Pacific Southwest

Title: Gap-based silviculture in a sierran mixed-conifer forest: effects of gap size on early survival and 7-year seedling growth

Author: York, Robert A.; Battles, John J.; Heald, Robert C.

Date: 2007

Source: In: Powers, Robert F., tech. editor. Restoring fire-adapted ecosystems: proceedings of the 2005 national silviculture workshop. Gen. Tech. Rep. PSW-GTR-203, Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: p. 181-191

Station ID: GTR-PSW-203

Description: Experimental canopy gaps ranging in size from 0.1 to 1.0 ha (0.25 to 2.5 acres) were created in a mature mixed conifer forest at Blodgett Forest Research Station, California. Following gap creation, six species were planted in a wagon-wheel design and assessed for survival after two growing seasons. Study trees were measured after seven years to describe the effect of gap size on early growth of planted trees. Giant sequoia had the lowest mortality (2.4 – 5.0 percent), sugar pine, incense-cedar, ponderosa pine, and Douglas-fir all had comparable levels of mortality (5.8 - 18.9 percent), and white fir had the highest level of mortality (35.7 – 47.2 percent). To rank candidate models according to goodness of fit while penalizing for model complexity, we used an information-theoretic approach using Akaike Information Criteria. An asymptotic fit of height growth to gap size was most commonly selected as the best model among a set of feasible a priori candidate models, although there was some model parity. As gap size increased, height gains tended to diminish between 0.3 and 0.6 ha (0.75 to 1.5 acres). Shade tolerance classifications did not predict relative mortality levels or functional responses of height growth to gap size.

Keywords: 

View and Print this Publication (280 KB)

Publication Notes: 

• We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
• This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
• You may send email to pubrequest@fs.f ed.us to request a hard copy of this publication. (Please specify exactly which publication you are requesting and your mailing address.)

 Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

Citation

York, Robert A.; Battles, John J.; Heald, Robert C.  2007.  Gap-based silviculture in a sierran mixed-conifer forest: effects of gap size on early survival and 7-year seedling growth.   In: Powers, Robert F., tech. editor. Restoring fire-adapted ecosystems: proceedings of the 2005 national silviculture workshop. Gen. Tech. Rep. PSW-GTR-203, Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: p. 181-191.