A Root Anchorage Model for Shallowly Rooted Sitka spruce

Blackwell, Paul G.; Rennolls, K.; Coutts, M. P.

doi:10.1093/forestry/63.1.73

Cited by 68 publications

(39 citation statements)

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“…On the one hand, the high rigidity and mass of the soil-root plate of trees (Coutts 1986) found in the predominately boulder-rich areas of the core plot increased the uprooting resistance of shallow-rooting spruce with top heights up to 40 m and more (cf. Blackwell et al 1990). On the other hand, much lower spruces of 20-25 m tree height were thrown on stagnic and peat soils that constrain root development and provide low soil rigidity (Nicoll et al 2008).…”

Section: Disturbance Impactsmentioning

confidence: 99%

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

et al. 2009

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It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 ''Gudrun'' hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce-beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech's contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894-1949 and 1950-2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.

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Section: Disturbance Impactsmentioning

confidence: 99%

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

et al. 2009

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“…A conceptual basis of a model of conifer root development with an emphasis on root biomechanics has been constructed by Coutts et al, (1999). It should be possible to link such a root development model to root anchorage models, such as the ones described by Blackwell et al (1990) and Dupuy et al (2005a), and ultimately to wind damage risk models (e.g. Peltola et al, 1999;Gardiner et al, 2004).…”

Section: Mechanical Properties Of Rootsmentioning

confidence: 99%

“…In performing these functions, fine roots depend on the whole root system being held together by a structure of coarse roots, and it will be necessary in modelling exercises to consider ways to relate coarse root architecture to fine root mass. Existing root anchorage models, such as the one described by Blackwell et al (1990), require data including soil physical properties, root system depth, the position and stiffness of roots at the hinge point, and angles and strength of windward roots. However, in developing more sophisticated models that include rootplate flexibility, more detailed root architecture data will be required.…”

Section: Mechanical Properties Of Rootsmentioning

confidence: 99%

“…Coutts (1986) and Blackwell et al (1990) modelled the resistance of a shallow root system to overturning by separating it into four mechanically important components; weight of the root soil plate, tensile strength of the windward roots, tensile strength of the soil, and resistance to bending of roots at the hinge. The force needed to overturn the tree is this overall resistance multiplied by the length of the lever arm, that is, the distance from the tree centre to the hinge point on the root system.…”

Section: Modelling Root System Mechanical Propertiesmentioning

confidence: 99%

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Towards developmental modelling of tree root systems

Tobin

Čermák

Chiatante

et al. 2007

Plant Biosystems - An International Journal Dealing with all As

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Knowledge of belowground structures and processes is essential for understanding and predicting ecosystem functioning, and consequently in the development of adaptive strategies to safeguard production from trees and woody plants into the future. In the past, research has mainly been concentrated on growth models for the prediction of agronomic or forest production. Newly emerging scientific challenges, e.g. climate change and sustainable development, call for new integrated predictive methods where root systems development will become a key element for understanding global biological systems. The types of input data available from the various branches of woody root research, including biomass allocation, architecture, biomechanics, water and nutrient supply, are discussed with a view to the possibility of incorporating them into a more generic developmental model. We discuss here the main focus of root system modelling to date, including a description of simple allometric biomass models, and biomechanical stress models, and then build in complexity through static growth models towards architecture models. The next progressive and logical step in developing an inclusive developmental model that integrates these modelling approaches is discussed.

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“…Nevertheless, few studies have been carried out on the location of this axis, due to the difficulty in observing it in field experiments (Crook and Ennos, 1997). In the few models of root anchorage which exist, the rotation axis has been considered as a fixed point at the base of the tree trunk (Niklas et al, 2002) or on the leeward side of the stem (Blackwell et al, 1990). However, it is likely that the position of the rotation axis depends on root system architecture and soil properties, but no studies have yet been carried out to test this hypothesis.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Impact of Root Morphology on Overturning Mechanisms: A Modelling Approach

et al. 2007

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Aims The Finite Element Method (FEM) has been used in recent years to simulate overturning processes in trees. This study aimed at using FEM to determine the role of individual roots in tree anchorage with regard to different rooting patterns, and to estimate stress distribution in the soil and roots during overturning. † Methods The FEM was used to carry out 2-D simulations of tree uprooting in saturated soft clay and loamy sandlike soil. The anchorage model consisted of a root system embedded in a soil block. Two root patterns were used and individual roots removed to determine their contribution to anchorage. † Key Results In clay-like soil the size of the root-soil plate formed during overturning was defined by the longest roots. Consequently, all other roots localized within this plate had no influence on anchorage strength. In sand-like soil, removing individual root elements altered anchorage resistance. This result was due to a modification of the shape and size of the root-soil plate, as well as the location of the rotation axis. The tap root and deeper roots had more influence on overturning resistance in sand-like soil compared with clay-like soil. Mechanical stresses were higher in the most superficial roots and also in leeward roots in sand-like soil. The relative difference in stresses between the upper and lower sides of lateral roots was sensitive to root insertion angle. Assuming that root eccentricity is a response to mechanical stresses, these results explain why eccentricity differs depending on root architecture. † Conclusions A simple 2-D Finite Element model was developed to better understand the mechanisms involved during tree overturning. It has been shown how root system morphology and soil mechanical properties can modify the shape of the root plate slip surface as well as the position of the rotation axis, which are major components of tree anchorage.

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A Root Anchorage Model for Shallowly Rooted Sitka spruce

Cited by 68 publications

References 0 publications

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

Climate change impacts on stand structure and competitive interactions in a southern Swedish spruce–beech forest

Towards developmental modelling of tree root systems

Understanding the Impact of Root Morphology on Overturning Mechanisms: A Modelling Approach

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