Final answer:
Two tree species with similar characteristics in different environments are likely exhibiting convergent evolution, where they have independently developed similar traits due to similar environmental pressures, resulting in analogous structures.
Step-by-step explanation:
The most likely reason two tree species living in different environments that share many similar characteristics is due to a phenomenon known as convergent evolution. This happens when species from different lineages independently develop similar traits or adaptations in response to similar environmental conditions, despite not sharing a close evolutionary relationship. This results in analogous structures, like the wings of insects, bats, and birds, which fulfill similar functions but are not derived from a common ancestral trait. Such traits are an example of analogy or homoplasy, different from homologous traits that are inherited from a common ancestor.
For example, in similar cold environments, different species such as the arctic fox and ptarmigan have evolved seasonal white colorations to blend with the snow and ice. These similarities are due to the similar selection pressures, such as camouflage from predators, rather than from being closely related genetically. This is a classic example of convergent evolution where environmental factors lead to similar trait development to aid in survival.