Spruce root is a fantastic lashing material. Spruce has a good strength to weight ratio, and is quite pliable when wet. When harvested mindfully, spruce root is a nifty sustainable fiber.
Week in the Woods (http://weekinthewoods.org/) is a week long camp held in old growth forest on state land outside of Fairbanks, Alaska. The majority of the photos in this Instructable are from Week in the Woods and were taken by Alex Kamerling. A few photos are from second growth forest in Fairbanks and were taken by Jesse Hensel and John Manthei.
Step 1: Location and Tools
This project does not require any tools. However, it may be useful to have a knife, a key, a bucket of cool water, and/or a pot of boiling water.
All spruce trees have workable roots. However in many places the roots are too tangled to be easily harvested. Ideal harvesting locations are eroding river banks and mixed old growth forest.
Look for an area that has both birch and spruce trees, an open canopy, and a natural unkept understory. Look for long straight lines of moss across the forest floor. Peel back a little moss and ideally you will find the rotting bark of a long dead tree.
Step 2: Digging
Tear, peel or cut back the bark and start sifting through the severely rotten wood/soil/dirt. The rotten log forms a rich pipeline for roots to travel along. Attempt to remove the soil and free the roots. As more soil is removed, the roots may be gently lifted and excavation can continue. The roots will break if they are pulled too hard.
Step 3: Trimming
Eventually the roots will end, break, or need to be cut. Usable roots are smaller in diameter than your thumb. When no more root can be excavated the end can be broken or cut. The longer, straighter and more consistent the diameter of the root the nicer it will be to work with (tiny roots are particularly useful).
Step 4: Coiling
A long root (or a group of roots) can be coiled into a bundle. Bundles are easy to carry. Additionally, a small bundle can be soaked in a bucket.
Step 5: Peeling
Although bark may be scraped off with your fingernails, I prefer to use a key. I hold the tool as though I were curling ribbon. I point the blade toward my thumb and pull the root between my thumb and the blade. I feel most secure doing this with a key because I am less likely to cut myself.
Step 6: Splitting
The pith in the center of roots is a weak spot. Generally wood curves away from the pith as it dries. The lashing will be stronger and more flexible if it is split in half (or quarters). The split can be started by pressing a knife or fingernail into the middle of the end of the root. The split can also be started where the root naturally branches. Once the split is initiated it can be propagated along the length of the root. The split naturally wants to travel away from the core and out one side of the root. The split can be kept in the middle by bending one half on a tighter curve than the other. The split will migrate toward the side with the tighter bend. By working slowly back and forth the entire root can be split in half.
Step 7: Lashing
Split root can be tied or woven. Fresh root can be used as is or it can be dried for future use. Dried root can be reconstituted by soaking in a bucket of water. Spruce root will dry a darker brown unless it has been boiled. If there is an obstinate portion of root that isn't bending appropriately it may be pinched or bitten to crush the grain in the problem spot.
These images show people making a knife and a axe sheath with spruce root and birch bark.