So you've heard of a Pando, right?
its estimatted the Fishlake pando has 40,000 trees on 1 root system.
Fortunately plants don't feel windchill, only warm blooded animals do. Unfortunately, you live outside aspen trees preferred comfort zone. Your trees won't have a long life. They are very prone to several fungal diseases, even in the right growing conditions.
A barrier 24 inches deep should be enough... should be.
