Driveway dilemma

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While it is difficult to make an accurate assessment without actually observing the tree first-hand, it’s probably a safe bet that cutting off the roots will cause a number of problems, not least that the tree’s stability in the wind will be compromised.

Pseudotsuga menziesii (Douglas fir) typically produces roots near the soil surface because its roots require oxygen. Under pavement, soil will generally be compacted and dry, so the roots grow at the surface. The ideal solution is to remove the pavement, rehabilitate the soil and create a bridge of some kind over the area in which roots are present or are likely to colonize. Barring that, removal of the pavement and replacement with a deep layer of coarse gravel will allow water and air to penetrate and will prevent compaction.

It is important to keep such a tree healthy, as this species is prone to branch breakage, and stress will increase the likelihood of this occurring.