Jump to Completed Projects

Leveraging temporal variation in climate and management across national parks in the western U.S. to characterize three decades of landscape vegetation dynamics


Funding through NASA’s

New Investigator Program

P.I. Robert Kennedy

Spatial patterns of vegetation reflect a history of interacting biotic and abiotic factors, including competition, dispersal, climatic effects, topographic position, nutrient and soil status, disturbance, and management by humans. Several of these driving factors are thought to be changing under human influence, and as they change the spatial patterns of vegetation type and condition are likely to change as well. Because changes in vegetation dynamics can adversely affect ecological and socioeconomic systems, understanding vegetation dynamics and the processes that drive them is critical for long-term management and health of those systems, and, by extension, of the Earth system as a whole. The goal of this project is to develop satellite-based maps of changes in vegetation dynamics over time, and to test the extent to which spatial and temporal patterns of change can be used to infer the relative importance of human management and climate change on those vegetative dynamics.

The project will develop maps of 30+ years of landscape dynamics for a suite of national parks in the western U.S. Mapping vegetation dynamics will be done with the Landtrendr algorithm, which captures change in vegetative cover through analysis of temporal trajectories of spectral data from satellites, in this case from the Landsat Thematic Mapper family of sensors.

Conducting this research at national parks also provides an excellent means of communicating the importance of space-based research to the public. Through a series of trainings and workshops, the PI will help NPS staff build the expertise needed to integrate the products of this research into existing programs and to build new programs and materials from the research.


Testing a new satellite-image analysis technique to monitor pest related-, fire-, and post-fire-mortality in the Northwest Forest Plan area of Oregon

Tree mortality caused by pest epidemics has long been thought to increase risk of subsequent wildfire, but recent studies have shown the relationships to be far more nuanced and situation-specific than previously assumed. In addition to short and medium-scale climatic conditions, pest agent, forest type and age, time since pest outbreak, and post-outbreak vegetation dynamics likely all contribute to variation in fire dynamics and risk over space and time. If pest epidemics and fire activity in the western U.S. change as expected under climate change scenarios, then greater understanding of the interactions between these two disturbance agents will be required. Spatial and temporally consistent maps of pest mortality, fire severity, and post-fire vegetation dynamics must be mapped across a range of forest type, climatic, and management regimes. While the Forest Health Monitoring (FHM) and the Monitoring Trends in Burn Severity (MTBS) programs produce maps that meet portions of these goals, no spatially and temporal consistent measurement tool exists to capture the full suite of dynamics related to pest, fire, and management. This gap must be filled if spatially-explicit monitoring and modeling of fire and pest dynamics are to be improved.

We are investigating the extent to which our LandTrendr (Landsat Detection of Trends in Disturbance and Recovery) algorithms can meet these mapping needs and lay foundations for predictive modeling of pest-related fuel loading and risk.

1. Determine the appropriate spatial and temporal grain at which the LandTrendr algorithms can create maps that complement and augment FHM aerial surveys in monitoring severity and trends in pest-related mortality.  
2. Utilize derived maps to examine relationships between mortality caused by pest epidemics, post-epidemic community change, wildfire, post-fire management, and post-fire vegetation response to build foundations for future predictive modeling.


Characterizing landcover trends within Oregon Coast Coho Salmon habitat



This project is designed to characterize spatial and temporal forest disturbance patterns that could potentially affect the habtitat suitability for the Oregon Coast Coho Salmon. Disturbance information will be mapped using trajectory-based techniques derived from annual Landsat Thematic Mapper (TM) data, potentially merged with existing maps of seral stage as appropriate. Analytical techniques will focus on understanding and characterizing spatial patterns according to watershed, basin, ownership, and management regime, and temporal patterns related to changes in policy, economic drivers, and climate.


Developing protocols for remote-sensing based inventorying & monitoring (I&M) of vegetation patterns across several I&M networks of the National Park Service

A primary goal of the National Park Service’s Inventory and Monitoring program (NPS I&M) is to “monitor park ecosystems to better understand their dynamic nature and condition and to provide reference points for comparisons with other, altered environments.”  In conjunction with several networks within the NPS I&M, we are developing protocols for long-term, remote-sensing based monitoring of landscape patterns and vegetation changes.

Sierra Nevada Network (SIEN)

Southwest Alaska Network (SWAN)

Northern and Southern Colorado Plateau Networks (NCPN & SCPN)

North Coast and Cascades Network (NCCN)







North American Forest Disturbance and Regrowth since 1972 (Phase I): Within the North American Carbon Program (NACP), there is a strong recognition that analysis of the forest carbon cycle must include the effects of disturbance processes. Two key sources of information to address this problem are: (1) passive optical remote sensing from the 35+ year Landsat archive and (2) plot-level forest inventory data from the US Forest Service Forest Inventory and Analysis (FIA) system. Integrating these two data sources allows us to produce detailed statistical summaries and maps of disturbance and regrowth. Phase I work focused on construction of dense Landsat time series and  obtaining a valid statistical sample of disturbance rates spread across US forests and demonstrating techniques to obtain changes in aboveground live biomass associated with disturbance and regrowth by integrating Landsat reflectance trajectories with FIA plot-level biomass data.   Status: Ongoing

Role of North American Forest Disturbance and Regrowth in NACP (Phase II): Building on the first phase of NAFD, Phase II relies on the use of dense (annual or biennial) time series of Landsat imagery that have been integrated with FIA data to produce biomass trajectories for as many as 50-75 Landsat scenes nationally. This phase has six major objectives: (1) Reduce error in nationwide estimates of forest disturbance and regrowth, (2) Convert data cube reflectance to data cube biomass, (3) Develop nationwide maps of forest biomass dynamics, (4) Partner with Canada and Mexico, (5) Develop formal collaborative relationships with other NACP-funded scientists, and (6) Quantify the forest component of woody encroachment nationally. Collectively, these activities will expand and refine our knowledge of North American forest dynamics, and thus significantly reduce uncertainties in carbon flux estimates.


Northern Eurasia Land Dynamics Analysis

The Northern Eurasia Land Dynamics Analysis (NELDA) project seeks to harness NASA remote sensing technology and local knowledge of land-cover conditions in order to validate and improve land cover/land-cover change products for Northern Eurasia.  The NELDA project will establish a network of test sites for analyzing land cover, land-cover change, and disturbance captured with time series of Landsat-resolution imagery.  The test sites will provide data for validation of existing coarse-resolution land-cover products and samples of important vegetation change and disturbance processes. We will use these samples to develop and test methods for continental mapping of vegetation disturbance.  Finally, we will produce a new, updated land cover map for Northern Eurasia based on MODIS data for circa 2005 at 500-m spatial resolution.



Northwest Forest Disturbance Mapping Update

LARSE has a long tradition of mapping stand-replacing disturbance in Pacific Northwest forests (see Northwest Forest Plan Disturbance Mapping in completed projects section; Cohen et al., 1996; Cohen et al., 1998; Oetter et al., 2000; Cohen et al., 2002). Previous projects have resulted in disturbance maps for the Northwest Forest Plan Area between 1972 and 2002. Currently, we are updating our maps to 2007 using yearly imagery and trajectory based change detection as described in the North American Forest Disturbance Project.


Mapping Current Conditions & Modeling the Dynamic Responses of Riparian Vegetation & Salmon Habitat in Oregon

The proposed research integrates riparian zone mapping with dynamic models to project the response of riparian zones, stream channels and salmon habitat to natural disturbance and land-use activities. The overall objective of this work is to produce a decision support tool for habitat restoration planning that incorporates advanced remote-sensing technology and information about disturbance-recovery processes with existing knowledge of critical habitat needs for salmonids. The proposal has two components: 1) remote sensing and riparian mapping, 2) riparian and aquatic modeling. We will apply the remote sensing and mapping methods to two intensively monitored watersheds – Nehalem and Middle Fork John Day Rivers – and apply modeling to them to examine current conditions relative to the historic range of variability, examine potential of passive restoration to meet recovery goals, and examine the potential of active restoration to accelerate recovery.


Landsat and Vegetation Change: Towards 50 Years of Observation and Characterization


The Landsat Data Continuity Mission (LDCM) is the next-generation Landsat satellite, expected to be launched during the summer of 2011. LARSE Director Warren Cohen serves as a member of the Landsat Science Team, which provides advice and recommendations to the USGS and other partners on topics that will affect the overall success of the LDCM mission. In that capacity, he draws upon various past and present projects that take advantage of the Landsat archive, the most temporally extensive, spatially-explicit data record for understanding vegetation change at a global scale. The two most important of those projects include the North American Forest Dynamics Study (NAFD) and the various National Park Service Inventory & Monitoring projects, both of which focus on the vegetation monitoring capabilities of Landsat data when used in combination with inventory and related field and airphoto data.


Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

Our primary goals were to provide a regional test of the overall North American Carbon Program (NACP) strategy by demonstrating bottom-up and top-down approaches to determine the carbon balance of the West Coast of the US, and to develop global carbon cycle modeling and analysis focused on the use of remote sensing data.

Phase I of this project focused on modeling and understanding disturbance and climate effects on the carbon balance of Oregon and Northern California. Phase II extended this work to include all of Oregon, Washington and California.

Mapping Urbanization in the Snohomish Watershed, WA

To satisfy the goals of the Washington Department of Fish and Wildlife (DFW) and the Washington Governor’s Office, we are producing maps of urbanization in the Snohomish watershed during the period 1972-2004.  The resulting maps and write-up will be incorporated by the Salmon Recovery Office into the "State of the Salmon" report.


Landsat Ecosystem Disturbance Adaptive Processing System

LEDAPS is a NASA-funded project to map North American forest disturbance since 1975 from the Landsat satellite record. LEDAPS will also produce comprehensive maps of surface reflectance for 1975, 1990, and 2000 for the United States and Canada. LEDAPS is part of NASA's contribution to the North American Carbon Program (NACP), a component of the USGCRP Carbon Cycle Science Program.


Satellite Laser Altimetry of Forests

This research is exploring how lidar waveforms from the GLAS sensor can be used to estimate forest height and aboveground biomass over three pilot study areas: the Pacific Northwest, southeast of the U.S. and the northwestern Amazon Basin. With no other global lidar data collection scheduled for the near future, GLAS data represent an importnant source of information for global forest canopy height and aboveground biomass.


Assessing Eastern North American Forest Disturbance and Regrowth: Potential from Passive Optical Remote Sensing Evaluated in the Mid-Atlantic Region

This project was funded by NASA Terrestrial Ecology Program in support of the North American Carbon Program (NACP). The Forest Cover Change Project had the following goals:
1. To evaluate approaches for monitoring Mid-Atlantic land- and forest-cover change, disturbance, and recovery with passive optical satellite remote sensing observations (i.e. Landsat, MODIS, IKONOS).
2. To create a validated set of techniques for exploiting passive optical remote sensing to provide the needed forest measurements in Eastern U.S. forests that will support NACP goals.
3. To address a hierarchy of increasing measurement difficulty: (a) mapping forest disturbance, regrowth, and change; (b) obtaining forest age assessments for regenerating forests; and (c) obtaining direct estimates of biomass and biomass change for regenerating forests.


Partial Harvest Mapping Project

We collected field and photo data to support an effort to map partial harvests in central Washington. This project complemented previous and ongoing work to map stand-replacing harvests and fires in the Pacific Northwest. Our goal was to estimate change in forest cover as a continuous variable for two focus areas identified as critical by the Washington Department of Fish and Wildlife (DFW). We also provided estimates of the loss of biomass associated with detected partial harvests. This project was funded by the Washington DNR and DFW.


Linking In Situ Measurements, Remote Sensing, and Models to Validate MODIS Products Related to the Terrestrial Carbon Cycle

The overall goal of BigFoot was to provide validation of MODLand (MODIS Land Science Team) science products, including land cover, leaf area index (LAI), fraction absorbed photosynthetic active radiation (fAPAR) , and net primary production (NPP). To do so, we used ground measurements, remote sensing data, and ecosystem process models at sites representing different biomes. BigFoot sites measured 5 x 5 km in size and surrounded the relatively small footprint (1 km2) of CO2 flux towers. At each site we made multi-year in situ measurements of ecosystem structure and functional characteristics related to the terrestrial carbon cycle. Our sampling design allowed us to explicitly examine scales of fine-grained spatial pattern in these properties, and provided for a field-based ecological characterization of the flux tower footprint. Multi-year measurements ensured that inter-annual validity of MODLand products were assessed.


Northwest Forest Plan Disturbance Mapping Project

This project's goal was the detection and mapping of stand replacement disturbances occurring in the Northwest Forest Plan Area between 1984 and 2002. Both clear-cuts and major fire events produce significant changes in forest cover that are readily detected in sequential Landsat images. Building on earlier LARSE research (Cohen et al., 1998; Oetter et al., 2000; Cohen et al., 2002), we employed a relatively simple, cost-effective change-detection method that is roughly 90% accurate (Cohen et al., 2002). The immediate use of this map was to monitor the effectiveness of the Late-Successional and Old-Growth Module of the Northwest Forest Plan. Other potential uses may include habitat modeling and regional evaluation of changing forest management practices.


Modeling Carbon Dynamics and Their Economic Implications in Two Forested Regions: Pacific Northwestern USA and Northwestern Russia

This research project was drafted to compare two significant forest regions, the United States Pacific Northwest and the St. Petersburg region of Russia, with the overall objective of determining the relative importance of land-use versus biogeoclimatic factors in controlling spatial and temporal patterns of carbon dynamics. Our laboratory's involvement in the effort was to provide the remote sensing components of the land cover and disturbance maps that drive the carbon flux modeling process.


Regional Analysis of Net Ecosystem Productivity of Pacific Northwest Forests: Scaling Methods, Validation and Results Across Major Forest Types and Age Classes

Net ecosystem productivity (NEP) is a critical characteristic of terrestrial ecosystem response to environment. Processes controlling NEP operate on a variety of temporal and spatial scales and are influenced by physiology, allocation, forest development, climate and disturbance. We are simulating NPP and NEP in Oregon and Washington using a combination of remote sensing, site data, and process models. Model outputs are being tested using detailed ecosystem studies at intensive sites, more basic ecological measurements at other existing intensive sites, and survey data from Forest Health Monitoring (FHM), Forest Inventory and Analysis (FIA) plots, and Current Vegetation Survey (CVS) plots. In spatially explicit applications, we are predicting and evaluating forest productivity for an east-west longitudinal swath along a steep climatic gradient through central Oregon from the coast to the semi-arid east side of the Cascade Mountains, and a north-south latitudinal swath from the south.


Interagency Vegetation Mapping Project (IVMP)

The Interagency Vegetation Mapping Project (IVMP) is a joint effort by the Forest Service and Bureau of Land Management to map forest structure and composition variables (quadratic mean diameter, percent canopy cover, and percent cover of broadleaves and conifers) in western Oregon and Washington using Landsat-5 TM data. Project products will be used in the effectiveness monitoring of the Northwest Forest Plan (NWFP) modules including late-successional / old-growth forests, northern spotted owls, marbled murrelets and aquatic / riparian species. IVMP is using regression modeling to relate satellite spectral values to “ground truth” derived from inventory plots in order to map forest characteristics as continuous variables rather than as classes. This technique allows the same map product to be delivered to each NWFP module team, which then can break the map into classes appropriate for their specific needs.


Integration of Enhanced Thematic Mapper Plus and Lidar for Forest Ecosystems

The overall goal of this project is to provide a framework for integrating Landsat, lidar, ground, and environmental data for applications in forest ecology. The research addresses two primary objectives:
Objective 1. Statistically relate lidar waveforms to ground-measured forest structural attributes.
Objective 2. Develop alternative strategies for characterizing forest structure and composition over large landscapes using combined Landsat, lidar, ground, and environmental data.


Pacific Northwest Ecosystem Research Consortium: Willamette River Basin Mapping Project

The Pacific Northwest Ecosystem Research Consortium (PNW-ERC), funded by the Environmental Protection Agency, was created "to address specific priority environmental problems in the Northwest, while at the same time developing the ecological understanding and scientific approaches needed to implement ecosystem management on a broad scale." There are 31 focused projects within the PNW-ERC, addressing a wide variety of ecological research questions over two different ecological provinces. The Willamette River Basin Mapping Project (WRBMP) is an effort to provide a detailed land use/ land cover map of the Willamette River Basin from Landsat Thematic Mapper (TM) data. This map will be used to correlate current land use patterns with existing ecological conditions, and to provide the reference for the generation of future land cover scenarios. In addition, the map will be used by various local planning groups, including the Willamette Valley Livability Forum and the Governor's Watershed Councils.


Causes and Consequences of Land Cover Change in a Greater Ecosystem: Trend and Risk Assessment, Monitoring, and Outreach

The Greater Yellowstone Ecosystem (GYE) is probably typical of many greater ecosystems surrounding nature reserves. Abiotic factors result in biodiversity and intense human land use overlapping on private lands outside of nature reserves. Thus, these reserves, typically thought of as refugia for biodiversity, may be insufficient for maintaining native species. The goal of this study is to better understand these linkages between biodiversity and land use. Hopefully, with this knowledge, decision makers can find ways to better sustain both native species and the growing human community in the GYE.



Warren Cohen, Director
Zhiqiang Yang, co-Director

Maureen Duane, Lab Manager
USDA Forest Service and Oregon State University
3200 SW Jefferson Way
Corvallis, OR 97331