All Forests and all Saprolings are 1/1 green Saproling creatures and Forest lands in addition to their other types.
2/1/2007 Each Forest and Saproling will have the card types creature and land, and the subtypes Forest and Saproling. Each subtype maintains its correlation to the proper type: Forest is not a creature type and Saproling is not a land type.
2/1/2007 When Life and Limb leaves the battlefield, the effect ends and the permanents go back to what they were (unless another effect grants these card types and/or subtypes to the affected permanents).
2/1/2007 Forests that enter the battlefield while Life and Limb is on the battlefield will enter the battlefield as creatures. They’ll have summoning sickness.
2/1/2007 Saprolings that are on the battlefield while Life and Limb is on the battlefield have the ability “: Add .” Although they’re Forests, they are not basic lands.
2/1/2007 With Life and Limb on the battlefield, Mistform Ultimus will be a legendary 1/1 green land creature that has land type Forest and has all creature types.