<Citation> <Acknowledgement> <Disclaimer> Griffiths, R. 2002. Influence of tree-fall gaps on soil characteristics in the Andrews Experimental Forest, 1999. Long-Term Ecological Research. Forest Science Data Bank, Corvallis, OR. [Database]. Available: http://andlter.forestry.oregonstate.edu/data/abstract.aspx?dbcode=SP019. Accessed 2024-11-21. Data were provided by the HJ Andrews Experimental Forest research program, funded by the National Science Foundation's Long-Term Ecological Research Program (DEB 2025755), US Forest Service Pacific Northwest Research Station, and Oregon State University. While substantial efforts are made to ensure the accuracy of data and documentation, complete accuracy of data sets cannot be guaranteed. All data are made available "as is". The Andrews LTER shall not be liable for damages resulting from any use or misinterpretation of data sets.
This is the third and final study in a series of tree-fall gap studies conducted at the HJA addressing the effects of tree-fall gaps on forest soil characteristics. The first looked at the effects of gap size on changes in soil carbon cycling within the gap along N-S transects. The second 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 the gaps. The current study expands the number of variables studied and sampling intensity. By using the same grid system as Dr. Gray in his vegetation survey work, we are able to relate below-ground processes with above-ground vegetation.
Soil properties in two large 9 year-old tree-fall gaps were compared with soils in the surrounding old-growth Douglas-fir forest by intensive sampling of a circular grid that extended 12 m into the forest. This study was designed compare below-ground soil properties with above-ground vegetation and coarse woody debris distribution patterns using three-dimensional response surfaces and to compare soil properties in and outside the gap. To accomplish this goal, samples were collected along a grid already established by Gray, A.N., and Spies, T.A. (1996) designed to study vegetative succession in tree-fall gaps of varying sizes. We chose to measure soil characteristics at 4-meter intervals using the Gray/Spies grid design. The sample grid was essentially a circle centered within the gap. The sample grid was expanded 12 meters into the surrounding forest so that comparisons could be made between soils within the gap and those in the forest. During the same summer that the soils work was done, Dr. Gray and his students conducted studies of vegetation and coarse woody debris distribution patterns within these same gaps, generating GIS data layers which could be used to directly compare with our soils data.
