Since excessive heat and extremes in relative, or indoor, humidity are not good for any wood product, the secret to youthful furniture is to moderate both of these.
Just enough humidity keeps your handcrafted wood furniture supple and fresh. On the contrary, too much humidity makes your furniture expand, and not enough humidity is the solid wood equivalent to dry wrinkled skin.
Wood is very sensitive to changes in relative humidity. As the weather changes, so does the relative humidity in your home and in the moisture content of the wood in your furniture. This means that furniture is constantly expanding and contracting.
Ideally, the relative humidity in your home should be between 40 -45%. In the summer, relative humidity is more likely to be high, but central air conditioning helps regulate this. If it is too high, consider running a dehumidifier.
Conversely, in the winter, when air is already dry, heating your home aggravates the problem. You might need a humidifier to add moisture back into your home.
Most of the time, if you are comfortable, your relative humidity is probably in this range, but you can use a hygrometer to get an accurate reading.
Just like the sun's harmful rays can burn your skin, excessive heat can scar and burn your fine wood furniture.
Wood does best in moderate conditions of around 70°F. If possible, place your furniture away from all heat sources including under or over heat vents. If you must put furniture near an air duct, use a shield or guard to direct the heat away.
Always protect your table from hot pans and dishes, and look for hot pads or trivets that will not trap steam between your pan and the table. Wicker trivets are the worst offenders.
Also, if you must temporarily store your beautiful Amish furniture, look for a climate controlled storage space. Avoid warm attics, damp basements, and hot storage sheds.