SP009
Role of vegetation and coarse wood debris on soil processes and mycorrhizal mat distribution patterns at the Hi-15, Andrews Experimental Forest, 1994-1995

CREATOR(S): Robert P. Griffiths

PRINCIPAL INVESTIGATOR(S): Robert P. Griffiths

ORIGINATOR(S): Robert P. Griffiths

DATA SET CONTACT PERSON: Robert P. Griffiths

ABSTRACTOR: Robert P. Griffiths

METADATA CREATION DATE:

24 Feb 2001

MOST RECENT METADATA REVIEW DATE:

15 Jan 2014

KEYWORDS:

Inorganic nutrients, Organic matter, Long-Term Ecological Research (LTER), biological processes, inorganic nutrients, organic matter, ecosystems, mycorrhizae, ecosystem processes

PURPOSE:

We have long been interested in determining the extent to which plants and coarse woody debris (CWD) influenced forest soils. It has been speculated that plants impart changes in soils that effectively increase the resiliency of a stand to disturbance; this idea has been formalized in the concept of forest legacies (Perry et al., 1989). We have also been interested in factors influencing the distribution of ectomycorrhizal fungi. Earlier studies on 2 x 10 m plots showed not relationship between the distribution of rocks, trees and CWD and mat distribution patterns on the scale of a few meters. We wanted to determine if relationships between these features and mat distribution patterns could be detected at a larger scale. In this study we jumped from a 1 to at 5 m resolution. At this scale, the effects of large groupings of understory vegetation and large assemblages of CWD on mat distribution could be assessed. It also provided another opportunity to look at the role mats play in soil biogeochemical processes, supporting earlier studies (Griffiths et al., 1990, 91, 92; Aquiera and Griffiths, 1993).

METHODS:

Experimental Design - SP009:

Description:

The objective was to determine if there were relationships between forest floor attributes; individual trees, clusters of undergrowth vegetation, coarse woody debris, rocks and topography influenced soil characteristics and the distribution patterns of ectomycorrhizal fungi. All forest floor features were mapped within a 25 x 260 m plot and digitized into GIS data layers. A sample grid was established within this plot with 4, 250 m parallel transects separated by 5 m. Samples were taken every 5 m along these transects to form a sampling grid with nodes every 5 m. The data contained within this dataset are the measurements made at those nodes.

Field Methods - SP009:

Description: In the field, sketches were made of the location of individual trees, clusters of undergrowth vegetation, coarse woody debris, rocks and topography within a 25 x 260 m plot. These sketches were digitized using ArcInfo®. At each of the grid nodes, a 4.7 x 10 cm soil core was taken for subsequent analysis. The samples were transported to the laboratory in an ice chest and subsequently stored at 15°C until the initiation of analyses, usually within 16 h of their receipt. The following measurements were made in the field: litter depth, mineral soil respiration, soil temperature, and the presence of ectomycorrhizal mats in the cores. At each sample location (grid node) the presence or absence of moss, rocks and woody debris was also noted. Field (forest floor) respiration rates were measured with a nondispersive, infrared CO₂ analyzer (Li-Cor®, LI-6200). Measurements were made over a period of 1 min after the chamber gas reached ambient CO₂ concentration. The instrument was calibrated on site against a known standard at each location. A Q10 adjustment was made for ambient soil temperature. Soil temperature was measured by electronic thermometers calibrated at 0°C with ice water. The temperature probes were inserted into the mineral soil to a depth of 10 cm.

Laboratory Methods - SP009 :

Description:

In preparation for laboratory analyses, all soils were sieved through a 2-mm sieve. Soil moisture was determined by drying duplicate 10 g field-moist sieved soils at 100 C for at least 8 h. The percent soil moisture was calculated by dividing the difference between wet and dry samples and dividing that number by the dry wt., which was then multiplied by 100. Soil organic matter was measured by loss-on-ignition at 550°C for 6 h after oven drying at 100°C.

Extractable ammonium was determined by shaking 10 g of field-moist soil with 50 mL 2 M KCl for 1 h (Keeney and Nelson 1982), adding 0.3 mL 10 M NaOH to the slurry, and measuring ammonium concentration with an Orion model 95-12 ammonium electrode (Orion Research Inc., Boston, MA). Mineralizable N was measured by the water-logged technique of Keeney and Bremner (1966). For each analysis, 10 g of field-moist soil were added to 53 mL of distilled water in a 20 x 125 mm screw-cap test tube, and incubated at 40°C for 7 d. Then 53 mL of 4 M KCl were added to the slurry, and ammonium concentration was determined with the ammonium electrode. Mineralizable N was calculated as the difference between initial and final ammonium concentrations.

SUPPLEMENTAL INFORMATION:

Alan Swanson, Amy Chadwick, Merrilee Robatzek, and Krista Schauer conducted the research. Jennifer Simmons digitized field sketches forest floor attributes using ArcInfo®. The National Science Foundation provided financial support from grants BSR-8717849, BSR-9011663, BSR-9106784, BIO-9200809, and DEB-9318502 from the Long-Term Ecological Research program.

SITE DESCRIPTION:

Sample plot located at REU synoptic site #130: longitude = 122° 10.247' N; latitude = 44° 15.939' W. Site 200 meters south of the terminus of USFS road #327. Andrews Experimental Forest

TAXONOMIC SYSTEM:

None

GEOGRAPHIC EXTENT:

Andrews Experimental Forest near High 15 site

MEASUREMENT FREQUENCY:

once only

PROGRESS DESCRIPTION:

Complete

UPDATE FREQUENCY DESCRIPTION:

notPlanned

CURRENTNESS REFERENCE:

Ground condition

RELATED MATERIAL:

Additional References:

Keeney, D.R., and Bremner, J.M. 1966. Comparison and evaluation of laboratory methods of obtaining an index of soil nitrogen availability. Agronomical Journal 58, 498–503.

Keeney, D.R., and Nelson, D.W. 1982. Nitrogen—inorganic forms. In Methods of soil analysis. Edited by A.L. Page, R.H. Miller, and D.R. Keeney. American Society of Agronomy, Madison, Wis. pp. 643–698.