Logging is a technology that can be researched at an Alchemy Lab. Every upgrade of Logging increases your wood production by 10%. Each level requires that the Alchemy Lab and Sawmill level is the same or higher than the level to be researched e.g. Level 9 Logging requires at least a level 9 Sawmill and level 9 alchemy lab. you have to get logging to level 4 to be able to research Fletching therefore this should be one of your 1st researches
The research only needs to be done in one city in order to affect your wood production in all cities. This is different from the conquest of woods wilderness, which only affects the conquering city.
To view a detailed information for the required Resources per research level please view the Research page.