skip to main content


Title: Patterns of physical, chemical, and metabolic characteristics of sugar maple leaves with depth in the crown and in response to nitrogen and phosphorus addition
Abstract

Few previous studies have described the patterns of leaf characteristics in response to nutrient availability and depth in the crown. Sugar maple has been studied for both sensitivity to light, as a shade-tolerant species, and sensitivity to soil nutrient availability, as a species in decline due to acid rain. To explore leaf characteristics from the top to bottom of the canopy, we collected leaves along a vertical gradient within mature sugar maple crowns in a full-factorial nitrogen (N) by phosphorus (P) addition experiment in three forest stands in central New Hampshire, USA. Thirty-two of the 44 leaf characteristics had significant relationships with depth in the crown, with the effect of depth in the crown strongest for leaf area, photosynthetic pigments and polyamines. Nitrogen addition had a strong impact on the concentration of foliar N, chlorophyll, carotenoids, alanine and glutamate. For several other elements and amino acids, N addition changed patterns with depth in the crown. Phosphorus addition increased foliar P and boron (B); it also caused a steeper increase of P and B with depth in the crown. Since most of these leaf characteristics play a direct or indirect role in photosynthesis, metabolic regulation or cell division, studies that ignore the vertical gradient may not accurately represent whole-canopy performance.

 
more » « less
Award ID(s):
1637685
NSF-PAR ID:
10430935
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Oxford University Press
Date Published:
Journal Name:
Tree Physiology
Volume:
43
Issue:
7
ISSN:
1758-4469
Format(s):
Medium: X Size: p. 1118-1129
Size(s):
p. 1118-1129
Sponsoring Org:
National Science Foundation
More Like this
  1. Foliar chemistry can be useful for diagnosing soil nutrient availability and plant nutrient limitation. In northern hardwood forests, foliar responses to nitrogen (N) addition have been more often studied than phosphorus (P) addition, and the interactive effects of N and P addition have rarely been described. In the White Mountains of central New Hampshire, plots in ten forest stands of three age classes across three sites were treated annually beginning in 2011 with 30 kg N ha −1 y −1 or 10 kg P ha −1 y −1 or both or neither–a full factorial design. Green leaves of American beech ( Fagus grandifolia Ehrh.), pin cherry ( Prunus pensylvanica L.f.), red maple ( Acer rubrum L.), sugar maple ( A. saccharum Marsh.), white birch ( Betula papyrifera Marsh.), and yellow birch ( B. alleghaniensis Britton) were sampled pre-treatment and 4–6 years post-treatment in two young stands (last cut between 1988–1990), four mid-aged stands (last cut between 1971–1985) and four mature stands (last cut between 1883–1910). In a factorial analysis of species, stand age class, and nutrient addition, foliar N was 12% higher with N addition ( p < 0.001) and foliar P was 45% higher with P addition ( p < 0.001). Notably, P addition reduced foliar N concentration by 3% ( p = 0.05), and N addition reduced foliar P concentration by 7% ( p = 0.002). When both nutrients were added together, foliar P was lower than predicted by the main effects of N and P additions ( p = 0.08 for N × P interaction), presumably because addition of N allowed greater use of P for growth. Foliar nutrients did not differ consistently with stand age class ( p  ≥ 0.11), but tree species differed ( p  ≤ 0.01), with the pioneer species pin cherry having the highest foliar nutrient concentrations and the greatest responses to nutrient addition. Foliar calcium (Ca) and magnesium (Mg) concentrations, on average, were 10% ( p < 0.001) and 5% lower ( p = 0.01), respectively, with N addition, but were not affected by P addition ( p = 0.35 for Ca and p = 0.93 for Mg). Additions of N and P did not affect foliar potassium (K) concentrations ( p = 0.58 for N addition and p = 0.88 for P addition). Pre-treatment foliar N:P ratios were high enough to suggest P limitation, but trees receiving N ( p = 0.01), not P ( p = 0.64), had higher radial growth rates from 2011 to 2015. The growth response of trees to N or P addition was not explained by pre-treatment foliar N, P, N:P, Ca, Mg, or K. 
    more » « less
  2. Inselsbacher, Erich (Ed.)
    Abstract

    Stomatal density, stomatal length and carbon isotope composition can all provide insights into environmental controls on photosynthesis and transpiration. Stomatal measurements can be time-consuming; it is therefore wise to consider efficient sampling schemes. Knowing the variance partitioning at different measurement levels (i.e., among stands, plots, trees, leaves and within leaves) can aid in making informed decisions around where to focus sampling effort. In this study, we explored the effects of nitrogen (N), phosphorus (P) and calcium silicate (CaSiO3) addition on stomatal density, length and carbon isotope composition (δ13C) of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britton). We observed a positive but small (8%) increase in stomatal density with P addition and an increase in δ13C with N and CaSiO3 addition in sugar maple, but we did not observe effects of nutrient addition on these characteristics in yellow birch. Variability was highest within leaves and among trees for stomatal density and highest among stomata for stomatal length. To reduce variability and increase chances of detecting treatment differences in stomatal density and length, future protocols should consider pretreatment and repeated measurements of trees over time or measure more trees per plot, increase the number of leaf impressions or standardize their locations, measure more stomata per image and ensure consistent light availability.

     
    more » « less
  3. The influence of nutrient availability on transpiration is not well understood, in spite of the importance of transpiration to forest water budgets. Soil nutrients have the potential to affect tree water use through indirect effects on leaf area or stomatal conductance. For example, following addition of calcium silicate to a watershed at Hubbard Brook, in New Hampshire, streamflow was reduced for 3 years, which was attributed to a 25% increase in evapotranspiration associated with increased foliar production. The first objective of this study was to quantify the effect of nutrient availability on sap flux density in a nitrogen, phosphorus, and calcium addition experiment in New Hampshire in which tree diameter growth, foliar chemistry, and soil nutrient availability had responded to treatments. We measured sap flux density in American beech ( Fagus grandifolia, Ehr.), red maple ( Acer rubrum L.), sugar maple ( Acer saccharum Marsh.), white birch ( Betula papyrifera Marsh.), or yellow birch (Betula alleghaniensis Britton.) trees, over five years of experiments in five stands distributed across three sites. In 2018, 3 years after a calcium silicate addition, sap flux density averaged 36% higher in trees in the treatment than the control plot, but this effect was not very significant ( p = 0.07). Our second objective was to determine whether this failure to detect effects with greater statistical confidence was due to small effect sizes or high variability among trees. We found that tree-to-tree variability was high, with coefficients of variation averaging 39% within treatment plots. Depending on the species and year of the study, the minimum difference in sap flux density detectable with our observed variability ranged from 46% to 352%, for a simple ANOVA. We analyzed other studies reported in the literature that compared tree water use among species or treatments and found detectable differences ranging from 16% to 78%. Future sap flux density studies could benefit from power analyses to guide sampling intensity. Including pretreatment data, in the case of manipulative studies, would also increase statistical power. 
    more » « less
  4. The MELNHE study looks at patterns of resource limitation through nutrient manipulations in three study sites in New Hampshire: Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook, located in the White Mountain National Forest. The investigation is monitoring stem diameter, leaf area, sap flow, foliar chemistry, leaf litter production and chemistry, foliar nutrient resorption, root biomass and production, mycorrhizal associations, soil respiration, heterotrophic respiration, N and P availability, N mineralization, soil phosphatase activity, soil carbon and nitrogen, nutrient uptake capacity of roots, and mineral weathering. This data set includes phosphate, nitrate and ammonium availability measured using resin exchange strips. Additional detail on the MELNHE project, including a datatable of site descriptions and a pdf file with the project description and diagram of plot configuration can be found in this data package: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-hbr&identifier=344 These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. The following papers describe and make use of these data: Fisk MC, Ratliff TJ, Goswami S, Yanai RD. 2014. Synergistic soil response to nitrogen plus phosphorus fertilization in hardwood forests. Biogeochemistry 118:195-204. https://doi.org/10.1007/s10533-013-9918-1 Goswami S, Fisk MC, Vadeboncoeur MA, Johnston M, Yanai RD, and Fahey TJ. 2018. Phosphorus limitation of aboveground production in northern hardwood forests. Ecology 99: 438-449. https://doi.org/10.1002/ecy.2100 Shan S, Fisk MC, Fahey TJ. 2018. Contrasting effects of N on rhizosphere processes in two northern hardwood species. Soil Biology and Biochemistry 126: 219-227. https://doi.org/10.1016/j.soilbio.2018.09.007 Shan S, Devens H, Fahey TJ, Yanai RD, Fisk MC. 2022. Fine root growth increases in response to nitrogen addition in phosphorus-limited northern hardwood forests. Ecosystems, https://doi.org/10.1007/s10021-021-00735-4 Gonzales KE, Yanai RD, Fahey TJ, Fisk MC. 2023. Evidence for P limitation in eight northern hardwood stands: Foliar concentrations and resorption by three tree species in a factorial N by P addition experiment. Forest Ecology and Management 529: 120696. https://doi.org/10.1016/j.foreco.2022.120696 Li S, Fisk MC, Yanai RD, Fahey TJ. 2023. Co-limitation of root growth by nitrogen and phosphorus in early successional northern hardwood forest. Ecosystems. https://10.1007/s10021-023-00869-7 
    more » « less
  5. Summary

    Foliar fungal endophytes are one of the most diverse guilds of symbiotic fungi found in the photosynthetic tissues of every plant lineage, but it is unclear how plant environments and leaf resource availability shape their diversity.

    We explored correlations between leaf nutrient availability and endophyte diversity amongPinus muricataandVaccinium ovatumplants growing across a soil nutrient gradient spanning a series of coastal terraces in Mendocino, California.

    Endophyte richness decreased in plants with higher leaf nitrogen‐to‐phosphorus ratios for both host species, but increased with sodium, which may be toxic to fungi at high concentrations. Isolation frequency, a proxy of fungal biomass, was not significantly predicted by any of the same leaf constituents in the two plant species.

    We propose that stressed plants can exhibit both low foliar nutrients or high levels of toxic compounds, and that both of these stress responses predict endophyte species richness. Stressful conditions that limit growth of fungi may increase their diversity due to the suppression of otherwise dominating species. Differences between the host species in their endophyte communities may be explained by host specificity, leaf phenology, or microclimates.

     
    more » « less