Whole-tree biomass and carbon allocation of juvenile trees of loblolly pine (Pinustaeda): influence of genetics and fertilization

Abstract

To assess the contribution of belowground biomass allocation towards total carbon (C) allocation of two provenances of loblolly pine (Pinus taeda L.), we examined the total biomass allocation of a fast- and slow-growing family from each provenance. Since planting on a xeric, infertile site in Scotland County, N.C., U.S.A., trees in this study have been subjected to one of two nutrient treatments: optimal nutrition or control (no fertilization). Total biomass of 24 (1 tree/family plot × 2 families × 2 provenances × 2 treatments × 3 blocks) 5-year-old (juvenile) trees was harvested in January 1998. Fertilization increased total root, total shoot, and total tree biomass in all families as compared with harvested trees in control plots. Fertilization also increased biomass of coarse-root, woody-root, taproot, stem, branch, and foliar components of families as compared with trees in control plots. Although there were treatment and family differences in standing-crop biomass of the total root, total shoot, total tree, and various individual root and shoot components, the percent biomass (whole-tree) allocation to these tissues remained similar across treatments. Total nonstructural carbohydrate (TNC) analysis indicated some treatment, family, and provenance differences in TNC concentrations and partitioning to starch and soluble sugars. At the time of harvest, TNC concentrations of belowground tissues were much higher than those of aboveground tissues, and enhanced partitioning towards starch in root tissues indicates an important C storage role for belowground tissues at this time. Indeed, more than 90% of the trees starch content was present in root tissue in January. Although constrained by a sample size of three harvested trees per family, this study suggests that biomass allocation on a whole-tree level was similar between fast- and slow-growing families of different provenances of juvenile loblolly pine and was not affected by fertilizer treatment.

Biomass Estimates of Small Diameter Planted and Natural-Origin Loblolly Pines Show Major Departures from the National Biomass Estimator Equations

“…In addition, their greater ages made it more likely that they experienced crown damage from weather events (e.g., ice or wind storms) that periodically affect the study area, although saplings with obvious impacts were excluded from sampling. Similar to other studies (e.g., Retzlaff et al 2001), our data found loblolly pine taproots to contribute approximately 15% of the total biomass. The effects of stem origin on taproot biomass emerged for stems greater than 8 cm dbh (Figure 3).…”

“…The additional biomass in taproots of natural-origin stems may have implications for carbon storage. Taproots, which represent the largest root fraction (Retzlaff et al 2001), are slow to decay Kapeluck 1995, Ludovici et al 2002). Increasing management of natural forests to decrease rotation lengths will increase carbon stocks sequestered in taproot biomass .…”

Irrigation and Fertilization Effects on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Damage Levels and Pupal Weight in an Intensively-Managed Pine Plantation2

“…Contrast comparisons showed that fertilization significantly increased diameter, height, and volume after year one, but only height and volume after year two (Table 2). These results are in agreement with other studies examining the effects of fertilization on P. faeda growth in the Southeast (Samuelson 1998, Jokela and Martin 2000, Retzlaff et al 2001, Yin and Sedjo 2001. Irrigation and fertilization, in addition to weed control, significantly increased tree height and volume after each of the first three growing seasons in the Georgia Coastal Plain (Nowak and Berisford 2000).…”

“…Particularly susceptible is loblolly pine, Pinus faeda L., the most commercially important tree species in the southeastern U.S. (Schultz Intensively-managed forest plantations now occupy over 14 million ha of timberland in the southeastern U.S. (Guldin and Wigley 1998). Large gains in P. faeda productivity can be achieved with intensive forest management practices such as herbaceous weed control, irrigation and fertilization (Pritchett and Smith 1972, Jokela and Martin 2000, Nowak and Berisford 2000, Borders and Bailey 2001, Retzlaff et al 2001. However, intensive management has, at times, resulted in an increased frequency and severity of pest infestations (Cade andHedden 1987, Ross et al 1990).…”

Loblolly Pine Growth Patterns on Reclaimed Mineland: Allometry, Biomass, and Volume

“…The ratio of belowground to aboveground biomass is one commonly studied allometric relationship. Most studies have found the root-shoot ratio in loblolly is highly ontogenetic, especially for long-term data on different resource gradients [24][25][26]. Coyle, et al [25] has provided a composite of the literature concerning loblolly root-shoot allometry.…”