Cook, Bruce: NASA GSFC (Project Lead)
Andersen, Hans: U.S. Forest Service Pacific Northwest Research Station (Co-Investigator)
Morton, Douglas (Doug): NASA GSFC (Co-Investigator)
Pattison, Robert: USDA Forest Service, Anchorage Forestry Sciences Laboratory (Co-Investigator)
Chase, John: USDA Forest Service (Collaborator)
Babcock, Chad: University of Minnesota (Participant)
Legner, Kate: University of Washington (Participant)
Project Funding:
2015 - 2019
NRA: 2014 NASA: Terrestrial Ecology
Funded by NASA
Abstract:
Climate change impacts on vegetation cover, composition, and productivity have been documented from field and satellite remote sensing studies for boreal forest regions such as interior Alaska, where temperature changes over the last three decades are significantly higher than in other terrestrial biomes. However, vegetation response to recent warming and disturbance (insects, fire) is highly variable, due in part to strong environmental gradients across a range of spatial scales. Not all resource environments are equally vulnerable to change, and drivers of ecosystem change differ along these gradients of topography, cover, and disturbance history. Fingerprinting changes in vegetation cover and composition over time is a critical step to characterize the vulnerability and likely future trajectories of these landscapes under projected warming and scenarios of future disturbances-two key goals of NASA's Arctic-Boreal Vulnerability Experiment (ABoVE).
Here, we propose to use a unique combination of field data, airborne remote sensing, and satellite time series to characterize the spatial heterogeneity of vegetation changes in interior Alaska since 1982. The proposed research emphasizes both temporal and spatial scaling; long time series of observations are needed to track slow changes in vegetation structure and composition in high-latitude systems, and detailed observations from field measurements and high-resolution airborne data (≤1 m) are critical to characterize the pattern and process of ecosystem responses in heterogeneous landscapes typical of the ABoVE study domain. This project specifically targets section 3.1.2.1 (Development and Analysis of Remote Sensing Data Products) using 2014 data from NASA Goddard's Lidar, Hyperspectral, and Thermal (G-LiHT) airborne imager to scale information from large (8 ha) field inventory plots measured in 1982 and re-measured during 2010 to 2017 and low-altitude air photos (1982-83 and 2012-14) on a 20 km grid for the Tanana Valley of interior Alaska (120,000 km2) to satellite spatial (30 m) and spectral resolutions (e.g., Landsat, HyspIRI). The multi-scale, multi sensor approach will specifically target four types of changes listed in Table 4.2 of the ACEP using this unique combination of field and airborne remote sensing observations: 1) changes in surface water extent, including drying of wetlands and subsequent encroachment of woody vegetation, 2) post-disturbance vegetation recovery and burn severity, with an emphasis on post-fire succession, 3) biotic disturbances, including mortality and defoliation due to increased insect activity, and 4) forest cover change, emphasizing changes in tree growth (height, diameter) and expansion of woody vegetation at tree line. The complementary nature of these ground and airborne remote sensing observations offers the possibility to develop new, multi-sensor fusion approaches to quantify changes in composition, cover, and productivity for this critical region.
The scientific outputs of the proposed research include 1) an assessment of 30 years of vegetation change in a large, diverse and remote region of interior Alaska; 2) benchmark datasets from field data, air photos, and G-LiHT for contemporary topography, surface inundation, composition, and vegetation cover; and 3) an assessment of tradeoffs regarding spatial and spectral resolution for efforts to characterize fine-scale ecological processes with moderate resolution satellite remote sensing data. Re-measurement for a subset of
the 1982-83 field plots directly addresses Section 3.1.2.2 (Collection and Analysis of Field Data), and estimates of the rate and nature of vegetation changes during the 30+ year interval in this study will directly inform synthesis and study design elements for ABoVE (Section 3.1.2.5), including model parameterization and validation for ecosystem responses to warming conditions.
Publications:
Alonzo, M., Andersen, H., Morton, D., Cook, B. 2018. Quantifying Boreal Forest Structure and Composition Using UAV Structure from Motion. Forests. 9(3), 119. DOI: 10.3390/f9030119
Alonzo, M., Morton, D. C., Cook, B. D., Andersen, H., Babcock, C., Pattison, R. 2017. Patterns of canopy and surface layer consumption in a boreal forest fire from repeat airborne lidar. Environmental Research Letters. 12(6), 065004. DOI: 10.1088/1748-9326/aa6ade
Babcock, C., Finley, A. O., Andersen, H., Pattison, R., Cook, B. D., Morton, D. C., Alonzo, M., Nelson, R., Gregoire, T., Ene, L., Gobakken, T., Naesset, E. 2018. Geostatistical estimation of forest biomass in interior Alaska combining Landsat-derived tree cover, sampled airborne lidar and field observations. Remote Sensing of Environment. 212, 212-230. DOI: 10.1016/j.rse.2018.04.044
Montesano, P. M., Neigh, C. S., Wagner, W., Wooten, M., Cook, B. D. 2019. Boreal canopy surfaces from spaceborne stereogrammetry. Remote Sensing of Environment. 225, 148-159. DOI: 10.1016/j.rse.2019.02.012
More details may be found in the following project profile(s):
