About 3.5 billion or about 50 for each person. Yes, there’s some guesstimating but it can’t be far out.  Of course you can argue the toss about what counts as a tree and if you count tiny saplings you might get it up to 5 billion. Here’s the basis for this number - the UK is just over 60 million acres, of which about 14% is woodland.  That’s a big increase from 1900 when it was only about 5% and it’s far less than Europe where the average is almost 40%.  Anyway, suppose there are another 50% of trees outside woodlands - such as those in parks, field edges, urban trees, and on moorlands. That would be the equivalent of 12 million acres with tree cover.  How many trees per acre is a big question because large majestic trees can be so large that there can be only about 20 on each acre whereas for young saplings the number can be as high as 2,000. Conifers can be as many as 1,000 per acre but, as the tree crop is thinned, that reduces to the low hundreds. So a figure of just under 300 trees per acre looks typical and on 12 million acres that would give about 3.5 billion trees. They are not evenly distributed between different parts of the UK - for example Scotland has almost 20% tree cover and about 20M acres so of the UK’s trees, almost a third are in Scotland. That brings us onto what species these trees are. It turns out that in woodlands a quarter of the trees are Sitka spruce and half as much again are Scots pine.  Other conifers (Douglas fir, Norway spruce and Lodgepole pine) make up another 15% so over half our trees are conifers.  Of the deciduous trees English oak and Silver birch each make up another 10% or so with Beech and Hazel together making 15% of our trees. It’s a concentrated picture, with 87% of our trees being made up of the top 10 species. Whereas the British population is around a hundredth of the world’s population (1%) we are far less significant in tree terms. There are probably around 3 trillion trees worldwide so the UK has nearer to a thousandth of the trees in the world.  At least the UK is going in the right direction - whilst the world’s tree cover is reducing due to deforestation from fires, drought and agricultural expansion, the UK’s has been increasing, albeit gradually.  Since the start of the millennium we have probably increased tree cover by around 1%. [caption id="attachment_30295" align="aligncenter" width="650"] Chestnut coppice[/caption]