Evolution of field garments..
Why wool has become my go-to gear for field use (or: How I learned To Stop Worrying And Love The Wool)
Once upon a time, it was rather common to find wool in use by military units. From the Navy peacoat to the winter field pants (both axis and allied) circa WW2. Problem was; it was heavy and itchy. In more recent years we have seen an ever increasing amount of synthetics being fielded, such as fleece, under-armor type shirts and the much loved "smoking-jacket". While having a decent weight to insulation ratio and being fairly cost effective, they did have their shortcomings. Not the least of which was the tendency to exacerbate thermal injuries and the marked increase in various skin infections due to the microbe friendly environment created by operating for days on end in the field.
( If you have some time on your hands, HERE is an in depth piece on the subject of battlefield burns over the years).
I began trying various Merino wool garments a couple years ago and have been impressed with my findings. The merino wool, having a finer fiber than traditional wools, is very soft, has good wicking properties and is naturally antibacterial due to it's lanolin content. I began with merino socks, as the synthetic blends would always give me a case of "slime-foot" before the day was through, which of course led to various fungal pleasantries. The difference was amazing. Not only did the merino wool not itch, but I could go days in a pair if needed without having my feet rot off. I then tried some light weight merino long sleeve quarter zip tops. These worked great as a base layer in cold weather or as a standalone in the summer months. The merino's ability to regulate temperature is truly impressive. Another factor for consideration, going back to the burn issue mentioned earlier, is that merino is remarkably fire resistant, requiring 1100F to reach flashpoint with zero melting point - compared to cotton @ 490F and synthetics with a melting point of 480F.
(Some textile burn data HERE)
There are limited choices right now for "tactical" garments in merino, but plenty of neutral/earthtone choices are marketed by the various hiking outfitters. I have abused and ignored the "proper laundering" instructions with my various merino garments and so far they are still going strong.
Guess it's still hard to beat "mother nature"...(and I mean that in the most non-greenie way possible)