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TV025

Ecosystem responses to the creation of tree-fall gaps in the western Cascades of Oregon and Washington (Experimental Gap Study), 1990 to 2006

  • Creator: Jerry F. Franklin, Thomas A. Spies, Kristiina A. Vogt
  • PI: Thomas A. Spies
  • Originator: Thomas A. Spies, Jerry F. Franklin, Kristiina A. Vogt
  • Other researchers: Robert P. Griffiths, Andrew N. Gray, Robert J. Pabst
  • Dates of data collection: Apr 1 1990 - Sep 1 2006
  • Data collection status: Study collection is completed and no new collection is planned
  • Data access: Restricted: proprietary (publication issues)
  • Last update: Oct 17 2002 (Version 2)
<Citation>     <Acknowledgement>     <Disclaimer>    
Franklin, J.; Spies, T.; Vogt, K. 2002. Ecosystem responses to the creation of tree-fall gaps in the western Cascades of Oregon and Washington (Experimental Gap Study), 1990 to 2006. USFS PNW Ecosystem Processes Research. Forest Science Data Bank, Corvallis, OR. [Database]. Available: http://andlter.forestry.oregonstate.edu/data/abstract.aspx?dbcode=TV025 (24 February 2020) .
Data sets were provided by the Forest Science Data Bank, a partnership between the Department of Forest Science, Oregon State University, and the U.S. Forest Service Pacific Northwest Research Station, Corvallis, Oregon.
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 FSDB shall not be liable for damages resulting from any use or misinterpretation of data sets.
ABSTRACT:
Small canopy disturbances are important to the structure and function of forest ecosystems. Fine-scale disturbances (the death of one to many trees) largely control the population dynamics in our forests between larger catastrophic events. An experimental study of ecosystem responses to the creation of tree-fall gaps of varying size was conducted in northwestern coniferous forests. Gaps were created in the fall of 1990 in mature (80 to 150 years) and old-growth (400-500 years old) ecosystems dominated by Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla). Five gap sizes ranging from 0 to 2000 m2 were created in four stands, with gap diameters scaled in fixed proportion to the average canopy height in each stand. Roots were severed in trench plots placed in open- and closed-canopy areas to compare with gap responses. Both above-ground and below-ground processes were studied. Establishment, survival, and growth of trees and understory vegetation were measured within and surrounding gaps. Solar radiation, air and soil temperature, and soil moisture were measured. Litter input, decomposition, root density, N-mineralization and N-leaching, soil microbial response and myccorrhyzal mats have been studied. Population biology of selected understory herbs, and composition and abundance of small mammal communities, have also been examined.

Study Description Taxonomic Hierarchy Download Study Location Information: (CSV)
Download Full Documentation: (PDF)(EML)
ENTITY TITLES:
1Cover measurements of understory vegetation METADATAData not online
Vascular plant species cover measurents for microplots in and around gaps, from 1990-1997; 1999 data is still being cleaned
2Stem measurements of understory vegetation METADATAData not online
Vascular plant stem measurents for microplots in and around gaps, used in calculating biomass when cover is not appropriate, from 1990-1999
3Sampling categories for vegetation METADATAData not online
Vascular plant species categorized by sampling strategy and biomass calculation approach
4Ground cover METADATAData not online
Surface cover conditions (e.g. soil, litter, wood) on microplots in and around gaps
5Tree status and measurements METADATAData not online
Measurements and status (live/dead) of trees before and after gap creation, from 1990-2000
6Tree locations within each gap METADATAData not online
Coordinate locations of measured trees in gaps, including snags (tree number 6000+) for which species and size attributes are not yet entered
7Sapwood measurements METADATAData not online
Measurements of tree sapwood area at multiple locations along stems of selected cut trees
8Mortality assessments METADATAData not online
Characteristics of trees that died and estimated causes, from 1990-2000
9Soil moisture probe location and substrate METADATAData not online
Location and characteristics (depth, substrate, study type) of soil moisture probes
10Soil moisture probe measurements METADATAData not online
Volumetric soil moisture measurements from within and around gaps, from 1990-2000

RELATED PUBLICATIONS:
 Gray, Andrew N.; Spies, Thomas A.; Pabst, Robert J. 2012, Canopy gaps affect long-term patterns of tree growth and mortality in mature and old-growth forests in the Pacific Northwest (Pub. No: 4781)