Influence of Aggregate Versus Dispersed Live Tree Retention on an Arboreal Forage Lichen

EPA Grant Number: U915768
Title: Influence of Aggregate Versus Dispersed Live Tree Retention on an Arboreal Forage Lichen
Investigators: Rambo, Thomas R.
Institution: University of California - Davis
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2000 through September 1, 2003
Project Amount: $80,410
RFA: STAR Graduate Fellowships (2000) RFA Text |  Recipients Lists
Research Category: Fellowship - Forestry , Academic Fellowships , Biology/Life Sciences , Ecological Indicators/Assessment/Restoration


The objectives of this research project are to compare growth rates of the arboreal lichen (Bryoria fremontii): (1) between aggregate and dispersed live tree retention silvicultural treatments; (2) within treatments before and after manipulation; (3) between two overstory trees, red fir, and white fir; (4) between riparian and upland trees; and (5) between southwest and northeast aspects within tree crowns.


Transplants of Bryoria have been installed in the canopies of red and white firs (nine each) that have been assigned to either aggregate or dispersed live tree retention patterns from planned silvicultural treatments. Samples will be in place for two growth seasons before treatments and left in place another two growth seasons following treatments. Samples will be retrieved, weighed, and reinstalled annually. Additionally, temperature and humidity dataloggers have been installed in the red fir study trees. Canopy openness will be measured by digital imaging through a fisheye lens before and after treatments. Canopy openness and within-crown humidity will be compared within treatments before and after manipulation, and between aggregate and dispersed live tree retention. Data will be further analyzed to correlate changes in environmental conditions with changes in Bryoria growth rates.

Expected Results:

Working hypotheses state that there will be no differences in mean Bryoria growth rates within or between treatments, or between red and white firs, or within-crown aspects; but there will be a difference between riparian and upland trees, with greater growth rates in riparian-influenced trees. Results will provide forest managers with information on which silvicultural treatment, overstory species, and habitat conditions are more favorable for fostering Bryoria populations. Conservation of Bryoria, in turn, has broad implications for the conservation of sensitive species and ecosystem biodiversity in Sierra Nevada mixed-conifer forests.

Supplemental Keywords:

Bryoria fremontii, forest canopy, epiphyte, lichen, mixed-conifer, green-tree retention, Sierra Nevada, California Spotted Owl, northern flying squirrel, red fir, ecology, habitat., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Ecosystem/Assessment/Indicators, Ecosystem Protection, Forestry, Habitat, Ecology and Ecosystems, ecological exposure, red fir, growth rates of arboreal lichen, live tree retention, riparian trees, Bryoria fremontii, arboreal forage lichen, dispersed live tree retention, upland trees, aggregate live tree retention, forests, white fir, forest conservation, arboreal lichen

Progress and Final Reports:

  • 2001
  • 2002
  • Final