Planting trees in the tropics, rather than in higher latitudes, could be more rewarding in terms of cooling the planet, according to a new study on regional effects of afforestation.

Researchers, including those from the University of California Riverside, US, said that planting trees provides an overall positive effect for the world's climate by pulling out warming carbon from the atmosphere.

However, local effects on temperature not related to carbon varied significantly by region. For instance, trees at higher latitudes could have a slight heating effect, while the opposite is true in the tropics, they said.