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40+-year old maple is dying

leec

Only noticed three days ago that our 40+-year old maple tree is dying -

many borer holes in branches above head high
many dead branches which I have removed
the main trunk seems okay on the surface
the side of the branches facing ground still has some greenish colour
a couple of thin branches (1-2 cm diameters) are shooting a few tiny leaves

What I have done since -

fed it with Amgrow Harvest fertiliser, Seasol, plenty of water
drenched 5mg of very old Confidore
trimmed off the dry/dead tips of the branches that are not completed dead

What I am thinking of doing -

drench in the soil a bottle of diluted 250g Richgro Bug Killa (50g/Kg imidacloprid)
spray diluted 1:100 Hovex Ultra Lo Odour Termite & Insecticide Concentrate to the branches
paint the branches with IV Organic 3-in-1 Plant Guard

Can it still be saved? Your guidance is much appreciated.

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Comments

MitchellMc

Welcome to the Bunnings Workshop community @leec. It's great to have you join us and many thanks for your question.

I'm sorry to hear your established maple is struggling with several afflictions.

Let me mention a couple of our gardening experts @Noelle and @Adam_W to see if they can offer some advice.

I look forward to hearing what advice they have and how you can go about saving this tree.

Mitchell

Adam_W

Hi @leec , sorry to hear that your maple is doing badly. Looks like it provides nice shade for you courtyard.
Okay... in any situation like this we have to clearly separate symptom from cause and consider & treat them accordingly.
From the looks of the framework of branches that tree has seen a lot of pruning already and this can contribute to the problems you are seeing, I'll explain shortly.
First off we need to understand a little about how trees live in their environment.
Trees grow and adapt to their given situation. Their root network and branch canopy reflects the conditions they are growing in. They will spread the amount needed and this will also be governed by conditions like soil type, available moisture etc.
All of this happens over a long period of time & it's a careful balancing act. So, for example, a tree that doesn't like excess water might avoid sending its roots into a spot that's too damp. Similarly it's root network will spread over the area required not just for support and stability but to pick-up water, nutrients and air and it's canopy shape will reflect the prevailing sunlight.
A tree may takes decades of growth to get this balance right.
We then come along to a tree that was in a big lawn and we build a house close to it, cutting roots off as we do so, we change the amount of sunlight, we pave areas, impacting the flow of water, air & nutrients into the soil, and we compact that soil.
The tree has adapted itself to a given situation and then literally overnight, in tree-years, that all changes - it's getting too much or too little water, it's had roots damaged, it can't breathe etc. etc.
The tree suffers.

Most trees are quite resilient but this only goes so far and just as it took them decades to reach that size and shape it will often take time for them to start showing signs of stress and decline. Sometimes just months, other times years.
I am, frankly, terrified when I see new housing developments built in former bushland areas where they retain trees as part of the approvals & to maintain the 'character' of the area. Below is a photo of what happens to those trees in a couple of years time once you get a strong wind... Damaged roots, changed conditions and...
Now, back to your tree... I believe that what you are seeing is the long-term & slow decline of a tree that has suffered with extensive changes to its growing conditions and the new conditions do not suit it.
This is likley the cause & that conclusion is backed up by the symptoms you are seeing.
Borer are a great example. Trees under stress are more prone to borer attack and badly pruned trees doubly-so. The pruning in this case becomes both a cause and a symptom - the canopy may have been lifted or trimmed for convenience. This then impacts the tree's health and the pruning, if not done well, leaves it open to borer and fungal rots etc.
In the world of arboriculture (tree care) trees are often looked at and rated for their ability to survive and if they can't be helped back to health they are 'managed in their decline'. That is where I believe your maple is at - Too much has changed around it, too much damage has been done and it will not survive. The fact that you've only recently noticed tells me that perhaps it has likely reached a tipping point and it's decline from here will be fast.
How much longer will it last? Who knows but the fact is it will become less useful as it's canopy thins and dead branches increase.
What would I do? First thing... stop the chemical use. It will not make the tree better. It might slow its decline but realistically all you are doing is saturating your living environment with chemicals which are not going to be achieving very much at all.
Next I would be investing in a good pruning saw and very carefully appropriately pruning off damaged and dying wood. This need to be done properly with branches removed back towards the trunk - don't leave 'coat hooks' of branch stumps and don't flush prune hard against the trunk. Look for what they call a branch collar, it often looks like a wrinkle in the branch base, just out from the trunk and prune about 1cm to the branch side above this.
Then... just think about watering - is it too wet... too dry... Yes, apply some seaweed products but don't overdo it and don't overfeed.
And cross your fingers.
Sorry I couldn't give you a magic-bullet solution but I'm afraid it's a case of caring for it in its decline and starting to plan for what to replace it with.

leec

https://www.workshop.bunnings.com.au/discussion/comment/9792#Comment_9792

Hi Adam

Thank you very much for your advice.

It was last year or the year before last, I saw the root, about 4 cm in diameter, pushing against our shower/toilet external wall, running towards the boundary trap.

I was alarmed by it and took action by cutting off that section from the root system and did not pay any attention to it afterwards. No watering in drought seasons either.

Sigh.

Noelle

https://www.workshop.bunnings.com.au/discussion/comment/67217#Comment_67217

Hi @leec

I have to completely agree with Adam's summation of the situation, tragic and terminal as it may be. Soil and other treatments etc are not going to fix the problems, because the damage has been done over a great many years and cannot be undone.

Enjoy it while it's still there but I'd certainly be planning for something else in a spot where its root run will not be paved over, nor buildings encroach on it.

Adam_W

https://www.workshop.bunnings.com.au/discussion/comment/67217#Comment_67217

If it's any consolation @leec I think this tree's ticket was punched well before you trimmed that root off. A decline like this can be very, very slow as the changes that have happened will have been bit by bit.

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