AHCARB810 — Analyse edaphic interactions of trees and structures

Elements & performance criteria

Performance evidence

• analysed the edaphic interactions of trees and structures for a specific site and has prepared a minimum of two reports, which must include: a report on damage to structures by tree roots; a report on the stability of tree with a defective or damaged root plate.
• investigated soil conditions that contribute to structure and tree stability, including: angle of repose of soil materials; soil plasticity; impact of soil moisture on soil cohesion and plasticity; modes of soil liquefaction
• investigated and tested soils for properties affecting soil conditions, including: measured soil moisture content and field capacity; determined soil texture; assessed level of soil cohesion; determined shear strength of the soil; investigated load bearing capacity of soil; calculated mass of the soil plate
• determined root morphology, division and distribution and amount of buttressing of tree
• determined species characteristics for development of tap root system
• determined anatomical features of tree roots and identified tree roots for a given tree
• conducted research tests to determine forces and pressures exerted by trees through the soil
• estimated and measured dimensions of roots exerting a force on a structure
• calculated total surface area of the roots exerting a force on a structure
• calculated force exerted by roots per unit of surface area of structure
• calculated total force exerted by roots of a given surface area
• measured and determined volume of structure
• researched and calculated mass of structures
• determined impact of gravity on mass
• determined effect of leverage on the forces exerted by tree roots on structure
• determined factors of root–soil matrix interactions
• investigate area of contact between root and soil
• investigated elasticity, tensile strength and breaking stress of roots
• investigated root cross-sectional morphology
• assessed root plate for damage, deficiencies or defects that may contribute to tree failure
• estimated impact of static and dynamic testing for root plate stability
• evaluated possible root failure by root breakage
• evaluated possible anchorage failure by soil breakage or slippage
• investigated and assessed: effects of increasing mass; methods for, and effects of, increasing the modus of rupture; effects of use of curved structures; effects of soil mass and friction; effects of use of anchors, braces and props
• compiled investigations and assessments into reference portfolio
• created a report of potential tree damage to structure and provided design suggestions to mitigate damage
• reviewed root plate assessment, prepared final report on stability of tree and provided design advice to mitigate potential tree failure
• created an expert witness report on potential structure or tree stability
• discussed installation and protection measures with project personnel
• negotiated and resolved anomalies in installation and protection measures.

Knowledge evidence

• impact of soil on the stability and structural integrity of structures and trees, including: angle of repose of soil; soil plasticity; soil moisture content; field capacity of soil; effects of soil moisture on soil cohesion and plasticity; modes of soil liquefaction
• testing soils for performance characteristics and soil stability, including: soil texture; soil cohesion; soil moisture and field capacity; shear strength of soils; load bearing capacity; calculating mass of soil plate
• tree root structures and their impact on soils and stability, including: root morphology; root division; root distribution; buttressing; species development of tap root systems; identification of tree roots based on anatomical features
• pressures exerted by tree roots, including: experimental modelling of tree root damage; testing tree roots impact on structures and soils; direct and indirect forces and pressures exerted in soils by trees; techniques and methods of estimating and measuring dimensions of roots
• factors of root–soil matrix interactions
• area of contact between root and soil
• elasticity of roots
• tensile strength of roots
• breaking stress of roots
• root cross-sectional morphology
• calculations for determining forces exerted by tree roots, including: total surface area of the roots exerting forces on structures; forces exerted by roots per unit of surface area of structure; total force exerted by roots of a given surface area
• measurement of volume of structures
• calculating the mass of structures and the impact of gravity on mass
• effect of leverage on the forces exerted by tree roots onto structure
• tree root health and condition and impact on tree stability, including: size of root plate and extent of root plate damage; extent of root plate deficiencies; extent of root plate defects; impact of static and dynamic testing for root plate stability; likelihood of root failure by root breakage and failure of root plate; likelihood of anchorage failure by soil breakage or slippage
• considerations of structural design and development, and tree support to mitigate potential tree or structure damage, including: effects of increasing mass of structure; effects of structure design and curvature of shape on strength of structures; effects of soil mass and friction; effects of increasing the modus of rupture; effects of use of tree support mechanisms
• Australian standards relevant to trees on development sites
• structure designs for mitigation of tree damage and failure
• tree protection measures
• creating reference portfolios of research and investigations, including annotations and calculations
• documenting and reporting procedures, report preparation and communicating results of analysis, including: test results and assumptions; expert witness reports, their purpose and design; using the correct language in reports and reporting
• fundamentals of the concepts, basic science and technology of structural engineering, construction and architecture as relates to arboriculture and impact of trees on structures.

Foundation skills

• Reading: Identify and interpret relevant information from complex texts, reports, maps and plans to formulate a detailed understanding of soil characteristics and impact on trees
• Writing: Create complex arborist reports, demonstrating control over a range of writing styles and using industry-specific language appropriate for target audience
• Numeracy: Interpret complex numerical data and use complex formulae to measure and calculate volumes and mass of soils and structures for impact on tree roots

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