Petrarch's letter MOST LIKELY reflects the ideals of humanism.
Explanation:
Petrarch was a poet and scholar who pave the way of the Renaissance with his humanistic philosophy. He is also regarded as one of the father of contemporary Italian.
As a priest Petrarch was eligible for ecclesial posts, which promoted his belief in antiquity. He has also been able to seek lost classical texts as a diplomatic ambassador to the vatican. Petrarch gathered a good collection of such texts during his lives, which he then legacy to Venice in return for a house to shelter the pestilence.
Petrarch continued to admire the past and protest against shortcomings of his own day as he learned as much about the high middle ages. While Petrarch believed he existed "in varying and confounding winds," he hoped that civilization would again reach the heights of past achievements. His philosophy became recognized as humanism and formed a link between the Medieval period and the Renaissance.
In order to answer this question, I will use two different perspectives of ethics: the consequentialist perspective, and the deontological perspective.
Consequentialism argues that the morality of an action lies with its consequences. This means that an action with bad consequences is an immoral action, and vice versa. In this case, killing the last remaining Redwood would not have any negative consequence on any being in the world, as no one benefits from it anymore. This means that the act is not immoral.
A deontological perspective states that there are principles that should be taken as rules, and which govern what is right and what is wrong. Therefore, rules and duties are central. For example, a principle might state that "all life is valuable." As the Redwood falls under the definition of life, killing it would be considered an immoral action.