Abstract Detail

Forest Tree Responses to a Changing Climate

Hacke, Uwe G. [1], Schreiber, Stefan G. [1], Thomas, Barb R. [1].

Hydraulic and wood anatomical traits of hybrid poplar plantation trees - leaf size emerges as a key trait.

The increasing demand for wood fiber will require a sustainable and efficient use of tree plantations on a diminishing forest landbase. Plantation trees are typically selected for fast growth, disease resistance and favorable wood properties. However, recent droughts in the United States and Canada remind us that drought tolerance may become a trait of increasing significance for tree breeders, particularly when managing such water demanding species. In parts of western Canada, drought periods are predicted to increase in frequency and severity. Less predictable precipitation patterns coupled with increased temperatures could cause not only reductions in tree growth, but plantation failures, especially in areas where irrigation of trees is not economical. In Alberta, hybrid poplar clones are grown on marginal farmland with no supplementary irrigation. Although hybrid poplars may show fast growth under favorable conditions, most poplar genotypes are very vulnerable to drought-induced xylem cavitation, limiting the range of water potentials under which they can extract and transport water. In this talk, the hydraulic and wood anatomical traits of hybrid poplar clones will be discussed in the context of water limitations. We tested five hybrid poplar clones and found that they differed in key hydraulic parameters such as cavitation resistance, vessel diameter, and leaf area. Variation was found across clones, but also between branch type within a tree. Vigorously growing current year long shoots tended to have higher transport capacity over the entire range of xylem pressures than older branches. Leaf size was also much greater in the fast-growing current year shoots than in older branches. Leaf size was correlated with various xylem traits, emerging as an interesting trait to watch in future studies.

1 - University of Alberta, Renewable Resources, Edmonton, AB, T6G 2E3, Canada

Keywords:
xylem
cavitation
wood traits
poplar
water transport
leaf size
plantation trees
drought
climate change.

Presentation Type: Symposium Presentation
Session: SY13
Location: Hall A/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:45 AM
Number: SY13003
Abstract ID:152
Candidate for Awards:None