ISA Certified Arborist Practice Exam

Trees are typically measured on a pH scale, which ranges from 0-14. A low pH (between 0-7) is considered acidic, while a high pH (between 7-14) is considered basic. Therefore, the opposite of acidic on the pH scale for trees would be basic. The incorrect options in this question are choices B, C, and D. Choice B, "Sweet," is not a measurement on the pH scale and is therefore not a suitable opposite for acidic. Choice C, "Sour," is also not a measurable option on the pH scale and is more often associated with taste rather than acidity. Choice D, "Neutral," sits in the middle of the pH scale and is not considered an opposite of acidic, as it does not have a high or low pH. Therefore, of the given choices, the only correct answer and opposite of acidic on the pH scale for trees is choice A, "Basic."