field maple leaves with dried leaves

I planted 50 bareroot (field maple at the end of march . over 40 of them are thriving but the rest have brown crispy leaves . I scratched the bark on the ones with crispy brown leaves and the bark is still green inside so i know there still alive . What can i do to help them . I planted all these trees with well rotted cow manure , compost and top soil and i water them heavy every 10 days .