The statement that is most likely correct is:
• The proportion of short-tailed squirrels may have decreased due to an increase in trees.
This is because the long-tailed squirrels have an advantage in jumping and balancing, which would likely lead to better survival and reproduction in an environment with more trees. As a result, the long-tailed squirrels would thrive, and the proportion of short-tailed squirrels would likely decrease.