Biomechanical and biochemical effects recorded in the tree root zone – soil memory, historical contingency and soil evolution under trees

Abstract

Background and aims The changing soils is a neverending process moderated by numerous biotic and abiotic factors. Among these factors, trees may play a critical role in forested landscapes by having a large imprint on soil texture and chemical properties. During their evolution, soils can follow convergent or divergent development pathways, leading to a decrease or an increase in soil spatial complexity. We hypothesized that trees can be a strong local factor intensifying, blocking or modifying pedogenetic processes, leading to local changes in soil complexity (convergence, divergence, or polygenesis). These changes are hypothetically controlled by regionally predominating soil formation processes. Methods To test the main hypothesis, we described the pedomorphological features of soils under tree stumps of fir, beech and hemlock in three soil regions: Haplic Cambisols (Turbacz Reserve, Poland), Entic Podzols (Žofínský Prales Reserve, Czech Republic) and Albic Podzols (Upper Peninsula, Michigan, USA). Soil profiles under the stumps, as well as control profiles on sites currently not occupied by trees, were analyzed in the laboratory for 20 physical and chemical properties. In total, we analyzed 116 soil samples. The age of trees and time of tree death were determined using the radiometry (14 C), dendrochronology and repeated tree censuses. To process the data, we used multivariate statistics, namely, redundancy analyses (RDAs) and principal component analyses (PCAs). The statistical significance of variables was tested using Kruskal-Wallis, Dunn, and permutation tests. To reach the main aims of the present study, we examined the dataset at three levels of data complexity: 1) soil regions, 2) microsite (i.e., tree stump versus control site), and 3) soil horizon. Results Living tree roots and empty or infilled root channels were the most important pedogenic factors that affected the dimensions of soil horizons and the moisture in the root zone under tree stumps. Microsites explained almost 6% of the soil variability (p < 0.001,

Lake level controls the recurrence of giant stromatolite facies

“…Furthermore, sedimentological and geochemical observations demonstrated that freshwater–alkaline water mixing as a result of neither forest flooding events (Awramik & Buchheim, 2015) nor spring inputs (Jagniecki et al ., 2021) was requisite for the initiation or accretion of multi‐metre mounds. First, the strata immediately below the giants lack geological evidence for a long‐lived shoreline forest environment, such as root traces, mottling and organic‐rich facies (Pawlik & Samonil, 2018). Second, both the ooid‐based estimates of Ω arag ( ca 2 to 5 throughout deposition) and the prevalence of carbonate precipitates in both shallow and deep‐water facies demonstrated that carbonate production in the Sand Wash Basin did not require a freshwater calcium source.…”

“…First, the strata immediately below the giants lack geological evidence for a long-lived shoreline forest environment, such as root traces, mottling and organic-rich facies (e.g. Pawlik & Samonil, 2018). Second, both the ooid-based estimates of Ω arag (ca 2 to 5 throughout deposition) and the prevalence of carbonate precipitates in both shallow and deep-water facies demonstrated that carbonate production in the Sand Wash Basin did not require a freshwater calcium source.…”

Recent advances on geomorphology of the Gorce Mountains, the Outer Western Carpathians – state-of-the-art and future perspectives

“…As suggested by the formation of pit-mound microtopography (i.e., mounds and pits resulting from tree throw and degradation of the fallen tree trunks), this process can modify the hillslope microrelief for hundreds of years. Such effects were observed and analyzed on Hala Długa, the montane meadow close to Mt Turbacz, and in the Turbacz Reserve (Pawlik & Kasprzak, 2018;Pawlik & Šamonil, 2018). In these cases, electrical resistivity measurements and soil analyses showed a significant impact of trees on weathering processes, both within root systems of living trees and places disturbed by tree uprooting (tree throw pits and mounds formed after uprooting).…”

Evolutionary creativity in landscapes

“…Human and other biological impacts are one example; others may include storms, floods, and fires ( Figure 4). Numerous examples exist of divergent geomorphic evolution due to the persistence and/or growth of local disturbances (see Phillips, 1999Phillips, , 2006bBrunsden, 2001 for syntheses and overviews; Toomanian et al, 2006;Pawlik and Šamonil, 2018; Šamonil et al, 2018 for soil geomorphology examples; Fryirs, 2017 for fluvial examples). The possibility exists that at least some of these features that are new on a local scale may also be novel more generally.…”