While much more can always be said, I summarized the relevant links on the possible reason behind not-so-lasting settlement attempts of the Norse people in "Vinland" before in: It’s now established fact that Vikings were in Canada around five centuries before Columbus made his voyage. Why didn’t they remain in America, why didn’t they settle more of the continent?
The following passage is just a [part of] copy & paste from the linked thread, and the point is relative shortage of the natural resources in Newfoundland (compared with Greenland) could be the possible reason behind the early abandonment of the Norse settlement attempt as well as more lasting Norse settlements in medieval Greenland.
As for the walrus ivory [as well as gyrfalcons], two main exotic exports from medieval Norse colonies in Greenland, on contrary to /u/Jingfengopteryx's post below, AFAIK we don't have almost any positive evidence on the large-scale export of walrus ivory from Newfoundland or other New World origin. The recent research suggests that (corrected) the walrus ivory circulated in medieval Europe could be hunted in Greenland, not necessarily in Canada (Star et al. 2018).
On this (possible) misunderstanding sometimes found in the recent popular history books, you can also refer to /u/textandtrowel's recent excellent complement in: Was indirect trade between the Vikings and China (or the Far East in general) exhaustive ?
(Added): Thus, timber resource for building/ maintaining ocean-going ship was probably the most useful natural resource in now Canada (Labrador Peninsula) for Norse Greenlanders, but it was not necessarily the direct export ware to the European market.
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