When Brittanie Dreghorn first plugged information about her wedding into a carbon footprint calculator created by Less Stuff, More Meaning, an eco-friendly wedding blog, she was surprised to see the environmental impact of just one day.

She then made an increased effort to reduce the carbon footprint of her 100-person wedding to Peter English in October in a number of ways, including locally sourcing all flowers, food and drinks. But her wedding still had an estimated 22,000 kilograms of CO2 emissions, which mostly stemmed from her guests traveling to Australia’s Mornington Peninsula by plane to attend. She donated money to Greenfleet, a nonprofit that plants trees to offset CO2 emissions, so that she could have a carbon-neutral wedding. She also planted a flowering gum, a native Australian tree, on her wedding day.

"The tree-planting ceremony was symbolic of our commitment to holding an environmentally friendly wedding and a small contribution to offsetting the carbon,” says Dreghorn, 30.