I've heard that dry weather, the kind we get in the winter, can cause damage to guitars. Do I need to do anything to protect my MacKenzie & Marr acoustic?
Do I need to humidify my MacKenzie & Marr Guitar?
You bet you do - at least in the colder months! Come October the relative humidity where we live (Eastern Canada) starts to drop and by mid November it can be far less than the 40% required for safe guitar storage. In northern Alberta it plunges into the single digits. That means trouble. Wood moves as it takes on and gives off moisture. That movement is across the grain. But bracing strips inside the guitar running at angles to the wood grain of the body constrain any movement of the top and back. In extremely dry conditions, as the wood contracts and begins straining against braces it has nowhere to go and eventually cracks.
This phenomenon is not unique to guitars or other wooden musical instruments. Look at an antique table. You'll likely see one or two cracks running along the length of the top. Either the leg braces or the end caps, both running perpendicular to the grain of the top, have prevented seasonal expansion and contraction and eventually the table split.
Caring for your guitar in winter and keeping it humidified is not difficult. Follow a couple of simple rules and you'll be fine.
We have an extensive article on guitar humidification here
A couple of caveats:
Don't count on a furnace-attached humidifier to keep your guitar above 45% relative humidity. It won't happen despite what the company that installed it told you! You need in-room or (as a backup) in-case humidification.
Spend $40 and buy a full room hygrometer - and then calibrate it! Knowing the exact humidity in your guitar room is critical to controlling it. Small hygrometers are not expensive and the Internet has dozens of sites that show how to calibrate them. The best investment you can make!