John D Marshall

John D Marshall
Swedish University of Agricultural Sciences | SLU · Department of Forest Ecology and Management

Ph.D.

About

213
Publications
44,653
Reads
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9,090
Citations
Additional affiliations
June 2014 - present
Swedish University of Agricultural Sciences
Position
  • Guest Professor
January 1990 - December 2013
University of Idaho
Position
  • Professor
Description
  • Currently on leave at Swedish Agricultural University in Umeå
May 1988 - December 1989
University of Utah
Position
  • PostDoc Position
Description
  • Mistletoes and juniper ecophysiology, mostly

Publications

Publications (213)
Article
Full-text available
The boreal forest is an important global carbon (C) sink. Since low soil nitrogen (N) availability is commonly a key constraint on forest productivity, the prevalent view is that increased N input enhances its C sink-strength. This understanding however relies primarily on observations of increased aboveground tree biomass and soil C stock followin...
Article
There is evidence that carbon fluxes and stocks decrease with increasing latitude in boreal forests, suggesting a reduction in carbon use efficiency. While vegetation and soil carbon dynamics have been widely studied, the empirical finding that ectomycorrhizal fungi (ECM) become more abundant towards the north has not been quantitatively linked to...
Article
Alternative water uptake pathways through leaves and bark complement water supply with interception, fog or dew. Bark water‐uptake contributes to embolism‐repair, as demonstrated in cut branches. We tested whether bark water‐uptake could also contribute to supplement xylem‐water for transpiration. We applied bandages injected with 2H‐enriched water...
Article
Full-text available
Using water-stable isotopes to track plant water uptake or soil water processes has become an invaluable tool in ecohydrology and physiological ecology. Recent studies have shown that laser absorption spectroscopy can measure equilibrated water vapour well enough to support inference of liquid-stable isotope composition of plant or soil water, on-s...
Article
Full-text available
Vegetation changes can strongly influence the hydrological cycle, including streamflow, but the effects of plant diseases have seldom been described. In the mid-20th century, the invasion of an exotic disease, white pine blister rust, precipitated widespread mortality of western white pine (WWP; Pinus monticola Dougl.) in the northern Rocky Mountai...
Preprint
Full-text available
Using water stable isotopes to track plant water uptake or soil water processes has become an invaluable tool in ecohydrology and physiological ecology. Recent studies have shown that laser absorption spectroscopy can measure equilibrated water vapour well enough to support inference of liquid stable isotope composition of plant or soil water, on-s...
Chapter
Full-text available
Trees are long-lived organisms that contribute to forest development over centuries and beyond. However, trees are vulnerable to increasing natural and anthropic disturbances. Spatially distributed, continuous data are required to predict mortality risk and impact on the fate of forest ecosystems. In order to enable monitoring over sensitive and of...
Article
Rationale: New methods to measure stable isotopes of soil and tree water directly in the field enable us to increase the temporal resolution of obtained data and advance our knowledge on the dynamics of soil and plant water fluxes. Only few field applications exist. However, these are needed to further improve novel methods and hence exploit their...
Article
Nitrogen (N) addition causes rapid accumulation of carbon (C) in the soils of boreal forests. The C accumulation has been attributed to an increase in C supply to the soil, to a decrease in mineralization of organic C to CO2, or some combination of the two. We sought to quantify the proportional causes in a case study in a boreal Scots pine forest...
Article
Full-text available
Climate-smart forestry (CSF) consists of an extensive framework of actions directed to mitigating and adapting to global climate change impacts on the resilience and productivity of forest ecosystems. This study investigates the impact of the pan-European 2018 drought on carbon exchange dynamics in typical highland and mountain forests in the Czech...
Article
Mixed forests have been recommended to replace monocultures, often being more productive and resilient ecosystems. Those benefits of species mixing have been suggested to be attributed to lower competition (above- and belowground) due to potential separation of resource acquisition strategies, yet a mechanistic understanding of belowground processe...
Article
Boreal forests undergo a strong seasonal photosynthetic cycle; however, the underlying processes remain incompletely characterised. Here, we present a novel analysis of the seasonal diffusional and biochemical limits to photosynthesis (Anet) relative to temperature and light limitations in high‐latitude mature Pinus sylvestris, including a high‐res...
Article
Considering the temporal responses of carbon isotope discrimination (Δ13C) to local water availability in the spatial analysis of Δ13C is essential for evaluating the contribution of environmental and genetic facets of plant Δ13C. Using tree-ring Δ13C from years with contrasting water availability at 76 locations across the natural range of lobloll...
Article
Full-text available
The intensity and frequency of droughts events are projected to increase in future with expected adverse effects for forests. Thus, information on the dynamics of tree water uptake from different soil layers during and after drought is crucial. We applied an in situ water isotopologue monitoring system to determine the oxygen isotope composition in...
Article
Full-text available
The occurrence of extreme drought poses a severe threat to forest ecosystems and reduces their capability to sequester carbon dioxide. This study analysed the impacts of a central European summer drought in 2015 on gross primary productivity (GPP) at two Norway spruce forest sites representing two contrasting climatic conditions—cold and humid clim...
Article
Full-text available
Trees receive growth‐limiting nitrogen from their ectomycorrhizal symbionts, but supplying the fungi with carbon can also cause nitrogen immobilization, which hampers tree growth. We present results from field and greenhouse experiments combined with mathematical modelling, showing that these are not conflicting outcomes. Mycorrhizal networks conne...
Article
Full-text available
Understanding how plant water uptake interacts with acquisition of soil nitrogen (N) and other nutrients is fundamental for predicting plant responses to a changing environment, but it is an area where models disagree. We present a novel isotopic labelling approach which reveals spatial patterns of water and N uptake, and their interaction, by tree...
Article
Full-text available
Adding nitrogen to boreal forest ecosystems commonly increases gross primary production (GPP). The effect of nitrogen addition on ecosystem GPP is convoluted due to the impacts of and interactions among leaf scale photosynthetic productivity, canopy structure, site fertility, and environmental constraints. We used a unique controlled nitrogen ferti...
Article
Full-text available
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 fores...
Article
Full-text available
Boreal forests store approximately 470 Pg of carbon (C) in the soil, and rates of soil C accumulation are significantly enhanced by long-term nitrogen (N) enrichment. Dissecting the compositional profile of soils could help better understand the potential mechanisms driving changes in C cycling under enriched N conditions. We examined the impacts o...
Article
Full-text available
It is well established that nutrient addition influences ecosystem features such as productivity, carbon storage, soil acidification and biodiversity. Less studied are long-term effects of sustained fertiliser application on forest soil characteristics and nutrient supplies, and especially direct and indirect mechanisms underlying changes. We inves...
Preprint
The mycorrhizal symbiosis is ubiquitous in boreal forests. Trees and plants provide their fungal partners with photosynthetic carbon in exchange for soil nutrients like nitrogen, which is critical to the growth and survival of the plants. But plant carbon allocation to mycorrhizal symbionts can also fuel nitrogen immobilization, hampering tree grow...
Article
Full-text available
Although aspects of forest ecophysiology and forest environments have received considerable attention from research scientists in the last three decades, assessment of implications for meeting the climate targets and international agreements is still a matter of debate [...]
Article
Full-text available
Forests pass water and carbon through while converting portions to streamflow, soil organic matter, wood production, and other ecosystem services. The efficiencies of these transfers are but poorly quantified. New theory and new instruments have made it possible to use stable isotope composition to provide this quantification of efficiencies wherev...
Article
Full-text available
Interpreting phloem carbohydrate or xylem tissue carbon isotopic composition as measures of water‐use efficiency or past tree productivity requires in‐depth knowledge of the factors altering the isotopic composition within the pathway from ambient air to phloem contents and tree‐ring. One of least understood of these factors is mesophyll conductanc...
Article
Photosynthetic water‐use efficiency (WUE) describes the link between terrestrial carbon and water cycles. Estimates of intrinsic WUE (iWUE) from gas‐exchange and carbon isotopic composition (δ13C) differ due to an internal conductance in the leaf mesophyll (gm) that is variable and seldom computed. We present the first direct estimates of whole‐tre...
Article
Full-text available
Stable isotopologues of water are widely used to derive relative root water uptake (RWU) profiles and average RWU depth in lignified plants. Uniform isotope composition of plant xylem water (δ xyl) along the stem length of woody plants is a central assumption of the isotope tracing approach which has never been properly evaluated. Here we evaluate...
Article
Several studies have suggested that CO2 transport in the transpiration stream can considerably bias estimates of root and stem respiration in ring-porous and diffuse-porous tree species. Whether this also happens in species with tracheid xylem anatomy and lower sap flow rates, such as conifers, is currently unclear. We infused 13C-labeled solution...
Preprint
Gross primary production (GPP) is a key component of the forest carbon cycle. However, our knowledge of GPP at the stand scale remains uncertain because estimates derived from eddy covariance (EC) rely on semi‐empirical modeling and the assumptions of the EC technique are sometimes not fully met. We propose using the sap flux/isotope method as an a...
Article
Resilience is a key concept in ecology, describing the capacity of a system to resist a disturbance, recover from it and return to a stable state (Lloret et al., 2011; Hodgson et al., 2015; Ingrisch & Bahn, 2018, see Box 1). Whilst it is indisputable and a matter of intensive research (e.g., Mcdowell et al., 2008; Meinzer et al., 2009; Vicente‐Serr...
Article
Full-text available
Forest water use has been difficult to quantify. One promising approach is to measure the isotopic composition of plant water, e.g., the transpired water vapor or xylem water. Because different water sources, e.g., groundwater versus shallow soil water, often show different isotopic signatures, isotopes can be used to investigate the depths from wh...
Article
Full-text available
1. Climate change is a world-wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere contin...
Article
Gross primary production (GPP) is a key component of the forest carbon cycle. However, our knowledge of GPP at the stand scale remains uncertain, because estimates derived from eddy covariance (EC) rely on semi-empirical modelling and the assumptions of the EC technique are sometimes not fully met. We propose using the sap flux/isotope method as an...
Article
Drought frequency and intensity are projected to increase throughout the Southeastern USA, the natural range of loblolly pine (Pinus taeda L.), and are expected to have major ecological and economic implications. We analyzed the carbon and oxygen isotopic compositions in tree ring cellulose of loblolly pine in a factorial drought (~30% throughfall...
Article
Full-text available
Climate change is a worldwide threat to biodiversity and ecosystem structure, functioning, and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate‐change impacts across the soil–plant–atmosphere continuum...
Article
Full-text available
Mesophyll conductance (gm) is a critical variable for the use of stable carbon isotopes to infer photosynthetic water-use efficiency (WUE). Although gm is similar in magnitude to stomatal conductance (gs), it has been measured less often, especially under field conditions and at high temporal resolution. We mounted an isotopic CO2 analyser on a fie...
Article
Low-molecular weight organic compounds (LMWOC) play a key role in soil respiration. Thus, a detailed understanding of their dynamics is important for any attempt to describe carbon cycling of ecosystems. Measurements of LMWOC have been compromised by the perturbation associated with traditional soil extraction methods. Due to the fast turnover of L...
Poster
Full-text available
In situ methods enabling high-resolution measurements of water isotopes in the tree xylem have already been tested but are not yet widely applied. However, such methods would be tremendously helpful in understanding water uptake in plants and related research questions (e.g. uptake depths, non-steady-state of transpiration, impact on groundwater re...
Presentation
Full-text available
Photosynthetic models are widely used to estimate photosynthetic rate for leaves and canopies. Canopy-scale measurements have mostly been based on eddy-covariance data, as have model parameterizations. There has been no adequate means of testing the resulting estimates of gross primary production (GPP). It has been noted that it should be possible...
Presentation
Full-text available
Terrestrial ecosystems play a very significant role in driving two large global cycles: the carbon and the water cycle. The balance between these two cycles can be described from the plant perspective as water-use efficiency (WUE), briefly photosynthesis/transpiration (A/E). WUE can be defined and interpreted on leaf- to plant- to stand or ecosyste...
Article
Full-text available
Woody plants vary in their adaptations to drought and shade. For a better prediction of vegetation responses to drought and shade within dynamic global vegetation models, it is critical to group species into functional types with similar adaptations. One of the key challenges is that the adaptations are generally determined by a large number of pla...
Article
Cellular respiration via the alternative oxidase pathway (AOP) leads to a considerable loss in efficiency. Compared to the cytochrome pathway (COP), AOP produces 0‐50% as much ATP per carbon (C) respired. Relative partitioning between the pathways can be measured in vivo based on their differing isotopic discriminations against ¹⁸O in O2. Starting...
Article
Full-text available
In this commentary, we summarize and build upon discussions that emerged during the workshop "Isotope-based studies of water partitioning and plant-soil interactions in forested and agricultural environments" held in San Casciano in Val di Pesa, Italy, in September 2017. Quantifying and understanding how water cycles through the Earth's critical zo...
Preprint
Full-text available
Handbook for standardized methods in terrestrial global change experiments
Article
Full-text available
In this commentary, we build on discussions that emerged during the workshop "Isotope-based studies of water partitioning and plant-soil interactions in forested and agricultural environments" held in San Casciano Val di Pesa, Italy, in September 2017. Quantifying and understanding how water cycles through the Earth's critical zone is important to...
Article
Mountainous terrain creates variability in microclimate, including nocturnal cold air drainage and resultant temperature inversions. Driven by the elevational temperature gradient, vapor pressure deficit (VPD) also varies with elevation. Soil depth and moisture availability often increase from ridgetop to valley bottom. These variations complicate...
Article
Full-text available
Apparent net uptake of carbon dioxide (CO2) during wintertime by a ∼ 90-year-old Scots pine stand in northern Sweden led us to conduct canopy decoupling and subcanopy advection investigations over an entire year. Eddy covariance (EC) measurements ran simultaneously above and within the forest canopy for that purpose. We used the correlation of abov...
Article
Trees are able to reduce their carbon (C) losses by refixing some of the CO2 diffusing out of their stems through corticular photosynthesis. Previous studies have shown that under ideal conditions the outflowing CO2 can be completely assimilated in metabolically active, young stem and branch tissues. Fewer studies have, however, been carried out on...
Article
Mixed species stands are on the advance in Central Europe and many recently published studies have reported that they can overyield monocultures in terms of volume growth. However, as forest research has in the past been focused on monocultures, knowledge of how mixed-species stands and monocultures compare in terms of wood quality remains limited....
Article
Net uptake of carbon dioxide (CO2) was observed during the winter when using the eddy covariance (EC) technique above a ~90-year-old Scots pine (Pinus sylvestris L.) stand in northern Sweden. This uptake occurred despite photosynthetic dormancy. This discrepancy led us to investigate the potential impact of decoupling of below- and above-canopy air...