Portsmuth2006
Data contributor: Angelika Portsmuth
Email: angelika.portsmuth@gmail.com
Address:
- Institute of Ecology, Tallinn University, Uus-Sadama 5, Tallinn 10120, Estonia
Citation: Portsmuth A and Niinemets Ü (2006). 'Interacting controls by light availability and nutrient supply on biomass allocation and growth of Betula pendula and B. pubescens seedlings.' Forest Ecology and Management, 227(1-2), pp. 122-134.
DOI: 10.1016/j.foreco.2006.02.020
Abstract: Interactions among environmental drivers commonly occur in natural environments, but their influence on plant performance is not fully understood. We tested for significant interactive effects of light and nutrient availabilities on foliage architecture, chemistry, biomass allocation and growth in shade intolerant temperate deciduous trees Betula pendula Roth. and B. pubescens Ehrh. First-year seedlings were grown at four irradiance and four N and P availability combinations, and the experiment was repeated in two consecutive years. In both species, increases in light availability resulted in larger net assimilation rate ({NAR}, total plant biomass production rate per unit leaf area), root mass fraction ({FR)} and leaf mass per unit area ({MA)}, but reductions in leaf area ratio ({LAR}, foliage area per total plant dry mass), stem mass fraction ({FS)} and leaf mass fraction ({FL).} The strong decrease in {LAR} ({LAR = FL/MA)} with light mainly resulted from increases in {MA.} The light-dependent increase in {NAR} was larger than the decline in {LAR} such that plant relative growth rate ({RGR = NAR  LAR)} scaled positively with light in both species. Nutrient availability mainly enhanced {LAR}, and moderately {NAR}, further improving {RGR.} The increase in {LAR} was primarily associated with increases in {FL} and decreases in {FR.} Significant interactions between light and nutrients were found for most of the studied variables, overall indicating that plant allocation and growth were more responsive to nutrients at higher light availability. Several significant species and year-to-year differences were observed among the allocation and growth characteristics that were driven by plant size, climate and seedling source. Greater {RGR} of B. pubescens that is a species colonizing habitats with lower nutrient availability was linked to its greater foliage nitrogen concentrations. Overall, the study highlights a significant light  nutrient interaction that can modify seedling performance along natural gap-understory gradients.
The dataset includes records for 343 individuals from 2 species belonging to 1 family(ies), presenting 1 functional type(s), growing in 1 condition(s) within 1 major type(s) of habitat, with data included for the following variables:
| Variable | Label | Units | N | Min | Median | Max |
|---|---|---|---|---|---|---|
| latitude | Latitude | deg | 343 | 59 | 59 | 59 |
| longitude | Longitude | deg | 343 | 24 | 24 | 24 |
| a.lf | Leaf area | m2 | 326 | 0.000091 | 0.004 | 0.026 |
| a.stba | Stem area at base | m2 | 326 | 0.00000018 | 0.0000022 | 0.000017 |
| h.t | Height | m | 326 | 0.01 | 0.07 | 0.26 |
| d.ba | Basal diameter | m | 326 | 0.00048 | 0.0017 | 0.0046 |
| m.lf | Leaf mass | kg | 326 | 0.000005 | 0.00016 | 0.0011 |
| m.st | Total stem mass | kg | 326 | 0.0000031 | 0.000066 | 0.00064 |
| m.so | Aboveground mass | kg | 326 | 0.00001 | 0.00022 | 0.0017 |
| m.rf | Fine root mass | kg | 326 | 0.0000045 | 0.000093 | 0.0012 |
| m.rc | Coarse root mass | kg | 326 | 0 | 0.000043 | 0.00072 |
| m.rt | Total root mass | kg | 326 | 0.0000045 | 0.00014 | 0.0018 |
| m.to | Total mass | kg | 326 | 0.000025 | 0.00039 | 0.0032 |
| ma.ilf | Leaf mass per area | kg m-2 | 326 | 0.016 | 0.038 | 0.076 |
| n.lf | Leaf [nitrogen] | kg kg-1 | 297 | 0.013 | 0.024 | 0.035 |
And locally within the country:
The sites sampled are:
| Location | Longitude | Latitude | Vegetation |
|---|---|---|---|
| Institute of Ecology, Tallinn Station, Estonia | 24 | 59 | Temperate forest |
The growing conditions of sampled plants was:
| Location | growingCondition |
|---|---|
| Institute of Ecology, Tallinn Station, Estonia | glasshouse |
| Species | Family | Pft |
|---|---|---|
| Betula pendula | Betulaceae | deciduous angiosperm |
| Betula pubescens | Betulaceae | deciduous angiosperm |
Sampling strategy: Two species Betula pendula and B. pubescens seedlings were grown in 4 different light (Light: 1- 100%, 2 - 34%, 3- 10%, 4- 5% of full sunlight) and nutrient (Nutrition: - A-control, B-low, C-medium, D-high (concentrations in the article)) availabilities.
Leaf area: All leaves were harvested and scanned fresh for leaf area using a flatbed scanner.
Stem cross sectional area: diametr at soil level: measured with caliper.
Height: Seedling height: height of seedling trunk from soil level to the top.
Biomass: ALL DRY MASS at least 48 h at 75oC.
Growth environment: Shade house.
Year collected: 1999-2000
Acknowledgements: Estonian Science Foundation (grant 5702) and the Estonian Ministry of Education and Science (grant 0182468As03), the Estonian Academy of Sciences, and the Estonian National Culture Foundation
This is how the study Portsmuth2006 fits in the entire dataset (grey). each colour represents a species. A legend of species names with colours is included at the end for reports with 1 < n < 20 species.
