Baku, February 9, AZERTAC

The assumption that planting new forests helps limit climate change has been challenged by a new study.

Researchers found that in Europe, trees grown since 1750 have actually increased global warming, according to the BBC News.

The scientists believe that replacing broadleaved species with conifers is a key reason for the negative climate impact.

Conifers like pines and spruce are generally darker and absorb more heat than species such as oak and birch.

The authors believe the work has implications for current efforts to limit rising temperatures through mass tree planting.

Management issues

Europe's green canopy was dramatically thinned between 1750 and 1850, when the forested area diminished by 190,000 sq km.

Ironically the greater use of fossil fuels, particularly coal, slowed the timber rush, and from 1850 to the present day, Europe's forests grew by some 386,000 sq km and now cover 10% more land than before the industrial revolution.

However, the form and content of these new woods differed considerably from what went before.

In the distant past, these forests ran wild - but in the modern world, some 85% of Europe's trees are managed by humans. And 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.

Removing trees in an organized fashion tends to release carbon that would otherwise remain stored in forest litter, dead wood and soil.

The authors suggest the world should look carefully at both the types trees that we are planting and the ways in which they are managed.

The study has been published in the journal Science.