Muwatta Imam Malik Book of Hajj, Hadith 262

Yahya related to me from Malik that he asked Ibn Shihab about making a condition in the hajj that one could leave ihram at any place where an obstacle befell one and he said, "Does anyone do that?' and disapproved of it.
Malik was asked whether a man could cut plants from the Haram for his mount, and he said, "No."

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ سَأَلَ ابْنَ شِهَابٍ عَنْ الاِسْتِثْنَاءِ، فِي الْحَجِّ فَقَالَ أَوَيَصْنَعُ ذَلِكَ أَحَدٌ وَأَنْكَرَ ذَلِكَ . سُئِلَ مَالِكٌ هَلْ يَحْتَشُّ الرَّجُلُ لِدَابَّتِهِ مِنَ الْحَرَمِ فَقَالَ لاَ .