Vapour pressure deficit and solar radiation are the major drivers of transpiration of balsam fir and black spruce tree species in humid boreal regions, even during a short-term drought

Oogathoo, Shalini; Houle, Daniel; Duchesne, Louis; Kneeshaw, Daniel

doi:10.1016/j.agrformet.2020.108063

Cited by 76 publications

(52 citation statements)

References 50 publications

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“…Another study in a 60‐year‐old upland P. mariana stand reported that daily sap velocity increased with VPD, peaking between 0.5 and 1 kPa. Beyond that point, sap velocity remained flat indicating hydraulic limitations to flow that limited additional foliar water use (Oogathoo et al 2020). As midday VPD across SPRUCE enclosures was 2–4 kPa in midsummer, the lack of a response in peak sap velocity for P. mariana is not surprising, as hydraulic limitations were likely present for trees in all treatments.…”

Section: Discussionmentioning

confidence: 99%

Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland

Warren

Jensen

Ward

et al. 2021

Global Change Biology

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Boreal peatland forests have relatively low species diversity and thus impacts of climate change on one or more dominant species could shift ecosystem function. Despite abundant soil water availability, shallowly rooted vascular plants within peatlands may not be able to meet foliar demand for water under drought or heat events that increase vapor pressure deficits while reducing near surface water availability, although concurrent increases in atmospheric CO2 could buffer resultant hydraulic stress. We assessed plant water relations of co‐occurring shrub (primarily Rhododendron groenlandicum and Chamaedaphne calyculata) and tree (Picea mariana and Larix laricina) species prior to, and in response to whole ecosystem warming (0 to +9°C) and elevated CO2 using 12.8‐m diameter open‐top enclosures installed within an ombrotrophic bog. Water relations (water potential [Ψ], turgor loss point, foliar and root hydraulic conductivity) were assessed prior to treatment initiation, then Ψ and peak sap flow (trees only) assessed after 1 or 2 years of treatments. Under the higher temperature treatments, L. laricina Ψ exceeded its turgor loss point, increased its peak sap flow, and was not able to recover Ψ overnight. In contrast, P. mariana operated below its turgor loss point and maintained constant Ψ and sap flow across warming treatments. Similarly, C. calyculata Ψ stress increased with temperature while R. groenlandicum Ψ remained at pretreatment levels. The more anisohydric behavior of L. laricina and C. calyculata may provide greater net C uptake with warming, while the more conservative P. mariana and R. groenlandicum maintained greater hydraulic safety. These latter species also responded to elevated CO2 by reduced Ψ stress, which may also help limit hydraulic failure during periods of extreme drought or heat in the future. Along with Sphagnum moss, the species‐specific responses of peatland vascular communities to drier or hotter conditions will shape boreal peatland composition and function in the future.

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Section: Discussionmentioning

confidence: 99%

Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland

Warren

Jensen

Ward

et al. 2021

Global Change Biology

View full text Add to dashboard Cite

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“…Integrating dendrometer time-series and xylogenetic data disentangles swelling caused by stem water replenishment from increases that can be attributed to actual radial growth (Cuny et al 2015;Cruz García et al 2019) leading to a better understanding of wood formation processes and their response to environmental conditions (Cocozza et al 2016;Steppe et al 2015). Automatic dendrometers could also be useful tools for monitoring the response of trees to extreme climatic events (Burri et al 2019), as they can provide high-frequency and longterm information on tree water status across large scales (Vilas et al 2019), in particular when coupled with sap-flow sensors (Oogathoo et al 2020, section 2.1.1).…”

Section: Tree Growthmentioning

confidence: 99%

“…While this expectation is also met in dry boreal forests, such as in Western Canada (Pappas et al 2018), it is not met in moist humid boreal forests. This has been demonstrated by Oogathoo et al (2020) who harnessed a network of forest plots equipped with Granier-type sap-flow probes (Granier et al 1996), which measure transpiration flow as the ascent of sap within xylem tissue, coupled with point dendrometers. Indeed, in the moist boreal forests of Eastern Canada, soil moisture was found to exert little influence on sap-flow rates, which continued to be driven by VPD and radiation even during a drought (Oogathoo et al 2020).…”

Section: Evapotranspirationmentioning

confidence: 99%

“…This has been demonstrated by Oogathoo et al (2020) who harnessed a network of forest plots equipped with Granier-type sap-flow probes (Granier et al 1996), which measure transpiration flow as the ascent of sap within xylem tissue, coupled with point dendrometers. Indeed, in the moist boreal forests of Eastern Canada, soil moisture was found to exert little influence on sap-flow rates, which continued to be driven by VPD and radiation even during a drought (Oogathoo et al 2020). There is thus likely a threshold of absolute rather than relative soil moisture beyond which the drivers of transpiration change.…”

Section: Evapotranspirationmentioning

confidence: 99%

“…Data from trees monitored with coupled sap-flow sensors, which estimate transpiration at the tree level (Cermak et al 2015), and automatic dendrometer bands can be used to relate tree-rehydration, dehydration, and sap-flow to the commencement of growth in ring porous and diffuse-porous trees, as well as in conifers (Oogathoo et al 2020). These real-time measurements can be linked to other physiological (e.g., water potential, stomatal conductance, photosynthetic efficiency, hydraulic architecture) and biometric (e.g., basal area, crow projection, tree height, root volume) measurements to evaluate tree function and forest health.…”

Section: Evapotranspirationmentioning

confidence: 99%

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A new generation of sensors and monitoring tools to support climate-smart forestry practices

et al. 2021

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Climate-smart forestry (CSF) is an emerging branch of sustainable adaptive forest management aimed at enhancing the potential of forests to adapt to and mitigate climate change. It relies on much higher data requirements than traditional forestry. These data requirements can be met by new devices that support continuous, in-situ monitoring of forest conditions in real time. We propose a comprehensive network of sensors, i.e. a wireless sensor network (WSN), that can be part of a world-wide network of interconnected uniquely addressable objects, an Internet of Things (IoT), which can make data available in near real time to multiple stakeholders, including scientists, foresters, and forest managers, and may partially motivate citizens to participate in big data collection. The use of in-situ sources of monitoring data as ground-truthed training data for remotely sensed data can boost forest monitoring by increasing the spatial and temporal scale of the monitoring, leading to a better understanding of forest processes and potential threats. Here, some of the key developments and applications of these sensors are outlined, together with guidelines for data management. Examples are given of their deployment to detect early warning signals (EWS) of ecosystem regime-shifts in terms of forest productivity, health and biodiversity. Analysis of the strategic use of these tools highlights the opportunities for engaging citizens and forest managers in this new generation of forest monitoring.

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Quantifying the vertical water exchange of dominant tree species in a reclaimed landscape in the Athabasca oil sands region, Alberta

et al. 2022

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Large-scale oil sands mining in the Athabasca oil sands region has caused significant disturbance to forest and peatland ecosystems of the Western Boreal Plains in northeastern Alberta, Canada. Reclamation of these ecosystems has faced many challenges, including successful re-vegetation of uplands. The trajectory of reclaimed uplands depends on the community structure of tree species, which in turn influences vertical water exchanges via increases in rainfall interception and transpiration.The trajectory therefore influences vadose zone moisture dynamics and reduces water available for recharge to adjacent reclaimed peatlands. The objectives of this study were to assess trends in transpiration of dominant tree species in a reclaimed upland and quantify canopy-rainfall dynamics and its impact on near-surface soil moisture regime and tree water use. To assess these trends, throughfall, interception and stemflow were measured throughout the growing season. Tree transpiration was measured using sap flow sensors, along with soil tension measurements using soil tensiometers. Results indicate that tree transpiration and water use are controlled by water availability, and at this stage (6 years since reclamation), canopy interception has begun to play an important role in partitioning growing season rainfall. At this time in canopy development, transpiration accounted for 52% of water losses from the system, with broadleaf trees contributing 71%. However, coniferous trees had greater interception capabilities, as Picea mariana intercepted 35% and Pinus banksiana 32%, while broadleaf Populus tremuloides and Populus balsamifera contributed 29% and 26%, respectively. As this reclaimed upland canopy continues to evolve, moisture partitioning, including groundwater recharge to the adjacent fen will continue to change over time, suggesting that the successional pathway of constructed watersheds is strongly influenced by hydrometeorological conditions within the first decade.

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Vapour pressure deficit and solar radiation are the major drivers of transpiration of balsam fir and black spruce tree species in humid boreal regions, even during a short-term drought

Cited by 76 publications

References 50 publications

Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland

Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland

A new generation of sensors and monitoring tools to support climate-smart forestry practices

Quantifying the vertical water exchange of dominant tree species in a reclaimed landscape in the Athabasca oil sands region, Alberta

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Vapour pressure deficit and solar radiation are the major drivers of transpiration of balsam fir and black spruce tree species in humid boreal regions, even during a short-term drought

Cited by 76 publications

References 50 publications

Divergent species‐specific impacts of whole ecosystem warming and elevated CO2on vegetation water relations in an ombrotrophic peatland

Divergent species‐specific impacts of whole ecosystem warming and elevated CO2on vegetation water relations in an ombrotrophic peatland

A new generation of sensors and monitoring tools to support climate-smart forestry practices

Quantifying the vertical water exchange of dominant tree species in a reclaimed landscape in the Athabasca oil sands region, Alberta

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Product

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Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland

Divergent species‐specific impacts of whole ecosystem warming and elevated CO₂on vegetation water relations in an ombrotrophic peatland