Rick, “Other than late Winter, are there other times of the year that are good/bad to prune risers from apple trees?” – Yes… The following link will take you to a discussion I initiated on this forum. Though it ‘evolved,’ I’ll paste my best recommendations below:

viewtopic.php?t=485

[Rick] I suspect there's an optimal time to prune, like when things are completely dormant, prior to Spring... But we can't always work like that. "Summer Pruning's" been recommended to me for years, I'm told it balances the trees vigor by removing some of the solar collecting leaves / vegetation before they store an abundance of energy that generally results in hundreds of unwanted "water-sprouts." ...Then again, we're told those "water-sprouts" are what feed the fruit development... Confused? Me too! So I continue to rely on my gut instinct -- and 25 years of experience...

Spring works -- other than you'll be 'rubbing off' a lot of emerging buds as you drag material from the tree. And, you'll have to carefully tip-snip (using your hand pruners) to avoid clipping off the emerging leaves as you make your heading cuts at the end of each branch. I've pruned a few trees 'late' like that, it's more work, and damage, disregarding any flowers...

Summer, it's hot and cluttered in those trees! And by removing large 'shading shoots,' you can allow the main scaffold limbs to be sunburned ... I have. And it's always best (for me) to view the structure of the tree as you prune; this is nearly impossible when it's fully leafed out. And, as you'd drag anything big from the tree, you'd definitely tear up some remaining leaves, and snap off some fruit spurs in the process... If you're simply trying to head off those pesky 'water-sprouts,' like I said, it's been discovered that they're what's feeding the fruit development.

Fall: That's working better for me all the time. There's still enough 'juice' in the tree to seal the cuts; it lowers the trees wind profile and snow/ice-load surface area; the fruits been harvested, and you can somewhat 'regulate' how much energy gets transferred to the roots from the still green leaves; and - the trees look great all winter! …did I mention it's still warm ? And if you can't see 'next years buds,' they're at the base of every leaf -- just run your fingers down the shoots to knock them off. Then you can rake up excess fruit, leaves, and prunings all at once. ...then you can spray them (with lime sulfur) and not smell like rotten eggs after climbing in and out of them -- or waste coating material you'd cut off anyway.

Winter: Classic pruning; there stands you - and your specimen -- it's 38 degrees and raining... Its form's fully visible, and the faster you work - the warmer you stay; less problems navigating the leafless framework, and the water sprouts nearly beg to be snipped off. I've read that if there's extremely cold weather after you make your heading cuts (end cuts on a branch 'aiming' the bud the direction you'd like to see it grow) the end bud can dieback leaving stubs that harbor disease, and 'aim' your limbs differently as growth would begin from the next live bud... I've never seen such damage, thus have learned to start earlier than later 'around here.'

But you "have a neglected apple and pear orchard." I'd have been cutting very hard most of this winter... You no doubt have the 'trees within a tree' look..? Where water-sprouts were allowed to grow for years, each heading straight up, then branching... Those need to be removed. But remember, doing so will expose the "Branch" they're growing from to intense sunlight -- so don't remove every 'little' twig or shoot on those horizontal main branches, leave a few to leaf-out and shade them. I've been in trees so overgrown with those big upright shoots that I'd cut em, grab on, and dive off the limb! I'd be lucky to get the first 3 or 4 ripped down through the tangled canopy. But it got easier ... and more dangerous! They're a lot of work to remove, but after you do, what remains looks more like a 'fruit tree.'

I'd ignore any moss, the sun might take care of that, and it'll keep down the sunburn (for now). Next you thin, and thin… While circling the tree, remove anything growing straight up, or off the bottom of a main branch. You'll be cutting 'fruiting wood' for sure, but re-establishing a framework that will support far more than you 'remove.' It ain't Rocket-science... What you'll be left with are the lengthy tips of limbs; either shorten them back to a nicely aimed branch, or snip the tip, with the bud generally aimed down. It's about that simple … but an aluminum 3-leged "orchard ladder," sharp "bypass" hand pruners and loppers, and a small handheld pruning saw should be all you need. I've taken a small chainsaw into some trees with me -- but that's extremely dangerous ... you're on a ladder, and generally working in close proximity to your neck, surrounded by a thicket of knurly limbs - so saw that stuff out by hand - you'll stay even warmer!

Enough? It's not too late by any means, just get some help to pile the debris so you can burn it (if you can legally burn); stay supported by both an arm and a leg if you free climb inside a tree; but try to stay out of wet (slick) trees, you can prune from a good ladder. And make it fun! Chickadees, Juncos and Nuthatches will often land while I'm in a tree -- and you know you've done a good job if a Robin can fly through it … and you'll likely find its nest next year!

--- Rick, ‘real-time’ -- the discussion that followed centered around the tree transferring its nutrients from the ‘suckers’ to the fruit. Without reading it again… I believe research has shown that dose not happen; that energy is basically used to produce the ‘shoot.’ But that’s neither here-nor-there with regard to your question; I’d say prune when you feel like it!