Fig. 13 shows two methods of seasoning timber. The timber has been selected for its working properties and appearance. Different types of timber have differ...

(a) Naming the two methods of seasoning timber:

• Method P is air seasoning (air drying). [1] The diagram shows timber planks stacked outdoors on a raised platform with stacking sticks (thin strips of wood) placed between each layer. The stacking sticks create air gaps that allow air to circulate around every surface of the planks, enabling moisture to evaporate gradually over months or years.
• Method Q is kiln seasoning (kiln drying). [1] The diagram shows timber placed inside a heated, enclosed chamber. Fans circulate warm air around the timber to accelerate the drying process. Temperature and humidity are carefully controlled to achieve the desired moisture content.

(b) The purpose of seasoning timber is to reduce its moisture content to a usable level. [1] Freshly felled (green) timber contains a high proportion of water. If used without seasoning, the timber would shrink, warp, crack, and become susceptible to fungal attack (rot) as it dried out in service. Seasoning brings the moisture content down to a level appropriate for the timber's intended use, typically 10-20%.

(c) Two advantages of Method Q (kiln seasoning) over Method P (air seasoning):

1. Kiln seasoning is much faster: timber can be dried in days or weeks, compared with the months or even years required for air seasoning. [1] This means timber can be processed and made available for use far more quickly.
2. The moisture content can be precisely controlled and reduced to a lower level than air seasoning can achieve. [1] In a kiln, temperature and humidity sensors allow the operator to target an exact final moisture content, whereas air seasoning relies on ambient weather conditions and typically cannot reduce moisture below the equilibrium moisture content of the local climate.