What trees should we plant to combat global warming

An old oak tree at Ashridge

Climate change is a fully proved fact.
Keep our woods and our forests intact.
But should we plant more?
Conifers I deplore;
Oak and beech are the trees that attract.

This limerick was inspired by today's news on the BBC web site "Wrong type of trees in Europe increased global warning." 

The article says that  over the past 150 years, foresters have adopted a scientific approach to woodlands - planting faster growing, more commercially valuable trees such as a Scots pine and Norway spruce. The rapid re-forestation of great swathes of Europe has generally been seen as a good thing due to the trees' ability to soak up carbon, something that has become particularly relevant in recent decades.

The problem is that removing trees in an organised fashion tends to release carbon that would otherwise remain stored in forest litter, dead wood and soil. In addition choosing conifers over broadleaved varieties had significant impacts on the albedo - the amount of solar radiation reflected back into space. Even well managed forests today store less carbon than their natural counterparts in 1750.

The truth is that a well managed commercial modern woodland is not as efficient as "wild" woods at removing carbon dioxide - and conifers are worse than deciduous trees. What we need in Englans are more projects such as the Heartwood project in Hertfordshire.