How slowly does the rubber tree sack make spruce resin? It seemed to take ages just to get 1 bucket's worth.
1 mb per 400/(summ of light brightness (from 0 to 1) of all leaves blocks in a range of 2 from log and 12 in height) tick.
For example if it is full bright sun and tree have 40 leaves blocks it will be 1 mb per 10 ticks or 1/2 second.