Some math to make you feel good

Once a day your workers will take 75K from the kingdom coffins.
In return you get:

800 maples – 80K
330 coal – 60-66K
2-3 gems – 1-5K
8 bird nests (with rings, tree seeds and eggs) – hmm, hard to say, maybe 80-100K on average
So your daily profit is: 146-176K. Not bad, huh?
And, of course, this is the perfect way to raise farming, by getting daily supply of free tree seeds. Assuming you plant all tree seeds, you still get daily profit of 66-76K.