# Influence of tree-fall gaps on soil characteristics in gaps of varying sizes in the Andrews Experimental Forest, 1995 ## Dataset - **Database Code:** SP017 - **Title:** Influence of tree-fall gaps on soil characteristics in gaps of varying sizes in the Andrews Experimental Forest, 1995 - **Abstract:** This is the first of three tree-fall gap studies conducted at the H.J. Andrews Experimental Forest addressing the effects of tree-fall gaps on forest soil characteristics. The second (Gap2) compared the effects of gaps on soil properties along both N-S and E-W transects to better differentiate between microclimate and vegetation effects within gaps. The final study (Gap3) expanded the number of variables studied and sampling intensity. By using the same grid system as Dr. Andy Gray in his vegetation survey work, the Gap3 study provided the most definitive connection between above-ground vegetation and associated below-ground processes. Soil properties in 10, 20, 30, and 50 meter tree-fall gaps were compared with soils in the surrounding old-growth Douglas-fir forest by sampling at 1 meter intervals along transects running north and south through the gaps. These transects extended one radius into the surrounding forest. This study was designed to determine if carbon cycling within these gaps were different from those in the soils of surrounding undisturbed forests. If there were differences, she wanted to determine what sized gap was required to show an effect. These transects were divided into four zones. Two zones were north of the E-W centerline; one in and one out of the gap. The other two zones were south of the E-W centerline; one in and one out of the gap. - **Keywords:** disturbance; inorganic nutrients; soil; forests; canopy gaps; Long-Term Ecological Research (LTER); disturbance; inorganic nutrients - **Temporal coverage:** 1995-01-07 to 1995-01-08 - **Principal Investigator:** Robert P. Griffiths ## Data Entities 1. SP01701 ## Entity 1: SP01701 ### Attribute list - **GAPNUMBR** — numeric(1.000000), range 110.0000 210.0000, number Site designator; gap 100 was a none-cut gap control - **GAPSIZE** — numeric(1.000000), range 10.0000 50.0000, meters Gap diameter in meters - **LOCATION** — numeric(1.000000), range 1.0000 50.0000, number Sampling location along transect - **N_S** — numeric(1.000000), range 0.0000 1.0000, number Sample location north or south of gap center - **ZONE** — numeric(1.000000), range 1.0000 4.0000, number 1=Nout; 2=Nin; 3=Sout; 4=Sin; - **IN_OUT** — varchar, freetext OUT = out of gap, IN = in gap - **MOIST** — numeric(0.100000), range 0.0000 100.0000, percent Percent moisture - **SOILTEMP** — numeric(0.100000), range 5.0000 15.0000, degrees Celsius Soil temperature - **SOM** — numeric(0.100000), range 5.0000 40.0000, percent Soil organic matter - **LITTER** — numeric(0.100000), range 0.0000 20.0000, centimeters Litter depth - **BULKDENS** — numeric(0.010000), range 0.0000 1.0000, grams per square centimeter Bulk density - **TOTALN** — numeric(0.001000), range 1.0000 1.0000, percent Total nitrogen - **TOTALC** — numeric(0.001000), range 1.0000 20.0000, percent Total carbon - **C_NRATIO** — numeric(1.000000), range 15.0000 45.0000, number Total carbon/total nitrogn - **LABRESP** — numeric(1.000000), range 0.0000 4.0000, micrograms per gram per hour Laboratory respiration rates (dry weight basis, as C) ## Attribute Definitions **BULKDENS** Bulk density **C_NRATIO** Total carbon/total nitrogn **GAPNUMBR** Site designator; gap 100 was a none-cut gap control **GAPSIZE** Gap diameter in meters **IN_OUT** OUT = out of gap, IN = in gap **LABRESP** Laboratory respiration rates (dry weight basis, as C) **LITTER** Litter depth **LOCATION** Sampling location along transect **MOIST** Percent moisture **N_S** Sample location north or south of gap center **SOILTEMP** Soil temperature **SOM** Soil organic matter **TOTALC** Total carbon **TOTALN** Total nitrogen **ZONE** 1=Nout; 2=Nin; 3=Sout; 4=Sin;