The rate of defoliation and forest decline in Slovenia was relatively stable until 2020, with a slightly negative trend. After 2020, a deterioration of tree defoliation was observed.

Forests in Slovenia are relatively well preserved, especially in terms of the diversity of the natural tree species composition and the vertical and horizontal stand structure. The share of preserved forests exceeds 50%. Heavily modified, mostly forests where natural tree species are altered with spruce, and altered forests make up just over a tenth of all forests.

In Slovenia, forests have been growing in terms of growing stock and increment for decades. They have increased by more than 140% over the last 70 years. In addition to natural conditions, harvesting depends on socioeconomic factors, and recently on the occurrence of natural disasters (windbreaks, icebreakers) and bark beetles outbreaks. By 2014, the felling accounted for about 50% of the increment. After the ice storm in 2014, it increased substantially and accounted for 60 to 75% of the total increment of conifers and deciduous trees.

In the past centuries, forest area has been increasing constantly after 2010; however, the rate of expansion has slowed down and remains relatively stable in recent years. Since 1875, when forests covered only 36% of the Slovenian territory, forest cover has increased to 58.5% in the year 2009 and rests stable today at 58.0 %. In terms of forest share, Slovenia ranks third among EU-28 countries, behind Sweden and Finland.

Regarding the forest area, deforestation accounts for an insignificant share. The average of the last ten years is approximately 405 ha (350–550 ha per year) and thus does not represent a significant factor in forest cover changes. Until 2008, most deforestation is a result of infrastructure facilities construction. In 2008, the unprecedented increase in deforestation for agricultural purposes occurred. The increase was due to the amendment to the Forest Act, which subject to the conditions allows the issuance of an authorisation for deforestation for agricultural purposes up to 0.5 ha.

Deadwood is an important animal and plant habitat that contributes to the biodiversity of forest ecosystems. According to Slovenia Forest Service data, the volume of standing and fallen trees without stumps and branches in 2022 was 21.3 m³/ha, which represented approximately 6% of the entire wood stock of forest stands. In virgin forests, however, the deadwood volume can be even several dozen times greater.

The number and area of wildfires varies greatly between years, as the incidence depends on the weather conditions in each year. In Slovenia, the western, sub-Mediterranean part of the country is the most endangered. Climate change will also pose a greater fire risk in the eastern part of Slovenia.

According to the state of epiphytic lichens, the preservation of forests and air quality is poor in the entire territory of the Republic of Slovenia, except in forests at higher altitude in the Alps and partially in the Dinaric mountain range.