Where does tissue paper come from?

Yesterday, S started to have a sudden interest on where things came from. He asked me so many questions while he was having his breakfast.

S: "Mummy, where does tissue paper come from?"
Me: "Err, tissue? They come from trees."
Before I could further elaborate how they are processed, he bombarded me with another question.

S: "Where does the rain come from?"
Me: "Rain comes from the cloud. When the clouds gets too heavy, it will turn into rain. That is called condensation."
I explained to both of them about condensation (reinforced from a Winnie-the-Pooh book which he read earlier)

Then he asked me where the plastic plate, the stainless steel spoon, the mirror, curtain, cloth (and many more that I can't remember), all came from. He also asked me to explain step by step, how they come from and go through the factory process until it reaches the end user. E, also started to follow his brother, asking me where certain things came from.

Today, he asked me: "Mummy, where does paper come from?"
Me: "They come from trees".
I didn't really bother to elaborate how they are made.

Thank goodness for the internet. I can now google up the answer. LOL!