If you really are interested in height, you should look at one of the telescopic models. Echo Tools manufactures the PPT-265ES power pruner with telescopic shaft, adjusting from 2.72m to 3.72m and carrying a 30cm saw head. If that isn't long enough, there is a 1.5m extension pole. I believe this is by far the longest petrol-powered pole pruner on the market.
Stihl has a couple of pole pruners in its offering. With the same overall length, including a bar and chain of 2.7m to 3.9m, these units are telescopic and provide a long reach into trees. Model HT101 has a 31.4cc engine, developing 1.05kW, and the HT131 has a 36.3cc engine giving 1.4kW of power. Both have Stihl 4-MIX engines, so their tone is lower and deeper than a two-stroke.
With a fixed shaft of 1.75m, Husqvarna's 323P4 is a dedicated tree-care saw for professionals. When tested it proved to be precise and at 5kg it is nice and light. Power comes from a 24.5cc engine, developing 0.9kW and featuring SmartStart for 40 per cent less resistance in the starter cord. Controls feature an auto-return stop switch, which automatically resets to the "on" position for trouble-free starting. At the cutting end, there is a 30.4cm bar with tool-free adjustable chain tensioner. Expect to pay £417 (ex VAT).
New from Husqvarna is the 327P5x. This is another 24.5cc pole saw but with a shaft length of 2.75m and we understand it to be a rapid accelerator. However, the main difference between this model and the P4 lies in the adjustable 30.4cm cutter head and automatic chain lubrication.
This machine has Husqvarna's easy-starting E-TECH II engine and can be supplied with a harness to reduce stress on the arms. You might need it - the weight is 6.2kg. Price is £485 (ex VAT).
With a length of 2.3m, the Efco PT2500 from Emak UK is not the longest unit but it is a tidy machine and its 25.4cc gives 0.9kW of power. The cutting head is a small 25cm saw - and it's adjustable through five positions from zero to 90 degs. It weighs 5.9kg.
More interesting is the PTX2500. It has the same high-torque engine but is a telescopic pole pruner. It also has the same cutting head, but fully extended the unit stretches to 3.8m.
The 38mm-diameter pole on the Efco machines provides a superb grip; you don't really notice the 7.4kg weight of the heavier PTX version. We found this machine capable of slicing through 25cm branches with ease. What's more, the fine-toothed saw chain helps protect against kickback. The PTX2500 is a neat and tidy machine.
Have you considered going electric? Lamberhurst Engineering offers the battery-powered Pellenc Selion pole saw to cut the weight down to as little as 2.7kg.There are four models in the range, two with fixed-length poles of 1.3m and 1.8m, and a further two models of the telescopic type to give reaches of 1.5m to 2m and 2.2m to 3m. The saw heads have automatic oil-flow control, automatic chain-tensioning and a head that can be set in high, low or axial position. The battery pack is worn in a harness on your back and should give you sufficient power for a full day's work.
And don't forget that Silky Fox offers non-powered solutions in the form of pole saws and rope-pull pole loppers.