Krysta Giles‐Hansen

Okanagan University College

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Xiaohua Wei

Okanagan University College

Qiang Li

Gansu Agricultural University

Wenfei Liu

Nanchang Institute of Technology

Mingfang Zhang

Northeast Forestry University

Yiping Hou

University of British Columbia

Yi Wang

Guiyang University

Houbao Fan

Nanchang Institute of Technology

Honglang Duan

Guizhou University

Chloé Orland

University of California, Santa Cruz

Qiang Li

Northwest A&F University

Cooperative Institutions

University of British Columbia

Chinese Academy of Sciences

Ministry of Forests

Nanchang Institute of Technology

Swedish University of Agricultural Sciences

Government of British Columbia

Plant & Food Research

Universitat Politècnica de València

University of Electronic Science and Technology of China

Okanagan University College

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Vegetation cover—another dominant factor in determining global water resources in forested regions

Global Change Biology (2017)

Xiaohua Wei Qiang Li Mingfang Zhang Krysta Giles‐Hansen Wenfei Liu

Abstract Forested catchments provide critically important water resources. Due to dramatic global forest change over the past decades, the importance of including forest or vegetation change in the assessment of water resources under climate change has been highly recognized by Intergovernmental Panel on Climate Change (IPCC); however, this importance has not yet been examined quantitatively across the globe. Here, we used four remote sensing‐based indices to represent changes in vegetation cover in forest‐dominated regions, and then applied them to widely used models: the Fuh model and the Choudhury‐Yang model to assess relative contributions of vegetation and climate change to annual runoff variations from 2000 to 2011 in forested landscape (forest coverage >30%) across the globe. Our simulations show that the global average variation in annual runoff due to change in vegetation cover is 30.7% ± 22.5% with the rest attributed to climate change. Large annual runoff variation in response to vegetation change is found in tropical and boreal forests due to greater forest losses. Our simulations also demonstrate both offsetting and additive effects of vegetation cover and climate in determining water resource change. We conclude that vegetation cover change must be included in any global models for assessing global water resource change under climate change in forest‐dominant areas.

Global Change

Forest cover

10.1111/gcb.13983

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Citations (111)

The forest mitigation-adaptation nexus: Economic benefits of novel planting regimes

Forest Policy and Economics (2020)

Caren C. Dymond Krysta Giles‐Hansen Patrick Asante

Tree planting

10.1016/j.forpol.2020.102124

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Citations (9)

The cumulative effects of forest disturbance and climate variability on baseflow in a large forested watershed

AGUFM (2016)

Q. Li Aihua Wei Krysta Giles‐Hansen M. Zhang W. Liu

Base flow

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The cumulative effects of forest disturbance and climate variability on baseflow in a large watershed in British Columbia, Canada

Qiang Li Xiaohua Wei Mingfang Zhang Wenfei Liu Krysta Giles‐Hansen

Abstract. Assessing how forest disturbance and climate change affect baseflow or groundwater discharge is critical for understanding water resource supply and protecting aquatic functions. Previous studies have mainly evaluated the effects of forest disturbance on streamflow, with rare attention on baseflow, particularly in large watersheds. However, studying this topic is challenging as it requires explicit inclusion of climate into assessment due to their interactions at any large watersheds. In this study, we used Upper Similkameen River watershed (USR) (1810 km2), located in the southern interior of British Columbia, Canada to examine how forest disturbance and climate variability affect baseflow. The conductivity mass balance method was first used for baseflow separation, and the modified double mass curves were then employed to quantitatively separate the relative contributions of forest disturbance and climate variability to annual baseflow. Our results showed that average annual baseflow and baseflow index (baseflow/streamflow) were about 85.2 ± 21.5 mm year-1 and 0.22 ± 0.05 for the study period of 1954–2013, respectively. The forest disturbance increased the annual baseflow of 18.4 mm, while climate variability decreased 19.4 mm. In addition, forest disturbance also shifted the baseflow regime with increasing of the spring baseflow and decreasing of the summer baseflow. We conclude that forest disturbance significantly altered the baseflow magnitudes and patterns, and its role in annual baseflow was equal to that caused by climate variability in the study watershed despite their opposite changing directions. The implications of our results are discussed in the context of future forest disturbance (or land cover changes) and climate changes.

Base flow

10.5194/hess-2016-291

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Citations (1)

Comparison of xylem sap mineral concentrations between kiwifruit shoot types using spittlebugs for non-destructive sampling of sap

Functional Plant Biology (2007)

Katrina Norah Buxton Michael J. Clearwater Krysta Giles‐Hansen E.W. Hewett Ian B. Ferguson

Excreta of the meadow spittlebug [Philaenus spumarius L. (Homoptera: Cercopidae)] feeding on leaves and pedicels of kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa 'Hayward'] were collected from insects from two different positions in the vine: from long, non-terminating axillary shoots producing fruit that are high in Ca2+ and low in K+ and from short-terminating axillary shoots producing fruit that are low in Ca2+ and high in K+. The Ca2+, Mg2+, K+ and P concentrations in the excreta were determined, and found to be similar to those in the xylem sap. Daily and seasonal changes in xylem sap composition were compared in excreta collected from the two different shoot types. On average, Ca2+ and Mg2+ concentrations were higher and K+ and P concentrations were lower in xylem sap collected from pedicels on long, non-terminating axillary shoots than in sap collected from pedicels on short-terminating shoots. Differences in the mineral concentration between these two shoot types may therefore be due to differences in the xylem sap mineral concentration reaching the fruit. There was no measurable gradient in xylem sap composition within the parent shoots that could explain the differences between sap composition of the two axillary shoot types. Long, non-terminating shoots had higher leaf area, were more exposed, had higher stomatal conductance and rates of transpiration, and more negative leaf water potentials than short-terminating shoots. The higher xylem sap Ca2+ and Mg2+ concentrations of long shoots were therefore associated with higher rates of water transport to the long shoots. Xylem sap concentration differences between these two shoots types may have been because of differential loading or unloading of minerals between shoot types, associated with differences in transpiration rate or shoot growth rates. The higher transpiration rate of long shoots may cause phloem immobile minerals such as Ca2+ to accumulate to higher levels at cation exchange sites in the shoot apoplast, resulting in increased xylem sap concentrations arriving at the fruit.

Actinidia deliciosa

Pedicel

10.1071/fp07091

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Citations (8)

Cumulative forest disturbances decrease runoff in two boreal forested watersheds of the northern interior of British Columbia, Canada

Journal of Hydrology (2021)

Yiping Hou Xiaohua Wei M. E. Vore Stephen J. Déry Tom Pypker

Cumulative effects

10.1016/j.jhydrol.2021.127362

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Citations (7)

The Cumulative Effects of Forest Disturbance and Climate Variability on Streamflow in the Deadman River Watershed

Forests (2019)

Krysta Giles‐Hansen Qiang Li Xiaohua Wei

Climatic variability and cumulative forest cover change are the two dominant factors affecting hydrological variability in forested watersheds. Separating the relative effects of each factor on streamflow is gaining increasing attention. This study adds to the body of literature by quantifying the relative contributions of those two drivers to the changes in annual mean flow, low flow, and high flow in a large forested snow dominated watershed, the Deadman River watershed (878 km2) in the Southern Interior of British Columbia, Canada. Over the study period of 1962 to 2012, the cumulative effects of forest disturbance significantly affected the annual mean streamflow. The effects became statistically significant in 1989 at the cumulative forest disturbance level of 12.4% of the watershed area. The modified double mass curve and sensitivity-based methods consistently revealed that forest disturbance and climate variability both increased annual mean streamflow during the disturbance period (1989–2012), with an average increment of 14 mm and 6 mm, respectively. The paired-year approach was used to further investigate the relative contributions to low and high flows. Our analysis showed that low and high flow increased significantly by 19% and 58%, respectively over the disturbance period (p < 0.05). We conclude that forest disturbance and climate variability have significantly increased annual mean flow, low flow and high flow over the last 50 years in a cumulative and additive manner in the Deadman River watershed.

Cumulative effects

Watershed area

10.3390/f10020196

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Citations (30)

Forest harvesting and hydrology in boreal Forests: Under an increased and cumulative disturbance context

Forest Ecology and Management (2022)

Xiaohua Wei Krysta Giles‐Hansen Sheena A. Spencer Xiaowen Ge А. А. Онучин

Boreal forests cover about one-third of the global forested area and are under rapid alteration due to increased natural and human-induced forest disturbance, which have important impacts on forest carbon cycling, hydrology, biodiversity, and many other ecological characteristics, processes, and functions. In this review, we focus on how forest harvesting affects hydrological processes in boreal forests within the context of increased and cumulative forest disturbance across various spatial scales. At the stand level, harvesting affects snow processes (i.e., snow interception, snow water equivalent, ablation, and snowmelt), decreases evapotranspiration (ET) and water use efficiency (WUE), and has negative impacts on soil dynamics (i.e., infiltration and soil moisture). These hydrological changes at the stand level can be counteractive or additive, cumulatively leading to more varied effects at larger spatial scales. In small watersheds, spring freshets (or high flows) are consistently increased following harvesting, while annual streamflow is often increased but some contradictory results are found in Siberia, Russia. These varied responses are likely dependent upon differences in energy budgets, climate, post-disturbance vegetation trajectories, and their dynamic interactions over space and time. For larger watersheds and regions, cumulative forest disturbance interacts with climate, leading to more complicated and varied hydrological responses. Forest management implications and future research topics are also suggested.

Snowmelt

Ecohydrology

Interception

10.1016/j.foreco.2022.120468

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Citations (26)

Topography significantly influencing low flows in snow-dominated watersheds

Qiang Li Xiaohua Wei Xin Yang Krysta Giles‐Hansen Mingfang Zhang

Abstract. Watershed topography plays an important role in determining the spatial heterogeneity of ecological, geomorphological, and hydrological processes. Few studies have quantified the role of topography on various flow variables. In this study, 28 watersheds with snow-dominated hydrological regimes were selected with daily flow records from 1989 to 1996. The watersheds are located in the Southern Interior of British Columbia, Canada and range in size from 2.6 to 1,780 km2. For each watershed, 22 topographic indices (TIs) were derived, including those commonly used in hydrology and other environmental fields. Flow variables include annual mean flow (Qmean), Q10%, Q25%, Q50%, Q75%, Q90%, and annual minimum flow (Qmin), where Qx% is defined as flows that at the percentage (x) occurred in any given year. Factor analysis (FA) was first adopted to exclude some redundant or repetitive TIs. Then, stepwise regression models were employed to quantify the relative contributions of TIs to each flow variable in each year. Our results show that topography plays a more important role in low flows than high flows. However, the effects of TIs on flow variables are not consistent. Our analysis also determines five significant TIs including perimeter, surface area, openness, terrain characterization index, and slope length factor, which can be used to compare watersheds when low flow assessments are conducted, especially in snow-dominated regions.

10.5194/hess-2017-560

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Citations (2)

Summary of the Forests and Water Workshop

Confluence Journal of Watershed Science and Management (2018)

Julia Jones Russell M. Smith Georg Jost Rita Winkler Dave Spittlehouse

With population growth, climate change, and increasing forest disturbance, understanding the complex relationships between forests and water is key to sustaining future forest resources, aquatic habitat, and water supplies. Research into forest and water interactions continues to expand our understanding of ecohydrological processes and our ability to assess the hazards associated with natural and human-related forest disturbances.

Natural forest

10.22230/jwsm.2018v2n1a10

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Citations (0)