Coldwood

Many fey creatures and woodland spirits have a special susceptibility to cold iron. This weakness has led alchemists and arcane gardeners among the fey worshipping world and druidic circles to develop Coldwood. First adapted from natural hickory, Coldwood replaces iron in most ways, allowing smiths and craftspeople to craft strong weapons and sturdy armors. Coldwood also allows druids to wear armor types usually made of metal, as it does not breach their nature-centric beliefs. 
Coldwood grows very much like hickory, only slightly slower, reaching its mature size in roughly two decades. The timber of the coldwood can be used for the crafting of any item normally made from steel, resulting in an object with the same hardness, strength, weight, and edge-holding properties of good-quality steel. Coldwood is difficult to work and harder still to cultivate, making it and the items made from it extremely expensive. 
Coldwood trees are identifiable as a tree that looks as though it has many trunks wound around each other in concentric circles. In addition, Coldwood is in fact cold to the touch, and maintains this characteristic even in the warmth of summer. For this reason, a Coldwood forest is a very cold place, always. However, such forests are extremely rare, due to the value of the trees.
A single healthy coldwood sapling sells for around 500 gp in most cities across the continent, and is valued for it's use in buildings a luxury furniture construction, if not for it's other uses. Properly tended, a coldwood tree can live for thousands of years.

The DC of any item crafted of coldwood is always 10 higher than the same item made from steel. Weapons or armors fashioned from coldwood are always masterwork items (the masterwork cost is included in the prices given below). Harvesting viable coldwood from a coldwood tree requires a DC 25 Knowledge (nature) check. A successful check provides 5 pound of material per five years of growth (to a maximum of 100 pounds of coldwood).
For a coldwood tree to thrive it requires regular attention. Transplanting a coldwood tree or taking a viable cutting from one requires a DC 25 Knowledge (nature).