א אֵין עוֹלִים בְּאִילָן, בֵּין לַח בֵּין יָבֵשׁ, וְאֵין נִתְלִים בּוֹ וִאֵין מִשְׁתַּמְּשִׁין בִּמְחֻבָּר לַקַּרְקַע כְּלָל, גְּזֵרָה שֶׁמָּא יַעֲלֶה וְיִתְלֹשׁ. עָלָה בְּאִילָן בְּשַׁבָּת, בְּשׁוֹגֵג מֻתָּר לִירֵד; בְּמֵזִיד, אָסוּר לִירֵד. וְאִם עָלָה מִבְּעוֹד יוֹם, בְּכָל גַּוְנֵי מֻתָּר לִירֵד מִשֶּׁחָשְׁכָה. וְיֵשׁ אוֹמְרִים דְּהָנֵי מִלֵּי כְּשֶׁהָיָה דַּעְתּוֹ לִירֵד מִבְּעוֹד יוֹם, אֲבָל לֹא הָיָה דַּעְתּוֹ לִירֵד מִבְּעוֹד יוֹם לֹא יֵרֵד מִשֶּׁחָשְׁכָה, כֵּיוָן שֶׁהָיָה דַּעְתּוֹ לִישֵׁב שָׁם בְּאִסוּר. הַגָּה: וְדַוְקָא אָדָם שֶׁעָלָה שָׁם, אֲבָל אִם הִנִּיחַ שָׁם חֵפֶץ מִבְּעוֹד יוֹם אָסוּר לִטְּלוֹ מִשָּׁם בְּשַׁבָּת (הַמַּגִּיד פֶּרֶק כ"א). וְכָל זֶה בְּאִילָן וְכַיּוֹצֵא בּוֹ, אֲבָל קָנִים הָרַכִּים כְּיָרָק, מֻתָּר לְהִשְׁתַּמֵּשׁ בָּהֶם אַף עַל פִּי שֶׁמְּחֻבָּרִים בַּקַּרְקַע, דְּאֵין אִסּוּר לְהִשְׁתַּמֵּשׁ בַּיָּרָק (הַגָּהוֹת אֲשֵׁרִי פֶּרֶק בַּכֹּל מְעָרְבִין בְּשֵׁם אוֹר זָרוּעַ וּבֵית יוֹסֵף).
1 If It Is Permissible to Walk on Grass or Climb a Tree, 13 Seifim: We do not climb a tree, whether it is wet or dry, nor do we hang from it, nor do we use anything attached to the ground. This is a rabbinic decree lest one come to climb the tree and pick something from it. If someone climbed a tree on Shabbat by mistake, he is permitted to descend. If he did it on purpose, he is not allowed to descend. If he climbed the tree when it was still day on Friday, he is always allowed to descend after it gets dark. There are some who say that this only applies when it was his intention to descend while it was still day, but if it was not his intention to descend while it was still day, he should not descend when it gets dark, as he intended to sit in a forbidden place. Rema: This only applies to a person who ascended the tree, but if he left an object there while it is still day, it is forbidden for him to remove it from there on Shabbat (Magaid Chapter 21). All of this applies to a tree or the like, but one is permitted to use reeds that are soft like an herb, even if they are connected to the ground, because there is no prohibition against using herbs (Hagahot Oshr"i Perk Bechol Me'arvin in the name of the Or Zarua and Beit Yosef).