(NAFD): A NACP Core Project - North American Carbon Program

US Forest Disturbance Trends observed with Landsat Time Series Samuel N. Goward1 (PI), Jeffrey Masek2, Warren Cohen3, Gretchen Moisen4, Chengquan Huang1, Robert Kennedy5, Karen Schleeweis1, Rama Nemani6 1Department

of Geography, University of Maryland, College Park MD 2Biospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD 3U.S.D.A. Forest Service, Pacific Northwest Research Station, Corvallis, OR 4U.S.D.A. Forest Service, Rocky Mountain Research Station, Ogden, UT 5Earth and Environment Dept., Boston University, Boston MA 6NASA Ames Research Center, Moffett Field, CA

Disturbance, Age Structure, and Carbon Understanding the history of land use, management, and disturbance is critical because disturbance and recovery are major determinants of the net terrestrial carbon flux.” - 2007 SOCCR (SAP 2.2) Biologic C Flux

Biomass

Atmospheric source

Disturbance Dominated Regrowth Dominated

Balanced

area histograms

Old

time

Forest Disturbance and NACP • 56 NACP project descriptions include “Disturbance”

• NACP Disturbance Synthesis 2010-2011 (Kasischke) • JGR-B Special Section “Impacts of Disturbance on the North American Carbon Cycle” • Many new products, analyses

North American Forest Dynamics (NAFD): Landsat-based sample of US forest disturbance

•50 sample scenes across US; probability-based sample for area estimates (East, West strata) •Annual time series of Landsat data for each sample (1985-2005) •Disturbance events mapped using Vegetation Change Tracker (VCT approach) (Huang et al, 2010)

Vegetation Change Tracker (VCT): Huang et al (2010) Example: Fire & Harvest, Sierra Nevada CA

% US Forest Cover Disturbed

NAFD National Disturbance Rates estimates 1985-2005 average = 2.77 Mha/yr (+/- 0.76) = 1.1% US Forest Land

Masek et al, in review

% Forest Cover Disturbed

East versus West East

West

US Quadrants Western US

Central

Eastern US

Southeast

Coastal Northeast

Forest Area Disturbed (Mha/yr)

Estimates of US Disturbance Rates 9

8 7

Harvest (Smith et al, 2009)

6 5 4 3

Fire (EPA, 2010) Insects (USFS, 2010)

2

1 0

Western Insect Mortality (200510)

US Forest Carbon Fluxes from Recent Disturbance (Williams et al., 2012 GBC; in review RSE) • CASA calibrated to match FIA biomass-age curves for each forest type & region • Landscape age distribution from FIA and NAFD time since disturbance • Landscape-scale estimates of NPP, NEP, biomass based on age, type, region

Higher NAFD Disturbance = Lower NEP Estimate

Williams et al., in review

NAFD Phase III 0

%disturbed /yr

>2.0

LEDAPS Disturbance Map 1990-2000 (Masek et al., 2008)

• Annual Time Series (1972 -2012) • Wall-to-wall (440 * 40+ = > 17,000 annual maps) via NEX computing environment (Nemani – NASA ARC) • Systematic Validation (Cohen – USFS PNW) • Disturbance Causes (Moisen USFS RMS) • Regrowth Dynamics (Masek – NASA GSFC)

Geography of Disturbance Causes (No Insects yet)

Schleeweis , 2012

Conclusions • US Forest Disturbance Rates estimated at 1.1%/yr from 1985-2005 via NAFD Landsat analysis … but RS methods tend to miss considerable partial disturbance (thinning, insect mortality, storm damage) • Overall disturbance rates varied by ~x2 during mapping epoch • Western variability driven by fire, insects; Eastern variability driven by management (GDP?)

Forest Carbon Dynamics

“The relative importance of these broad factors in accounting for the current [forest carbon] sink is unknown… Understanding the history of land use, management, and disturbance is critical because disturbance and recovery are major determinants of the net terrestrial carbon flux.” 2007 SOCCR (SAP 2.2)

Attribution of Disturbance Variability

Masek et al, in review

US Forest Biomass and C Storage Potential (PgC)

Williams et al., in review

US forests could ~double current stocks

NAFD Staff & Collaborators University of Maryland (Goward, Huang) Feng Zhou Research Associate

Mary Ann Lindsey GRA

Louis Keddell GRA

Elaine Denning GRA

USFS PNW/OSU (Cohen, Kennedy) Stephen Stehman Syracuse University

Zhiqiang Yang Research Associate

Peder Nelson GRA

USFS RMRS (Moisen) Karen Schleeweis

Todd Schroeder

Chris Toney

NASA GSFC (Masek) Chris Neigh

Khaldoun Rishwami

Collaborators Liz LaPoint USFS FIA

J. Collatz NASA GSFC

Bev Law OSU

J. Dwyer USGS/EROS

Z. Zhu USGS

H. Bastian USGS