Biomechanical effects of trees in an old‐growth temperate forest

Abstract

The role of biomechanical effects of trees (BETs) in ecosystem and landscape dynamics is poorly understood. In this study, we aim to (i) describe a widely applicable methodology for quantifying the main BETs in soil, and (ii) analyze the actual frequencies, areas and soil volumes associated with these effects in a mountain temperate old‐growth forest. The research took place in the Boubínský Primeval Forest in the Czech Republic; this forest reserve, predominated by Fagus sylvatica L. and Picea abies (L.) Karst., is among the oldest protected areas in Europe. We evaluated the effects of 4000 standing and lying trees in an area of 10.2 ha from the viewpoint of the following features: tree uprooting, root mounding, bioprotection, trunk baumsteins (rock fragments displaced by trunk growth), root baumsteins, stump hole infilling, trunk and root systems displacements, depressions formed after trunk fall, stemwash, and trunkwash. BETs were recorded in 59% of standing and 51% of lying dead trees (excluding the pervasive soil displacement by thickening trunks and roots and the infilling of decayed stumps). Approximately one tenth of the trees showed simultaneous bioprotective and bioerosion effects. Different tree species and size categories exhibited significantly different biomechanical effects. A bioprotective function was the most frequent phenomenon observed, while treethrows prevailed from the viewpoint of areas and soil volumes affected. The total area influenced by the BETs was 342 m2 ha−1. An additional 774 m2 ha−1 were occupied by older treethrow pit‐mounds with already decayed uprooted trunks. The total volume of soil associated with the studied phenomena was 322 m3 ha−1, and apart from treethrows, volumes of the living and decaying root systems and bioprotective functions predominated. Other processes were not so frequent but still significant for biogeomorphology. Copyright © 2017 John Wiley & Sons, Ltd.

Changes in the radial growth of trees in relation to biogeomorphic processes in an old‐growth forest on flysch, Czechia

“…In total, 11 BETs were evaluated according to methodology by Šamonil et al . (2018), including the effects of tree uprooting, root mounding, baumsteining, stemwashing and bioprotective functions of standing or lying trees. We approximated expressions of BETs visible on the soil surface using elemental geometric 3D forms such as prisms or ellipsoids.…”

“…As explanatory variables we used the cumulative diameter of the stem, calendar year (the middle year of the 5‐year‐long window), slope (mean slope in the vicinity of the stem base – calculated from terrestrial laser scanning data in a 1 × 1 m rectangle), indication of canopy release and BET according to Šamonil et al . (2018). The tree itself represented a random effect in all models.…”

“…Countless ongoing interactions occur in forest ecosystems, affecting both their biotic and abiotic components (Phillips et al ., 2017; Šamonil et al ., 2018). Undoubtedly, trees are among the most influential components of such ecosystems, and they are therefore considered to be so‐called ecosystem engineers (e.g.…”

“…Various biomechanical effects of trees in soils have been distinguished (Phillips, 2006; Pawlik, 2013; Šamonil et al ., 2018). Each individual tree grows under different habitat conditions and interacts with its nearby surroundings from the first stage of its life.…”

“…For example, Šamonil et al . (2018) calculated that in an old‐growth temperate forest at least 330 m 3 ha −1 were directly influenced by biomechanical effects of trees. Similarly, Šamonil et al .…”