You can create up to twelve tree trunks, that are 1 ft wide, that grow into any shape that you want within a 10 ft radius sphere. You do not need to create or use all the trunks at once. They can be summoned any time during the duration of the spell. Alternatively, you can use all the trunks to create a fully enclosed 10 ft radius dome around the center point. 

Each trunk has AC 5 and 20 hit points.

If a trunk is used to restrain a creature, that creature must succeed on a Dexterity saving throw or be trapped by the trunk. On a success, the target dodges the trunk.

The restrained creature can use an action to make a Strength check against the spell’s saving throw DC. On a success, the creature is no longer restrained and breaks the entire trunk restraining it.

After 30 minutes you lose the ability to control the trunks unless you recast the spell as a ritual, trunks don't decay while the ritual is happening, in which you add another 30 minutes to the duration and can regrow any lost trunks up to your limit of twelve.

If you decide to cancel your spell or run out of time before starting the ritual, the remaining wood immediately rots and, if all twelve trunks are present, turns into 1d6 seeds of the type that you initially used.