The Companions of the Tree (i e. those who swore fealty under the tree) were one thousand and three hundred, and the people of Aslam tribe were one-eighth of the Muhajirs.  

كَانَ أَصْحَابُ الشَّجَرَةِ أَلْفًا وَثَلاَثَمِائَةٍ وَكَانَتْ أَسْلَمُ ثُمُنَ الْمُهَاجِرِينَ  

[Machine] "Abdullah ibn Abi Aufa was one of the companions of the Prophet ﷺ and he was one of the 1,400 individuals from the Ansar who embraced Islam on that day which was known as "The Day of the Migrants.""  

عَنْ عَبْدِ اللَّهِ بْنِ أَبِي أَوْفَى «وَكَانَ مِنْ أَصْحَابِ الشَّجَرَةِ أَلْفًا وَأَرْبَعُمِائَةٍ وَكَانَتْ أَسْلَمُ ثُمُنَ الْمُهَاجِرِينَ يَوْمَئِذٍ»  

[Machine] I heard Abdullah ibn Abi Awfa saying, "On the Day of the Tree (i.e. Hudaybiyyah), we were one thousand three hundred, and on that day, the tribe of Aslam was an eighth of the Muhajirun. May Allah have mercy on them."  

سَمِعْتُ عَبْدَ اللَّهِ بْنَ أَبِي أَوْفَى يَقُولُ «كُنَّا يَوْمَ الشَّجَرَةِ أَلْفًا وَثَلَاثَ مِائَةٍ وَكَانَتْ أَسْلَمُ يَوْمَئِذٍ ثُمْنَ الْمُهَاجِرِينَ رَحِمَهُمُ اللَّهُ»