Variation in carbon concentrations and allocations among Larix olgensis populations growing in three field environments

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Key messageVariation in carbon concentration amongLarix olgensisA. Henry provenances and tree tissues was significant, suggesting importance of such variation to carbon stock calculation. Provenance variation in carbon allocation was only significant in allocations to some tissues, including stem wood, and was strongly site-specific. Some allocation patterns correlated significantly with provenance growth and were related to geographic/climatic variables at the provenance origins.ContextUnderstanding variation in carbon concentrations and allocations to tree tissues among genetic entries is important for assessing carbon sequestration and understanding differential growth rates among the entries. However, this topic is poorly understood, in particular for mature trees in field conditions.AimsThe study aims to assess genetic variation in C concentrations and allocations to tree tissues and further to link the variation to tree growth and to assess their adaptive nature.MethodsIn 2011, carbon concentrations and allocations to tree tissues (stem wood, stem bark, branches, foliage, and root components) were measured on 31-year-old trees of ten Larix olgensis A. Henry provenances growing at three sites located in northeast China: CuoHai Forest Farm (CH), LiangShui Forest Farm (LS), and MaoErShān Forest Farm (MES). Variation in carbon allocation was analyzed using allometric methods.ResultsVariation in C concentration among tree tissues and among provenances was significant and site-specific. The cross-tissue variation in concentration was driven primarily by high concentration in branches and leaves and low concentration in stem wood and coarse roots. Differences between the minimum and maximum provenance means reached 1% at the tree level. Provenance variation was only significant in allocations to stem wood, branches, and fine roots and was strongly site-specific. Provenance variation in stem wood allocation was independent of provenance growth rate. Some allocation patterns correlated significantly with provenance growth; the faster-growing provenances allocated more to branches and less to fine roots at the LS site, but an opposite pattern was true at MES site. Most significant allocation traits were related to geographic/climatic variables at the provenance origins, but the driving factors varied with site.ConclusionProvenance variation in C concentration and allocation existed for L. olgensis but was strongly site-specific. Similarly, relationships of provenance variation in C allocation with provenance growth and their adaptive nature varied greatly with site. Our results will be of interest to ecologists and tree breeders studying dynamics of plantations in terms of climate change.