Media used for the propagation and growth of trees
The quality of media is of vital importance to the health and growth of a tree. Poor quality media may be infected with weeds, insects and diseases, including fungal diseases, they may not have sufficient aeration and drainage resulting in the roots being at risk of dying from being waterlogged or from excessive heat as a result of the soil temperatures becoming too hot.
At Tree Sales all our trees are grown in quality media sourced from Debco, the media used is specifically developed for our air pruning containers and complies with the Australian Standards AS3743 and has undergone rigorous quality testing during its development. This ensures that the media has the required aeration and drainage characteristics necessary for the growth and development of our trees.
The implementation of hygiene practices ensures that the nursery has a proactive approach to minimising the risk of trees becoming infected from pests and diseases that may be transferred from another property to the tree nursery.
At Tree Sales access to the tree nursery is restricted until people have undertaken our hygiene procedures. This includes the removal of all debris from their footwear and clothing and stepping into a footbath with a specific chemical to eliminate any fungal spores remaining on their footwear.
All vehicles and machinery must be washed down with a specific wash to again eliminate the transfer of any fungal spores to our tree stock.
Any equipment used for the pruning and general maintenance of trees is sterilised from one tree to another, regardless of species and location, to minimise the risk of transferring pests and diseases that may have infected stock.
As part of quality assurance for our clients, all advanced trees grown by Tree Sales undergo a stringent hardening off process before the point of sale.
Trees that are exposed to the different uniform stresses are, in most cases, more structurally stable, vigorous trees that are less likely to suffer from 'transplant shock'.
The term 'transplant shock' refers to a tree being subjected to a number of environmental stresses at the time of transplanting. Primarily, it involves failure of the tree to root well and subsequently the tree does not establish in the surrounding landscape efficiently. Water stress is another significant extreme that can place a tree under significant stress, these trees are more susceptible to damage being sustained from pests, diseases or the extremes of weather and when combined with several stresses, trees are unable to function adequately and can suffer an early demise.
Symptoms of 'transplant shock' include:
- Leaf scorch, appearing as a yellowing or bronzing of the leaf tissue, usually between the veins or along the margins of the leaves for deciduous plants. The leaf tissue then dries and becomes brown.
- Wilting of leaves includings yellowing and leaves rolling or curling,
- Reduction in new growth including shortened internodes, resulting in shortened branch tips,
- New leaves are smaller in size,
'Transplant shock' can result from a number of factors including:
- A poor quality root system, bare root trees are more susceptible to 'transplant shock' due to the lack of fibrous roots,
- Improper planting techniques, including the planting depth required, the location where the tree is to be planted needs to be assessed to determine the PH levels of the soil, the quality of the soil, the drainage characteristics and the soil amendments required. If these areas are not addressed issues such as a tree having 'wet feet' can result leading to the demise of the tree,
The process of 'hardening off' is an integral component in the development of a quality tree. This process subjects the trees to the variations in environmental conditions that can be anticipated once the tree is transplanted, this includes subjecting the trees to:
- external temperature variations from -3 degrees to 42+ degrees, in the greenhouse environment temperatures do not fluctuate as extensively as they do in the external environment,
- a gradual reduction in irrigation to minimise water requirements once the tree is transplanted, this can also assist in reducing the risk of 'transplant shock' once planted,
- increased exposure to light, in the greenhouse environment the trees have a reduced exposure to the UV light emitted by the sun by as much as 50-70% when compared to the external environment. By exposing the trees to the UV extremes we are reducing the risk of 'transplant shock' and damage to the foliage, branches and trunk as a result of scorching.
- increased exposure to wind stresses, in the greenhouse environment, again, the trees have a reduced exposure to the extremes of wind by as much as 50-70%, by exposing our trees to the variations in wind speed, direction and temperature we are assisting in the formation of a quality root structure in conjunction with a higher trunk caliper.
How to recognise a healthy, structurally sound tree
In general most people rely on the information provided to them at the nursery without a clear understanding of what to look for. Below we have provided a brief synopsis of some of the aspects that should be considered when looking to select a tree. For further assistance on the information listed please contact us either by phone or email with your enquiry.
- The tree trunk shall be relatively straight, vertical, and free of wounds (except properly made pruning cuts), sunburned areas, conks (fungal fruiting bodies), wood cracks, bleeding areas, signs of boring insects, galls, cankers, girdling ties, or lesions (mechanical injury).
- There will be no co-dominant stems, v-shaped crotches or crossing over of major branches across the trunk.
- The root system shall be substantially free of injury from biotic (e.g., insects and pathogens) and abiotic (e.g., herbicide toxicity and salt injury) agents.
- Root distribution shall be uniform throughout the container substrate, and growth shall be appropriate for the species or cultivar.
- At time of inspection and delivery, the root ball shall be moist throughout.
- Roots shall not show signs of excess soil moisture conditions as indicated by stunted, discolored, distorted, or dead roots.
- Are the roots girdled or circling (pot bound) in appearance? An air pruned tree with a strong root system is less likely to suffer from 'transplant shock'.
- Can you see white, fibrous roots? These new adventitous roots will develop more rapidly after transplanting enabling the tree to access vital nutrients to encourage new vigorous growth and overall the tree will establish itself in its new location a lot quicker.
- The form and density of the crown shall be typical for a young specimen of the species or cultivar, for example a pine has a conical formation different from that of an Elm tree.
- Changes in form caused by wind, pruning practices, pests, or other factors shall not substantially alter the form for the species or cultivar.
- The size, color, and appearance of leaves shall be typical for the time of year and stage of growth of the species or cultivar,
- Trees shall not show signs of prolonged moisture stress as indicated by wilted, shriveled, or dead leaves,
- Is there evidence of pest or disease damage? including leaf chew or sucking damage, leaf spots or fungal infections?
- Shoot growth (length and diameter) throughout the crown should be appropriate for the age and size of the species or cultivar.
- Trees shall not have dead, diseased, broken, distorted, or otherwise injured branches
- major branches should not touch,
- branches should be no more than 2/3 diameter of the trunk,
- branches should be evenly spaced and appropriate for the species and age of the tree,
- temporary branches should be maintained on the lower region of the trunk, these temporary branches assist in the development of the trunk caliper and a quality root system,
For councils, developers, landscapers and home gardeners, the information provided above represents a cost saving when consideration is given to the loss ratios of trees that are structurally unsound, not hardened off and have a poor root system.