BER launches Environmental System Science Program. Visit our new website under construction!

U.S. Department of Energy Office of Biological and Environmental Research

PI-Submitted Research Highlights for
Terrestrial Ecosystem Science Program

Seedling Responses to Climate Warming May Slow Tree Advance Upslope

Lara M. Kueppers

Highlight

1 December 2016

Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest.

The Science 
Using field experiments in the Rocky Mountains, scientists tested the sensitivity of emerging tree seedlings to artificial warming and watering at three locations along a mountainside to understand whether trees will be able to migrate upward in elevation as the climate changes.

The Impact
Most vegetation models assume that forest trees will track their environmental “niche” as climate warms, including upslope to higher elevations. But there is little understanding of climate constraints on seedlings, which are the future of the forest. The unexpected results of intensive field experiments in Colorado indicate that warming reduces the odds of seedlings establishing at and above their current upper limits, as well as in the forest, or provides no net benefit. Seeds sourced from higher-elevation trees also performed relatively poorly, suggesting that past genetic adaptation to local conditions may hinder upslope tree advances, a finding counter to current theory.

Summary
Climate warming is expected to promote upslope shifts in forests. However, common gardens sown with seed collected from two different elevations and subjected to climate manipulations using infrared heaters and manual watering indicate that warming and local genotype may constrain tree seedling recruitment above current treeline. Negative effects of warming in forest, treeline, and alpine sites were partly offset by watering, suggesting growing season moisture may limit establishment of future subalpine forests. Greater climate sensitivity of Engelmann spruce compared with limber pine portends potential contraction in the elevational range of Engelmann spruce and changes in the composition of high-elevation Rocky Mountain forests. The greater availability of poorer-quality seed at the upper forest edge could act to further slow upslope shifts.

Contacts
BER Program Manager
Daniel Stover and Jared DeForest
SC-23.1
Daniel.Stover@science.doe.gov (301-903-0289)
Jared.DeForest@science.doe.gov (301-903-1678)

Principal Investigator
Lara M. Kueppers, Research Scientist
University of California, Merced, and Lawrence Berkeley National Laboratory
lkueppers@ucmerced.edu or lmkueppers@lbl.gov (510-486-5813)

Funding
This research was supported by the Office of Biological and Environmental Research, within the U.S. Department of Energy Office of Science (DE-FG02-07ER64457).

Publication
Kueppers, L. M., et al. “Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest.” Global Change Biology 23(6), 2383–2395 (2016). [DOI:10.1111/gcb.13561]

Related Link
Alpine-Treeline Warming Experiment website

UC Merced. This research was supported by the Office of Science (BER), U.S. Department of Energy (DE-FG02-07ER64457)

Search TES PI-Submitted Highlights

  • Search

Highlight Submission