Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Demographic Responses of Herb Layer Species to Experimental Canopy Gaps in a Northern Hardwoods Forest

B. S. Collins and S. T. A. Pickett
Journal of Ecology
Vol. 76, No. 2 (Jun., 1988), pp. 437-450
DOI: 10.2307/2260604
Stable URL: http://www.jstor.org/stable/2260604
Page Count: 14
  • Read Online (Free)
  • Download ($18.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Demographic Responses of Herb Layer Species to Experimental Canopy Gaps in a Northern Hardwoods Forest
Preview not available

Abstract

(1) To determine whether herbs respond to the mean (single-tree) and median (multiple-tree) sizes of gaps in a 70-year old hardwoods forest on the Allegheny Plateau of Pennsylvania, U.S.A., herb growth and reproduction were monitored for one season before and for three years after gap creation. Gaps were created by cutting canopy and understorey trees at 1 m above ground, and comparisons were made between plots inside the gaps and beneath the adjacent intact canopy. There was no soil turnover associated with the experimental gaps. (2) There were no significant changes of minimum daily air temperature, soil temperature and moisture, or inorganic nitrogen content of soil beneath the gaps. Maximum daily air temperature was higher in gaps than in surrounding closed forest. Midday insolation on clear days increased significantly, with maximum illumination north of gap centre. (3) Analysis of vegetation in 1008 permanent 0.25-m2 plots found no consistent zonation of cover response around the gaps that would indicate herb layer response to the open canopy. (4) Erythronium americanum beneath single- and multi-tree gaps had greater leaf area than beneath closed forest; however, most of the variation in Erythronium population and plant size was independent of plant location. Flowering was greater than expected in single-tree, but not in multiple-tree gaps. (5) Prunus serotina, the summer dominant of the understorey and potential competitor with herbaceous species, was examined to help understand herb response. Height of Prunus seedlings increased each year from 1981 to 1984, while the number of plants declined. (6) Number and size of fern leaves, and number of minor herbs as a group, increased during this study; growth was not statistically greater or lower beneath gaps.

Page Thumbnails

  • Thumbnail: Page 
437
    437
  • Thumbnail: Page 
438
    438
  • Thumbnail: Page 
439
    439
  • Thumbnail: Page 
440
    440
  • Thumbnail: Page 
441
    441
  • Thumbnail: Page 
442
    442
  • Thumbnail: Page 
443
    443
  • Thumbnail: Page 
444
    444
  • Thumbnail: Page 
445
    445
  • Thumbnail: Page 
446
    446
  • Thumbnail: Page 
447
    447
  • Thumbnail: Page 
448
    448
  • Thumbnail: Page 
449
    449
  • Thumbnail: Page 
450
    450