Can I allow a pine tree to share root space with a group of birch trees? If not, which should I cut down?

Question

I have a group of birch trees, with a pine growing in the midst of them, in my front yard. My friend is telling me the pine must be cut down to save the birches. I see her concern, however: I think the entire arrangement is pretty; the pine looks healthy; I don't like to kill anything; and tree removal in Massachusetts is very expensive. I'd prefer to leave it alone, or, if anything, take down the birch directly to the right of the pine (see the third picture below), as it's leaning over the driveway.

This view is from the road.

This is a side view from the driveway.

The roots of the pine, on the left, are virtually tucked under the birch on the right,

and are also encroaching on another birch to the left.

Is cutting one of the trees down strongly recommended? If so, which?

Answer 1

Only you can make the decision about what is to be done but a little more information may assist you:

• the idea that some species have deep tap roots and other have surface roots is not considered to be as correct as it once was. All trees have the bulk of their roots within six inches of the surface to exchange air and water. So the two species are competing for water and nutrients and probably exchanging and cooperating all at the same time.
• birches are not particularly long lived in urban environment. In areas where the birch leaf miner and birch borer are found twenty years is a long life for a birch. Your clump is likely to be at least fifteen years old already.
• the pine appears to be a white pine and can easily live fifty to seventy five years in an urban environment. It can grow to twenty feet wide (7 M) and sixty feet tall (~20 M) which makes it poorly placed. It's location is too close to the driveway
• the white pine does not bud off old wood. If it's shape is distorted now by the birches it will not "fill in" later

If this were my house I would take my little pruning saw and remove the pine now. Half an hours work now avoids a bill later from the arborist.

By the way, if those birches are the same ones you asked about here then those birches are dying. This is a great opportunity to get both trees removed and put in something just right for you.

Answer 2

Leave them. I see poplar and spruce living together in sin all the time, especially in grazed pasture. (Young spruce more than a foot away from something get stepped on.)

The birch is short lived, typically only about 30 years. Most birch suffer from lack of water, then, under water stress succumb to other diseases. Locally birch are always found native only in areas that have an additional source of water -- seep, slough nearby, runoff channel, creek. Give it 2 feet extra water per year over a circle = twice the tree's height in radius, and it will live a century or more.

The pine appears to be a 5 needle pine. White pine? Swiss Stone Pine? Most of these can tolerate wet ground. The 2 and 3 needle pines are not found of soggy ground. If your soil is reasonably deep loam, they can both be happy. If the soil is sandy, you will have a hard time keeping the birch healthy as it grows taller. The pine however will do fine. If your soil is thin with clay underneath, you can drown the pine with excess moisture.