The overall science objective of this research is to quantitatively document the current status and rate of change of how land cover and land use and how trajectories of these changes are linked to population and demographic transitions for the Southeast (SE) Asian countries of Vietnam (VN), Cambodia (CB), and Laos (LS). This is directly and closely relevant to the A.02 element on Land Cover and Land Use Change (LCLUC) in SE Asia. In the scope of this proposal, given the finite resources and schedule, we will focus the research on three interconnected science questions, each with specific aspects: Q1: It is known that rapid LCLUC has occurred over VN, CB, and LS, especially the loss of important forest regions since the turn of the 21st century, considered as ecocide [Cdr. Jah, ISBN 978-93-82652-77-9, 2014]. Now a key question is what has happened over those deforested land as well as non-deforested land in terms of the current land use status, specifically: (1) Whether the deforested areas are still denuded and/or deforestation has expanded to other areas; (2) whether the deforested land has converted to a more natural state (e.g., grass land) or is being used for agriculture (e.g., rice fields); and (3) where reforestation exists, whether it is on previously denuded land, or the natural forests are replaced by commercial tree plantations (e.g., rubber trees). Q2: From the quantitative delineation of the above current land cover and land use status (denoted as LCLUS henceforth), the next connected component is quantifying spatial patterns and temporal trends of LCLUC, specifically: (1) How does multi-scale spatial fragmentation in rural and natural landscapes vary within a country and across borders of different countries; (2) with recent shifts in LCLUC, what type of seasonal vegetation change has emerged over rural and natural land in a country and in different countries? And (3) what is the quantitative characterization of the recent rate of LCLUC since year 2000. Q3: The above observations of LCLUS together with the LCLUC patterns, trends, and rate of change are coupled/integrated with population and demographic data for each country, specifically to address: (1) How population distribution (e.g., rural versus urban) is associated with LCLUS for built, agricultural, and forested lands and how the population change trajectories in relation to the observed LCLUC patterns occur differently in the tri-nations; (2) how subnational demographic changes in working-age versus dependent populations may affect or be impacted by LCLUC; and (3) how policies in different regions and in different countries may be driving or impacted by LCLUC. Here, we consider specific case studies of factors that may drive the differences in LCLUC and force different impacts within and across borders of the different countries (e.g., plantation development in VN, Economic Land Concessions policy in CB, and population resettlement policy in LS). We expect an array of new products that accurately and quantitatively document the LCLUS and LCLUC to answer Q1, Q2, and Q3 in the interconnected physical and socioeconomic dimensions in the tri-nations. Answering Q1/Q2/Q3 involves three tasks. Task 1: Massive SAR data products for LCLUS and derivative products from fusions of multi-sourced datasets. Task 2: Products for LCLUC obtained from multiple SAR data, decadal scatterometer data, and ancillary datasets. Task 3: Products for high-resolution population distribution also broken down by age group and gender, subnational dependency ratios for each year since 2000, which significantly advance the understanding of relationship between population dynamics and LCLUC to study policy effects in VN/CB/LS. Remote sensing results will be verified with ground truth data, and population results will be verified with census data and with independent satelliteobserved patterns. Deliverables will include reports, presentations, and publications.