Above- and below-stump biomass and nutrient content of a mature loblolly pine plantation

Above- and below-stump biomass and nutrient content were estimated for a mature loblolly pine (Pinustaeda L.) plantation on an eroded site in the upper Piedmont of South Carolina. Pine above-stump biomass was 144.9 t•ha−1; below-stump biomass was 36.0 t•ha−1, 20% of total pine biomass. Total pine biomass was partitioned as 17% crown, 63% stem, and 20% roots. About 55% of below-stump biomass was in taproots and 45% in lateral roots. Dominant and codominant trees had a greater proportion of below-stump biomass in lateral roots, indicating that larger trees absorb a disproportionate quantity of the site's moisture and nutrients. Lateral roots contained 66 to 75% of below-stump nutrients. Fine roots (<0.6 cm diameter) accounted for 11% of below-stump biomass, but contained 24 to 30% of below-stump nutrients. Nutrient content (kg•ha−1) of above-stump biomass ranked as follows: N 164.7, Ca 154.2, K 78.0, and P 14.0. Nitrogen was also the most abundant nutrient in below-stump biomass (60.2 kg•ha−1), followed by ...