The response of coarse root biomass to long-term CO enrichment and nitrogen application in a maturing Pinus taeda stand with a large broadleaved component.

Elevated atmospheric CO (eCO ) typically increases aboveground growth in both growth chamber and free-air carbon enrichment (FACE) studies. Here we report on the impacts of eCO and nitrogen amendment on coarse root biomass and net primary productivity (NPP) at the Duke FACE study, where half of the eight plots in a 30-year-old loblolly pine (Pinus taeda, L.) plantation, including competing naturally regenerated broadleaved species, were subjected to eCO (ambient, aCO plus 200 ppm) for 15-17 years, combined with annual nitrogen amendments (11.

Biomass increases attributed to both faster tree growth and altered allometric relationships under long-term carbon dioxide enrichment at a temperate forest.

Increases in atmospheric carbon dioxide (CO ) concentrations are expected to lead to increases in the rate of tree biomass accumulation, at least temporarily. On the one hand, trees may simply grow faster under higher CO concentrations, preserving the allometric relations that prevailed under lower CO concentrations. Alternatively, the allometric relations themselves may change.

Dynamics of soil CO efflux under varying atmospheric CO concentrations reveal dominance of slow processes.

We evaluated the effect on soil CO efflux (F ) of sudden changes in photosynthetic rates by altering CO concentration in plots subjected to +200 ppmv for 15 years. Five-day intervals of exposure to elevated CO (eCO ) ranging 1.0-1.

Identification of a Pheromone Component and a Critical Synergist for the Invasive Beetle Callidiellum rufipenne (Coleoptera: Cerambycidae).

The invasive Asian cerambycid beetle Callidiellum rufipenne (Motschulsky), informally known as the Japanese cedar longhorned beetle, was first detected in North America in North Carolina in 1997. The beetle has since been detected in neighboring states and is expected to further expand its range. However, delineating the current distribution of C.

On the complementary relationship between marginal nitrogen and water-use efficiencies among Pinus taeda leaves grown under ambient and CO2-enriched environments.

Background And Aims: Water and nitrogen (N) are two limiting resources for biomass production of terrestrial vegetation. Water losses in transpiration (E) can be decreased by reducing leaf stomatal conductance (g(s)) at the expense of lowering CO(2) uptake (A), resulting in increased water-use efficiency. However, with more N available, higher allocation of N to photosynthetic proteins improves A so that N-use efficiency is reduced when g(s) declines.

Soil incorporation of logging residue affects fine-root and mycorrhizal root-tip dynamics of young loblolly pine clones.

Loblolly pine (Pinus taeda L.) plantations cover a large geographic area of the southeastern USA and supply a large proportion of the nation's wood products. Research on management strategies designed to maximize wood production while also optimizing nutrient use efficiency and soil C sequestration is needed.

Relationships between stem CO(2) efflux, substrate supply, and growth in young loblolly pine trees.

*We examined the relationships between stem CO(2) efflux (E(s)), diameter growth, and nonstructural carbohydrate concentration in loblolly pine trees. Carbohydrate supply was altered via stem girdling during rapid stem growth in the spring and after growth had ceased in the autumn. We hypothesized that substrate type and availability control the seasonal variation and temperature sensitivity of E(s).

Pinus taeda clones and soil nutrient availability: effects of soil organic matter incorporation and fertilization on biomass partitioning and leaf physiology.

The combined effects of intensive management and planting of improved seedlings have led to large increases in productivity on intensively managed pine forests in the southeastern United States. To best match clones to particular site conditions, an understanding of how specific clones respond to changes in nutrition in terms of biomass partitioning, leaf physiology and biochemistry will be necessary. This study measured the response of biomass partitioning, light-saturated net photosynthesis (A(Sat)) and photosynthetic capacity to a range in soil fertility and fertilization between two contrasting Pinus taeda L.

Acclimation of leaf hydraulic conductance and stomatal conductance of Pinus taeda (loblolly pine) to long-term growth in elevated CO(2) (free-air CO(2) enrichment) and N-fertilization.

We investigated how leaf hydraulic conductance (K(leaf)) of loblolly pine trees is influenced by soil nitrogen amendment (N) in stands subjected to ambient or elevated CO(2) concentrations (CO(2)(a) and CO(2)(e), respectively). We also examined how K(leaf) varies with changes in reference leaf water potential (Psi(leaf-ref)) and stomatal conductance (g(s-ref)) calculated at vapour pressure deficit, D of 1 kPa. We detected significant reductions in K(leaf) caused by N and CO(2)(e), but neither treatment affected pre-dawn or midday Psi(leaf).

Emergence, trapping, and seasonal abundance of adult Cerambycidae (Coleoptera) associated with Cupressaceae in Connecticut.

Emergence, attraction to traps, and seasonal abundance of cerambycids (Coleoptera) whose larvae injure Cupressaceae were studied under natural conditions in southern Connecticut between 1999 and 2005. Adults of the Asian cerambycid Callidiellum rufipenne (Motschulsky) emerged from trunk sections of Thuja occidentalis L. between late March and mid-May.

Short-term effects of fertilization on photosynthesis and leaf morphology of field-grown loblolly pine following long-term exposure to elevated CO(2) concentration.

We examined effects of a first nitrogen (N) fertilizer application on upper-canopy needle morphology and gas exchange in approximately 20-m-tall loblolly pine (Pinus taeda L.) exposed to elevated carbon dioxide concentration ([CO(2)]) for 9 years. Duke Forest free-air CO(2) enrichment (FACE) plots were split and half of each ring fertilized with 112 kg ha(-1) elemental N applied in two applications in March and April 2005.

Distribution and hosts of Callidiellum rufipenne (Coleoptera: Cerambycidae), an asian cedar borer established in the eastern United States.

The distribution and hosts of the exotic cedar-boring beetle, Callidiellum rufipenne (Motschulsky) (Coleoptera: Cerambycidae), were determined in five northeastern U.S. states by capturing adults on cedar trap logs and by rearing adults from various conifers.

Physiological girdling of pine trees via phloem chilling: proof of concept.

Quantifying below-ground carbon (C) allocation is particularly difficult as methods usually disturb the root-mycorrhizal-soil continuum. We reduced C allocation below ground of loblolly pine trees by: (1) physically girdling trees and (2) physiologically girdling pine trees by chilling the phloem. Chilling reduced cambium temperatures by approximately 18 degrees C.

Relationship between stem CO2 efflux, stem sap velocity and xylem CO2 concentration in young loblolly pine trees.

We measured diel patterns of stem surface CO2 efflux (Es, micromol m(-2) s(-1)), sap velocity (vs, mm s(-1)) and xylem CO2 concentration ([CO2]) (Xs, %) in 8-year-old loblolly pine trees during the spring to determine how vs and Xs influence Es. All trees showed a strong diel hysteresis between Es and stem temperature, where at a given temperature, Es was lower during the day than at night. Diel variations in temperature-independent Es were correlated with vs (R2= 0.

Selfing results in inbreeding depression of growth but not of gas exchange of surviving adult black spruce trees.

In most tree species, inbreeding greatly reduces seed production, seed viability, survival and growth. In a previous large-scale quantitative analysis of a black spruce (Picea mariana (Mill.) B.

Branch growth and gas exchange in 13-year-old loblolly pine (Pinus taeda) trees in response to elevated carbon dioxide concentration and fertilization.

We used whole-tree, open-top chambers to expose 13-year-old loblolly pine (Pinus taeda L.) trees, growing in soil with high or low nutrient availability, to either ambient or elevated (ambient + 200 micromol mol-1) carbon dioxide concentration ([CO2]) for 28 months. Branch growth and morphology, foliar chemistry and gas exchange characteristics were measured periodically in the upper, middle and lower crown during the 2 years of exposure.