Arborist Reports
Preliminary Tree Assessment
Preliminary Assessment of trees is generally conducted at the beginning of a project. once site surveyance has been completed. The purpose of a preliminary assessment is to provide information on the trees withing and surrounding the project area.
These reports can provide you with the following information;
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Genus & Species
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Common Name
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Origin
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Location
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Height & Canopy Width
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Health & Structure
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Age
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Useful Life Expectancy (ULE)
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Arboricultural Rating
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Retention Value
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Diameter at Breast Height (DBH) or Trunk Circumference at Breast Height
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Diameter at Base (DAB) or Trunk Circumference at Base
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Tree Protection Zone (TPZ)
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Structural Root Zone (SRZ)
This report should also provide an accurate site map to scale that shows the tree location along labels indicating Tree identification number
Tree Survey Reports
A Tree Survey is a comprehensive surveyance and assessment of a tree population within a designated area. These assessments are generally conducted to collect arboricultural data and information relating to trees within the designated area. Some data that can be collected within a tree survey are as follows;
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Genus & Species
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Origin
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Height & Canopy Width
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Diameter at Breast Height (DBH)
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Age
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Significance
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Useful Life Expectancy
In some cases, information may be collected relating to canopy density, carbon offsets, monetary value of total & individual trees, oxygen production. Tree Surveys are an excellent tool for clients such as local governments to compile a tree database that can allow them to plan for the future.
Construction Impact Report
Construction Impact Assessment reports are conducted to better determine how your proposed design will conflict with trees subjected to remain within your property or how they will impact trees located outside of your property. These levels of impacts are in accordance with the Australian Standards AS4970:2009 Protection of Trees on Development Sites and are described as Minor (less than 10%) or Major (greater than 10%). A Tree with a level of impact greater than 10% may not remain a viable tree and may require further investigation or design modifications to ensure it remains viable.
These reports can generally be undertaken when you already have a proposed design and provide you with the following information;
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Genus & Species
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Common Name
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Origin
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Location
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Height & Canopy Width
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Health & Structure
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Age
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Useful Life Expectancy (ULE)
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Arboricultural Rating
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Retention Value
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Diameter at Breast Height (DBH) or Trunk Circumference at Breast Height
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Diameter at Base (DAB) or Trunk Circumference at Base
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Tree Protection Zone (TPZ)
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Structural Root Zone (SRZ)
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Percentage of Impact % - Minor <10% - Major >10%
These assessments reports are undertaken to determine some of the following questions.
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How will the design impact the trees subjected for retention?
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if the design does in fact impact the trees, how much does it impact, and will they remain healthy and viable?
Tree Protection Management Plans (TPMP)
Tree Protection Management Plans are comprehensive reports that detail how trees that are remaining within the site or neighboring trees that may be impacted by the construction. These reports are undertaken to ensure adequate protection through all stages of construction such as Demolition, Site Preparation, Construction & Post Construction.
Tree Protection Management Plans are annotated to demonstrate the respective tree protection zones along with the necessary protection measures required through the construction process.
These plans must be to scale and detail clear instructions of the Tree Management Plan.
These are some of the typical tree protection requirements in accordance with AS4970:2009 Protection of Trees on Development Sites
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No heavy machinery is to enter the tree protection zones without the express permission of the project arborist (emergency service vehicles are exempt).
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No trenching or removal of soil is to take place, existing soil levels are to be maintained.
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No Fill to a depth of greater than 100mm is to be installed.
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No trenched services are to pass through the Tree protection zone unless they are bored. beneath the root zone to a depth approved by the project arborist or NDD Non-Destructive Digging methods such as Hydro exaction to retain significant roots in situ; this it to be approved and supervised by the project arborist.
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No drainage is to be installed.
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No fuel, oil or chemical shall not be allowed within the Tree protection zone.
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No storage of materials, equipment or temporary building shall take place with the Tree protection zone.
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No fixtures of any sort shall be attached to the trees for any reason
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The project arborist must be consulted with prior to any equipment or personal entering the Tree protection Zone.
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All machinery is to be kept clear of tree canopies to prevent impact being caused, if work such as cranes are to be used within the area of trees it shall be supervised by the project arborist.
Tree Risk Assessment
A Tree Risk Assessment is a detailed assessment of the potential risk that may be posed by a tree. Generally, when conducting a risk assessment on a tree the first consideration should be what is the target & what is the site surrounding the tree used for. Howell Arboriculture Consultants uses a Quantified Tree Risk Assessment Method by (QTRA).
The Quantified Tree Risk Assessment Method uses three components to calculate the overall risk of Harm. These are as follows:
Target
Vehicle, Persons or property at risk of potential tree failure
Size
The size of the tree part that is most likely of impacting the target
Probability
The probability the tree part observed has of failing within a given time period.
Following the site assessment, a full comprehensive tree report is conducted detailing the trees assessed for risk along with their respective risk of harm. this report will provide remedial recommendations based on those findings to reduce the overall risk to as low as reasonably possible.
