I confess that I have run Wildwood Trail for 20 years without seeing the trees for the forest. It wasn't until this spring when I made an effort to walk all the trails in Hoyt Arboretum that I noticed many of the trees are marked with common and scientific names, there are varieties of trees from all over the world and they are somewhat clumped by type. If your reason to choose walking is that you love it, continue to do it and don't ever apologize for your choice. I want to stay injury free. I see similar injury rates, but different kinds.
Runners tend to get more knee injuries while walkers' shins and feet seem to have more problems.
Any sport has injuries when too much mileage is added too fast, when you work too hard, when you don't have adequate rest days or when you are not wearing the proper shoes. It is difficult to compare the literature on sports injuries when the definitions of injury differ. Running injuries are usually defined as an event leading to a change in normal training and walking literature has defined injury as events needing a doctor visit. You need to train properly, be blessed with good biomechanics or, at least, wear good shoes, have adequate muscle strength and do some stretching to stay healthy with either sport. If you want to be a faster walker, you need to learn some skills.