Question
How do I get the main stock of the tree fatter. They are very thin now. In plan on planting them this fall. Should I trim them to get the stock fatter and stonger. Cut the center leader. I dont want them tall and thin. Suggestions Thanks

Answer
The trunk diameter should grow after they are planted out of the pots. The pot has restricted the root system and caused the height growth. Cutting the tops off is near a good idea--it will damage the tree and could kill it.

These are fairly large tree about 40-50 feet tall at maturity.  Homeowners should attempt to place birch trees in locations where the soil will be shaded, cool, and moist. However, birch trees require full to partial sunshine on their leaves to grow well. The challenge is to select a growing site where the soil will remain cool and moist, but where the tree will also receive full sunshine on its leaves for much of the day. Excellent locations for placement of birch trees in the landscape generally are found on the east and north sides of a home where the building provides afternoon shade.