Lewis2013

Report for study: Lewis2013

Contact Information

Data contributor: David Tissue

Email: d.tissue@uws.edu.au

Address:

• Hawkesbury Insitute for the Environment, University of Western Sydney, Hawkesbury Campus, First Floor, Building L9, Locked Bag 1797, Penrith NSW 2751, Australia

Data source

Citation: Lewis JD, Smith RA, Ghannoum O, Logan BA, Phillips NG and Tissue DT (2013). 'Industrial-age changes in atmospheric [CO2] and temperature differentially alter responses of faster- and slower-growing Eucalyptus seedlings to short-term drought.' Tree Physiology, 33(5), pp. 475-488.

DOI: 10.1093/treephys/tpt032

Abstract: Climate change may alter forest composition by differentially affecting the responses of faster- and slower-growing tree species to drought. However, the combined effects of rising atmospheric CO2 concentration ([CO2]) and temperature on drought responses of trees are poorly understood. Here, we examined interactive effects of temperature (ambient, ambient oC) and [CO2] (290, 400 and 650mu;l l-1) on drought responses of Eucalyptus saligna Sm. (faster-growing) and E. sideroxylon A. Cunn. ex Woolls (slower-growing) seedlings. Drought was imposed via a controlled reduction in soil water over 1-2 weeks, re-watering seedlings when leaves visibly wilted. In ambient temperature, the effect of drought on the light-saturated net photosynthetic rate (Asat) in E. saligna decreased as [CO2] increased from pre-industrial to future concentrations, but rising [CO2] did not affect the response in Eucalyptus sideroxylon. In contrast, elevated temperature exacerbated the effect of drought in reducing Asat in both species. The drought response of Asat reflected changes in stomatal conductance (gs) associated with species and treatment differences in (i) utilization of soil moisture and (ii) leaf area ratio (leaf area per unit plant dry mass). Across [CO2] and temperature treatments, E. saligna wilted at higher soil water potentials compared with E. sideroxylon. Photosynthetic recovery from drought was 90% complete 2 days following re-watering across all species and treatments. Our results suggest that E. saligna (faster-growing) seedlings are more susceptible to drought than E. sideroxylon (slower-growing) seedlings. The greater susceptibility to drought of E. saligna reflected faster drawdown of soil moisture, associated with more leaf area and leaf area ratio, and the ability of E. sideroxylon to maintain higher gs at a given soil moisture. Inclusion of a pre-industrial [CO2] treatment allowed us to conclude that susceptibility of these species to short-term drought under past and future climates may be regulated by the same mechanisms. Further, the beneficial effects of rising [CO2] and deleterious effects of elevated temperature on seedling response to drought were generally offsetting, suggesting susceptibility of seedlings of these species to short-term drought in future climates that is similar to pre-industrial and current climate conditions.

Overview of data provided

The dataset includes records for 120 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	120	-34	-34	-34
longitude	Longitude	deg	120	151	151	151
a.lf	Leaf area	m2	120	0.025	0.18	0.44
m.lf	Leaf mass	kg	120	0.0027	0.0099	0.021
m.st	Total stem mass	kg	120	0.0016	0.0085	0.023
m.so	Aboveground mass	kg	120	0.0048	0.019	0.038
m.rt	Total root mass	kg	120	0.0019	0.008	0.031
m.to	Total mass	kg	120	0.0072	0.028	0.064
ma.ilf	Leaf mass per area	kg m-2	120	0.027	0.067	0.28

And locally within the country:

The sites sampled are:

Location	Longitude	Latitude	Vegetation
University of Western Sydney, Richmond, NSW, Australia	150.75	-33.61

The growing conditions of sampled plants was:

Location	growingCondition
University of Western Sydney, Richmond, NSW, Australia	glasshouse

Species sampled

Species	Family	Pft
Eucalyptus saligna	Myrtaceae	evergreen angiosperm
Eucalyptus sideroxylon	Myrtaceae	evergreen angiosperm

Methods used

Sampling strategy: Two Eucalyptus species (Eucalyptus saligna and Eucalyptus sideroxylon) were grown at full field capacity under a treatment combination of ambient or elevated temperature (26/18C or 30/22C) and subambient, ambient or elevated CO2 (280, 400 or 640 ?L L-1). Near the end of the experiment, one half of the seedlings were subjected to a short term drought. All Seedlings were grown for from 78 to 85 days from planting, at which time they were subjected to a destructive harvest of all biomass.

Leaf area: All leaves were measured in a leaf area meter (LI-COR 3100, LI-COR, Inc., Lincoln, Nebr.).

Height: Height was measured as the vertical distance from the pot surface to the highest apex.

Biomass: Stems, leaves and roots were destructively harvested on multiple days (78, 79, 80, 83 and 85 days) after planting, and dried for 1 week at 70degreesC.

Growth environment: Glasshouse.

Year collected: 2011

Plots of data

This is how the study Lewis2013 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.