Difficult to tell the size of those trees. I was up in Alaska for the first time doing some field work. I made the comment about some “new” trees because they were so small. Maybe 15 feet tall and 5 inches around.
My client said “New!? Those are probably 70 years old! Trees like that don’t grow very fast up here.” (Hmm - it was also in a boggy area, so yeah - I think you are right). Alaska obviously has huge trees on good soil.
Soil is not necessarily the growth problem.
Sunlight is a major factor. While it is the land of the midnight sun it is also the land of midday darkness. While that is not strictly true, there are also long periods of very short days. The summer very long days do not have the strong sunlight.
And then it is cold. Cold inhibits growth.