I got home last night and one of my younger trees was toppled over.  i lifted it back upright and realized that the pot was really light weight.  i watered it and it seemed like it was getting heavier.  this morning i went to check on the plant and lifted the pot and it was really light weight.    what does this mean???

Could be that your tree is getting root bound.......how big is the pot that it's in ...how old is the tree

its in a smaller pot, 1 gal pot.  it was purchased from one of the member here.   less than a year old i would say.

If you are getting some good growth you can transfer to a 3 or 5 gallon pot, but do it without disturbing the root ball. Do you have a picture of the tree?

If it's root bound it should come out pretty easy...

Small pot and most likely a very quick draining mix! Time to up pot. Best of luck and looking forward to those photos,

I definitely agree with everyone's comments thus far: It seems to me that it is time to up-pot into a 3 gallon, and use more soil if the mix is very "airy" and will drain very quick.  The constant loosing of water will most likely stress the plant and will result in less growth. I would suggest adding some pine back on mix, and even a nice coat on top of soil to prevent so much evaporation (if that's also affecting the loss of water).   Best of luck!