Travel by car one weekend a month for 300km (186 miles) roundtrip involves more than 800kg of CO2 per year, which can be absorbed by a forest of 83 trees!
Traveling by train instead of by car for 300km (186miles) roundtrip once a month avoids CO2 emission of half a ton per year. Equivalent to planting 49 trees.
A 1.400km (870 miles) roundtrip flight involves nearly 400kg of CO2 emission , equivalent to the amount of CO2 that can be absorbed by 39 trees in a year.
Go on the highway at 100km/h instead of 130 km/h allows you to avoid CO2 emission for nearly 900kg per year. Equivalent to planting 87 trees.