Is it safe to add soil around white pines?

We're revising our backyard and part of the job is to re-grade the lawn area with a swale that runs across the width so rain water flows from one neighbor, through our yard, to the next neighbor. It does that now, but without a swale it creates a soggy mess.

On the side of our property where the swale would begin are three 16 foot tall white pines, in about 10 feet of space. The swale would need to begin in between two of them to divert water away from other plantings we're putting in. To make that happen we will need to build up a sort of berm in the bed where the pines are by about 3-4 inches. Is it a problem to put soil up against 3-4 inches of the (now) exposed trunks to create the berm, or will that damage the pines? It will have mulch on top of that and when it rains, water will flow through there as well. Any issues with the mulch and water that we need to deal with? For the record: our street is terraced from one property to the next so we have to live with the direction of water flow.

Thank you!

This message was edited Apr 17, 2008 1:54 PM

Some trees don't like having soil piled up at all over their roots, not sure if pines are picky about that or not. But I don't think it's ever good to pile soil up around the base of the trunk so I would definitely avoid doing that.

I agree, trees don't like having soil built up around them. Most will die in a year or two.

I also agree. When we had our property bulldozed to level it out, the dirt guy piled extra dirt around 5 huge old oaks. We were busy with other things and didn't notice until all the trees began to die. Sadly, even though we removed all the extra soil, it was too late--they all died.

Do you have any pix? It's always easier to envision with pix. I think my first advice would be to remove a tree. 3 white pines in a ten foot area is pretty crowded. A single mature white pine will be 10 ft across at the bottom boughs. Will that help your situation? Could you then run something between two trees? Again it would be alot easier to imagine with a picture, but it sounds like you need to do this between two trees right? Is there a way you can work with your neighbors to maybe get this problem spot landscaped? I'm thinking of there is a way to gather and control runoff, and then develop a rain garden type plan. Is the downstream neighbor aware you are doing this? They might not like having more water coming their way if they aren't expecting it. Hopefully you can get us some pix and we can maybe help a bit more, but I don't think from what you are describing what you are doing is in everyone's (including your) best interests.