[Lewis Thomson (OP)]

Paul would like help finding answers to this question.

"There are hardwood and softwood trees, There are deciduous and evergreen trees. With regard to CO2 which types of trees are the most efficient at removing CO2 from the atmosphere? Pine trees have chlorophyll  as do oak trees with their flat leaves. If a deciduous tree loses it's leaves for half the year, then I presume for half a year the tree is not absorbing so much CO2 if any."

Leave your thoughts in the comments below...

[alancalverd]

The important property is sequestration. Evergreen softwoods grow very quickly but the fastest-growing types like cupressus leylandii aren't much use for construction or papermaking, so only sequester for their growing lives, say 50 - 100 years, then rot and yield all the carbon as methane. Slower softwoods like pinus sylvestris are cut and used for all sorts of purposes where the carbon  is effectively locked in for the life of the house, ship, church, or whatever. Likewise hardwoods which, though deciduous and slower to grow, can be harvested for exterior building works with very long life expectancy.

Generally speaking, evolution has determined that the dominant natural species in any location is probably the most efficient sequester of carbon  for that environment.