It would be odd because a tree that evolved to grow in the conditions found in Africa (a hot, dry climate) would be ill suited to grow in Nova Scotia (a wet, cold climate). For the sake of argument, let's say that these are African oaks on Oak Island --- and I don't believe for a minute that they are. The trees in the photo you linked to have grown quite well on an island that is close to the mainland. Oak being a tree species that germinates its seed easily ... why wouldn't there be African oaks growing on mainland Nova Scotia? Acorns would easily spread off the island, floating on the tide, carried by birds and animals, etc... Hundreds of years after the Templars or Vikings or aliens or whomever planted these trees on Oak island, there would be a population of these trees on the mainland... and there is not. Were there any samples taken of the wood of these African oak that can be examined? Even in the 1960's when, as you claim, these African oak were still on the island, the existence of hundreds of year old oak trees of a species only found on the other side of the world would have been noted.... but there is nothing mentioned anywhere.