Interesting discoveries. While I may not agree with the theory, I respect the sincerity that goes behind the belief in it, and the detective work involved.
It seems the tree's last growth ring was 1948, but it's suggested the tree could have remained standing for many years after it died until it eventually fell down, so hypothetically it could be the tree which killed and injured the hikers.
The tin can is more compelling as it is stamped 1958 for manufacture. But curious none of the rescuers saw it at the time, and how it didn't appear in any of the search photo's.
And how it came to be buried, found only by a metal detector. Burial of the can/it not being seen tends to suggest someone who either did not wish to litter the place (such as the Mansi burying it in fire ash if they sheltered there) or wanted to hide their actions (one or more of the rescuers).
Although I'm certain it would be Karelin's own actions and observations that nobody took anything, I don't completely buy the idea that none of the rescuers would ever take a tin of condensed milk, as they took all the cache contents, and there was some condensed milk found in the tent, not just the cache.
The photo below, where the rescuers pose for a souvenir picture, hoisting aloft a glove on a stick, does not communicate to me that they always treated everything with the respect it deserved, this taken at the cedar, where 2 young men had earlier been found dead.https://dyatlovpass.com/resources/340/gallery/2S-33-1.jpg