Several sumac trees have seeded themselves but they are very close together. The birds loved them last winter so I want to leave as many as possible but don't want them to be overcrowded and want to thin them while they are small. The largest is about 10' with a 2" diameter trunk. How far apart should they be?
Talbot County Maryland
Sumacs are native trees with great (as you've noticed) wildlife value. They spread by lateral roots and naturally form colonies. These are perhaps the 'seedlings' you are seeing, and don't need to be thinned as this is their normal habit.