Abstract: The invention relates to a protector for protecting a timber pole against subsoil decay. The protector, referred to specifically as a field liner, comprises a flexible sheet element in the form of a laminate structure including a plurality of material layers that provide the sheet element with required properties to serve as a field liner. For its field liner application the sheet element is used either in its sheet form as such, or in a sleeve form, both forms providing for the sheet element to be wrapped around a pole to be protected, the sleeve form providing for such wrapping after having been applied over the pole to cover the region to be protected. An adhesive substance applied to a suitable region of the sheet element then permits securing of the sheet element on the pole in its operative configuration tightly wrapped around the pole.