Exploring Drivers of Forest Microclimates in Central Italy

Climate across the globe is continuing to change drastically, and ecosystems are being affected through seasonal and inter-annual climate changes and extreme weather events, with the global averaged temperatures reaching record-breaking highs every year, with 2024 being the warmest on record since 1850.

It is known that forest ecosystems play a key role in mitigating temperature, buffering it within the forest microclimate compared to the macroclimate, thus dampening the effects of extreme temperature conditions. But the extent of the effect of these drivers and macroclimate conditions on microclimate conditions is not well understood.

Macroclimate is defined as the set of meteorological variables on a large spatial scale (up to hundreds of kilometers), whereas microclimate is defined by climatic conditions on small spatial scales that result from the interaction between the macroclimate, and forest and topography factors.

As the climate continues to change, learning which features of microclimates help buffer against intense macroclimatic conditions will be paramount. The aim of this study is to quantify the relative effect of macroclimate conditions, forest structure measures, and topographical variables on the microclimatic conditions, through machine learning with gradient boosting machines, and further, to explore how remote sensing data can be used to predict the buffering capacity of microclimates with future macroclimatic conditions. A pilot test is conducted specifically in a mixed forest in Piegaro, central Italy.

With the use of innovative IoT (Internet of Things) sensors, the temperature, relative humidity, and spectral data for selected trees is measured from underneath the canopy. These microclimatic measurements are used to find relationships with macroclimate and other data sources, including NDVI measurements, hourly climate datasets, downscaled- and projected-hourly climate data, and a digital terrain model (DTM). Utilizing data at different scales, from meters to several kilometers, allows the elements of the climate to be explored at varying resolutions, and the differences between these can further uncover the drivers of microclimatic conditions and the importance of including microclimates within climate studies.

It is well understood that the most influential variables on the microclimatic conditions are the corresponding macroclimatic conditions, and it is expected that elements such as relative elevation and aspect play an influential role in microclimatic buffering. Quantifying these relationships can help improve modelling forecasts that generally make use of climate measured on a larger scale, as they disregard the intricacies of microclimates and the possible effects that microrefugia have on species preservation. With further knowledge of microclimates comes a better understanding of how we can prepare for individually-experienced changes in the climate, in a way that promotes native landscapes as well as conserving biodiversity and enhancing local species.