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Do hummocks provide a physiological advantage to even the most flood tolerant of tidal freshwater trees?

Wetlands

By:
, , , , and
DOI: 10.1007/s13157-013-0397-x

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Abstract

Hummock and hollow microtopography is pervasive in tidal freshwater swamps. Many tree species grow atop hummocks significantly more than in hollows, leading to the hypothesis that hummocks provide preferred locations for maximizing physiological proficiency of inhabiting trees that experience repeated flooding. We used thermal dissipation probes to measure the ecophysiological proficiency of a very flood-tolerant tree, Taxodium distichum, as manifested through in-situ changes in sapflow (a proxy for transpiration) in 11 trees on hummocks and 11 trees in hollows. Overall, sapflow increased significantly by 3.3 g H2O m−2 s−1 (11 %) in trees on both hummocks and hollows during flooding, contrary to our expectations. We found no significant differences in sapflow rates between T. distichum trees positioned on hummocks versus hollows in relation to discrete flood events. Coincidentally, hummock elevations were equivalent to the flood depths that promoted greatest physiological proficiency in T. distichum, suggesting a physiological role for the maintenance of hummock height in tidal swamps. While we reject our original hypotheses that flooding and positioning in hollows will reduce sapflow in T. distichum, this research reveals a potentially important feedback between hummock height, flood depth, and maximum tree physiological response.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Do hummocks provide a physiological advantage to even the most flood tolerant of tidal freshwater trees?
Series title:
Wetlands
DOI:
10.1007/s13157-013-0397-x
Volume
33
Issue:
3
Year Published:
2013
Language:
English
Publisher:
Springer
Contributing office(s):
National Wetlands Research Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Wetlands
First page:
399
Last page:
408