How to Restore a Sick Tree Back to Health

Is your tree displaying any other following symptoms of poor tree health? * Branch die-back, * Excessive leaf drop, * Excessive bark peeling off, * Healthy branches snapping in calm conditions, * Borer attack,  * Sap oozing from the trunk, * Excessive lean developing, * Decay in the trunk.  If so, there’s a good chance your tree is stressed and needs your help.

The health and structural stability can be negatively affected for a number of reasons such as;

  • Lack of water
  • Root damage or bark damage
  • Soil compaction
  • Soil contamination with chemicals, herbicides or pesticides
  • Attached from pests and diseases
  • Changing the height of surrounding soil level
  • Over pruning or incorrect pruning techniques
  • Storm damage
Figure 1 – Tree January 2019

This article is relevant to all trees but will focus on one particular case study relating to a much loved and very stressed Crows Ash “Flindersia Australis”.  I was called in to assist in restoring this tree located in North-West Brisbane in January 2019.   As can be seen in Figure 1 the tree had extensive “Die-Back” of about 30%, foliage chlorosis (yellowing of the leaves) and  it was inundated with Mistletoe. Over half of the foliage you can see in this photo is actually Mistletoe.  Mistletoes are parasitic in that they rob the host tree of water however most species of mistletoe create their own energy via photosynthesis.  The other way Mistletoes can effect the health of the host tree is through sheer inundation whereby they simply overcrowd the host tree and thereby reduce the amount of foliage (the energy source) the host tree would normally enjoy.

In the case of this Crows Ash, I found the reason for it’s very poor health was due to soil compaction through pedestrian foot traffic around the tree. As mentioned above, this tree was very important to the property owners and they even designed their house around this tree, so they were willing to do whatever it took to attempt help there beloved tree. With this in mind I formulated the following plan of attack:

  1. Remove the mistletoe from the tree and wrap black plastic around the mistletoe to ensure that it dies
  2. Carefully poison the grass around the tree out to the drip line, being very careful not to spray the roots, trunk or leaves of the tree. (This may not be required as most of the drip line has pot plants, and not grass)
  3. Apply a 25mm layer of quality compost out to the drip line.
  4. Apply a 200mm layer of AGED forest mulch out to the drip line.
  5. Barricade or fence of the area around the tree out to the drip line to prevent pedestrian traffic around the base of the tree.
  6. Apply 20 x 9L watering containers of Seasol or equivalent seaweed emulsion (30ml of solution per 9L of water). These 20 watering containers should be applied throughout the entire drip line, ie: over the entire mulched area.
  7. Then apply approximately 4000L of water throughout the drip line. This should be done SLOWLY so that the water soaks in and penetrates deep in to the soil. Future watering may be required but this is dependent on rainfall. The soil should remain consistently moist/damp (NOT saturated). The only accurate way monitoring soil moisture content is to occasionally dig back the mulch layer burrow into the soil with your finger in a few different places throughout the dripline. If the soil is dry apply another DEEP watering.
  8. Repeat the application of seasol every 4 weeks for the next 3 months. ie total of 4 applications. 
Figure 2 – Black plastic was wrapped around the severed mistletoe to starve it of sunlight and effectively kill the mistletoe without the use of chemicals

To the credit of the property owners they followed all my recommendations.  The total cost of to implement all the above recommendations amounted to a fair investment totalling $2750 Inc GST, with all but step 1 carried out by the property owners themselves.  Step 1 (the removal of the mistletoe) was carried out by the North Brisbane Trees team of Qualified Arborists.

Fortunately the time, effort and financial investment paid dividends with their beloved Crows Ash tree being fully restored to it’s former glory just 14 months later (see Figure 3) and the property owners couldn’t be happier and they had the below to say.  “We had been watching the health of our beautiful Crows Ash slowly decline over the last 3 years and we finally decided we couldn’t just watch it die.  We’re so happy we made the decision to have a Qualified Consulting Arborist attend to help and the results speak for themselves.  Thank you so much to Craig and the entire team at North Brisbane Trees.” 

If the health of one of your trees is declining, call in a Level 5 (AQF5) Qualified Consulting Arborist and please don’t wait until it’s too late.