Treekly is described as 'Engage in walking challenges to plant free trees in Madagascar. Track steps via pedometer or fitness devices and contribute to reaching 5 million trees' and is an app in the sport & health category. There are more than 25 alternatives to Treekly for a variety of platforms, including iPhone, Android, iPad, Apple Watch and Linux apps. The best Treekly alternative is Gadgetbridge, which is both free and Open Source. Other great apps like Treekly are Google Health (Fitbit), watchOS, Amazfish and Garmin Connect.