Trends in seedling growth and carbon-use efficiency vary among broadleaf tree species along a latitudinal transect in eastern North America

The rate at which forests take up atmospheric CO2 is critical with regard to their potential to mitigate climate change as well as their value for wood production. The allocation of carbon fixed through photosynthesis into biomass is crucially dependent on tree carbon use efficiency (CUE), which is determined by gross primary production (GPP) and plant respiration (Ra) via the relation CUE=(GPP-Ra)/GPP. The effect of future climate on CUE is unclear due to the unknown response of plant respiration to more severe increases in temperature. This motivates assessing spatial patterns in CUE across climatic gradients with marked temperature variations. &#160;Within the &#8221;Improving tree carbon use efficiency for climate-adapted more productive forests&#8221; (iCUE-Forest) project, we aim to develop novel data-driven estimates of plant respiration, net primary production (NPP=GPP-Ra) and tree CUE covering the northern hemisphere boreal and temperate forests. These will be based on recent satellite-driven maps of tree living biomass, databases of N concentration measurements in tree compartments (leaves, stem/branches, roots) and the relationships between respiration rates and tissue N concentrations and temperature. Such estimates will enable the detection of spatial relationships between CUE and environmental conditions and facilitate the parameterization of dynamic global vegetation models which allow predicting the change in CUE in response to future climate and forest management.Here we will present an extensive database of N concentration measurements in tree stems/branches and roots that we have compiled in addition to data available mainly for leaves from databases like TRY. More than 5000 measurements have been collected from the literature covering all common boreal and temperate tree species. Currently, we are exploring how the variation in tissue N concentrations is influenced by climate and tree species. Subsequently, we apply the derived tree-level relationships between tissue N concentrations and underlying drivers in combination with tree species distribution maps and estimates of tree compartment biomass based on satellite remote sensing products. In this way, we will derive novel estimates of the spatial distribution of N content in northern boreal and temperate forests that will in turn be used to assess CUE variations.

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Critical Seed Transfer Distances for Selected Tree Species in Eastern North America

Journal of Ecology ◽

10.1111/1365-2745.13605 ◽

2021 ◽

Author(s):

John H. Pedlar ◽

Daniel W. McKenney ◽

Pengxin Lu

Keyword(s):

North America ◽

Tree Species ◽

Eastern North America ◽

Seed Transfer

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C3and C4photosynthesis inCyperus(Cyperaceae) in temperate eastern North America

Canadian Journal of Botany ◽

10.1139/b98-216 ◽

1999 ◽

Vol 77 (2) ◽

pp. 209-218 ◽

Cited By ~ 4

Author(s):

Mei-Rong Li ◽

David A Wedin ◽

Larry L Tieszen

Keyword(s):

North America ◽

Stable Carbon Isotopes ◽

Stable Carbon Isotope ◽

Summer Precipitation ◽

Atlantic Coastal Plain ◽

Eastern North America ◽

Mean Annual Temperature ◽

Stable Carbon ◽

Use Efficiency ◽

Ecological Success

All species in the genus Cyperus (Cyperaceae) that occur in temperate eastern North America were assigned to either the C3or C4photosynthetic pathway using leaf anatomical characteristics and stable carbon isotope ratios. Of the 39 species in the study area, 32 had C4photosynthesis while 7 had C3. The numbers of C3, C4, and total Cyperus species were significantly and positively correlated with both summer precipitation and mean annual temperature. However, the proportional abundance of C4species within Cyperus was not significantly related to either climatic variable. The highest Cyperus diversity was found on the Atlantic Coastal Plain, a pattern that remained after climatic differences between regions were accounted for. All the C3species and the majority of the C4species were restricted to wetlands or damp soil habitats; 13 of the 32 C4species occurred in dry, sandy habitats. Given that the C3pathway is ancestral in the genus Cyperus, it appears that C4photosynthesis evolved in a wetland context for this genus. We suggest that the high nitrogen use efficiency associated with the C4pathway is largely responsible for the evolution and ecological success of C4Cyperus species in infertile, temperate wetlands.Key words: C3and C4photosynthetic pathways, Cyperus, Cyperaceae, eastern North America, stable carbon isotopes.

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Hemlock Legacy Project (HeLP)

Progress in Physical Geography Earth and Environment ◽

10.1177/0309133312469218 ◽

2012 ◽

Vol 37 (1) ◽

pp. 114-129 ◽

Cited By ~ 5

Author(s):

Amy Hessl ◽

Neil Pederson

Keyword(s):

North America ◽

Environmental History ◽

Tree Species ◽

Foundation Species ◽

American Chestnut ◽

Eastern North America ◽

Old Growth ◽

Translational Ecology ◽

Dead Material ◽

Extensive Body

Eastern North American forests have effectively lost two major tree species (American chestnut and American elm) in the last 100 years and two more, eastern and Carolina hemlock, will be functionally extinct over much of their ranges within a couple of decades. The loss of eastern hemlock is of particular concern because hemlock is: (1) a foundation species; (2) one of the longest-lived tree species over much of temperate eastern North America; and (3) sensitive to climatic variation and ecosystem disturbance, making it an ideal species for the reconstruction of environmental history. Unlike American chestnut, we have a small window of opportunity to salvage environmental histories from hemlock before they are lost. In this progress report, we review the extensive body of science derived from this paleoenvironmental archive and urge scientists from eastern North America to sample and archive old-growth hemlock while living and dead material remain. Here we describe a community-based approach to salvaging paleoenvironmental archives that could serve as a model for collections from other foundation species currently threatened by exotic forests pests and pathogens (e.g. whitebark pine, ash). The approach supports Schlesinger’s (2010) call for ‘translational ecology’ by building connections between scientists, students, environmental NGOs, and land managers focused on old-growth forests.

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Contrasting Litter Nutrient and Metal Inputs and Soil Chemistry among Five Common Eastern North American Tree Species

Forests ◽

10.3390/f12050613 ◽

2021 ◽

Vol 12 (5) ◽

pp. 613

Author(s):

Neil F. J. Ott ◽

Shaun A. Watmough

Keyword(s):

North America ◽

Tree Species ◽

Soil Chemistry ◽

Mineral Soil ◽

Abies Balsamea ◽

Base Cations ◽

Forest Composition ◽

Eastern North America ◽

Betula Alleghaniensis ◽

Yellow Birch

Forest composition has been altered throughout Eastern North America, and changes in species dominance may alter nutrient cycling patterns, influencing nutrient availability and distribution in soils. To assess whether nutrients and metals in litterfall and soil differed among sites influenced by five common Ontario tree species (balsam fir (Abies balsamea (L.) Mill.), eastern hemlock (Tsuga canadensis (L.) Carr.), white pine (Pinus strobus L.), sugar maple (Acer saccharum Marsh.), and yellow birch (Betula alleghaniensis Britt.)), litterfall and soil chemistry were measured at a managed forest in Central Ontario, Canada. Carbon (C) and macronutrient (nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)) inputs in litterfall varied significantly among sites, primarily due to differences in litterfall mass, which was greatest in deciduous-dominated sites, while differences in elemental concentrations played relatively minor roles. Trace metal inputs in litterfall also varied, with much higher zinc (Zn) and cadmium (Cd) in litterfall within yellow birch dominated stands. Mineral soil oxide composition was very similar among sites, suggesting that differences in soil chemistry were influenced by forest composition rather than parent material. Litter in deciduous-dominated stands had lower C/N, and soils were less acidic than conifer-dominated sites. Deciduous stands also had much shorter elemental residence times in the organic horizons, especially for base cations (Ca, Mg, K) compared with conifer-dominated sites, although total soil nutrient pools were relatively consistent among sites. A change from stands with greater conifer abundance to mixed hardwoods has likely led to more rapid cycling of elements in forests, particularly for base cations. These differences are apparent at small scales (100 m2) in mixed forests that characterize many forested regions in Eastern North America and elsewhere.

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