Summary:
According to עולא, regular trees receive sixteen אמות; trees with branches that exceed 16 אמה receive an additional כמלא אורה וסלו. Even if we maintain קנין פירות כקנין הגוף דמי, nevertheless one who is קונה אילן אחד is not מביא וקורא, either because his קנין פירות could end immediately, or his rights are very limited.
Summary:
Both רש"י and תוספות agree that we are not גורס the word וידוי in the משנה; however according to רש"י it does not require קרקע, while according to תוספות (based on the ירושלמי) it does require קרקע כ"ש.
And to write a Prusbul on it - ולכתוב עליה פרוזבול
Summary:
We cannot write a פרוזבול for מטלטלין; however, we write for קרקע כ"ש either because אין אונאה לקרקעות, or because we can collect it repeatedly.