Defoliation values indicate the level of resilience or susceptibility of different species to the impact of atmospheric deposition and gaseous pollutants.
Data collected over the past 28 years (1997–2024) show a fluctuating trend up to 2020, with alternating periods of decrease and increase in the phenomenon, and a greater sensitivity observed in broadleaved species. Starting in 2021, however, a worsening of the phenomenon was recorded, with exceptionally high defoliation levels never observed before.
In 2023, these values reached 45% for both broadleaved and coniferous species.
This deteriorating trend, which will need to be confirmed by future monitoring, slightly eased in 2024, when defoliation levels reached 35.6% in conifers and 43.3% in broadleaved species.

The wildfire phenomenon, analyzed on the basis of data collected from 1970 to 2024 by CUFA of the Carabinieri Corps (formerly the State Forestry Corps), shows a fluctuating trend, with peak years (1993, 2007, 2017, 2021) alternating with periods of decline (2013, 2014, 2018, 2024).
Wildfires occurring within Protected Areas (recorded since 2003), although showing annual fluctuations, remain at high levels, with an average of 11,000 hectares burned over the last three years.
The incidence of deliberately caused fires is very high, representing about half of all recorded events and exceeding 60% in some years.

The indicator examines the series of data relating to forest areas affected by large fires on a national, regional and protected area scale over the period 2018 to 2024.

The distribution and extent of forest areas affected by fires generally show significant interannual variability. In particular, 2024 was a year less severely affected by the extent of forest areas impacted by fires compared to previous years. The forest area burned was higher only than that burned in 2018 and 2019, but significantly lower than all the years from 2020 to 2023.

In 2024, the most affected regions were Sicily (2,588 ha), Calabria (2,494 ha) and Sardinia (1,734 ha), which together accounted for 66% of the total national forest area affected by fires.

The most affected forest classes are evergreen broadleaved forests (e.g., holm oak woods and Mediterranean scrub), followed by deciduous broadleaved forests (e.g., oak and beech forests), and much less by coniferous forests (e.g., pine, fir, and larch forests).

Linear regression analysis of the national forest cover series affected by fires does not show an increasing trend, although the size of the series does not allow for medium- and long-term evaluations. A weak but statistically significant increasing trend was instead observed for the regions of Apulia, Basilicata and Calabria.