Nontree Wood

We have achieved the ability to make plastics that are 70% to 100% plants. We have only been able to make paper that is only made out of trees. Instead of trees, why can't we use another more populant plant that we can use to make paper out of? Or wood out of recycled aluminum and plastic. Or, we could use cotton to make paper or wood, as they grow almost out of hand. Another good suggestion would be to use wheat for more than food.