Narrated Abu Bakhtari At-Tai:

I asked Ibn 'Abbas about Salam for (the fruits of) date-palms. He replied "The Prophet forbade the sale a dates on the trees till they became fit for eating and could be weighed." A man asked what to be weighed (as the dates were still on the trees). Another man sitting beside Ibn 'Abbas replied, "Till they are cut and stored." Narrated Abu Al-Bakhtari: I heard Ibn Abbas (saying) that the Prophet forbade ... etc. as above.

حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، أَخْبَرَنَا عَمْرٌو، قَالَ سَمِعْتُ أَبَا الْبَخْتَرِيِّ الطَّائِيَّ، قَالَ سَأَلْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ عَنِ السَّلَمِ، فِي النَّخْلِ. قَالَ نَهَى النَّبِيُّ ﷺ عَنْ بَيْعِ النَّخْلِ، حَتَّى يُؤْكَلَ مِنْهُ وَحَتَّى يُوزَنَ. فَقَالَ الرَّجُلُ وَأَىُّ شَىْءٍ يُوزَنُ قَالَ رَجُلٌ إِلَى جَانِبِهِ حَتَّى يُحْرَزَ. وَقَالَ مُعَاذٌ حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرٍو، قَالَ أَبُو الْبَخْتَرِيِّ سَمِعْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ نَهَى النَّبِيُّ ﷺ مِثْلَهُ.