T-Shirts are ideally suited to all types of outdoor activities, including walking, fishing, shooting and hunting.
They can be worn on their own in the summer or as a base layer in the winter.
For many people a cotton t-shirt or singlet is the automatic choice on a hot summer day. If this is your preference, make sure it is good quality, and made from at least 170 gsm cotton.
You can get Cotton T-Shirts at very good prices, and a good quality one should last a few years.
Helly Hansen T-Shirts
A good alternative to the traditional cotton t-shirt would be a Helly Hansen base layer t-shirt like the Pace.
These are more expensive but, unlike cotton, will not absorb moisture but wick it away to help keep you cool and dry.