Research highlights
Here, I have selected five representative publications that I had worked on. I have tried to explain the essential idea of these publications in plain english, so that one can get an idea of the type of work I do.
'How are forest plantations doing in my region? Are most trees growing well?': Sustainably managed forest plantations represent a great opportunity to produce timber (think beautiful and cozy wooden buildings!) while helping sequester carbon (i.e., fight climate change) and help conserve biodiversity. Now, imagine that you are in charge of a huge region with forest plantations, in the order of 100,000 sq. km. Needless to say, there are economic and societal expectations from you that these plantation forests are healthy and well-growing through the entire area. Now, the question arises: how does one make sure that all parts of this large forested area are doing okay? Maybe are there big patches of forests out there where growth is poor..? Answering this simple question about spatial patterns in forest growth is quite difficult. My research had used the example of a large area in southeast USA and demonstrated how such questions may be tackled using remote sensing data (think satellite image data, think sensors mounted on airplanes). For example, in the map shown on the right, one can make out several areas of low forest growth - the next (much more challenging!) question is 'why'? Variants of this research may also be applied to large-scale afforestation projects, to make sure that all planted trees grow well and are healthy over the study area. See the full paper here.
'Can we detect and map wildfire-causing understory shrubs from airplane-based sensors?' 'Airborne laser scanning' is a very innovative and powerful way to scan and analyze the forest floor. It involves mounting a special laser-based sensor underneath an aircraft and flying it over forested regions. My research focused on combining previously collected airborne laser scanning data with field data to understand whether good maps of understory shrubs can be made. Of course, more understory shrubs means more wildfire risk. Hence, such maps can help us identify such areas of fire risk and take effective counter-action. Read all about it here!
'Can we generate forest canopy height maps over large areas from airplane-based sensors?' Forest canopy height, or the height of the tallest trees in a forested patch is a very important variable for foresters. For example, think about a dense tropical forests (large canopy height) versus a dry stunted forest in an arid region (low canopy height). My research focused on methods to generate canopy height maps for very large areas (i.e., 300,000 sq. km.) in a consistent manner. In the process, I had also outlined several caveats that should be kept in mind while producing such maps. A sample canopy height map is shown on the right (the rightmost pic, labelled (b)). Notice the parts of the map in deep red: there are some really tall trees there! Such areas could be prioritized for conservation and biodiversity protection efforts. Its an open access publication!
'What will be the impact of climate change over Indian forests over the next 50 years?' This is a very difficult question to answer, and there is quite some debate even to this day. Climate change is a very complex phenomena which might involve increasing temperatures, changing precipitation patterns (including more extreme events), changing cloudiness levels, changes in wind patterns and such. Again, forests of India are extremely diverse and varied. The work I did back (at the Indian Institute of Science, India) was one of the first that took a scientific, quantitative, modeling-based approach to this question. We estimated that around 35% of the forested area of India is vulnerable to effects of climate change. By this modeling exercise, we gave a first solid outline of how climate change may impact Indian forests. See this publication for more details. We also estimated the vulnerability of each forested grid in India (see map to the right) where 1 (green) indicates low vulnerability and 7 (red) indicates high vulnerability. Want to know even more? Here is a summary of our efforts that I wrote quite sometime back.
'Rapid afforestation in India: what good can it do?' India has an ambitious plan to afforest approximately 33% of its total geographic land cover. A very relevant question in this context is is how much of carbon does such a project help sequester. In this work, we compare a 'rapid afforestation' scenario with a 'slower afforestation' one and quantify the additional benefits of rapid afforestation. Furthermore, we show that the rapid afforestation scenario has the potential to offset approximately 9% of India’s average national emissions projected by five models, for the same period.