U.S. Department of the InteriorU.S. Geological Survey

TAKING THE PULSE OFMOUNTAIN FORESTS:

THE CORDILLERA FORESTDYNAMICS NETWORK

(CORFOR)

CORFOR is a collaboration of scientists with permanent foreststudy plots arrayed along the American Cordillera

Nate Stephenson U.S. Geological Survey, USAAlvaro Duque Univ. Nacional de Colombia, MedellínEsteban Alvarez Interconexión Eléctrica S.A., ColombiaJulieta Carilla Univ. Nacional de Tucumán, ArgentinaLori Daniels Univ. of B.C., Vancouver, CanadaRicardo Grau Univ. Nacional de Tucumán, ArgentinaGreg Greenwood Mountain Res. Initiative, SwitzerlandMark Harmon Oregon State Univ., Corvallis, USASergio Orrego Univ. Nacional de Colombia, MedellínPhil van Mantgem U.S. Geological Survey, USATom Veblen University of Colorado, Boulder, USA

Part 1: Information needs: mountain forests in achanging climate

Part 2: Permanent forest plots uniquely meet some ofour information needs

Part 3: Need for, and birth of, the Cordillera Forest Dynamics Network (CORFOR)

Part 4: CORFOR progress report

Road map:

Mountain forests provide:• Wood and other products• Hydrologic regulation• Recreational and spiritual

opportunities• Critical wildlife habitat and

biodiversity conservation

Mountain forests provide:• Wood and other products• Hydrologic regulation• Recreational and spiritual

opportunities• Critical wildlife habitat and

biodiversity conservation

With rapid climatic change,we potentially face:• Changes (included losses) in

some of these goods andservices

• Large feedbacks to climaticchange

If we hope to adapt to and mitigatethe effects of climatic changes on forests,

we have at least two critical needs:

(1) Ability to detect ongoing changes.

(2) Ability to forecast future changes.

Hicke et al. 2002, Global Biogeochem. Cycles

2. PERMANENT FOREST PLOTS UNIQUELYMEET SOME OF OUR INFORMATION NEEDS

Change detection:

Advantages of remote sensing:• Wall-to-wall coverage across a range of spatial scales!

Need for plot-based data:• Ground-truthing of remotely-sensed data• Detecting things not detected by remote sensing

- Changes in reproduction- Subtle changes in mortality rates- Ongoing compositional shifts

The two approaches are complementary!

Change detection:

Tropical (Amazonian) forest DYNAMICS are changing(e.g., recruitment, growth, and mortality rates are increasing)

Phillips et al., Phil. Trans. B, 2004

Recruitment

Mortality

Phillips et al., Nature, 2002

Credit: Yadvinder Malhi

Tropical (Amazonian) forest COMPOSITION is changing(e.g., lianas [woody vines] are increasing)

Lewis et al., Phil. Trans. B, 2004

Tropical (Amazonian) forest STRUCTURE AND FUNCTIONare changing (e.g., aboveground biomass, hence C storage,

may be increasing)

Basal area gainBasal area loss

Difference

Year1960 1970 1980 1990 2000

Mor

talit

y ra

te (%

yr-1

)

0.0

0.5

1.0

1.5

2.0P<0.0001, n=76

Temperate (western USA) forest DYNAMICS are changing(background mortality rates are increasing)

van Mantgem et al. 2008

Year1990 2000 2010 2020 2030 2040 2050

PIL

A p

opul

atio

n si

ze

0

100

200

300

400

500observedprojection using 83-88 dataprojection using 88-94 dataprojection using 94-2000 data

van Mantgem et al. Ecol. Appl. 2004

Temperate (western USA) forest COMPOSITION is changing(e.g., 5-needled pines are declining)

Temperate forest STRUCTURE AND FUNCTIONare almost certainly changing, but …

Trust us,George … we’re

working on it!

Temperate forest STRUCTURE AND FUNCTIONare almost certainly changing, but …

Change detection:Permanent forest plots provide our

“Keeling curve” for forests

Most currentmodels are driven

by sets of untestedassumptions,

many of which aredecades old.

Forecasting:

Growth rate

Pro

babi

lity

of d

eath

The well-known inverse relationship between tree growth rate and probability of death is at the heart of “gap” models.

Growth rate

Pro

babi

lity

of d

eath

A key model assumption: The only way climatic changes affect probability of death (in the absence of catastrophic

disturbance) is by altering tree growth rate.

How do we test assumptions like this when thegreat spatial and temporal scales of forest dynamics

preclude experimentation?

Replicatedmountain

forestsin bell jars

We take advantage of natural experimentsin space and time … permanent forest plots

arrayed along environmental gradients

Credit: A. Caprio

Elevation (m)1500 2000 2500 3000 3500

Fore

st t

urno

ver

(% y

r-1)

0

1

2

3y = 2.76 - 0.00066 xr 2 = 0.49, P < 0.001

In the forests of California’s Sierra Nevada,forest turnover rate (mortality and recruitment)

declines significantly with elevation.

Stephenson & van Mantgem, Ecol. Lett., 2005

0

1

2

3

4

550 46 30 27 27

Rich

er s

oils

Poor

er s

oils

Angi

ospe

rm

Gym

nosp

erm

Mixe

d

Tropical Temperate(Amazonia) (global)

Fore

st t

urno

ver

(% y

r-1)

Stephenson & van Mantgem 2005

Fore

st t

urno

ver

(% y

r-1)

0

1

2

3

4

5158 84

Trop

ical

Tem

pera

te

• Globally, forests of productive environments have higher turnover rates …

• ... at least partly because environments that favor tree growth alsofavor the organisms that kill trees.

Natural experiments in space suggestthe need for a fundamental change in the nature

of the gap model mortality function.

Mor

talit

y ra

te

Site productivityIndividual treegrowth rate

Low

High Low

High

Summary: some roles of permanent forest plots

(1) Change detection

(2) Provide a mechanisticfoundation forforecasting

Year1960 1970 1980 1990 2000

Mor

talit

y ra

te (%

yr-1

)

0.0

0.5

1.0

1.5

2.0P<0.0001, n=76

Mor

talit

y ra

te

Site productivityIndividual treegrowth rate

Low

High Low

High

3. NEED FOR, AND BIRTH OF, THE CORDILLERAFOREST DYNAMICS NETWORK (CORFOR)

The RAINFOR plot networkhttp://www.geog.leeds.ac.uk/projects/rainfor/

Only two other broad, international forest dynamics networksexist, and both focus on lowland tropical forests

The Center for Tropical Forest Science (CTFS) plot networkhttp://www.ctfs.si.edu/

CORFOR’s vision: a network taking advantage of thebroadest environmental gradients possible

Latitudes: Subarctic – temperate – tropical (and back).Temperature (elevation): Sea level to >3500 m.Precipitation: West-to-east gradients.Soils and topography: Local variation.

CORFOR’s vision: a network taking advantage of thebroadest environmental gradients possible

Based on this vision, CORFOR was born at the CONCORDclimate change conference in Mendoza, Argentina,

4 - 6 April 2006

4. CORFOR PROGRESS REPORT

CORFOR workshop,13 June 2008, thanks to:

http://www.corfor.com/http://mri.scnatweb.ch/content/view/88/67/

- Mountain ResearchInitiative (MRI),Switzerland

- USGS Western MountainInitiative (WMI)

- MTNCLIM 2008organizers

Among other things, tomorrow’s workshop will:

- Establish a set of minimum standards for forestdynamics plots in the network.

- Create a road map for the future: identifyresearch needs and opportunities of broadsignificance that CORFOR can address.

- As a “proof of concept,” work on a papercomparing forest dynamics along elevationalgradients in the southern temperate zone,tropics, and northern temperate zone.

Northern temperate zone:California,Oregon,

and Washingtonplot networks

California

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.54, P < 0.0001

Mortality rate vs. elevation, northern temperate zone

California

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.54, P < 0.0001

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.08, P = 0.08

Oregon & Washington

Mortality rate vs. elevation, northern temperate zone

.....

.

...

.

.

.

.

5-ha

25-ha

2-ha

1-ha

Tropics:Colombian

plot network

Colombia

Mortality rate vs. elevation, tropics

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.31, P = 0.07

Colombia Venezuela

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.09, P = 0.24

Mortality rate vs. elevation, tropics

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.31, P = 0.07

Southern temperate zone:Tucumán, Argentina plot network

Argentina,mature forest

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.08, P = 0.42

Mortality rate vs. elevation, southern temperate zone

Argentina,mature forest

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.08, P = 0.42

Elevation (m)0 1000 2000 3000

Mea

n m

orta

lity

rate

(% y

r-1)

0

1

2

3

4R2 = 0.20, P = 0.14

Argentina,secondary forest

Mortality rate vs. elevation, southern temperate zone

CORFOR Challenges:

• Time: All of us have many other pressing obligations.

• Funds: It is very difficult to capture funds for long-term forest research, much less to hire someone tocoordinate CORFOR activities.

• Communication: We are literally continents apart. Weaccomplished more in a few hours together yesterdaythan we had during weeks of email exchanges.

CORFOR Challenges:

• Time: All of us have many other pressing obligations.

• Funds: It is very difficult to capture funds for long-term forest research, much less to hire someone tocoordinate CORFOR activities.

• Communication: We are literally continents apart. Weaccomplished more in a few hours together yesterdaythan we had during weeks of email exchanges.

Happily, we have a dedicated, motivated, andexcited core group of scientists, ready to acceptthese challenges.

Thank you for your attention!