In May 2004, at the request of local nursery owners, young Acer ×freemanii 'Autumn Blaze' (Autumn Blaze maple) trees previously grown in a number 20 (#20) container pot-in-pot (PIP) system were planted at the Colorado State University Horticultural Farm alongside similarly sized trees field grown, balled and burlapped (B&B). These trees were planted using methods recommended by the International Society of Arboriculture with half receiving 30% by volume soil amendment consisting of Organix compost mixed with the native soils. In addition, five trees grown for one year using the #20 PIP container system were maintained a second year in the same containers and compared to five trees transferred to #45 containers. After one season, the PIP-grown trees showed significantly more shoot growth and increased trunk caliper than the B&B trees. The application of amendments had no effect on the growth for either the B&B or PIP trees. Trees maintained in PIP containers for a second year had similar growth regardless of the container size.
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