[@Estylwen]

For Timber, it'd be noted that the material requirements would be non-poisonous plants, wooden planks or sticks, or a pouch full of seeds, for casting. Either that, or channeling sufficient 'kindness' emotional and 'growth' conceptual essence mixed together while performing the casting motion and uttering the spell name - the motion in this case being to slam your palm upon the ground while either wielding the materials or channeling and expelling the required essence.

If preferable, I'll try to remember to include details like this in future spell learning that characters undertake!