When to prune my maple ?

I have a maple tree in my front garden. Its been there for 2 and a half years now, and I would like to prune it. I am growing it as a screen to give my garden a bit more privacy, but don't want it to cut out any precious light. My aim is to stem it's height, but keep it a nice bushy screen.

When is the best time to go hacking at it ? does this matter at all ? anything else I need to know ?

Cheers guys

 

Do you know which type of maple it is? it's a big, diverse group of trees.

Where are you?

Trees want to grow upwards, if you take out the top, the side branches take over the job of growing upwards, so instread of one trunk, you'll get several, cutting out more light.

Generally, if in doubt, tree pruning is best in the late Autumn, after the leaves have dropped.

... and please don't go "hacking at it". Prune it with care and thought

 

I'm sorry but my limited knowledge only tells me it's a maple, not what type.
I'm up in Yorkshire.
"hacking at it" was only a turn of phrase. I intend to look up where on the branches to lop. Worry not for the little fella.

Thanks for the advice, I'll wait til it has shed and then have a look at it.

I ideally want to have a go at this every year, as I am hoping to keep it somewhere around the 20 foot height mark. Dunno how this will work out in advancing years though.

 

Post a pic and you would get better advice (acknowledging that the advice from Quercus is already good )