Sediment transport by uprooting in the forested part of the Tatra Mountains, southern Poland

- Sediment transport by windthrow and its dependencies are investigated.
- Tree size and content of coarse material in soil mostly influenced root plate sizes.
- Sediment flux by windthrow during extreme event was at an order of 10− 4 m3 m− 1 yr− 1.
- Mean sediment flux by windthrow for 48-yr period was at an order of 10− 5 m3 m− 1 yr− 1.

The process of tree uprooting plays an important role in sediment transport within forested slopes. In this study we determine the intensity of sediment transport by uprooting and its dependencies. We use the Principal Component Analysis (PCA) to determine the most important factors influencing root plate sizes, and we calculate sediment flux by windthrow for the area of the Tatra National Park (211.6 km2), for the year 2013, when an extreme windthrow event occurred. For this purpose we combine field data with the results of windthrow areas mapping based on satellite imagery. We also use data recorded by the Tatra National Park concerning the amount of destroyed wood in the forests of the Tatra National Park to calculate sediment flux by windthrow for the period between 1968 and 2015 (48 years). To calculate the transport distance by the uprooting needed to compute sediment flux, we modified the Gabet et al.'s (2003) Eq. (11), which in our opinion gives results which are twice the actual size. The PCA identified two the most important factors influencing root plate sizes. The first factor shows that all root plate dimensions increase with increasing tree DBH (diameter at breast height), and, to a lesser degree, with an increase in the content of coarse material. The second factor shows that the depth of a root plate increases with the downslope angle of tree fall, decreasing slope inclination, and decreasing the content of coarse material. The sediment flux by windthrow in 2013 in the area of the Tatra National Park was 3.55 × 10− 4 m3 m− 1 yr− 1. Mean annual sediment flux for the period of the last 48 years was 2.76 × 10− 5 m3 m− 1 yr− 1.