What is the proper way to prune a tamarack tree?
Question:
Could you please advise as to the appropriate method of pruning the long lower limbs of my tamarack (aka larch) tree? They are hitting the house. Do I prune them all the way to the trunk or is it healthier for the tree to prune them back halfway or so?
Answer:
We generally recommend cutting a branch in contact with your house all the way back to the collar on the trunk (i.e., remove the entire branch), as described in our UMaine Bulletin 2169 on pruning woody landscape trees. The collar is a ring of slightly bulged, specialized tissue that forms the junction between the trunk and the branch–this tissue readily generates what is known as plant callus tissue (the plant equivalent of stem cells) and heals over faster and stronger than other parts of the branch. Old school wisdom advocated cutting an unwanted branch back flush with the trunk or (as in your case) just shy of the contact point with another object, and then sealing it with tar. However, many studies have since demonstrated that this technique results in a weaker heal for the tree than one that leaves the collar in place, potentially opening your specimen up to structural failure or pathogen/pest infection.
I will note that there is a good bit of anecdotal advice for Larch in particular being amenable to shaping as a Bonsai, which would suggest you *might* be able to cut the branch farther out if you so desired to maintain a shape for aesthetic reasons, and that the branch would heal normally at the cut point. However, I don’t have any experience with that practice and your question strikes me more as a mechanical/maintenance concern than one of pure aesthetics. Moreover, I’m skeptical that trimming branches facing your house in this fashion would really do much for overall appearance and could leave weaker branches in a poor environmental position (darker, less air movement, facing a wall), exacerbating the concerns outlined above. My advice is to prune back to the collar.