Do wire-free robot mowers work under trees?

It depends on how the mower finds its position. Trees are the classic weak spot for satellite-based navigation, and much less of a problem for LiDAR, cameras or a wire.

RTK mowers work out where they are from satellite signals, corrected to centimetre accuracy. They need a reasonably clear view of the sky. Dense tree canopy, tall hedges and nearby buildings block or reflect signals, so accuracy can drop in those spots, and the mower may pause, slow down or leave strips uncut until it recovers.

LiDAR and camera mowers measure their surroundings instead. Trees, walls and fences are useful landmarks for them, so they tend to cope well in enclosed, leafy gardens. Their weak spot is the opposite: large open areas with little around them to measure against.

Hybrid mowers combine the two, using RTK in the open and LiDAR or cameras under cover. Segway Navimow's Segway Navimow i2 LiDAR Pro and Segway Navimow H2 Series, and Mammotion's Mammotion LUBA 3 AWD (3000 and 5000 versions), all work this way.

Wired mowers follow a cable, so trees don't affect their navigation at all, though roots and low branches can still cause them to get stuck.

If your lawn is heavily shaded, favour LiDAR or a hybrid, or a wired mower. Our RTK vs vision vs LiDAR guide goes through the trade-offs, with a diagram of how trees affect satellite signals.