National series of long-term intensive harvesting trials in Pinus radiata stands in New Zealand: Initial biomass, carbon and nutrient pool data

Abstract Global interest in addressing knowledge gaps relating to the effect of forest harvest intensity on soil fertility and long-term site productivity has resulted in the installation of numerous experiments, including Long-Term Site Productivity (LTSP) trials. To explore this issue in the context of the New Zealand planted forest estate, six LTSP sites were established from 1985 to 1994 across differing climate and soil conditions, then subjected to varying levels of organic matter removal during the harvest of the trees. Here we present data describing live above ground, forest floor and mineral soil carbon and nutrient pools immediately prior to, and following, harvesting at each site. Harvest residue management practices employed included the removal of stem only, whole tree, whole tree plus forest floor, whole tree plus forest floor and topsoil, and the addition of double harvest slash material. The data provides an understanding of biomass, carbon and nutrient pools at harvest and the impact of different harvest removal treatments on these pools. With the maturation of the trees at the LTSP sites, the data acquires even greater future value by enabling changes in soil properties to be quantified and correlated to variations in the biological properties at the site, including site productivity and critical microbial parameters. Overall, these data sets comprise a foundation for New Zealand to address the question – can the productivity of intensively managed planted Pinus radiata be maintained or enhanced through the judicious management of organic matter and nutrient pools over successive growing and harvesting cycles?