The UK’s trees are under threat from an increasing range of invasive pests and diseases. Over the past decade, a least a dozen tree pests and diseases have been found here for the first time, or have become more damaging. Trade, Transport, Travel, Tourism are the key entry routes for Invasive Non-Native Species - or INNS, the acronym by which they are often referred to. Research from the US and UK highlights the greatly expanded horticultural trade in imported exotic and mature species from around the world as the main ‘Trojan Horse’ for new pests and diseases – accounting for 70% of invasive introductions to the US and 90% to the UK. Below we look at Dutch Elm Disease – we have unfortunately felled a number of affected Elms(predominantly young coppice / multi-stem Elms regrown from previously felled single Elms) over recent months due to a resurgence of the disease.