The elders see before them a rough year and make spiritual offerings to the gods, praying that things will not go poorly for their people.
1:
Continue fishing, by collecting oysters and molluscks from near the coast and having the fishermen try their luck with spears in the river, where they are less likely to lose them. Attempts are also made, with regards to fishing, to collect food that the fish themselves might eat. Clearly the food source was stable enough to last through last year, so it should last through this year as well, the elders figure. The elders try to inspire more brave acts of fishery by telling tales of awesome undersea creatures that would make worthy trophies, in the hopes that this will encourage the fishermen to do better, but also knowing the risks that such encouragement might have.
2:
The spicy root is venerated as a boon from a higher power. While it would be simple to try to keep foraging for it, it'd be better, the elders think, if they had a steady supply of it. Attempts are made by the tribes to grow the root in its natural habitat and clearing out all other competing plants and animals in the area continuously. With skill and luck, the root should be able to spread and effectively grow in the chosen spots. If all else fails, the tribe will just have to keep foraging for it.
3:
The trees are obviously suffering from an illness that we, as shepherds of the land, can cure! It also happens to be an excellent source of food and possibly other things. The tribes shall start collecting bugs from the oldest trees, knocking the ancient trees down and then stripping the bark to capture all manners of bugs, whether edible or useful in some other way.
4:
Start with smaller, yet sturdy trees. While these will not make as great boats, once we've got boat-making down to an art, the tribes can start to try something more ambitious afterwards. Since the older trees tend to be dead, it's obviously the younger trees that must be exploited. Trees that are easier to hollow out without tools are preferable, yet they need to be buoyant.