New Theory Connects Tree Uprooting and Sediment Movement

Tree throw from extreme wind events plays an important role in the movement of sediment and erosion on forested hillslopes. A new theory offers a novel way to measure its impact.

Effect of different wind loading frequencies on tree deflection and uprooting

Tree uprooting is the most common occurrence in hurricanes and storms; however themechanism is not well known. Numerous attempts have been made to model the damage causedto the trees by the storm. Less is known about the loading condition, which is important forpredicting the occurrence of uprooting. In this analysis, numerical models were used to investigatethe effect of loading frequency on tree resistance using theoretical soil and root parameters. Resultsshow that tree deflection under wind loading is highly dependent on loading frequency and lowfrequencyloading is highly probable.

Diversity and composition of moss guilds on uprooted trees in Central European mountain forests: effects of uprooting components and environmental variables

Key message The size of the structural components of the root–pit–mound complex was crucial for high moss species richness. Root plates, pits, and mounds were similar in terms of moss species composition, which was mostly determined by forest type. Context Uprooted trees may be colonized by different terricolous mosses including common species and specialists. Aims The main aim of the present study was to analyze the relative effects of tree uprooting on mosses. Methods We used the parametric ZIGLMM and GLMM models to explain the richness and abundance of the moss species and double constrained correspondence analysis (dc-CA) to analyze species composition. Results The size of components of RPM complexes had a positive effect on moss species richness. The species cover of mosses was positively correlated with elevation. Species richness was partly dependent on forest type and species cover on component type and age of the RPM complex. The most important factor diversifying species composition was the type of forest. Species traits were also related to forest communities. Conclusion Uprooted trees are worth keeping in forest community, especially large ones. Moreover, the conservation value of uprooted trees in woodlands is higher if they are dispersed in different forest types.

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

The increase of geomorphological research during the last decades in the Gorce Mts. caused the need for state-of-art review papers. The Gorce Mountains were formed as an isolated massif with Mt Turbacz (1310 m a.s.l.) as the highest summit. River channels are remodeled by sudden and high-level floods with the critical impact of log jams. The main processes influencing hillslope relief were landsliding, run-off, and tree uprooting. The review suggests the following issues await for studies: a long-term landscape evolution, monitoring of morphogenetic processes, and origin of landslides with their contribution to denudation rates. Also, current biomorphodynamics (uprooting process) has not been sufficiently studied.

Biological weathering by the Devonian trees

<p class="western" lang="en-US"><span>We applied the biogeomorphic ecosystem engineers concept to the Devonian Plant Hypotheses. By linking these two ideas we want to explore how recent discoveries on the role of trees in weathering processes could support the explanation of global environmental changes in the Devonian period. The occurrence of first land plants, vascular plants, trees, and complex forest ecosystems likely changed the nature and pace of many geomorphic and pedogenic processes. For instance, intensification of biological weathering driven by vascular plants might have influenced the global climate through consumption and accumulation of a large volume of atmospheric CO2. Innovation in the form and function of trees likely strongly influenced these processes, including soil stabilization via deep root systems. Mycorrhizal relationships further influenced weathering via chemical processes. While the lack of solid evidence in the fossil record still pose a problem, the progress in our understanding of soil-weathering processes induced by trees and root systems has expanded greatly in recent years, especially in terms of their biogeomorphic functions (e.g. tree uprooting, pedoturbations, biomechanical weathering, etc.), and can provide insights and testable hypotheses regarding the role of trees in the Late Devonian.</span></p>

Tree death as a crucial geomorphic agent in temperate forests: effects of weak and severe disturbances from local to continental scale

<p>Hillslope processes in terrestrial ecosystems are significantly modified by changes in climate and land use. At the same time they strongly influence ecosystem retention capacity, pedocomplexity and biodiversity. This undoubtedly makes hillslope processes one of the crucial components of terrestrial ecosystem dynamics. In this study we focus on the long overlooked biogeomorphological impact of tree death in forested landscapes. Tree uprooting caused by strong storms affects soil and regolith formation and movement quite differently from the decomposition of intact root systems of standing trees that died due to e.g. fire or bark beetle infestation. We quantify the biogeomorphic processes associated with tree death in various terrestrial forest ecosystems and specifically assess (i) the significance of these processes in hillslope dynamics (e.g. slope denudation) of forested landscapes and (ii) the extent to which infrequent severe disturbances can shape these dynamics.</p><p>We used data from repeated tree censuses carried out in ten permanent forest plots (13–74 ha in area) located in Central Europe and North America, differing in a range of characteristics such as tree species composition, climate and disturbance regime. In total, life history of more than 134,000 trees was recorded over periods of up to 47 years, during which about one third of these trees died. Using this information together with empirical models and allometric equations we were able to quantify the average areas and volumes of soil annually affected by dying trees. These quantities differed markedly between sites with different disturbance regimes. Tree uprooting-related volumes accounted annually for 0.01–13.5 m<sup>3</sup>ha<sup>−1</sup> reaching maximum values on sites with occurrence of infrequent strong windstorms (Zofin and Boubin primeval forests, Czech Republic). Volumes related to trees that died standing ranged anually between 0.17 and 20.7 m<sup>3</sup>ha<sup>−1</sup> and were highest in the presence of stand-replacing fires (Yosemite National Park, U.S.). Comparison of these quantities with long-term erosion rates derived using cosmogenic nuclides (<sup>10</sup>Be) suggests that on certain sites, over the last few millennia, tree uprooting can be the main driver of soil erosion.</p>

Magnitude of sediment transport due to extreme windthrow event in small catchments in the Tatra Mountains

<p>In the forested mountain areas tree uprooting plays important role among many other geomorphic processes. In some cases, during extreme wind events, large patches of forest may be destroyed, which causes transport of significant amount of sediment.</p><p>The aim of this research was to investigate magnitude of sediment transport during one intense windthrow event, which took place on 25 December 2013 in the Tatra Mountains, southern Poland. The research was conducted in three second- to third-order catchments (16-81 ha), in which 34 to 94 percent of their areas were affected by windthrow. This was achieved by combining field measurements and GIS analyses. During field work root plates located within selected research polygons were measured in order to recognize the amount of sediment transported by a single uprooted tree. Then, each root plate located in the investigated catchments was mapped in GIS software using high-resolution (40 mm) orthophoto. Based on this, total volume of sediment displaced by uprooted trees within each catchment was estimated. Next, taking into account directions of tree fall and slope inclination within each uprooted tree, sediment flux by windthrow event in 2013 was calculated.</p><p>In total 211 uprooted trees were measured in the field. Mean volume of measured root plates was 1.84 m<sup>3</sup>. It was assumed that half of that value is accounted for roots of a tree, thus on average 0.92 m<sup>3</sup> of sediment was transported by each root plate. Analysis of the orthophoto allowed for identification of 4650 uprooted trees located in the investigated catchments. Most of the trees have fallen in downslope direction. Sediment flux by windthrow event in 2013 calculated for each catchment was 1.0–4.6 × 10<sup>–3</sup> m<sup>3</sup> m<sup>–1</sup>.</p>

Spatial pedocomplexity in old-growth temperate forest driven by tree-uprooting: its formation and role in forest dynamics

<p>Soil formation is a complex process that depends on topography, biota, bedrock, climate, and time. Despite of the great effort dedicated to explore soil evolution, little is known about the role of stochastic phenomena such as soil disturbance in spatial pedocomplexity formation in old-growth temperate forests. Within this study we aim to (i) reveal spatial pattern of chemical soil properties, (ii) explain differences in spatial pedocomplexity formation in A and B soil horizons.</p><p>The issue was studied in Zofinsky Primeval Forest Reserve (hereinafter Zofin) in SW Czech Republic. The Zofin has been strictly protected since 1838 and it represented the 4th oldest forest reserve in Europe. Zofin belongs to the global network of forest research plots ForestGeo (www.forestgeo.si.edu/) as the first site in continental Europe. We sampled 309 soil profiles on an area of 74 ha. In total 34 chemical soil properties were analysed in A and B horizons, particularly those, which affect soil evolution and tree growth. We analysed concentrations of Al, Fe, Mn, Ca, Na, Sr, Si fractions, characteristics of sorption complex (CEC, EA, base content), pH etc. </p><p>We used descriptive statistics and geostatistics to spatial pedocomplexity study. The experimental variograms were modelled to fit them to the best theoretical distribution. From the theoretical distribution we calculated the spatial properties in each soil elements as the range, sill and nugget. Then, using AIC estimator, we selected the same best model for both horizons to compare the spatial parameters through parametric or not parametric statistical test depending on the normalization of the data.</p><p>The results indicate, for the first time, significantly longer ranges of spatial autocorrelation of soil properties in A horizon with comparison to B horizon, which is not common in geostatistical studies. It is most likely associated with rejuvenation of soil after tree uprooting. Neoformation of A horizon after soil disturbance proceeds quite rapidly and therefore some formerly disturbed A horizons are matured above immature B horizons. The range in both horizons for all chemical soil properties is independent (p-value <0.05), indicating that the driving factors for disturbance in horizon A and B are different. However, for rather biogenic soil properties as Mg, Ca, Na, EA, K there is dependence for horizon A and B (p-value>0.05), indicating similar effect of these elements in both horizons.</p>