Forests 2017, 8(11), 418; https://doi.org/10.3390/f8110418
Growth and Its Relationship to Individual Genetic Diversity of Mountain Hemlock (Tsuga mertensiana) at Alpine Treeline in Alaska: Combining Dendrochronology and Genomics
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School of Forestry, Northern Arizona University, 200 E Pine Knoll Dr, Flagstaff, AZ 86011, USA
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Department of Earth Science and Geography, California State University Dominquez Hills, 1000 E. Victoria St, Carson, CA 90747, USA
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Department of Forest Genetics and Tree Breeding, Georg-August University of Göttingen, Büsgenweg 2, D-37077 Göttingen, Germany
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Department of Ecosystem Science & Management, Texas A&M University, 305 Horticulture and Forest Science Building, MS 2138 TAMU, College Station, TX 77843, USA
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N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences, 3 Gubkina Str., 119333 Moscow, Russia
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Genome Research and Education Center, Siberian Federal University, 50a/2 Akademgorodok, 660036 Krasnoyarsk, Russia
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Department of Geography, Texas A&M University, 810 Eller O&M Building, MS 3147 TAMU, College Station, TX 77843, USA
*
Author to whom correspondence should be addressed.
Received: 13 September 2017 / Revised: 27 October 2017 / Accepted: 29 October 2017 / Published: 2 November 2017
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
Abstract
Globally, alpine treelines are characterized as temperature-limited environments with strong controls on tree growth. However, at local scales spatially heterogeneous environments generally have more variable impacts on individual patterns of tree growth. In addition to the landscape spatial heterogeneity there is local variability in individual tree genetic diversity (level of individual heterozygosity). It has been hypothesized that higher individual heterozygosity will result in more consistent patterns of growth. In this article, we combine genomics and dendrochronology to explore the relationship between individual genetic diversity and tree growth at a mountain hemlock (Tsuga mertensiana Bong. Carr) alpine treeline on the Kenai Peninsula, Alaska, USA. We correlated average observed individual heterozygosity with average tree-ring width and variance in tree-ring width within individuals to test the hypothesis that trees with higher individual heterozygosity will also have more consistent growth patterns, suggesting that they may be more resilient to climate and environmental fluctuations at the alpine treeline. Our results showed that there was no significant relationship between tree growth and individual heterozygosity. However, there was a significant positive relationship between average tree-ring width and variance in tree-ring width implying that overall, fast growing trees in stressful environments, such as the alpine treeline, grow unstably regardless of the level of individual heterozygosity. View Full-TextKeywords:
genomics; high-throughput sequencing; homeostasis; individual heterozygosity; mountain ecosystems; tree-rings
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Johnson, J.S.; Chhetri, P.K.; Krutovsky, K.V.; Cairns, D.M. Growth and Its Relationship to Individual Genetic Diversity of Mountain Hemlock (Tsuga mertensiana) at Alpine Treeline in Alaska: Combining Dendrochronology and Genomics. Forests 2017, 8, 418.
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