These are great ideas . Thanks for starting this topic that perhaps is the path into the future.
Injection technique can be used for both for saving trees from a pest like Carlos is doing, and I believe will allow people to grow certain plants in places they could not before.
But an idea occurred to me, what about fruit trees that are notoriously infamous for having a slow root system like the Mangosteen? a few weeks ago, I transplanted a potted mangosteen, when I did that, the fragile tap root broke, I put the plant so it would not et any direct sunlight, and been giving it extra water, but the leaves are starting to lose some of its green. this tree may be the perfect candidate to try the injection. problem is I have absolutely no experience in this, the "trunk" is not that thick, maybe 20mm. then there is the question of the right nutrients to use. as far as I know, nobody has tried this on mangosteen.
In theory, it should work, think about the implications, Mangosteen does not grow well in Florida, part of the reason is its soils. but what if we can eliminate that problem with injection? mangosteen has a extremely long juvenile period, mainly because of its poor root system. this is why consistent foliar spraying is so effective because you are giving the plant the nutrients it needs to grow directly, bypassing the roots. but why not go one further and tap right into the vascular system.
And one more thing that has not been studied, at least not printed anywhere I can find. is what about manipulating hormones though the IV? In subtropical latitudes, foliar application of KNO3 to initiate flowering is not very effective. but what if we could just inject the hormone responsible to trigger flowering? for commercial plantations of fruit trees, this would be very desirable. I do not see these systems anymore complicated than drip irrigation being used today, instead of drippers though we have little plastic injectors.
There seems to be many ways of using this technique. take a look at this system used on oil palms.
https://www.youtube.com/watch?v=6unOG-PvgTAAlthough I do not like what Oil Palm industry is doing to the forests around the world. that is a separate subject, my interest here is in how they can basically put a "inlet" in a tree, and just spray or pour fertilizer right into the tree. I can see where this way of applying fertilizer would be very effective in tall trees that would be very impractical to foliar feed, and traditional soil applications would be very wasteful.
Which brings me to another conclusion, every tree will need a different system, mango has been tested with permanent injection for both water and nutrients, Carlos is injecting fungicide, which I believe is temporary injection. Some Oil palm plantations are putting injectors that are used periodically for fertilizer only.
so there are many applications and uses for this system.
There are many questions I have.
What are the long term effects on the tree?
As the tree gets bigger, will the injector holes grow over? or seal up?