金光明經文句記 3.41

3.41

First, the characteristics of cultivating the cause. The four withered [trees] are emptiness, the four flourishing [trees] are provisionality, and the double negation is the Middle. In explanation there is a sequence, but in cultivation there is no before and after; this is the threefold contemplation in a single mind. Therefore, that the Buddha entered parinirvāṇa between the twin trees of four withered and four flourishing precisely symbolizes this.