Also known as a "Project Arborist"
AS 4373 - 2007 "Amenity Tree Pruning"
A Commercial Arborist takes 2 1/2 years of trainingeducation to become qualified to a competant standard of Level 3 in this field that allows Amenity pruning to be given in accordance to the above standard.
- Chainsaw operation
- Complex climbing
- Aerial rescue
- Tree Health
- Tree Identification
- Pest and desease
- Soil testing
- Tree planting
- Tree transplanting
- Amenity Tree pruning
- Complex tree pruning in confined spaces
- Small tree felling
- Large tree felling
- Traffic Management
- High Risk Elivated work plaform operation
- Line Clearence
- Job Site Analysis
- Equipment Checklists
Removing a tree or parts of a tree is more complex than it is thought. The operations has great significant for the remaining survival of the tree.Lopping of a tree is no longer acceptable, in which case required education is a competant standard needed to carry out these operations.
Reduction pruning (R)
Pruninug carried out to reduce the weight of branches that conrol the strcutral lean or balance of the tree. Also encroament of bulidings, pathways, roads and driveways.
Selective pruning (S)
Is an operation carried out to remove only selected branches or parts of the tree that are dead, damaged or over weight.
Formative pruning (F)
Junvenile trees need formative pruning to help the structural growth during the developing stages in order to obtain significant value within the surrounding environment.
The trees normal growth will cause limbs to compete for sun light. This will evetually cause the tree to present dead wood.
Crown reduction (C)
Is a controlled reduction method of the height of the tree.
Crown thinning (T)
Will reduce the crown to aleast 1m of the whole canopy area.
Selected growth points of the tree branches are used to reduce the tree from exposure to present conditions, to allow regrowth or controlled development to extend Useful Life Expectancy.
Excavation of soil will expose roots to girdling, damage or desease. Clean, sharp tools or machinery may only be used for this operation. Root diameter no less than 6cm may be removed.
Mulching is use for the protection and control of evaporation within the TPZ. Mulch may be coarse material 7mm to 20mm at 50mm to 100mm depth.
Line Clearence (L)
Power lines and service wires have a regulated clearence according to the voltage. Normal 600mm to 1m clearence need to be maintained through out the existance of the tree within the developing area of power lines. Time management will require the use of High Risk Elevated work platforms licenses and machinery.
A Tree's LIfe
A tree needs propagation of seeds to continue life, perfect soil, water, weather conditions, nutrients and sunlight for the type of tree, harvest or use. Once the seed is planted the tree will contiue to grow turning a stem into a trunk that hold the significant branches of the canopies scaffold covering itself with leaves to collect sunlight. During early stages of life the tree can produce growth problems that cause limbs to compete with sun light (photosynthesis). The sun light produces energy to transpire from the leaves to the roots gathering nutrients to exchange for food resource (sugars) this is then turned into wood cells that enable the tree to expand and grow.
Competion of limbs often change the structural integrity of the tree which may cause the trunk to lean, over weight limbs or provide lack of sunlight to understory vegetation that help the tree to survive. Topography or landscape design will also determine the structural integrity of the tree.
This will cause an overload of wood production that can generally become twisted or split presenting weakness in in the wood. Splits or cracks in the wood production may cause desease and break up the cell production that will provide lack of nutrients (sugars) to the tree, therefore becoming weak and unstable. The limb will eventual break or become infused with another limb. The strucual interity of the tree is then lost and the significance is less valuable to the environment and propagation of seeds occuring from this tree may be reduced to a lack of cell identification that will cause significant damage to the rest of the environment. Leaning trunks may cause compression and tension of wood production that wounds the tree through lack of nutirents, exposing the tree to desease or deaed tissue.
When a branch has been removed from the tree the healing process requires compartmentalisation, this means that inner bark layers that produce cambium need to form a calus around the exposed wood tissue that help block of exposure and desease.
Within the formation of the branch connected to the tree an area called the Branch Bark Ridge is existing. This area has the available resourses for the healling mechanisms of compartmentalisation. The ridges within this region allow the tree to identify the point of healing. Breaks or bark tearing beyond this point will provide incomplete repair and allow desease to manipluted the wound causing deadwood tissue or a decay process that occurs with excesive moisture that may result in contamination of the soil if the extent of damage has continued to the root or root system through vascular transpiration.
The crown or canopy of the tree will expand to the ratio of the root system, once determining the diameter of the trunk calculations can be made to provide an area of the root system, there for give an example of the acceptable crown or canopy size. The crown or canopy is referred to as a cone and is calculated by the height of the tree and width of the tree. Another way to assess the size of the root ball or system is to devide less than half of the width or spead of the tree for a radius of the root ball or system.
( Further calculations will determine the value of the tree by cubic squared metre, mainly use for Tree Selection, Tree Planning, Tree planting, Tree evaluation or tree replacement) .
Trees can live up to thousands of years old. In the urban development trees have been designed to cultivate in accordance to temperative weather conditions and food supply. This usually controls the growth period and determines the revegetation of propogation materials for the next havesting season. Generally these methods maintain a certain lifespan of the tree.
Propogation happens in many ways, through fruits, to winged seedlings, to fallen branches. Most fertilising periods will produce flowers for pollination which then produces seeds that will detatch from the tree and find a suitable place to regenerate. Sometimes a tree will become senescent; meaning that it has reached its use life expectancy therefore producing an abundace of flowers and seeds that can over weigh or over power surrounding vegetation, eventually the tree will die and surrounding vegetation will become declined and possibly die. Storms and fire can help these situations naturally repair its, but due to urban development people are living close to these environments.
Arborists are needed to maintain the mechanical use of the physical compartmentalisation, by physically removing damaged or wounded parts of the trees or the whole tree. Educated training will help assess the method use to remove th tree or parts of the tree, and will provide a controlled environmental safe hazzards, bush fires, excess evaportation causing heat disturbance and irractic weather conditions (Storms etc.)