Tree surgery wobbles

This is the pond and rockery in our garden (house is to the right of the picture).  As you can see it's dominated by large conifers that have been there 25+ years and totally outgrown the space so you can't even see the rockery.  So too the acer to the left of the picture.  I replanted a sapling that was growing next to the house when we first moved to Linton having no idea what it was and not expecting it to survive...and completely forgot about the garden for the next 20 years.

The acer's now grown into a huge tree that's only going to get bigger, and everything I've planted is struggling beneath it because of shortage of light and water.  I'm agonised, I'd arranged to have the acer and two of the conifers cut down, but they are looking so beautiful I'm wavering.