Genetic Improvement

Hundreds of thousands of trees were measured and compared with their neighbors, and a small percentage with the very best for growth, form and health were selected (our "Plus Trees").

Small branch segments from these trees were grafted onto seedling rootstocks growing at carefully selected orchard sites, with several grafts planted from each Plus Tree. As these grafts grew, we applied special treatments to induce early crops of cones and pollen so that we could interbreed them.

The resulting pedigreed groups of offspring were grown into seedlings and planted into scientifically designed, multi-year field tests on a wide range of typical forest sites. After several years in the field tests, the Plus Trees that produced the very best-performing offspring were identified. The best Plus Tree 'parents' were retained in the orchards (now 15-20 years old) and harvest of seed from these tested orchards provided our first Weyerhaeuser Select seed lots.

But we didn't stop there. The best trees from the best offspring groups in the field tests were selected, grafted into a new 'second generation' orchard, and the breeding and testing cycle was started again. Today Weyerhaeuser is producing most of its Weyerhaeuser Select seed from second generation tested orchard parents, and a third cycle is well underway with field test offspring from the best second-generation crosses.