Changes to the water repellency and storage of different species of deadwood based on decomposition rate in a temperate climate

Abstract

The aim of this study is to demonstrate the changes to the physical properties and water repellency (WR) of deadwood depending on the species and rate of decomposition. An innovative element of this study is the measurement of droplets' contact angle to the surface of the wood. Five species of trees at three different stages of decomposition were selected for the present study. The deadwood Silver Fir (Abies alba), Common Hornbeam (Carpinus betulus), Common Ash (Fraxinus excelsior), Common Alder (Alnus glutinosa), and Common Aspen (Populus tremula) were selected.The WR of the wood was determined based on water drop penetration time; and the surface free energy (SFE) was determined based on the measured angles. Moreover, Owens-Wendt and Van Oss-Chaudhury-Good models were used to determine SFE. The advancement of deadwood decomposition can be determined by observing the physical changes to the wood. Marked changes in density, moisture, porosity, and weight loss in subsequent stages of degradation were found in the wood of all tested species. Changes to the physical properties of wood result in changes to its WR and wettability. As the degree of decomposition increases, different species of wood may absorb water more quickly, and the surface of the wood may become more hydrophilic. Our results indicate that deadwood increases water storage in forest ecosystems. Assuming that deadwood covers approximately 5.7 m 3 /ha in a Polish forest, total water storage could increase from 0.8 to 4.7 m 3 /ha depending on the wood species and decomposition rate.

Effect of Organic Matter Released from Deadwood at Different Decomposition Stages on Physical Properties of Forest Soil

“…The release of carbon from decomposing wood in successive stages of decay subsequently increases soil water content, porosity, and soil aggregation. A previous study confirmed the intensification of dissolved organic carbon release in the subsequent stages of wood decomposition [5] and an increase in the concentration of cations with the advancement of the deadwood decay class [9]. The cations released from deadwood also affect the physical properties of the soil by shaping the structure.…”

“…The present study also showed significantly higher carbon content in soil under the influence of strongly decomposed wood (fourth and fifth DC) regardless of the species. Deadwood influences soil properties through its fragmentation and dissolved organic carbon leaching [5,30]. The release of carbon from decomposing wood in successive stages of decay subsequently increases soil water content, porosity, and soil aggregation.…”

“…Although fungi are the dominant agents of wood decomposition, it has long been known that bacteria also inhabit deadwood [4]. Because of its porous, spongy structure, deadwood constitutes an extremely rich reservoir of water [5], originating both from precipitation and produced directly in the wood through the metabolic processes of bacteria and fungi [6]. Because lying deadwood has direct contact with the soil, soil microorganisms enter the wood and participate in the process of wood decomposition.…”

Dissolved carbon and nitrogen release from deadwood of different tree species in various stages of decomposition

“…In our study, the high concentration of DOC in leachates from deadwood in V decay class can be explained by its texture and fragmentation. The wood in V decay class is characterized by soft and loose texture which results in greater water capacity and hydrophilicity (Błońska et al 2018). The high DOC and TN concentration can be also associated with the term of the experiment which including snow melt period.…”

“…The amount of obtained leachates is associated with the physical characteristics of wood, especially density, and porosity. As the degree of decomposition increases, wood absorbs water more quickly (Błońska et al 2018).…”