I've heard that Adi shankara believed that 'immovable (apparently inanimate) objects (like the tree) are endowed with sentience'. Evidently, Adi Shankara viewed 'the tree' as an object like the 'immovable (apparently inanimate) objects'. According to the Vedas, the Absolute, called Brahman, was present in everything, be it living or Nonliving, and thus everything is, as believers in the Vedas believe, 'endowed with sentience'. From this, it evidently follows that he viewed plants & trees as as much 'endowed with sentience' as any other 'immovable (apparently inanimate) objects' are. Nevertheless, the 'immovable (apparently inanimate) objects' also include rocks, rivers, rain, clouds, thunder, the earth, the sun, the moon, etc. Of course, from this, it does Not follow that he believed that the 'immovable (apparently inanimate) objects' were, like dogs, cats, cows, etc., endowed with life.
Yes,Adi Shankaracharya was aware of it
प्राचीनशाल औपमन्यवः सत्ययज्ञः पौलुषिरिन्द्रद्युम्नो भाल्लवेयो जनः शार्कराक्ष्यो बुडिल आश्वतराश्विस्ते हैते महाशाला महाश्रोत्रियाः समेत्य मीमाꣳसां चक्रुः को न आत्मा किं ब्रह्मेति ॥ ५.११.१॥ ते ह सम्पादयाञ्चक्रुरुद्दालको वै भगवन्तोऽयमारुणिः सम्प्रतीममात्मानं वैश्वानरमध्येति तꣳ हन्ताभ्यागच्छामेति तꣳ हाभ्याजग्मुः ॥ ५.११.२॥ 1.If some one were to strike at the root of this large tree here, it would bleed, but live. If he were to strike at its stem, it would bleed, but live. If he were to strike at its top, it would bleed, but live. Pervaded by the living Self that tree stands firm, drinking in its nourishment and rejoicing; 2.But if the life (the living Self) leaves one of its branches, that branch withers; if it leaves a second, that branch withers; if it leaves a third, that branch withers. If it leaves the whole tree, the whole tree withers . In exactly the same manner, my son, know this.
(Above was Ch.Upanishad,6.11.1, and 6.11.2,)
Adi Shankaracharya’s commentary on verse 2 ends as such:
...That the tree is ensouled by the' Living Self' has been indicated by the phenomena of the flowing of juices and withering of-as shown by the illustration also vouched for the Vedic text; which means that immovable (apparently inanimate) objects (like the tree) are endowed with sentience; and this also shows that there is no truth in the Bauddha and Vaisheika view that' immovable objects are insentient.' -(2)