TD018
Nitrogen fixation and respiration potential of conifer logs at Andrews Experimental Forest, 1987 to 2006

CREATOR(S): Mark E. Harmon

PRINCIPAL INVESTIGATOR(S): Mark E. Harmon

ORIGINATOR(S): Mark E. Harmon

OTHER RESEARCHER(S): William T. Hicks, Jay M. Sexton

DATA SET CONTACT PERSON: Mark E. Harmon

METADATA CONTACT: Becky Fasth

ABSTRACTOR: Mark E. Harmon

METADATA CREATION DATE:

1 Jul 1990

MOST RECENT METADATA REVIEW DATE:

25 Oct 2016

KEYWORDS:

Inorganic nutrients, Organic matter, Long-Term Ecological Research (LTER), water content, respiration rates, respiration, nitrogen fixation, inorganic nutrients, coarse woody debris, nitrogen, organic matter, terrestrial ecosystems, logs, moisture stress

METHODS:

Experimental Design - TD018:

Description: The data are a time series, basically on an annual time step. Regression analysis will be used to test if the rates for species and tissue types changes with time. During any one time the design varies from a split-split plot to a split plot ANOVA. The effects of species, tissue type, or position in the log (top, bottom, side) can be tested.

Field Methods - TD018:

Description: During the spring cross-sections 8 cm thick are removed from logs with a chainsaw. These are placed in plastic bag and kept under refrigeration until samples are tested. Two to three samples with a fresh weight of 2 g are removed from each tissue type. These are placed in serum tubes, capped, and incubated at 15°C for 1-2 hours with lab air to determine the respiration rate. The tubes are then purged for 2 minutes with argon, acetylene is injected, and air is injected to give 1% oxygen. Incubations for acetylene reduction are at 15°C for 20-25 hours. Carbon dioxide and ethylene production are measured using a gas chromatograph. Moisture content is calculated after drying the samples 2 days at 70°C.

SUPPLEMENTAL INFORMATION:

This study takes advantage of a long-term (200 years) log decomposition study (TD014).

SITE DESCRIPTION:

Site 1: elevation is 1065m, average annual temperature 8.9 degree C, average annual precipitation is 229cm.

Site 4: elevation is 865m, average annual temperature 9.9 degree C, average annual precipitation is 219cm

TAXONOMIC SYSTEM:

Garrison et al., 1976

GEOGRAPHIC EXTENT:

Andrews Experimental Forest

ELEVATION_MINIMUM (meters):

ELEVATION_MAXIMUM (meters):

MEASUREMENT FREQUENCY:

irregular

PROGRESS DESCRIPTION:

Complete

UPDATE FREQUENCY DESCRIPTION:

asNeeded

CURRENTNESS REFERENCE:

Ground condition