ABOVEGROUND AND BELOWGROUND BIOMASS OF PRECOMPETITIVE RED PINE IN NORTHERN MICHIGAN

In 1984, red pine (Pinus resinosa Ait.) plantations were established a t three sites in northern Michigan. From 1985 through 1992, 3083 indiv idual trees from these stands were destructively sampled to determine aboveground biomass. The root systems were excavated on a subset of th ese trees (975 individuals). There were no significant differences in the relationships between either above- or below-ground biomass and gr oundline diameter and tree height across the range of biomass (3-6720 g for aboveground biomass and 1-319 g for belowground biomass), basal diameter (0.3-10.1 cm), or height (10-417 cm) of the sampled trees. Th ere were also no;significant differences in these relationships among the three sites. Relative height growth (the ratio of total height inc rement in a year and the total height at the beginning of the growing season) was found to have a very well defined maximum that was a funct ion of total height at the beginning of the growing season. This maxim um relative growth rate was used to develop a new height growth index that can be used to identify precompetitive red pine that are approach ing their potential height growth in field situations.