The plants I have included here have been chosen for their potential of a great return on the investment it poses to harvest them. An other requirement is that they are fairly common in the northern temperate-subarctic region of Norway. Even within these criteria, this is far from an exhaustive list, but it is meant to give you an idea of where to start.
Vegetables
Subsisting on vegetables in the boreal forest is virtually impossible. At times it can provide a good variation in the diet however. So it is worth exploring, but not as crucial to survival as meat.
Reedmace/Cattail (Typha latifolia)
This plant is found over a rather limited area in Norway, even if it more than likely could thrive in most of the lowlands and lower highlands all over the country. The reason of it's limited range is probably that it haven't had enough time since the ice age to spread. Where it is found however, it is often in large stands and has a starch production per area quite close to potato! Needless to say, this is probably one of the most interesting food plants found in the northern region and whole tribes of Native Americans depended on it. I haven't tried all of these plants yet. Those I have not I mostly take my information from pfaf.org. All soft parts of this plant is edible and delicious, even the green cobs. The leaves are also very strong and good for cordage, but that is a different story.
The rhizomes are fibrous with a slightly fire proof skin on. To cook them, just throw them on the coals and leave them for some minutes and the starch will be very sweet and can be sucked out of the fibres it sticks too.
Same goes with the stem base, but it must lay on the coals substantially longer. The texture is almost like Chinese Water Chestnut and the taste even better I would say. It can also be cleaned and cooked in a pot.
I have yet to try the cobs, shoots and the pollen, but they are all said to be good and exceptionally nutritious.
Cow parsley (Anthriscus sylvestris)
Many references I have seen states that the root of this plant must be cooked several times to remove it's bitterness. If you are intent on eating all of the root, then you have to. But I am not interested in eating the bitter, fibrous outer shell. This shell is very thick on cow parsley, but if you remove it before cooking you have a soft and palatable vegetable. Considere
d the sheer abundance of this plant at times, I have no problem being this picky. The leaves are very foul tasting, I think. But some people mix slight amounts of it in salads.
Nettle (Urtica sp.)
Nettle is very common, but as most vegetables, primarily in places disturbed by humans. It is extremely nutritious and very tasty. The young leaves can be eaten almost raw, but as they get older they need more cooking to remove the bitter taste. The calorie value is, despite appearances, quite high.
Dandelion (Taraxacum offenciale)
The leaves of the dandelion is a quite good in salads. I only eat the young ones though. Older leaves are too bitter for my taste. I am quite ashamed of not yet having tried the root yet, mostly due to being scared of the alleged bitterness. But this is definitely a root worth trying, considering it's extreme abundance and quite sizeable root.
Orpine (Sedum telephium)
The leaves are edible, either raw or cooked. Haven't tried them personally though. What I have tried is to eat the raw root. Quite good, like raw potato, but it is probably even better cooked. Cooking vegetables help you take advantage of starches that would otherwise be indigestible.
Silverweed (Potentilla anserina)
Common root vegetable, which I of some reason have yet to try.
Alpine bistort (Polygonum viviparum)
I have personally eaten the seeds and the root raw. The seeds are small, but easy to gather and high in calories. The root is small, but tastes very good and is probably even better when cooked.
Common plantain (Plantago major)
The seeds are small, but nutritious and easy to gather.
Common reed (Phragmites australis)
Never tried it, as it is doesn't exist in the region where I come from. The roots and shoots and seeds are edible and rich in calories. The green stems can be ground up and the sugar extracted by boiling or melting. Definitely a plant worth closer attention it seems.
Burdock (Arctium sp.)
This specie doesn't grow anywhere I have ventured, but the root is said to be very good eating.
Berries
In the autumn there is an abundance of berries in the boreal forest and the mountains. Despite appearances, it may provide quite a large portion of the daily calorie intake at that time of year. Some berries are more worthwhile than others, but for the sake of variation I snack on them all.
Cloudberry (Rubus chamaemorus)
Very good tasting berry, maybe not very rich in calories, but it has at least 10 times the vitamin C of orange.
Cowberry (Vaccinium vitis-idaea)
Not a personal favourite of mine, opposite of many of my countrymen. When it has been dried, the peculiar taste milden if dried. It is said to have bigger calorie percentage than most berries. 
Bilberry (Vaccinium myrtillus)
One of the most tasty of berries. And since the bear loves it that much, it is more than likely one of the most calorie rich ones as well.
Bog bilberry (Vaccinium uliginosum)
Quite tasty, but in my opinion not as tasty as the common bilberry. Probably has a reasonable calorie content.
Bearberry (Arctostaphylos uva-ursi)
Tastes a little like cowberry. It grows in the mountains.
Alpine bearberry (Arctostaphylos alpina)
Less substantial than bearberry, but of similar taste. Grows in the mountains.
Crowberry (Empetrum nigrum)
More than likely not much nutrition in these berries. But they are very juicy. When in the mountains I often grab a handful, chew out the liquid and spit out the tart skins. They grow in the forest as well as in the mountains.
Cranberries (Oxycoccus sp.)
Good after the frost and all the way until spring. Hard to gather a lot of them, so it is mostly for the taste of it.
Rowan (Sorbus aucuparia)
This is a berry I can't stand eating more than one or two of. Nothing more to say about it really.
Wild rose (Rosa sp.)
Fleshy, good tasting fruit. But you need to remove the irritating hairs inside the fruit prior to eating it. A messy process that make this berry hardly worthwhile.
Blackberries (Rubus fruticosus)
These berries are only found in the very south of the boreal region. They are very good, but in my opinion raspberries are better.
Raspberries (Rubus idaeus)
My favourite berry. Very sweet, but gathering any quantity takes considerably long time.
Wild strawberry (Fragaria vesca)
A very sweet berry, but also hard to gather in worthwhile quantity.
Nuts
Hazel (Corylus Avellana)
These are the most widespread of the nuts, but are still confined to the warmer areas. The crops can be heavy and the tasty fruits are definitely worth harvesting.
Oak (Quercus sp.)
I have not tried these nuts as oak is only found on the very edge of the zone written about here. The nuts have to be leached to be edible because of the great amounts of tannin found in them naturally.
Digging stick
The digging stick is the primitive gatherer's primary tool. It doesn't need to be much, any stout and pointed stick will do. While a shovel has two functions, breaking up the soil and hauling it out of the hole, the digging stick only breaks up the soil. The hands serve for hauling out the broken soil. The advantages of the digging stick is in it's simplicity and precision. While digging a ditch is easier with a shovel, digging up a single root is more easily accomplished with a digging stick. On the photo below I am digging up cow parsley.
Next Wednesday: Birds
