@article {bnh-3414, title = {Stomatal structure and physiology do not explain differences in water use among montane eucalypts}, journal = {Oecologia}, volume = {177}, year = {2015}, month = {04/2015}, pages = {1171-1181}, chapter = {1171}, abstract = {

Understanding the regulation of water use at the whole-tree scale is critical to advancing the utility of physiological ecology, for example in its role in predictive hydrology of forested catchments. For three eucalypt species that dominate high-elevation catchments in south-eastern Australia, we examined if whole-tree water use could be related to three widely discussed regulators of water use: stomatal anatomy, sensitivity of stomata [i.e. stomatal conductance (gs)] to environmental influences, and sapwood area. While daily tree water use varied sixfold among species, sap velocity and sapwood area varied in parallel. Combined, stomatal structure and physiology could not explain differences in species-specific water use. Species which exhibited the fastest (Eucalyptus delegatensis) and slowest (Eucalyptus pauciflora) rates of water use both exhibited greater capacity for physiological control of\ gs[indicated by sensitivity to vapour pressure deficit (VPD)] and a reduced capacity to limit\ gsanatomically [indicated by greater potential\ gs\ (gmax)]. Conversely,\ gs\ was insensitive to VPD and\ gmax\ was lowest for\ Eucalyptus radiata, the species showing intermediate rates of water use. Improved knowledge of stomatal anatomy will help us to understand the capacity of species to regulate leaf-level water loss, but seems likely to remain of limited use for explaining rates of whole-tree water use in montane eucalypts at the catchment scale.

}, doi = {10.1007/s00442-015-3252-3}, url = {https://link.springer.com/article/10.1007/s00442-015-3252-3}, author = {Gharun, Mana and Turnbull, Tarryn L. and Sebastian Pfautsch and Adams, Mark A.} } @article {BF-3122, title = {Differences in water use between mature and post-fire regrowth stands of subalpine Eucalyptus delegatensis R. Baker}, journal = {Forest Ecology and Management}, volume = {270}, year = {2012}, month = {4/2012}, pages = {1 - 10}, abstract = {We estimated plot level water use from sap flux measurements over a 9-month period, in post-fire regrowth and mature plots of Eucalyptus delegatensis R. Baker (Alpine ash) in high elevation catchments near Falls Creek, Victoria, Australia, seven years after a major stand-replacing bushfire. Water use was more than double (460 {\textpm} 100 mm year-1 more) in regrowth as compared to mature plots, whereas sap flux was similar between age classes. This difference in water use reflected 72\% greater sapwood area index and 35\% greater leaf area index in regrowth than in mature plots. A small part of the difference in water use can be attributed to nocturnal transpiration, which was greater in regrowth than in mature plots (10.3 {\textpm} 0.8\% vs 7.3 {\textpm} 0.8\% of diel totals). As evaporative demand was 41\% greater in mature than in regrowth plots, these data suggest mean transpiration rate and stomatal conductance per unit leaf area were approximately 1.6 and 2.3 times greater, respectively, in the regrowth. However, mid-day leaf water potential and photosynthetic capacity were similar in both age classes. Evaporative demand was the primary environmental driver of water use in all cases, whereas soil moisture was not a strong driver of either water use or canopy conductance (estimated as sap flux/evaporative demand). Together, our results suggest (a) stand water use rapidly recovers after fire in these high elevation forests and quickly surpasses rates in mature stands, confirming projections by Kuczera (1987) for lower-elevation Mountain Ash (E. regnans) forests and highlighting the potential impact of tree water use on water yield in the first decade of forest regeneration after fires, and (b) stomatal conductance and sapwood area/leaf area ratio are both less in tall, older Alpine ash trees, whereas leaf water status and photosynthetic capacity appear to be sustained {\textendash} consistent with predictions from optimisation theory but not Pipe-Model Theory.}, issn = {03781127}, doi = {10.1016/j.foreco.2012.01.008}, author = {Buckley, TN and Turnbull, Tarryn L. and Sebastian Pfautsch and Gharun, Mana and Adams, Mark A.} } @article {BF-1172, title = {Sap flow in Australian subalpine forests \& woodlands suggests nocturnal transpiration contributes significantly to stand water balance and is inversely related to soil moisture.}, journal = {Plant, Cell \& Environment}, year = {2007}, note = {37 pgs}, author = {Buckley, TN and Turnbull, Tarryn L. and Sebastian Pfautsch and Adams, Mark A.} }