Timothy J. Albaugh

Bio: Timothy J. Albaugh is an academic researcher from Virginia Tech. The author has contributed to research in topics: Pinus radiata & Biomass (ecology). The author has an hindex of 25, co-authored 79 publications receiving 2948 citations. Previous affiliations of Timothy J. Albaugh include North Carolina State University.

Leaf Area and Above- and Belowground Growth Responses of Loblolly Pine to Nutrient and Water Additions

Abstract: A 2 x 2 nutrient and water factorial experiment with four replications was installed in an 8-yr-old stand of Ioblolly pine (Pinus taeda L.) growing on an infertile, excessively drained sandy site in Scotland County, North Carolina. After the fourth year of treatment, estimated stem volume increment, total biomass production, and peak leaf area index (LAI) increased 152%, 99%, and 101%, respectively, with fertilization and 25%, 23%, 16%, respectively, with irrigation. Stem volume growth efficiency (growth per unit LAI) increased 21% with fertilization, 9% with irrigation, and 30% with both fertilization and irrigation. Total biomass production efficiency increased 91% with fertilization, 29% with irrigation, and 120% with both fertilization and irrigation. The observed increase in stem volume growth efficiency may have been due, in part,

Tree Nutrition and Forest Fertilization of Pine Plantations in the Southern United States

Abstract: The growth of many pine plantations in the southern United States is limited by soil nutrient availability. Therefore, forest fertilization is a common silvicultural practice throughout the South. Approximately 1.2 million ac of pine plantations were fertilized in 2004. In the last 10 years, considerable advances have been made in identifying the ecophysiological basis for stand growth and the response to fertilizer additions. Nitrogen (N) and phosphorus (P) are the nutrients that most commonly limit growth of southern pine. On wet clay soils in the lower Coastal Plain and on some well-drained soil in the upper Coastal Plain, severe P deficiencies exist. On these soils, P fertilization with 25–50 lb of P per acre at the time of planting produces a large and sustained growth response, on the order of 50 ft ac 1 yr 1 (1.5 tn ac 1 yr ) throughout the rotation. On most other soils in the South, chronic deficiencies of both N and P exist. On these sites, soil nutrient availability often is adequate early in the rotation when tree demand is small. However, around the time of crown closure, N and P frequently become limiting. Fertilization with both N and P in these intermediate aged stands typically increases growth for 8 –10 years. The growth response to a combination of 25 lb of P per acre plus 200 lb of N per acre averages around 55 ft ac 1 yr 1 (1.6 tn ac 1 yr ) for an 8-year period. The amount of leaf area in the stand is the main factor determining the current growth rate of the stand and the potential growth response after fertilization. When stand leaf area index is less than 3.5, light capture by the stand is restricted and growth is negatively affected. In many of these stands, fertilization will increase leaf area because of increased soil nutrient availability and thus increase growth. The financial return after fertilization depends on the growth response that occurs, the cost of the fertilizer treatment, and the stumpage value of the timber produced. Using a growth response of 55 ft ac 1 yr 1 over 8 years, a fertilizer cost of $90 ac , and stumpage values from the first quarter of 2006, the internal rate of return from midrotation fertilization of a loblolly pine plantation with N and P would be approximately 16%.

Below‐ground carbon input to soil is controlled by nutrient availability and fine root dynamics in loblolly pine

Abstract: Summary • Availability of growth limiting resources may alter root dynamics in forest ecosystems, possibly affecting the land–atmosphere exchange of carbon. This was evaluated for a commercially important southern timber species by installing a factorial experiment of fertilization and irrigation treatments in an 8-yr-old loblolly pine (Pinus taeda) plantation. • After 3 yr of growth, production and turnover of fine, coarse and mycorrhizal root length was observed using minirhizotrons, and compared with stem growth and foliage development. • Fertilization increased net production of fine roots and mycorrhizal roots, but did not affect coarse roots. Fine roots had average lifespans of 166 d, coarse roots 294 d and mycorrhizal roots 507 d. Foliage growth rate peaked in late spring and declined over the remainder of the growing season, whereas fine roots experienced multiple growth flushes in the spring, summer and fall. • We conclude that increased nutrient availability might increase carbon input to soils through enhanced fine root turnover. However, this will depend on the extent to which mycorrhizal root formation is affected, as these mycorrhizal roots have much longer average lifespans than fine and coarse roots.

Applying 3-PG, a simple process-based model designed to produce practical results, to data from loblolly pine experiments

Abstract: 3-PG is a simple process-based model that requires few parameter values and only readily available input data. We tested the structure of the model by calibrating it against loblolly pine data from the Control treatment of the SETRES experiment in Scotland County, NC, then altered the Fertility Rating to simulate the effects of fertilization. There was excellent correspondence between simulated values of stem mass and the values obtained from field measurements, and good correspondence between simulated and measured stem diameters and Leaf Area Index values. Growth efficiency values derived from the model were similar to those obtained from field data. We used the model, without further calibration, to predict tree growth in terms of stem diameter at SETRES 2, a genotype x environment interaction trial in the same locality. Simulated mean stem diameters of two provenances did not differ significantly, over 3 yr, from those observed in the Control (unfertilized) treatments, but rates of change were lower than those of fertilized provenances. We then used 3PG to simulate fertilized stand growth for an entire rotation length, and these results corresponded to those obtained with a traditional growth and yield model. This study showed that the model can simulate accurately the behavior and responses to environmental factors of loblolly pine and that it has considerable potential value as a management tool, for scenario analysis and as a research tool. FOR. SCI. 47(1):43-51.

The plastic plant: root responses to heterogeneous supplies of nutrients

Abstract: Contents I. Introduction 000 II. Morphological responses 000 III. Root demography 000 IV. Physiological plasticity 000 V. Root plasticity in patches in competition and symbiosis with microorganisms 000 VI. Influence of patch attributes 000 VII. Control of root proliferation 000 VIII. Conclusions 000 Acknowledgements 000 References 000 Summary When roots encounter a nutrient-rich zone or patch they often proliferate within it. Roots experiencing nutrient-rich patches can also enhance their physiological ion-uptake capacities compared with roots of the same plant outside the patch zone. These plastic responses by the root system have been proposed as the major mechanism by which plants cope with the naturally occurring heterogeneous supplies of nutrients in soil. Various attempts to predict how contrasting species will respond to patches have been made based on specific root length (SRL), root demography and biomass allocation within the patch zone. No one criterion has proved definitive. Actually demonstrating that root proliferation is beneficial to the plant, especially in terms of nitrogen capture from patches, has also proved troublesome. Yet by growing plants under more realistic conditions, such as in interspecific plant competition, and with a complex organic patch, a direct benefit can be demonstrated. Thus, as highlighted in this review, the environmental context in which the root response is expressed is as important as the magnitude of the response itself.

Plant and mycorrhizal regulation of rhizodeposition

Abstract: The loss of carbon from roots (rhizodeposition) and the consequent proliferation of microorganisms in the surrounding soil, coupled with the physical presence of a root and processes associated with nutrient uptake, gives rise to a unique zone of soil called the rhizosphere. In this review, we bring together evidence to show that roots can directly regulate most aspects of rhizosphere C flow either by regulating the exudation process itself or by directly regulating the recapture of exudates from soil. Root exudates have been hypothesized to be involved in the enhanced mobilization and acquisition of many nutrients from soil or the external detoxification of metals. With few exceptions, there is little mechanistic evidence from soil-based systems to support these propositions. We conclude that much more integrated work in realistic systems is required to quantify the functional significance of these processes in the field. We need to further unravel the complexities of the rhizosphere in order to fully engage with key scientific ideas such as the development of sustainable agricultural systems and the response of ecosystems to climate change. Contents I. Introduction 460 II. What is rhizodeposition? 460 III. Regulation of rhizodeposition 460 IV. How large is the root exudation C flux? 463 V. How responsive is the root exudation C flux? 463 VI. How responsive is the microbial community to root exudation? 464 VII. The role of root exudates in nutrient acquisition 464 VIII. Mycorrhizal fungi and rhizodeposition 471 IX. Future thoughts 474 Acknowledgements 474 References 474.

U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

Abstract: The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of “potential” biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable manner—enough to displace approximately 30% of the country’s present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available. In addition to updating the 2005 study, this report attempts to address a number of its shortcomings

Soil fertility limits carbon sequestration by forest ecosystems in a CO 2 -enriched atmosphere

Abstract: Northern mid-latitude forests are a large terrestrial carbon sink. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests. Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in particular nitrogen. Here we present evidence that estimates of increases in carbon sequestration of forests, which is expected to partially compensate for increasing CO2 in the atmosphere, are unduly optimistic. In two forest experiments on maturing pines exposed to elevated atmospheric CO2, the CO2-induced biomass carbon increment without added nutrients was undetectable at a nutritionally poor site, and the stimulation at a nutritionally moderate site was transient, stabilizing at a marginal gain after three years. However, a large synergistic gain from higher CO2 and nutrients was detected with nutrients added. This gain was even larger at the poor site (threefold higher than the expected additive effect) than at the moderate site (twofold higher). Thus, fertility can restrain the response of wood carbon sequestration to increased atmospheric CO2. Assessment of future carbon sequestration should consider the limitations imposed by soil fertility, as well as interactions with nitrogen deposition.

Inventory of U.S. Greenhouse Gas Emissions and Sinks

Abstract: This memorandum documents the updates implemented in EPA’s 2020 Inventory of U.S. Greenhouse Gas Emissions and Sinks (GHGI) for gathering and boosting (G&B) stations. Additional considerations for G&B were previously discussed in memoranda released November 2019 (Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2018: Updates Under Consideration for Natural Gas Gathering & Boosting Station Emissions),1 October 2018 (Inventory of U.S. GHG Emissions and Sinks 1990-2017: Updates Under Consideration for Natural Gas Gathering & Boosting Emissions),2 and April 2019 (Inventory of U.S. GHG Emissions and Sinks 1990-2017: Updates to Natural Gas Gathering & Boosting Pipeline Emissions).3