ועץ השדה יתן פריו… (בחוקותי כו)

And the tree of the field will give its fruit…

Rashi says this refers to “אלני סרק – fruitless trees”

Fruits were created to make a hundred brachos daily.  However, the fruitless trees stand on the side forlorn since we can’t make brachos over them.  However, when Moshiach comes, all fruitless trees will bear fruit, as it says “ועץ השדה יתן פריו” – and in Yeshaya, it says “וכל עצי השדה ימחאו כף” – the trees of the field will clap their hands (when Moshiach comes) which refers to the fruitless trees will ימחאו – be happy  because of כ’’ף – which has the numerical value of 100, the “אלני סרק” will bare fruit and be included in the hundred daily brachos.