It was first identified in California in 2000 and then later in Oregon, USA.  However, the form of P. ramorum in North America is of a different sexual mating type to the fungus in Europe.

Infection by P. ramorum is usually characterised by the presence of dark red to black sap oozing from the trunk: bleeding cankers or tarry spots.  This is often on the lower portion of the trunk but may also occur several metres up the stem. When the outer bark is removed from the bleeding canker, mottled areas of necrotic, dead and discoloured dinner-bark tissue can be seen. Black zonelines are often present within and around the edges of the necrotic region.

Frankly, I am glad not to be a Shrub or Tree.

The report, which sets out how Defra will continue to deal with the challenges and opportunities of climate change, gives a UK target of 23,000 ha of new tree planting per year over the next forty years.

In particular, the document highlights the benefit of urban green spaces in managing surface water, filtering pollution and cooling city air, suggesting that areas of woodland could reduce urban temperatures by up to 2°C. So it seems that in the future trees really will be seen as cool!

But whilst UK growers are no doubt enjoying the increase in demand, many are warning that the situation could lead to a shortage of trees, as demand could outstrip supply. Their advice – get your tree early to avoid disappointment!

Our conclusion is that the best option is to buy a real tree, grown in the UK and sold with roots on. With a little luck (and judicious watering over the festive season) it should last and can then be planted in the garden come January to be used in future years – very sustainable! Clearly, if you are really concerned about the environment then you should collect it from where it has been grown on foot or on a bicycle!

Number two in our eco-tree chart is a UK grown cut tree, and for extra green points recycle it after Christmas. But it is at this point that the debate gets tricky – is an imported tree worse than a fake tree? Well, clearly neither is ideal from a carbon point of view. Both have probably originated abroad and required transporting over vast distances, consuming considerable quantities of fossil fuel. And, whilst purchasing a new fake tree almost certainly wins you last place in our eco-chart, what if you’ve already got the fake tree – surely the damage is then done and it’s ongoing environmental impact is minimal.

So, if you want a green Christmas, buy local and replant afterwards or dig out that fake tree from the attic and keep on using it. But hurry if you want a local tree, as they are in short supply…