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Abstract Detail



Ecological Section

Hawkins, Tracy [1], Thornton, Rory [1].

Differences in germination response for acorns of Quercus pagoda and Q. phellos following varying flooding and cold stratification treatments.

Although southern bottomland hardwood forests typically experience seasonal flooding, time and duration of flooding in some of these forests may be controlled by levees in order to create greentree reservoirs (GTRs) for migrating and wintering waterfowl. The latter creates concern among forest and wildlife managers regarding deleterious effects of flood duration on various aspects of the life cycles of bottomland hardwood trees. Of particular note is the effect of flooding on Quercus species which are often a major component of hardwood bottomlands. We investigated the effects of varying winter flooding duration and cold stratification times on acorns of Quercus pagoda (cherrybark oak) and Q. phellos (willow oak). Acorns of both species were submerged (November-February) in a GTR for 21, 42, 63, and 84 days (flooding treatment). Acorns receiving a non-flooding treatment were cold stratified (5/1 º C) on moist sand in a low-temperature incubator for the same time periods. After each treatment interval, acorns were placed in incubators, on moist sand, in light, and at alternating temperature regimes of 15/6º, 20/10º, 25/15º, and 30/20ºC. Following 8 weeks of incubation at the four temperature regimes, cumulative germination percentages for Q. pagoda did not differ between pre-incubation treatments (i.e. flooding vs. cold stratification). Acorns germinated to ≥ 82% at the four incubation temperatures following 63 and 84 days of cold stratification or flooding. However, Q. phellos acorns receiving cold stratification germinated to significantly higher percentages at the four incubation temperatures than those that received the flooding treatments. Acorns of this species germinated to 52% and 94% at 30/20ºC after 84 days of flooding or cold stratification, respectively. Acorns of both Quercus species did not germinate during flooding or cold stratification and acorns that did not germinate during the 8 week incubation period were still viable. Acorns of Q. pagoda and Q. phellos appear to be tolerant to winter flooding; therefore, adverse effects on acorn viability would not be expected if winter flood duration does not exceed 12 weeks and water temperatures remain at or below approximately 15ºC. Although acorns of both species have nondeep physiological dormancy, extended winter flooding (8-12 weeks) is as effective as cold stratification for dormancy-break in Q. pagoda acorns, whereby the same winter flood water temperatures and duration do not fully satisfy dormancy break requirements for Q. phellos acorns.

Broader Impacts:


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1 - USDA - Forest Service, Box 9681, Mississippi State, MS, 39762, USA

Keywords:
Quercus
red oak
greentree reservoir
seed germination
seed dormancy
willow oak
cherrybark oak
flooding.

Presentation Type: Oral Paper:Papers for Sections
Session: 28
Location: Marlborough B/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 10:45 AM
Number: 28003
Abstract ID:416
Candidate for Awards:None


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