Instrumental Study of the Health Status of Picea abies [L.] Karst and Pinus mugo (Turra) and Their Relation to Environmental Parameters in the Eastern Alps

Many climatic models predict significant temperature rises in mountainous regions, which may influence the distribution of montane species. Thermophilization observed or predicted in mountainous areas to date may accelerate the shift of forest-forming trees to higher areas. Our aim was to detect how the health status of Norway spruce (Picea abies [L.] Karst) and dwarf mountain pine (Pinus mugo (Turra)) changes along an altitudinal transect, and to what extent the health status of trees depends on the studied environmental variables. Field measurements were performed in the Alps with an acoustic tomograph, which is able to determine the extent and exact location of rotten parts without damage. In the case of P. abies, the stands are currently considered to be the healthiest between 1000 and 1500 m, while they show the greatest deterioration near the lower limit of their distribution. At the lower limit of the vertical distribution of the species, a retreat of 50–100 m is expected. We observed a different trend in the relationship between deterioration values and altitude depending on the extent of the P. mugo belt. It seems the extent and speed of the upper movement may be different in different mountains, depending on environmental parameters.