Line a baking sheet or jelly roll pan (12" x 17") with wax paper. Set aside.
Put the dark or milk melting chocolate in a small ziplock bag. Microwave at 50% power for about 45 seconds, or until just melted. Set aside.
In a medium bowl, melt the white chocolate in the microwave at 50% power for 1 minute. Remove and stir. Return to the microwave and heat at 50% power for 1 minute or until just melted. Stir until smooth.
Pour the melted white chocolate onto the prepared pan. Spread evenly with a knife or spatula. Gently shake the pan side to side to even out the chocolate and smooth the surface.
Cut a tiny corner off the bottom of the ziplock bag containing the melted chocolate. Pipe 8 or 9 tree trunks with branches randomly around the white chocolate surface. Sprinkle the trees with fall leaves sprinkles. Add additional sprinkle leaves and balls over the entire surface.
Place in the refrigerator for 15-20 minutes, or until set. Use a knife to cut around the trees for individual portions.
Can be stored for at least 2 weeks at room temperature, wrapped in cellophane candy bags or in an airtight container with wax paper between layers.