Effects of forest disturbance on seasonal soil temperature changes in the Tatra Mountains in southern Poland

Joanna Paulina Siwek

doi:10.2478/forj-2021-0003

Abstract

Abstract The purpose of the study was to examine the effects of forest disturbance on seasonal changes in soil temperature in the Tatra Mountains (Poland). In the years 2015–2020 soil temperatures were measured at a depth of 20 cm on north- and south-facing mountain slopes in a catchment where forest was disturbed by hurricane-force winds in 2013 and in a control neighboring woodland catchment. The effect of forest disturbance was manifested first and foremost in an increase in the soil temperature during the summer months – average by 1.8 to 2.4 °C on a south-facing mountain slope – and by about 1 °C on a north-facing slope. The buffer effect of forest on soil temperature can be observed via lower coefficients of correlation between soil temperature and air temperature in a woodland catchment versus a disturbed catchment in the summer. In the winter, the effect of forest disturbance on soil temperature was less pronounced than in the summer. Small differences in soil temperature in the winter between the woodland catchment and the disturbed catchment were associated with the presence of snow cover and its capacity to yield thermal insulation. Good insulation of the soil from the atmosphere generated by snow cover yielded a very weak relationship between soil temperature and air temperature in the winter. In springtime the soil temperature increased the fastest on a south-facing slope in the disturbed catchment while in the autumn season, soil temperatures declined most rapidly on a slope facing north in the disturbed catchment.

Highlights

The increase in air temperature observed across the Earth in the last few decades (Allen et al 2018) is a cause of the rise in soil temperature
The largest differences between the highest and the lowest values of the soil temperature over the course of the year were noted on the south-facing slope in the disturbed catchment (DS site), while the smallest were noted on the north-facing slope in the woodland catchment (WN site) (Fig. 3)
On north-facing slopes, the difference in the soil temperature between the woodland catchment and disturbed catchment in the summer months was smaller at about 1 °C

Summary

Introduction

The increase in air temperature observed across the Earth in the last few decades (Allen et al 2018) is a cause of the rise in soil temperature. This pattern was examined in studies in the United States, where the soil temperature at most of nearly 300 stations has shown a trend of warming in the last 35 years, with the average warming rate at 0.38 °C per 10 years (Hu & Feng 2003). Forest disturbance as well as deforestation drive an array of feedback mechanisms They generally lead to a continuous increase in the soil temperature primarily due to an increase in near-ground solar radiation (Anderegg et al 2012). Forest disturbance along with the soil warming leads to changes in carbon cycling (Davidson & Janssens 2006; Allen 2009), as does nutrient cycling (Anderegg et al 2012) and soil respiration (Londo et al 1999; Schlesinger & Andrews 2000; Ney et al 2019)

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