Record Details
Specific Growth Rings to Which Douglas-fir Needles Are Attached: Site Variability
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Specific Growth Rings to Which Douglas-fir Needles Are Attached: Site Variability |
| Names |
Peterson, Alexandra M.
(creator) Lachenbruch, Barbara (advisor) |
| Date Issued | 2014-05-30 (iso8601) |
| Note | Honors Bachelor of Science (HBS) |
| Abstract | Stands of Douglas-fir (Pseudotsuga menziesii ssp. menziesii Mirb. (Franco)) near the Oregon Coast are showing signs of growth reduction from the foliar pathogen Phaeocryptopus gaeumannii that causes Swiss Needle Cast (SNC) disease. To better understand the mechanisms of needle drop through disease, and to learn the degree of variability in needle attachment, I tested the extent to which 3-year old needles have connections to xylem produced in the two years after needles were formed. I submerged the base of a stem with one needle attached into a basin of stain, and then placed the needle, whose tip had been cut off, into a vacuum for 5 minutes. I then surfaced the stem with a razor blade, to learn into which rings the dye had entered when sucked from the needle. Contrary to expectations, there was no significant difference in the proportion of 2011 needles that drew stain through only xylem produced in 2011. However, also in contrast to expectations, two of the three high-disease-impact sites had a higher number of connections than the three low-disease-impact sites, suggesting that there may be a disease effect. There was a wide variety of needle attachment patterns at both the site and region levels, which is important for physiologists when they extrapolate tree productivity from sap flow research. |
| Genre | Thesis |
| Topic | needle morphology |
| Identifier | http://hdl.handle.net/1957/51116 |
