TAKING THE PULSE OF
MOUNTAIN FORESTS:
THE CORDILLERA FOREST
DYNAMICS NETWORK
(CORFOR)
U.S. Department of the Interior
U.S. Geological Survey

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

Nate Stephenson U.S. Geological Survey, USA
Alvaro Duque Univ. Nacional de Colombia, Medellín
Esteban Alvarez Interconexión Eléctrica S.A., Colombia
Julieta Carilla Univ. Nacional de Tucumán, Argentina
Lori Daniels
Ricardo Grau
Univ. of B.C., Vancouver, Canada
Univ. Nacional de Tucumán, Argentina
Greg Greenwood Mountain Res. Initiative, Switzerland
Mark Harmon
Sergio Orrego
Oregon State Univ., Corvallis, USA
Univ. Nacional de Colombia, Medellín
Phil van Mantgem U.S. Geological Survey, USA
Tom Veblen University of Colorado, Boulder, USA

Part 1: Information needs: mountain forests in a changing climate
Part 2: Permanent forest plots uniquely meet some of our information needs
Part 3: Need for, and birth of, the Cordillera Forest
Dynamics Network (CORFOR)
Part 4: CORFOR progress report

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 and services
• Large feedbacks to climatic change

If we hope to adapt to and mitigate the 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.

2. PERMANENT FOREST PLOTS UNIQUELY
MEET SOME OF OUR INFORMATION NEEDS
Change detection:
Hicke et al. 2002, Global Biogeochem. Cycles

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!

Tropical (Amazonian) forest DYNAMICS are changing
(e.g., recruitment, growth, and mortality rates are increasing)
Recruitment
Mortality
Phillips et al., Phil. Trans. B , 2004

Tropical (Amazonian) forest COMPOSITION is changing
(e.g., lianas [woody vines] are increasing)
Credit: Yadvinder Malhi
Phillips et al., Nature , 2002

Tropical (Amazonian) forest STRUCTURE AND FUNCTION are changing (e.g., aboveground biomass, hence C storage, may be increasing)
Basal area gain
Basal area loss
Difference
Lewis et al., Phil. Trans. B , 2004

Temperate (western USA) forest DYNAMICS are changing
(background mortality rates are increasing)
2.0
1.5
1.0
0.5
0.0
P <0.0001, n=76
1960 1970 1980 1990 2000
Year van Mantgem et al. 2008

Temperate (western USA) forest COMPOSITION is changing
(e.g., 5-needled pines are declining)
500
400
300
200
100
0 observed projection using 83-88 data projection using 88-94 data projection using 94-2000 data
1990 2000 2010 2020 2030 2040 2050
Year van Mantgem et al. Ecol. Appl. 2004

Temperate forest STRUCTURE AND FUNCTION are almost certainly changing, but …

Temperate forest STRUCTURE AND FUNCTION are almost certainly changing, but …
Trust us,
George … we’re working on it!

Change detection:
Permanent forest plots provide our
“Keeling curve” for forests

Most current models are driven by sets of untested assumptions, many of which are decades old.
Forecasting:

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

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 the great spatial and temporal scales of forest dynamics preclude experimentation?
Replicated mountain forests in bell jars

We take advantage of natural experiments in space and time … permanent forest plots arrayed along environmental gradients
Credit: A. Caprio

In the forests of California’s Sierra Nevada, forest turnover rate (mortality and recruitment) declines significantly with elevation .
3 y = 2.76 - 0.00066 x r
2
= 0.49, P < 0.001
2
1
0
1500 2000 2500 3000 3500
Elevation (m)
Stephenson & van Mantgem, Ecol. Lett., 2005

• Globally, forests of productive environments have higher turnover rates …
• ... at least partly because environments that favor tree growth also favor the organisms that kill trees.
5 5
158 84
50 46 30 27 27
4 4
3 3
2 2
1 1
0
T ro p ic a l
T e m p e ra te
0
R ic h e r so ils
P o o re r so ils
A n g io sp e rm
M ix e d
G ym n o sp e rm
Tropical Temperate
(Amazonia) (global)
Stephenson & van Mantgem 2005

Natural experiments in space suggest the need for a fundamental change in the nature of the gap model mortality function.
Low
Indiv grow idua th ra l tree te
High
Lo w
Sit e p rod uc
Hig h tiv ity

Summary: some roles of permanent forest plots
(1) Change detection
2.0
1.5
1.0
0.5
0.0
P <0.0001, n=76
1960 1970 1980 1990 2000
Year
(2) Provide a mechanistic foundation for forecasting
Low
Indiv idua h ra l tree te
High w
Lo
Si te gh
Hi pr od uc tiv ity

3. NEED FOR, AND BIRTH OF, THE CORDILLERA
FOREST DYNAMICS NETWORK (CORFOR)
Only two other broad, international forest dynamics networks exist, and both focus on lowland tropical forests
The RAINFOR plot network http://www.geog.leeds.ac.uk/projects/rainfor/

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

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

CORFOR’s vision: a network taking advantage of the broadest 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.

Based on this vision, CORFOR was born at the CONCORD climate change conference in Mendoza, Argentina,
4 - 6 April 2006

4. CORFOR PROGRESS REPORT http://www.corfor.com/ http://mri.scnatweb.ch/content/view/88/67 /
CORFOR workshop,
13 June 2008, thanks to:
- Mountain Research
Initiative (MRI),
Switzerland
- USGS Western Mountain
Initiative (WMI)
- MTNCLIM 2008 organizers

Among other things, tomorrow’s workshop will:
- Establish a set of minimum standards for forest dynamics plots in the network.
- Create a road map for the future: identify research needs and opportunities of broad significance that CORFOR can address.
- As a “proof of concept,” work on a paper comparing forest dynamics along elevational gradients in the southern temperate zone, tropics, and northern temperate zone.

Northern temperate zone:
California,
Oregon, and Washington plot networks

Mortality rate vs. elevation, northern temperate zone
4
California
R
2
= 0.54, P < 0.0001
3
2
1
0
0 1000 2000 3000
Elevation (m)

Mortality rate vs. elevation, northern temperate zone
4
3
California
R
2
= 0.54, P < 0.0001
3
4
Oregon & Washington
R
2
= 0.08, P = 0.08
2
1
0
0 1000 2000 3000
Elevation (m)
2
1
0
0 1000 2000 3000
Elevation (m)

Tropics:
Colombian plot network
.
.
.
.
5-ha
25-ha
2-ha
1-ha
.
..
.
.
..
.
.

Mortality rate vs. elevation, tropics
Colombia
R
2
= 0.31, P = 0.07
4
3
2
1
0
0 1000 2000 3000
Elevation (m)

Mortality rate vs. elevation, tropics
Colombia
R
2
= 0.31, P = 0.07
4
Venezuela
R
2
= 0.09, P = 0.24
4
3
2
1
0
0 1000 2000 3000
Elevation (m)
3
2
1
0
0 1000 2000 3000
Elevation (m)

Southern temperate zone:
Tucumán, Argentina plot network

Mortality rate vs. elevation, southern temperate zone
4
Argentina, mature forest
R
2
= 0.08, P = 0.42
3
2
1
0
0 1000 2000 3000
Elevation (m)

Mortality rate vs. elevation, southern temperate zone
4
Argentina, mature forest
R
2
= 0.08, P = 0.42
4
Argentina, secondary forest
R
2
= 0.20, P = 0.14
3 3
2 2
1
0
0 1000 2000 3000
Elevation (m)
1
0
0 1000 2000 3000
Elevation (m)

• Time: All of us have many other pressing obligations.
• Funds: It is very difficult to capture funds for longterm forest research, much less to hire someone to coordinate CORFOR activities.
• Communication: We are literally continents apart. We accomplished more in a few hours together yesterday than we had during weeks of email exchanges.

• Time: All of us have many other pressing obligations.
• Funds: It is very difficult to capture funds for longterm forest research, much less to hire someone to coordinate CORFOR activities.
• Communication: We are literally continents apart. We accomplished more in a few hours together yesterday than we had during weeks of email exchanges.
Happily, we have a dedicated, motivated, and excited core group of scientists, ready to accept these challenges.