how long does it take to grow pecan tree
Marilyn Haddrill/iStock/Getty Images. Size. Pecan trees can grow to 70 feet tall have trunk diameters of 6 feet at full maturity. Trees can be spaced as close as 30 to 40 feet apart until they are about 15 years old, at which point they should be thinned.At 30 to 40 years old, pecan trees grow to a width of closer to 60 feet.Kennith Ponder/iStock/Getty Images.arilyn Haddrill/iStock/Getty Images. Size. Pecan trees can grow to 70 feet tall have trunk diameters of 6 feet at full maturity. Trees can be spaced as close as 30 to 40 feet apart until they are about 15 years old, at which point they should be thinned.