Tree surgeons climb on ropes, wearing a climbing harness and a helmet. A line is usually thrown or set over a strong branch union high in the tree, and the climber ascends the rope using friction hitches or mechanical devices, then works from the rope system. The Arboricultural Association says two personal fall protection systems (two ropes) on independent anchors should be the preferred way of working, so the climber is still held if one fails (see its Personal Fall Protection Systems update).
Climbing spikes are normally kept for trees that are being removed, because they wound the bark. Where climbing isn't safe, firms use a mobile platform (cherry picker) instead.
The HSE says a minimum of two people must be present during all aerial work, with one on the ground able to carry out an aerial rescue without delay. A tree surgeon working alone up a tree is a warning sign.
Often, yes: light rain doesn't normally stop work. Work stops when conditions make climbing or felling unsafe: strong or gusty winds, lightning, ice, or rain heavy enough to make the tree and the ground dangerously slippery. The crew decides on the day as part of their risk assessment.
If your job is rescheduled because of the weather, that's a good sign the firm takes safety seriously. Emergency work after storms often goes ahead in poor conditions, with extra precautions.
Late autumn to late winter suits most pruning and felling, while trees are dormant and most birds aren't nesting. Some trees are different: plums and cherries are pruned in spring or summer to avoid silver leaf disease, and birch and walnut bleed sap if cut in late winter or early spring, so they're better pruned in summer or early winter.
Work can happen all year, but wild birds, their eggs and nests are protected by law. It's an offence to intentionally damage or destroy a nest while it's being built or in use, so between March and August a good firm checks carefully before cutting. Bats and their roosts are protected all year, whether or not bats are present.
A small prune or a single small tree can take an hour or two. A large tree dismantled in sections over a house can take a full day or more, plus clearing up and stump grinding. Your quote should say how long the firm expects to be on site.
Most firms chip the branches on site and take the chippings away, and will either remove the logs or leave them for you. Some will leave the chippings as mulch if you ask. Make sure the quote says what happens to the waste, and check that a firm carrying waste away is a registered waste carrier.
Most do, usually by stump grinding, which grinds the stump to below ground level so you can returf or replant. It isn't always included in a felling quote, so ask.