Evaluation of Abiotic Controls on Windthrow Disturbance Using a Generalized Additive Model: A Case Study of the Tatra National Park, Slovakia

Abstract

Windthrows are the most important type of disturbance occurring in the forests of Central Europe. On 19 November 2004, the strong northeastern katabatic winds caused significant damage and land cover change to more than 126 km2 of spruce forests in the Tatra National Park. The risk of subsequent soil erosion and accelerated runoff has increased in the affected habitats. Similar situations may reoccur this century as a consequence of climate change. A geographical approach and detailed research of the damaged area with more comprehensive statistical analyses of 47 independent variables will help us to obtain a deeper insight into the problem of windthrow disturbances. The results are based on a detailed investigation of the damaged stands, soil, and topography. A comprehensive input dataset enabled the evaluation of abiotic controls on windthrow disturbance through the use of a generalized additive model (GAM). The GAM revealed causal linear and nonlinear relationships between the local dependent quantitative variables (the damage index and the uprooting index) and independent variables (various soil and topography properties). Our model explains 69% of the deviance of the total damage. The distribution of the wind force depended upon the topographical position—mainly on the distance from the slope’s foot lines. The soil properties (mainly the soil skeleton, i.e., rock fragments in stony soils) affect the rate and manner of damage (uprooting), especially on sites with less wind force. Stem breakage with no relation to the soil prevailed in places with high force winds. The largest number of uprooted trees was recorded in localities without a soil skeleton. The spruce’s waterlogged shallow root system is significantly prone to uprooting. The comprehensive research found a significant relationship between the abiotic variables and two different measures of forest damage, and can expand the knowledge on wind impact in Central European forests.

Mountain Landscape Dynamics after Large Wind and Bark Beetle Disasters and Subsequent Logging—Case Studies from the Carpathians

“…More than 126 km 2 of forests were damaged, with a wood volume of 2.3 million m 3 located at altitudes between 700 and 1350 m. The wind caused widespread damage, and it even contributed to the death of one person. 84,000 cubic meters of timber had to be removed from the intra-urban areas of various Tatra settlements [4].…”

“…Research of spruce stands wind disturbances in Central Europe identified the age of stands, higher percentages of spruce, georelief and soils as the most important factors influencing the degree of forest damage [3]. A detailed evaluation of abiotic controls on windthrow disturbances in Tatras was carried out by Falt'an et al [4]. conservation priorities from a systemic ecoregional approach [22].…”

30-Year Changes in Oak-Hornbeam Forest after Windthrow

“…Strong winds breaking or uprooting trees are one of the most important abiotic factors with a huge impact on the initiation of changes in vegetation [1,2]. They are the main cause of live biomass loss in northern European forests [3].…”

“…Wind disturbance has been studied in temperate forest ecosystems, especially in North America [11][12][13][14]. Studies in Eastern Europe investigating this problem have focused mainly on mountain forests and poor habitats that cover the largest areas [2,7,[15][16][17][18][19][20]. Studies investigating long-term transformations caused by windstorms are gaining a new meaning in the light of climate change.…”

“…Studies investigating long-term transformations caused by windstorms are gaining a new meaning in the light of climate change. Moreover, information on the long-term impact of various disturbances can help in understanding changes in tree abundance and the development of understory vegetation after disturbance [2].…”