About 16 years ago, my husband built me a dozen wonderful , board-enclosed raised beds 15" high. We filled them all with local municipal compost. Wonderful veggie plants for years - until, about 5 years ago, the roots of a locust tree about 10 feet from the nearest (asparagus beds) but not shading the beds apparently sent wiry roots into them all to such an extent that over several years the asparagus sent up uselessly skinny little stalks, it was impossible to dig the potatoes with my spading fork due to the entangled mass of roots, and the veggies in all the beds were less robust than previously. I had to think that the tree was invading the rich compost since it had more nutrients. ?? Then I discovered that roots also had invaded the extra compost stored in a 4'x4'x3' wooden bin for use as needed - about 30 feet away from the tree. So about 3 years ago, we laboriously broke down the old beds and hubby kindly built me new ones - but only 3 this time, and waist-high as a nod to my aging knees and back so I did not have to bend any more - wonderful! These are on the other side of the yard, far from the tree. We recycled into the new beds the soil my dear man sifted first to remove the bulk of the tree roots, and then topped off the beds with new loads of fresh municipal leaf compost (which is clean - no wood or root bits or anything but decomposed leaves). But last fall, as I was digging potatoes from the newer, waist-high beds, to my horror I encountered the same sort of wiry roots that had invaded the last set of beds!! These newer, taller beds are located about 30' north of a sugar maple next door, but far from the (hated for several reasons) locust tree. So, my question: do tree roots really "forage" many feet away from the trunk, and grow UPWARDS into soil 36" above grade??