It is not difficult to get roots in a dark spruce wood, where soil is soft and loose. One can dig and pull them out with bare hands, using only a knife occasionally.

Spruce roots were probably the most common sewing material in nordic boatbuilding — see sewing techniques overview. Some of them can be up to 3 meters long but quite even — between 4-7mm thick, and flexible enough to be tied into a knot. They have to be collected and immediately cleaned from bark, before they got dry and crisp. Then they must be also twisted to make them softer still, and then kept comletely immersed in water of tar, which would not let them dry. They were said to be boiled in tar in NW Russia, to make them more rot resistant, but, too long boiling was found to make them crisper.

Source: Mika Naimark, https://sewboat.narod.ru/tunaboat/roots.html