Large-scale forest dieback was reported in recent decades in many parts of the world. In Slovakia, the most endangered species is Norway spruce (Picea Abies). Spruce dieback affects also indigenous mountain forests. We analysed changes in snow cover characteristics in the disturbed spruce forest representing the tree line zone (1420 m a.s.l.) in the Western Tatra Mountains, Slovakia, in five winter seasons 2013-2017. Snow depth, density and water equivalent (SWE) were measured biweekly (10-12 times per winter) at four sites representing the living forest (Living), disturbed forest with dead trees (Dead), forest opening (Open) and large open area outside the forest (Meadow). The data confirmed statistically significant differences in snow depth between the living and disturbed forest. These differences increased since the third winter after forest dieback. The differences in snow density between the disturbed and living forest were in most cases not significant. Variability of snow density expressed by coefficient of variation was approximately half that of the snow depth. Forest dieback resulted in a significant increase (about 25%) of the water amount stored in the snow while the snowmelt characteristics (snowmelt beginning and time of snow disappearance) did not change much. Average SWE calculated for all measurements conducted during five winters increased in the sequence Living < Dead < Meadow < Open. SWE variability expressed by the coefficient of variation increased in the opposite order.

In our paper we deal with the changes in the rainfall interception process of a climax spruce forest in the growing season (approximately from May to October) during its die-back. Experimental data were collected at the research plot of Červenec situated in the West Tatras at an elevation of 1,420 m a.s.l. in the years from 2013 to 2015. Net precipitation was monitored at three localities in both living and dead forests: canopy gap, dripping zone at crown periphery and central zone of a crown. Gross precipitation was recorded at an open forest area (with a diameter of 1–2 tree heights). The comparison of net precipitation in the stands revealed the highest values in the dripping zone at crown periphery of the living forest due to its increase by occult (horizontal) precipitation and transport of rainfall captured in the crown to its periphery. The values in the growing season of 2014 exceeded also gross precipitation. The total interception loss (total gross – net precipitation in % of gross precipitation) the canopy gap during the monitored period was 10.1% in the living and 18.3% in the dead stand, in the dripping zone at crown periphery it was 1.7% in the living and 20.5% in the dead stand, and in the central zone of a crown it was 70.6% in the living and 59.9% in the dead stand. Forest die-back had an effect on the distribution of precipitation under canopy. The comparison of mean interception values at three localities of the living and dead stands revealed significant differences between the stands in all cases (

In the presented paper we deal with the impact of the mature spruce stand on the accumulation and melting of snow cover at Červenec research area located in the Western Tatras at an elevation of 1420 m a.s.l. The work analyses the data obtained from the monitoring of snow cover during the period 2009-2014 (6 seasons). Since the season 2012/2013 the measurements have been also performed in a dead part of the stand and in a meadow. The results proved significant impact of the spruce stand on hydro-physical characteristics of snow cover -snow water equivalent, snow density, as well as on their change due to the dieback of the stand. The data measured at individual locations (open space in the forest, open meadow area, living and dead forest) were tested with the paired t-test for the significance of average differences. Average snow water equivalent in the living forest, dead forest and meadow was 42%, 47% and 83% of the reference value measured at the open space in the forest, respectively. The process of snow accumulation and melting was fastest at the open space, followed by the dead forest. In the living forest, the processes were the slowest.

No abstract

The aim of the work was to compare the influence of a beech (B) and a spruce stand (S) on the accumulation and melting of snow cover in comparison to an open area (O). The measurements were performed in winter seasons from 2012/13 to 2014/15 in the Hučava catchment, Poľana Biosphere Reserve (BR). We monitored hydrological and physical parameters of snow cover (snow depth – SD, snow water equivalent – SWE, snow density – D) at 13 research plots in 100 m elevation intervals (567–1,259 m a.s.l.). Within one research plot, the listed snow parameters were measured in a stand of spruce (S), beech (B), and at an open area (O).Based on the snow conditions, we found different characters of winter during the monitored period (2012/13 – snow rich, 2013/14 snow poor). For each winter, we tested the difference in the average values of SWE between the stands and the open area separately for the phase of snow accumulation and melting. The differences in the accumulation phase were found significant (