Bava Kamma 102 - Question about the laws of Shmita year (Torts)

Every seven years, a farmer in Israel is supposed to give rest to the land. Foodstuff that grew of itself can be collected and eaten, but after the harvest is over, one cannot keep it in his home but should put it out in the street for everybody's consumption. Wood is included in the laws of shmita.

However, Rava noticed a contradiction. A rule about cane reeds and grapevine leaves states that if these are gathered for food, then they have the laws of shmita, but if they are gathered for kindling - they do not have the laws of shmita. He resolved the contradiction: the laws of shmita apply to produce where the benefit and consumption come simultaneously, just like with food. 

For example, wood is burnt (and destroyed) in an oven, but the benefit (baking) comes later. On the other hand, dyestuff is destroyed when dissolved in water, and the benefit - dying the cloth - comes simultaneously. The laws of shmita apply only to stuff that is destroyed simultaneously with giving benefit.

Art: Harvest Camille Pissaro