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Full-Text Articles in Life Sciences

Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan Aug 2015

Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan

Steven J. Hall

Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by the respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over 2 months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest). Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There …


Lignin Decomposition Is Sustained Under Fluctuating Redox Conditions In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel Jul 2015

Lignin Decomposition Is Sustained Under Fluctuating Redox Conditions In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel

Steven J. Hall

Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia is thought to suppress lignin decomposition, yet potential effects of oxygen (O2) variability in surface soils have not been explored. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical forest soils during ten-week laboratory incubations. We used synthetic lignins labeled with 13C in either of two positions (aromatic methoxyl or propyl side chain Cb) to provide highly sensitive and specific measures of lignin mineralization seldom employed in …


Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver Apr 2015

Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver

Steven J. Hall

It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised the …


Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González Nov 2014

Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González

Steven J. Hall

Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …


Breaking The Enzymatic Latch: Impacts Of Reducing Conditions On Hydrolytic Enzyme Activity In Tropical Forest Soils, Steven J. Hall, Jonathan Treffkorn, Whendee L. Silver Oct 2014

Breaking The Enzymatic Latch: Impacts Of Reducing Conditions On Hydrolytic Enzyme Activity In Tropical Forest Soils, Steven J. Hall, Jonathan Treffkorn, Whendee L. Silver

Steven J. Hall

The enzymatic latch hypothesis proposes that oxygen (O2) limitation promotes wetland carbon (C) storage by indirectly decreasing the activities of hydrolytic enzymes that decompose organic matter. Humid tropical forest soils are often characterized by low and fluctuating redox conditions and harbor a large pool of organic matter, yet they also have the fastest decomposition rates globally. We tested the enzymatic latch hypothesis across a soil O2 gradient in the Luquillo Experimental Forest, Puerto Rico, USA. Enzyme activities expressed on a soil mass basis did not systematically decline across a landscape O2 gradient, nor did phenolics accumulate, the proposed mechanism of …


Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver Jul 2013

Iron Oxidation Stimulates Organic Matter Decomposition In Humid Tropical Forest Soils, Steven J. Hall, Whendee L. Silver

Steven J. Hall

Humid tropical forests have the fastest rates of organic matter decomposition globally, which often coincide with fluctuating oxygen (O2) availability in surface soils. Microbial iron (Fe) reduction generates reduced iron [Fe(II)] under anaerobic conditions, which oxidizes to Fe(III) under subsequent aerobic conditions. We demonstrate that Fe (II) oxidation stimulates organic matter decomposition via two mechanisms: (i) organic matter oxidation, likely driven by reactive oxygen species; and (ii) increased dissolved organic carbon (DOC) availability, likely driven by acidification. Phenol oxidative activity increased linearly with Fe(II) concentrations (P < 0.0001, pseudo R2 = 0.79) in soils sampled within and among five tropical forest sites. A similar pattern occurred in the absence of soil, suggesting an abiotic driver of this reaction. No phenol oxidative activity occurred in soils under anaerobic conditions, implying the importance of oxidants such as O2 or hydrogen peroxide (H2O2) in addition to Fe(II). Reactions between Fe(II) and H2O2 generate hydroxyl radical, a strong nonselective oxidant of organic compounds. We found increasing consumption of H2O2 as soil Fe(II) concentrations increased, suggesting that reactive oxygen species produced by Fe(II) oxidation explained variation in phenol oxidative activity among samples. Amending soils with Fe(II) at field concentrations stimulated short-term C mineralization by up to 270%, likely via a second mechanism. Oxidation of Fe(II) drove a decrease in pH and a monotonic increase in DOC; a decline of two pH units doubled DOC, likely stimulating microbial respiration. We obtained similar results by manipulating soil acidity independently of Fe(II), implying that Fe(II) oxidation affected C substrate availability via pH fluctuations, in addition to producing reactive oxygen species. Iron oxidation coupled to organic matter decomposition contributes to rapid rates of C cycling across humid tropical forests in spite of periodic O2 limitation, and may help explain the rapid turnover of complex C molecules in these soils.


When Wet Gets Wetter: Decoupling Of Moisture, Redox Biogeochemistry, And Greenhouse Gas Fluxes In A Humid Tropical Forest Soil, Steven J. Hall, William H. Mcdowell, Whendee L. Silver Jan 2013

When Wet Gets Wetter: Decoupling Of Moisture, Redox Biogeochemistry, And Greenhouse Gas Fluxes In A Humid Tropical Forest Soil, Steven J. Hall, William H. Mcdowell, Whendee L. Silver

Steven J. Hall

Upland humid tropical forest soils are often characterized by fluctuating redox dynamics that vary temporally and spatially across the landscape. An increase in the frequency and intensity of rainfall events with climate change is likely to affect soil redox reactions that control the production and emissions of greenhouse gases. We used a 24-day rainfall manipulation experiment to evaluate temporal and spatial trends of surface soil (0–20 cm) redox-active chemical species and greenhouse gas fluxes in the Luquillo Experimental Forest, Puerto Rico. Treatments consisted of a high rainfall simulation (60 mm day-1), a fluctuating rainfall regime, and a control. Water addition …


Cultural Disturbances And Local Ecological Knowledge Mediate Cattail (Typha Domingensis) Invasion In Lake Pátzcuaro, México, Steven J. Hall Apr 2009

Cultural Disturbances And Local Ecological Knowledge Mediate Cattail (Typha Domingensis) Invasion In Lake Pátzcuaro, México, Steven J. Hall

Steven J. Hall

The influence of local actors and socioeconomic constraints on biological invasions is often ignored. Wetland plant harvesters appeared to intentionally influence cattail (Typha domingensis) invasion around Lake Pátzcuaro, México, by altering their harvesting regimes, according to interviews with 44 expert respondents and botanical surveys. The oldest and most experienced harvesters reported controlling Typha initially, sometimes through organized eradication efforts, in order to protect Schoenoplectus californicus, an economically and culturally valuable wetland plant. Later, outsiders commoditized Typha by introducing new weaving designs popular with tourists, while industrial products and new livelihood activities reduced Schoenoplectus harvest. Harvesters from several communities began to …


Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff Jan 2005

Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff

Lisa A. Schulte Moore

Within the northern Great Lakes region, mesoscale (10s to 100s of km2) forest patterning is driven by disturbance dynamics. Using original Public Land Survey (PLS) records in northern Wisconsin, USA, we study spatial patterns of wind and fire disturbances during the pre-Euroamerican settlement period (ca. 1850). Our goals were: (1) to determine how effectively wind and fire disturbance can be econstructed from the PLS, (2) to assess the roles of wind and fire in shaping vegetation patterns, (3) to evaluate landscape to regional controls of wind and fire regimes, and (4) to assess the potential for interactions between these disturbances. …


Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland Jan 2003

Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland

Lisa A. Schulte Moore

The rates and magnitudes of forest change have important social and economic implications. We address facets of change associated with 20th century recovery of the U.S. Lake States (Michigan, Wisconsin, and Minnesota) forests from the Great Cutover, and discuss ecological and socioeconomic implications for future forest resources.


Narrowing Historical Uncertainty: Probabilistic Classification Of Ambiguously Identified Tree Species In Historical Forest Survey Data, David J. Mladenoff, Sally E. Dahir, Eric V. Nordheim, Lisa A. Schulte, Glenn G. Guntenspergen Jan 2002

Narrowing Historical Uncertainty: Probabilistic Classification Of Ambiguously Identified Tree Species In Historical Forest Survey Data, David J. Mladenoff, Sally E. Dahir, Eric V. Nordheim, Lisa A. Schulte, Glenn G. Guntenspergen

Lisa A. Schulte Moore

Historical data have increasingly become appreciated for insight into the past conditions of ecosystems. Uses of such data include assessing the extent of ecosystem change; deriving ecological baselines for management, restoration, and modeling; and assessing the importance of past conditions on the composition and function of current systems. One historical data set of this type is the Public Land Survey (PLS) of the United States General Land Office, which contains data on multiple tree species, sizes, and distances recorded at each survey point, located at half-mile (0.8-km) intervals on a 1-mi (1.6 km) grid. This survey method was begun in …


A Buried Spruce Forest Provides Evidence At The Stand And Landscape Scale For The Effects Of Environment On Vegetation At The Pleistocene/Holocene Boundary, Douglas D. Stokke Feb 2000

A Buried Spruce Forest Provides Evidence At The Stand And Landscape Scale For The Effects Of Environment On Vegetation At The Pleistocene/Holocene Boundary, Douglas D. Stokke

Douglas D. Stokke

Due to a unique set of circumstances, we were able to excavate an entire spruce (Picea) forest in Michigan's Upper Peninsula, USA, which was buried in the early Holocene (9928 ± 133 uncalibrated 14C years bp). Trees ranged from < 5 cm to > 50 cm in diameter, and dominants were approximately 9 m tall. The stand was multi-aged, with a maximum tree age of 145 years. Well-preserved stem cross-sections (n = 140) were recovered and the entire stand was mapped. Stand reconstruction combined with pollen and sediment analysis revealed a pure spruce forest in the sandy lowlands surrounded by hills dominated by pine, oak …


Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov Jan 2000

Effects Of Resource Availability On Carbon Allocation And Developmental Instability In Cloned Birch Seedlings, Brian J. Wilsey, Janne H. Lappalainen, Jocelyn Martel, Kyösti Lempa, Vladimir Ossipov

Brian J. Wilsey

Abundant nitrogen improves seedling growth and establishment. Vigorous growth brings about changes in rates and patterns of plant development and changes in the relationship between primary and secondary metabolism, which may make seedlings more susceptible to herbivores and pathogens than are slow-growing seedlings. We studied how nitrogen fertilization and manual defoliation of source leaves affect growth, carbon allocation, and developmental instability in cloned seedlings of white birch (Betula pubescens Ehrh.). Biomass was higher, whereas concentrations of most classes of phenolic compounds were lower in the nitrogen-rich environment. Interestingly, fertilization did not change the concentrations of cell wall–bound proanthocyanidins, which represent …


Leaf Fluctuating Assymetry Increases With Hybridization And Elevation In Tree-Line Birches, Brian J. Wilsey, Erkki Haukioja, Julia Koricheva, Matti Sulkinoja Jan 1998

Leaf Fluctuating Assymetry Increases With Hybridization And Elevation In Tree-Line Birches, Brian J. Wilsey, Erkki Haukioja, Julia Koricheva, Matti Sulkinoja

Brian J. Wilsey

Fluctuating asymmetry (FA), or random non-directional deviations from perfect symmetry in bilaterally or radially symmetrical traits, has recently been proposed to be a useful indicator of genetic and environmental stress. However, the factors underlying fluctuating asymmetry, especially in plants, remain poorly understood. We sampled leaf fluctuating asymmetry among and within three species of even-aged birch (Betula pubescens, B. nana, and B. pendula) and their interspecific hybrids growing in common gardens of northern Finland to determine whether hybridization and environmental stress are associated with increased developmental instability. Our predictions were that: (1) interspecific hybrids among B. pubescens, B. nana, and B. …


Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek Jan 1997

Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek

Douglas D. Stokke

Many walnut plantation owners and woodworking hobbyists would like to process small quantities of walnut logs into lumber and discs for furniture and craft items. Various options exist for sawing, drying, and processing small diameter or short logs into lumber and cross-sectional discs. Portable band saws are a safe and inexpensive log breakdown option to commercial headsaw mills. Processing using the saw-dry-rip method will yield higher quantities of usable lumber from small diameter logs than the conventional saw-rip-dry method. Small quantities of lumber and discs can be inexpensively air dried under shelters or open sheds followed by approximately 15 to …


The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps Jan 1997

The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps

Douglas D. Stokke

The known effects of silvicultural practices on eastern black walnut (Juglans nigra L.) wood quality are reviewed. Since desirable quality differs from end user to end user, no specific recommendations are made.


Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan Jan 1997

Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan

Douglas D. Stokke

Risks and uncertainties are prevalent in timber production due to the nature and length of the production process. This paper examines the volatility of timber prices and the effects of some economic uncertainties and risks such as fluctuations in timber prices and the interest rate on the economic returns of black walnut and red oak plantations. Historical patterns of timber prices for black walnut and oaks are investigated and compared with those of other timber species and stock price. The sensitivity of economic returns from black walnut and red oak plantations to changes in timber prices and the discount rate …


Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr. Jan 1997

Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr.

Douglas D. Stokke

Walnut veneer frorn sites in Missouri, Illinois, and Indiana was analyzed for color attributes and chemical properties. Veneer color also was compared to an industry color standard. Soil chemical and physical properties were measured on selected sites in each state. In general, walnut trees grown on soils with equal proportions of sand, silt, and clay have better veneer color attributes than trees grown on soils with high clay I sand or clay I silt ratios.


Variation In Cell Dimensions And Fibril Angle For Two Fertilized Even-Aged Loblolly Pine Plantations, Douglas D. Stokke, Todd F. Shupe, Elvin T. Choong, Mark D. Gibson Jan 1996

Variation In Cell Dimensions And Fibril Angle For Two Fertilized Even-Aged Loblolly Pine Plantations, Douglas D. Stokke, Todd F. Shupe, Elvin T. Choong, Mark D. Gibson

Douglas D. Stokke

Increment core samples were obtained from randomly selected, nine-year-old lohlolly pine (Pinus faeda L.) in two even-aged plantations in Louisiana in order to determine the variation in cell dimensions and fibril angle of the sites. The Homer site is representative of the growing conditions in north Louisiana, and the Bogalusa site is typical of the conditions in southeastern Louisiana. Both sites were subjected to similar site preparation and weed control and were fertilized in the juvenile period. The anatomical properties that were measured include: fiber length, cell-wall thickness, and microfibril angle (MFA). Observations were made in order to compare corewood …


Presettlement Vegetation Of The Lower Chippewa River Valley, Lisa A. Schulte-Moore, William J. Barnes Jan 1996

Presettlement Vegetation Of The Lower Chippewa River Valley, Lisa A. Schulte-Moore, William J. Barnes

Lisa A. Schulte Moore

The lower Chippewa River of west-central Wisconsin is the portion that flows southwest from the city of Eau Claire to the Mississippi River at Nelson. The river has a gentle gradient of about 0.8 m/km and highly erodible banks of sand and gravel. The river valley occurs between 35 m to 70 m below the surrounding upland, is between 1 and 5 km wide, and was formed primarily by glacial meltwaters. The floodplain is defined by annual high water levels and is generally below the 25 year flood recurrence interval, which on this part of the Chippewa River is >5m …


Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps Oct 1995

Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps

Douglas D. Stokke

The objectives of this research were to generate a set of sample parameters for the lightness of planed white oak dimension stock, to investigate the effect of grain angle on lightness values, and to determine the level of sampling needed to color match white oak dimension stock on the basis of lightness or darkness as quantified by the parameter L* (psychometric lightness). This information is important when used to determine the feasibility of low-cost portable instruments for evaluating color in an edge-glued hardwood panel production setting. Color measurements were obtained with a portable spectrophotometer interfaced with a notebook computer. The …


Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg Jan 1994

Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg

Douglas D. Stokke

Birdseye grain distortions in sugar maple must be identified to capture the full value of a timber sale throughout the economic range of birdseye's occurrence. Even when relatively common, birdseye veneer typically makes up less than 1 percent of the harvested volume, but may account for one-half of the value of the sale. With prices recently reaching $50,000 per Mbf for prime logs, omission of birdseye (when present) from cruise data could cause significant economic loss for the forest landowner. But figured wood can sometimes be detected in standing timber (Pillow 1955). Field identification of birdseye sugar maple is critical …


Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke Jan 1992

Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke

Douglas D. Stokke

Wood is a major industrial raw material, with U.S. consumption approaching that of aluminum, plastics, cement, and steel combined. Partially as a result of the magnitude of wood and wood products in use, these products constitute a substantial portion of the solid waste stream. In order to reduce the amount of wood and wood fiber disposed in landfills, efforts to recycle these materials into useful products such as structural composites are needed. The success of such conversion depends in part on knowledge of the morphological characteristics of various sources of secondary wood and wood fibers, and the influence of wood …


Lignin Distribution In Thermomechanically Pulped Wood Fibers Via X-Ray Microanalysis, Douglas Stokke, Xuerong Wang Jan 1991

Lignin Distribution In Thermomechanically Pulped Wood Fibers Via X-Ray Microanalysis, Douglas Stokke, Xuerong Wang

Douglas D. Stokke

The three major framework organic constituents of the secondary xylem (wood) of trees are cellulose, hemicelluloses, and lignin. Lignin imparts a number of important physical properties to the woody cell wall. In addition, lignin serves as the "cement" which binds cells together, and is the material which must be softened, altered, or removed during pulping processes. The distribution of lignin within pulp cell walls is of importance with respect to use of the pulp fibers. In this study, x-ray analysis was used to investigate lignin distribution in thermomechanically pulped (i.e., pulped with heat and pressure, with no chemical treatment) aspen …


Sem Views Of Oak Wood, Douglas D. Stokke Jan 1986

Sem Views Of Oak Wood, Douglas D. Stokke

Douglas D. Stokke

The anatomical structure of the secondary xylem (wood) of trees varies with location in the tree. The size, shape, and distribution of cell types varies not only between locations (i.e., stem vs. branch vs. root), but also within an annual ring or across annual rings at a given cross-sectional plane.


Effects Of Three Vesicular-Arbuscular Mycorrhizal Fungi On Sweetgum Seedlings From Nine Mother Trees, Richard C. Schultz, Paul P. Kormanik, William C. Bryan Jun 1981

Effects Of Three Vesicular-Arbuscular Mycorrhizal Fungi On Sweetgum Seedlings From Nine Mother Trees, Richard C. Schultz, Paul P. Kormanik, William C. Bryan

Richard C. Schultz

Soil in microplots was infested with three vesicular-arbuscular (VA) symbionts then sown with seed of half-sib progeny from nine sweetgum mother trees. The VA treatments were Glomus fasciculatus, Glomus spp. (a mixture containing both Glomus mosseae and Glomus etunicatus), or a VA mixture of several fungi from the genera Glomus and Gigaspora. Before the seed was sown, all plots had calcium standardized and received an application of commercial fertilizer. During the growing season, NH4NO3 was applied to all plots in equal portions. Mycorrhizal seedlings with G. fasciculatus were slightly but not significantly larger in both height and root-collar diameter than …


Vesicular-Arbuscular Mycorrhiza Influence Growth But Not Mineral Concentrations In Seedlings Of Eight Sweetgum Families, Richard C. Schultz, Paul P. Kormanik, W. Craig Bryan, G. H. Brister Jun 1979

Vesicular-Arbuscular Mycorrhiza Influence Growth But Not Mineral Concentrations In Seedlings Of Eight Sweetgum Families, Richard C. Schultz, Paul P. Kormanik, W. Craig Bryan, G. H. Brister

Richard C. Schultz

Seedlings of eight half-sib sweetgum (Liquidambar styraciflua L.) families were grown for 6 months in a fumigated soil mixture, with or without inoculum from a mixture of Glomus mosseae and Glomus etunicatus fungi, at levels of 140, 280, 560, and 1120 kg/ha of 10-10-10 fertilizer. All seedlings received three additions of 187 kg/ha of N during the growing season. Inoculated seedlings had significantly greater biomass, height, and stem diameters at each fertilizer level than nonmycorrhizal control seedlings. Significant differences in growth occurred between families in mycorrhizal plants. However, fertilizer did not significantly affect growth or nutrient uptake of the seedlings. …


Influence Of Endomycorrhizae On Growth Of Sweetgum Seedlings From Eight Mother Trees, Richard C. Schultz, Paul P. Kormanik, William C. Bryan Dec 1977

Influence Of Endomycorrhizae On Growth Of Sweetgum Seedlings From Eight Mother Trees, Richard C. Schultz, Paul P. Kormanik, William C. Bryan

Richard C. Schultz

Sweetgum seedlings from eight mother trees were grown in fumigated soil with or without the endomycorrhizal fungus Glomus mosseae at four levels of soil fertility for one growing season in nursery microplots. Nonmycorrhizal seedlings of all families died or failed to exceed 5 cm in height regardless of soil fertility. Endomycorrhizal seedlings suffered little mortality, averaged about 36 cm in height, and fertility level did not significantly influence their biomass. These results demonstrate that to increase the percentage of plantable seedlings in nurseries sweetgum seedlings must be endomycorrhizal. The data further suggests that adequate endomycorrhizal inoculum in nursery beds can …