Guldin

Supervisory Ecologist and Project Leader,

Ecology and Management of Southern Pines

SRS-4159, Southern Research Station

US Forest Service

Hot Springs, Arkansas

One stand at a time—

silvicultural options

for stand-level response

to climate change

Questions about the

response of forests to

climate change have been

addressed with planning,

prediction, and modeling

the effects of climate

change on forested

landscapes

Recent synthesis :

April-May 2008

Journal of Forestry

From the April/May 2008 issue, Journal of Forestry:

“Earth is currently warmer than it has been in the recent past.”

“Eleven of the last twelve years rank among the 12 warmest years since 1850”

“Projections estimate that global average surface temperatures will be 3.25° to 7.2°F warmer at the end of the 21st century”

Changes in

temperature and

carbon dioxide (Source:

US EPA 2008).

From Harper’s Index, April 2013:

“Number of reports of record-high

temperatures by US cities in 2012:

362

Number of reports of record lows:

0”

According to interpretations of FIA data,

half of the species in the eastern US will

occupy sites for which other species are

better adapted in the future

Loblolly pine,

south Arkansas

Longleaf pine,

east Texas

So, maybe society should manage

ecosystems not for where they are, but

where they might be in a new climate

They argue that

our response to

climate change

must be a

management

program with

‘assisted

migration’ as a

key element

The goal would be to improve upon the 10-

50 km /100 yr rates of species migration that

are constrained by current and future

fragmented landscapes

Q: So, do we have any quantifiable data

or robust case studies in the Southern

US that can guide us about a landscape

management approach to climate

change?

In other words—what experience do

foresters have in removing an existing

forest and replacing it with a different

forest?

A: Yep. The past 60 years of pine

plantation forestry in the South!

There are practical lessons to be learned

in this case study, specifically:

Where has it been applied? By whom?

Over how much area? And at what cost?

Covnersion rate:

There are 200 million acres in Southern

forestlands. Conversion to plantations:

1950-2010 35 million acres

2010-2050 15 million acres

1950-2050 50 million acres;

25% of South’s forests

average 500K ac/yr for 100 yrs

Mostly on Forest Industry land, and now

REIT-TIMO land—easy to plant, no

political issues about it really

What has it cost?

1950-2010 $250/ac $9 billion

2010-2050 $400/ac $6 billion

1950-2050 $15 billion to convert

25% of South’s forests

average $150 million annually

Who paid for it? Mill owners, and now

REITs and TIMOs—to assure fiber

supply and returns to stockholders.

OK. Thinking about those numbers and

that land base.

Let’s assume we want to convert

another 25% of Southern forests to

“certified” climate-change-resistant

stands that support new species, not the

ones currently found there.

What will it cost, and where will it be?

Cost

Harvest 50 million ac in 50 years, and

replant with certified climate change

resistant species:

Cut 1 million ac annually

Reforest at $400/ac

costs $400 million annually

Land base:

All the industry-REIT-TIMO land is

already converted, so….the next 25%

comes from NIPF land or Government

land like National Forests.

Under what legal authority?

NIPF—cost share? Eminent domain?

National Forests—rewrite NFMA, NEPA,

ESA?

Federal program or policy?

Is the current Administration or

Congress likely to invest in a climate

change forest mitigation strategy in the

South to the tune of:

$400 million per year?

on 1 million acres per year?

for the next 50 years?

Nursery capacity and practice:

Do we have production capacity to

produce 400-500 million seedling

annually for any southern forest species

other than loblolly pine?

Do we know the practical details about

collecting seed and propagating the top

10 species in the South, much less

species like Carolina ash or even catalpa?

Research basis?

Do we have solid research on how to

enable species migration of forest

ecosystems at risk

-not just dominant overstory

-minor tree species components?

-perennials?

-annuals?

Cost No

Land base No

Federal law or policy Heck no

Nursery practice No way

Research basis OMG No!

Is the Nation ready for a major climate

change response in forested ecosystems?

So what do we do?

We work in stands already being

managed

We modify management in those

stands in ways that are robust in the

context if changing climate

We acknowledge that we will only

affect a small percentage (10%) of the

South’s forest land

We hope for the best on the rest

Little thought has been given to how, and what kind of, stand-level silvicultural practices would be appropriate to apply in an environment of climate change, and how a forester might apply them.

Ernest Lovett and the late Dr. John Gray inspect the 2004 harvest at Crossett EF

A PRACTICAL approach to managing

southern forests for climate change:

1) We work with forest stands currently

being managed or landowners willing to

start

2) We work on resistance, resilience,

restoration, rehabilitation, and recovery

3) We do what we know—modify

existing silvicultural practices that will

work in a changing climate.

First, do no harm—

• Anything done in the name of

climate change should also be

robust in the context of the

current climate and stand

conditions

• Why? The most difficult year

for a new age cohort will be

the first growing season

Secondly,

How many silvicultural systems

are carried from establishment

at year 0 to rotation age R??

IMO--not many!

Industry land—silvicultural systems

change every time land

ownership changes

Exceptions—when rotation age is

less than length of ownership

The sale of forest industry lands to

TIMO-REIT ownership has been the

most recent of many recent changes

on the ‘forest industry’ land base.

NIPF land—Nearly no examples,

because of estate tax issues--

landowner’s life is far less than

age to maturity of timber

The hard truth on NIPF lands-

long-term management plans

only rarely survive the ownership

transition from parents to

children

The few examples

involve estate

planning into

irrevocable

easements,

trusts and

foundations

e.g.,

Pioneer Forest,

central Missouri

Govt land, such as National Forests?

The challenge is ‘decennial micromanagement’! Every 10-yr compartment exam redraws stand boundaries and changes existing silvicultural plans.

The exception-

Significant work for habitat restoration of endangered species

A classic example—the shortleaf pine-

bluestem management area on the

Ouachita NF, dedicated to RCWs

IMO:

At the most, 5-10% of the

200MM ac of southern forestland

is managed under the same

silvicultural system from year 0

to maturity.

IMO:

Silvicultural practice in the future is the art and science of practices that

-improve stand conditions in the short term, and

-create, not limit, options for current or future landowners in the long term

IMO:

This can be developed into an

empirical decision model for

silvicultural practices that are

resistant, resilient, or robust in

the context of changing

climatic conditions.

Bottom line—

Manage for diverse stands and

ecosystems, regardless of the

stage of the extant silvicultural

system in light of the condition

of the current stand.


ecosystems

Elements of

diversity

Elements of the silvicultural system

Regeneration

treatments Intermediate

treatments

Reproduction

cutting

methods

Genetic

diversity High Low Low

Species

diversity Moderate Moderate Low

Structural

diversity Low Moderate Moderate

Thoughts parallel concepts of forest

sustainability

The first principle of sustainability at

the stand level–

Secure regeneration of the desired

species after reproduction cutting

Regeneration treatments

Genetic diversity

Diversity of naturally-regenerated stock

-seed-origin

-sprout origin

Diversity of artificially-regenerated stock

-planted

-direct-seeded

Natural

regeneration

Sprout origin Seed origin

Post-hravest

establishment

Advanced

regeneration

Stump

sprouts

Seedling

sprouts

Requires choices to optimize genetic and

species diversity of natural regeneration

cohort

More diverse Less diverse

Natural regeneration from seed

• Genetically variable, result of outcrossing

• Rely on natural seedfall or advance growth from seedfall

• Especially important in the oaks

• Seedling sprouts perfectly acceptable for genetic diversity if developed from advance growth of seed origin

Natural regeneration--stump sprouts

Genetically

identical to parent trees

Adapted to local site conditions

May not be the best model under changing climatic conditions

Biggest implications—oak regeneration

May need to increase reliance on seed-origin seedling sprout advance growth

Artificial regeneration—planting (pines)

First year is toughest for survival:

Plant stock appropriate for the

expected conditions

Site prepare for first-year survival;

containerized stock?

Artificial regeneration—planting (pines)

Unlike traditional practice—identify planting stock origin and ensure genetic diversity in seedlings being planted on a given site

Plant mixtures of species, such as longleaf, loblolly and shortleaf in east Texas sites?

Direct seeding

Same arguments as planting stock

from the genetic perspective—ensure

diversity of seed

Could be used :

If a species absent from the site

Where natural seedfall is unlikely

to occur

To develop mixtures with

multiple species or genetic stock

Moving planting stock?

Guidance found in the old Southwide Pine

Seed Source Study:

Seed sources can be moved northward a

modest distance (<~200 miles) to colder

conditions, where they will outgrow local

sources

If moved too far, they suffer cold damage

The most important climatic variable

associated with north-south variation in

growth in provenance tests of southern

pines was average yearly minimum

temperature at the source

20

30

40

50

60

70

80

90

Jan

Feb Mar

AprM

ay Jun

Jul

Aug Sep Oct

Nov

Dec

Annua

l

Month

Mean

min

imu

m t

em

p., d

eg

. F

Alexandria LA

Hot Springs AR

Springfield MO

Average annual monthly temperature, Crossett EF

high low

1931-1963 76.9º F 51.1º F

1970-2004 74.9º F 53.0º F

To enhance species diversity—

Underplanting or enrichment planting

A tool to restore

native species absent from the

stand because of historical activity or

management decisions

Managed hardwood stand

with shortleaf pine stumps

Pioneer Forest, fall 2004

Underplanting or enrichment planting

Can be used to add species in a stand

based on expected changes

There are technical questions about

planting to achieve partial stocking, to

fill in openings smaller than 2 tree

heights in diameter, and survival under

closed canopy conditions

Pay attention to silvics!

Trait - - - Characteristic - - -

Distribution Limited Wide

Scattered Continuous

Pollination vector Insect Wind

Seed dispersal Limited Effective

Reproduction Vegetative Sexual

Habitat specificity Specialized Broad

Seral stage Pioneer Climax

Increasing genetic variability with increasing

number of characteristics to the right-hand side in

the table (Myking 2002)


ecosystems:

Elements of

diversity


Regeneration

treatments

Intermediate

treatments

Reproduction

cutting

methods

Genetic


Species


Structural


Intermediate treatments

Maintain resistance and resilience of existing stands to effects of climate change

Structural diversity

Indicators:

Canopy strata—one, two, many

Outputs:

Ability to resist effects of climate

change, or recover if stands are

adversely affected

Thinning

Maintain high individual tree vigor, reduce density-dependent mortality

Maintain stocking at acceptable levels below full stocking

Thinned stands have low hazard to SPB, but admittedly susceptible to

other disturbance events

Thinned pine stand, age 15

PCT Study 99, Crossett EF

Thinned pine stand damaged during

Dec 2000 ice storm

Ouachita NF

Prescribed burning

Maintain stands with reduced midstory and understory prairie flora

Maintain conditions resistant to loss from wildfire

Prescribed burning is important in FS lands—hopefully, scale and scope can continue

Pine-bluestem stand

Poteau RD, Ouachita NF

An erstwhile

silviculturist

ignites a

prescribed burn

Poteau RD,

Ouachita NF

Presalvage, salvage, sanitation cutting

Decide upon rehabilitation or recovery based on the extent of damage

If recovery is indicated, feed back to regeneration decisions

Resilience: stands that recover when changes affect them

Longleaf pine stand after Hurricane Katrina

Harrison Experimental Forest, Saucier MS

For example, understocked stand rehabilitation research informs decisions about recovery from windstorm events

SI=90

SI=75

0

20

40

60

80

100

120

0 5 10 15

Time, years

Perc

ent sto

ckin

g

0

20

40

60

80

100

120

0 5 10 15

Time, years

Perc

ent

sto

ckin

g


ecosystems

Elements

of

diversity


Regeneratio

n treatments

Intermediate

treatments

Reproduction

cutting

methods Genetic


Species


Structural


Structural diversity

Indicators:

Number and distribution of age

cohorts

Stand tables, models, stocking charts

Outputs:

Ability to resist effects of climate

change, or recover if stands are

adversely affected

Reproduction cutting methods

Reproduction

cutting

Even-aged

methods

Uneven-aged

methods

Clearcutting

method

Seed-tree

methods

Shelterwood

method

Group

selection

Single-tree

selection

Timing of new age cohorts—

more frequently may be better!

45-120 yrs

25-80 yrs

7-20 yrs

Two very different alternatives:

Longleaf pine woodland

Classic 1- to 2-aged stand

Apalachicola NF, FL

Classic uneven-aged stand

after 75 years of management

Mixed loblolly-shortleaf pine

Crossett EF, AR

The alternative of no treatment

inappropriate for managed stands

A problem of stand development

Not a retrogression to pre-

Columbian conditions

Static stand development is

inconsistent with changing

environment

Silvicultural strategies to consider at

the stand and landscape scale

SUMMARY

1. Manage forest composition and

structure to improve the resistance to

disturbance and the ability to recover

from disturbance

2. Modify silvicultural practices to improve

diversity of age and species composition

3. Manage forest density for optimum

resistance to drought, fire and wind

4. Factor in the possibility of increased

stress when making decisions about

intermediate treatments (ex. thinning and

burning)

-combine objectives to improve

compositional, structural and genetic

diversity in single treatments

5. Time harvests and site prep practices to

expected seed crops, or to release

established advance growth, for species in

the desired composition

6. Plan for and use disturbance events as

opportunities to improve forest resilience

to climate change

7. Consider “enrichment plantings” within

existing stands to improve species and

genetic diversity

8. Allow a mixture of natural and planted

regeneration.

9. Maximize genetic diversity within the

limits of the desired composition

-natural vs planted

-coppice vs seed

-bulk lot vs open pollinated vs full-sib

-local vs moved source)

10. Minimize the use of single sources for

clonal planting stock.

11. Monitor regeneration and early

development success of desired species.

12. Experimental or “banked” plantings

outside the natural ranges and standard

guides for seed sources (test pollination,

cold hardiness and drought resistance).

13. Consider species and plant material

sources outside and from dryer areas than

the immediate geographic area.

14. Don’t forget to hedge your bet—

Anything done silviculturally to capture

climatic conditions we think will occur

in the future should also be robust in

today’s climate in case our predictions

are wrong!

one stand at a time silvicultural options for stand...

Documents