What are your research topics?
Despite their relatively slow and passive appearance, plants are extremely dynamic organisms that constantly adjust their functioning to the surrounding environment. These dynamics convey a rich source of information for ecological, biophysical, agricultural or forestry applications, but they remain largely hidden to the naked eye.
For example, the seasonality of photosynthetic CO2 uptake by the apple tree in your garden or by the forest around your family cottage convey essential information enabling us to understand how tree and forest productivity are influenced by climate, extreme events such as drought, or management practices. Yet we are still lacking effective methods to track these dynamics across scales.
I investigate how we can utilise the light reflected or emitted from leaves, plants and entire ecosystems to capture their functional dynamics across a continuum of spatial and temporal scales.
I use chlorophyll-a fluorescence – a very dim red light emitted by all plants under illumination – and hyperspectral reflectance measurements, combined with laboratory and field experimentation, to develop methods for the acquisition and interpretation of optical data in terms of plant functional dynamics, from the molecular to the global scales, from seconds to years.
Where and how does the topic of your research have an impact?
Relevant technology has been developing at a very fast pace in recent decades, much faster than the understanding required to turn these innovations into new research and business opportunities.
We can now order online a multi- or hyper-spectral camera and a drone, and use them to capture a spectral image of an agricultural field, a tree nursery or a forest. Hundreds of kilometres above us, an increasing number of satellites orbiting the Earth provide a growing stream of data capable of resolving the spectral dynamics of our planet at ever-finer spatial and temporal scales.
My research aims at providing the tools needed to translate these new streams of spectral data into meaningful and quantitative information: supporting the assimilation of satellite data into land-surface models for improving our understanding of climate change impacts, or the development of spectral methods for applications in precision forestry, agriculture, or spatial ecology and ecophysiology.
This information is relevant for the scientific community as well as for decision-makers at both the local and regional levels.
What is particularly inspiring in your field right now?
Traditionally, plant ecophysiologists have investigated the functioning of plants or ecosystems by measuring their parts and integrating these discrete observations into the next level of organisation using mathematical models. For example, discrete measurements across different parts of a plant can be used to infer whole-plant processes, and so on.
With the advent of versatile systems for hyperspectral imaging and laser scanning, combined with methods for data interpretation, the doors are now opening to the fields of optical as well as spatial ecology and ecophysiology. This has potential to revolutionise our understanding of how plants function and interact within an ecosystem. For example, how is the 3D structure of a plant connected to its 3D function? How do different individuals and species in a plant community interact among themselves, contributing in this way to the functioning of the overall ecosystem?
Albert Porcar-Castell is Professor of Physiological Forest Ecology at the Faculty of Agriculture and Forestry.