Event Title

Collecting tree seed in hot, dry places: Do progeny of these trees have drought tolerance and water-use efficiency needed for restoration of harsh sites?

Presenter Information

John-Pascal Berrill
Christa M. Dagley

Location

USU Eccles Conference Center

Event Website

www.restoringthewest.org

Abstract

Trees growing in the hottest/driest parts of their natural range may be better-adapted to hot, dry conditions and hold promise for restoration and resistance to climate change. If drought tolerance and water-use efficiency were heritable traits, we could select for these characteristics and raise seedlings for reforestation on marginal sites or in areas where adverse changes in climate were forecast. We sought to quantify heritability of these traits in coast redwood, a species with limited range and thought to be dependent on moist soils and mild summer temperatures moderated by coastal fog. The species is threatened by declining fog and warming trends at the drier extremes of its range, inland and to the south. We collected seed on dry ridges and upper slopes from the southernmost populations and inland locations where redwood experiences the hottest summertime temperatures. Our expectation was that - when planted on drier sites - their offspring would outperform seedlings from moister, more northern, coastal locations. Conversely, we expected seedlings adapted to moister locales to outperform the ‘dry site’ redwoods when planted on moister northern sites.

Coast redwood seedlings from southern/dry sites (from Monterey to Napa Counties), central sites (Mendocino County), and northern sites (Humboldt County) were outplanted in a replicated interlocking hexagonal experimental design, at a cool, wet northern coastal site and a hot, dry, high-elevation site (outside of redwood’s natural range) in Humboldt County, and at a hot, dry site in Mendocino County, California. A total of almost 3000 seedlings were planted by Humboldt State University students in 2010 and 2011. Seedling health status and height have been measured repeatedly. The experiment will continue to provide insights into outcomes of reclamation and “assisted migration” forest conservation/restoration strategies and the impact of climate change on regional sub-populations better- or worse-adapted to the new climate. A portion of the seed collected from each tree is in long-term storage at the state seed bank in Davis, California, to conserve their genes. This will allow for future tree breeding or restoration of vulnerable, isolated, small populations at the fringes of their natural range. This presentation describes the seed collection procedure and field experiment design, and shows how hundreds of students studying forestry and ecological restoration have been actively involved in this long-term study.

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Oct 16th, 12:00 PM Oct 16th, 12:05 PM

Collecting tree seed in hot, dry places: Do progeny of these trees have drought tolerance and water-use efficiency needed for restoration of harsh sites?

USU Eccles Conference Center

Trees growing in the hottest/driest parts of their natural range may be better-adapted to hot, dry conditions and hold promise for restoration and resistance to climate change. If drought tolerance and water-use efficiency were heritable traits, we could select for these characteristics and raise seedlings for reforestation on marginal sites or in areas where adverse changes in climate were forecast. We sought to quantify heritability of these traits in coast redwood, a species with limited range and thought to be dependent on moist soils and mild summer temperatures moderated by coastal fog. The species is threatened by declining fog and warming trends at the drier extremes of its range, inland and to the south. We collected seed on dry ridges and upper slopes from the southernmost populations and inland locations where redwood experiences the hottest summertime temperatures. Our expectation was that - when planted on drier sites - their offspring would outperform seedlings from moister, more northern, coastal locations. Conversely, we expected seedlings adapted to moister locales to outperform the ‘dry site’ redwoods when planted on moister northern sites.

Coast redwood seedlings from southern/dry sites (from Monterey to Napa Counties), central sites (Mendocino County), and northern sites (Humboldt County) were outplanted in a replicated interlocking hexagonal experimental design, at a cool, wet northern coastal site and a hot, dry, high-elevation site (outside of redwood’s natural range) in Humboldt County, and at a hot, dry site in Mendocino County, California. A total of almost 3000 seedlings were planted by Humboldt State University students in 2010 and 2011. Seedling health status and height have been measured repeatedly. The experiment will continue to provide insights into outcomes of reclamation and “assisted migration” forest conservation/restoration strategies and the impact of climate change on regional sub-populations better- or worse-adapted to the new climate. A portion of the seed collected from each tree is in long-term storage at the state seed bank in Davis, California, to conserve their genes. This will allow for future tree breeding or restoration of vulnerable, isolated, small populations at the fringes of their natural range. This presentation describes the seed collection procedure and field experiment design, and shows how hundreds of students studying forestry and ecological restoration have been actively involved in this long-term study.

http://digitalcommons.usu.edu/rtw/2013/Poster/12