Optimal management of Korean pine plantations in multifunctional forestry

Korean pine is one of the most important plantation species in northeast China. Besides timber, it produces edible nuts and plantations sequester carbon dioxide from the atmosphere. This study optimized the management of Korean pine plantations for timber production,seed production, carbon sequestration and for the joint production of multiple benefits. As the first step, models were developed for stand dynamics and seed production.These models were used in a simulation-optimization system to find optimal timing and type of thinning treatments and optimal rotation lengths. It was found that three thinnings during the rotation period were optimal. When the amount or profitability of timber production is maximized,suitable rotation lengths are 65-70 years and wood production is 5.5-6.0 m3 ha-1 a-1. The optimal thinning regime is thinning from above. In seed production, optimal rotation lengths are over 100 years. When carbon sequestration in living biomass is maximized, stands should not be clear-cut until trees start to die due to senescence. In the joint production of multiple benefits, the optimal rotation length is 86 years if all benefits (wood, economic profits, seed, carbon sequestration) are equally important. In this management schedule, mean annual wood production is5.5 m2 ha-1 and mean annual seed yield 141 kg ha-1. It was concluded that it is better to produce timber and seeds in the same stands rather than assign stands to either timber production or seed production.