Genetic gains from 20 years of cooperative tree improvement in New Brunswick

Abstract

The New Brunswick Tree Improvement Council analyzed 20-year data from plantations of unimproved and first generation improved black spruce (Picea mariana [Mill.] BSP) and jack pine (Pinus banksiana Lamb.). STAMAN, a computer model, conservatively projected an 11% merchantable volume gain at 40 years based on 20-year measurements of 36 000 trees. At age 20 years, first generation black spruce was 12% taller and 25-30% greater in total volume. Projections from over 160 000 individual measurements of height from age five to 20 years indicate that by 40 years, gains of 7-8% in height and 18-20% in total volume are likely. Ten year assessments from over 10 000 measurements of second generation black spruce indicate a 30% height gain over first generation material of the same age. For jack pine first generation material, the projections indicated a height gain of 14% and a total volume gain of over 30% at 40 years. Faster growth can provide greater volume at rotation age, a shorter rotation interval, or earlier interventions for commercial thinning.