Chestnut and carbon sink.

Instead of planting a tree as part of an attempt at combating climate change when travelling, just buy local timber, especially Chestnut.  When you buy a post or a fence or a pergola pole it allows us to cut more Chestnut coppice, which will grow again, without replanting, absorbing carbon dioxide, plus more CO2 is consumed during the first years growth.
So when you see a Chestnut coppice being cut, it is not the denuding of the Amazon rain forest, but a fantastic carbon sink and employer of local forestry workers.
Worried about carbon emissions or carbon offsetting ?  Buy some UK Chestnut products and get some thing for your money.  Forget treated softwood from Latvia that must be replanted, transported hundreds of sea and road miles.
Beware of FSC (Forestry stewardship council) it’s designed to enable Homebase, Tesco’s, etc, to sell you teak garden furniture and make them look good.  Your local woodcutter or hurdle maker can’t afford the time or money for the registration fee and endless paperwork. And he or she will be far more concerned about the continuation of their crop.