A. R. Mackenzie

A. R. Mackenzie
University of Birmingham · School of Geography, Earth and Environmental Sciences

BSc, PhD

About

238
Publications
52,883
Reads
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6,350
Citations
Introduction
The Birmingham Institute of Forest Research (BIFoR) is currently being established, bringing together research groups from across campus. BIFoR will focus on two linked challenges: the impact of climate and environmental change on woodlands; and the resilience of trees to pests and diseases.
Additional affiliations
November 2013 - present
University of Birmingham
Position
  • Director, Birmingham Institute of Forest Research
Description
  • The Birmingham Institute of Forest Research (BIFoR) aims to be an internationally leading Institute that will address the impact of climate and environmental change on woodlands and the resilience of trees to invasive pests and diseases.
May 1999 - July 2011
Lancaster University
November 1989 - April 1999
University of Cambridge
Position
  • Coordinator, Centre for Atmospheric Science

Publications

Publications (238)
Article
Full-text available
In the future, with elevated atmospheric CO2 (eCO2), forests are expected to increase woody biomass to capture more carbon (C), though this is dependent on soil nutrient availability. While young forests may access unused nutrients by growing into an unexplored soil environment, it is unclear how or if mature forests can adapt belowground under eCO...
Article
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The global climate is changing, and local authorities must respond to changing climate risk to protect citizens and the urban environment in which they live. This paper presents an open access approach to map climate risk and vulnerability using Birmingham, the UK's second city as a case study. A Climate Risk and Vulnerability Assessment (CRVA) was...
Article
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Background The manual study of root dynamics using images requires huge investments of time and resources and is prone to previously poorly quantified annotator bias. Artificial intelligence (AI) image-processing tools have been successful in overcoming limitations of manual annotation in homogeneous soils, but their efficiency and accuracy is yet...
Article
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Newly-planted forests require careful management to ensure the successful establishment of young trees; this can include herbicide application, irrigation, fertilization, or a combination of these treatments. The global rise in nitrogen (N) fertilizer application in managed forest plantations is driven by policies aiming at rapid tree growth and ca...
Article
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Enhanced CO2 assimilation by forests as atmospheric CO2 concentration rises could slow the rate of CO2 increase if the assimilated carbon is allocated to long-lived biomass. Experiments in young tree plantations support a CO2 fertilization effect as atmospheric CO2 continues to increase. Uncertainty exists, however, as to whether older, more mature...
Article
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Acorn production in oak (Quercus spp.) shows considerable inter-annual variation, known as masting, which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year. Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growt...
Article
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Many governments have set ambitious targets for tree planting and increased woodland cover as a key part of actions to reach net‐zero carbon emissions by 2050. However, many uncertainties remain concerning how and where to expand tree cover, what species to plant, and how best to manage new plantations. Much contemporary forestry has been based on...
Article
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Pollen are hygroscopic; therefore, they have the potential to act as cloud condensation nuclei (CCN) in the atmosphere. This could have uncertain implications for cloud processes and climate as well as plant biodiversity and human health. Previous studies have investigated the hygroscopic swelling of pollen, linked to CCN activity by the κ-Köhler t...
Article
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Introduction Insect herbivores and biotrophic pathogens are major stressors influencing natural regeneration in woodlands. Information on the effect of elevated CO 2 (eCO 2 ) on plant-insect-pathogen interactions under natural conditions is lacking. Methods We studied the effects of eCO 2 on leaf-out phenology, as well as on levels of insect herbi...
Article
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The impact of urban morphology on air quality, particularly within deep canyons with longer residence times for complex chemical processes, remains insufficiently addressed. A flexible multi-box framework was used to simulate air quality at different canyon heights (3 m and 12 m). This approach incorporated essential parameters, including ventilati...
Article
Pollen is a major issue globally, causing as much as 40 % of the population to suffer from hay fever and other allergic conditions. Current techniques for monitoring pollen are either laborious and slow, or expensive, thus alternative methods are needed to provide timely and more localised information on airborne pollen concentrations. We have demo...
Preprint
Full-text available
Predicting how increased atmospheric carbon dioxide levels will affect water usage by whole mature trees remains a challenge. The present study focuses on diurnal (i.e. daylight) water usage of old growth oaks within an experimental treatment season from April to October inclusive. Over five years, from 2017 to 2022, we collected 12,259 days of ind...
Article
Full-text available
Icelandic dust can impact the radiative budget in high-latitude regions directly by affecting light absorption and scattering and indirectly by changing the surface albedo after dust deposition. This tends to produce a positive radiative forcing. However, the limited knowledge of the spectral optical properties of Icelandic dust prevents an accurat...
Article
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Afforestation, as one of the major drivers of land cover change, has the potential to provide a wide range of ecosystem services. Aside from carbon sequestration, afforestation can improve hydrological regulation by increasing soil water storage capacity and reducing surface water runoff. However, afforested areas are rarely studied over time scale...
Article
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Arthropods underpin fundamental ecological processes such as herbivory, pollination and nutrient cycling, and are often responsive to subtle changes in environmental conditions. Thus, changes in their abundance and phenology may be crucial indicators of system-wide responses to climate change. The new Birmingham Institute for Forest Research (BIFoR...
Preprint
Full-text available
Pollen are hygroscopic and so have the potential to act as cloud condensation nuclei (CCN) in the atmosphere. This could have yet uncertain implications for cloud processes and climate. Previous studies have investigated the hygroscopic swelling of pollen, linked to CCN activity by the κ-Köhler theory, using methods that follow observed mass increa...
Preprint
Full-text available
Icelandic dust can impact the radiative budget in high-latitude regions directly by affecting light absorption and scattering and indirectly by changing the surface albedo after dust deposition. This tends to produce a positive radiative forcing. However, the limited knowledge of the spectral optical properties of Icelandic dust prevents an accurat...
Article
Full-text available
In forests, the residence time of air – the inverse of first-order exchange rates – influences in-canopy chemistry and the exchanges of momentum, energy, and mass with the surrounding atmosphere. Accurate estimates are needed for chemical investigations of reactive trace species, such as volatile organic compounds, some of whose chemical lifetimes...
Article
Pollen allergies affect a significant proportion of the global population, and this is expected to worsen in years to come. There is demand for the development of automated pollen monitoring systems. Low-cost Optical Particle Counters (OPCs) measure particulate matter and have attractive advantages of real-time high time resolution data and afforda...
Article
Full-text available
The extent to which nitrogen dioxide (NO 2 ) undergoes complex chemical-transport processes near strong nitrogen-oxide sources in street canyons is not fully understood. A multi-box framework with volatile organic compound (VOC) chemistry has been evaluated against large-eddy simulation (LES) data and observations, and then used to simulate NO 2 at...
Article
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Optimal stomatal theory predicts that stomata operate to maximise photosynthesis (Anet) and minimise transpirational water loss to achieve optimal intrinsic water‐use efficiency (iWUE). We tested whether this theory can predict stomatal responses to elevated atmospheric CO2 (eCO2), and whether it can capture differences in responsiveness among wood...
Preprint
Full-text available
The capacity to predict NO2 and the total oxidant (Ox = NO2 + O3) within street canyons is critical for the assessment of air quality regulations aimed at enhancing human wellbeing in urban hotspots. However, such assessment requires the coupling of numerous processes at the street-scale, such as vehicular emissions and tightly coupled transport an...
Article
Increasing CO2 levels are a major global challenge, and the potential mitigation of anthropogenic CO2 emissions by natural carbon sinks remains poorly understood. The uptake of elevated CO2 (eCO2) by the terrestrial biosphere, and subsequent sequestration as biomass in ecosystems, remain hard to quantify in natural ecosystems. Here, we combine fiel...
Article
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Key message In mature Q. robur, chlorophyll varied with season and canopy height, whilst eCO 2 -driven changes were consistent with M area, highlighting key factors for consideration when scaling photosynthetic processes and canopy N-use. Nitrogen-rich chlorophyll and carotenoid pigments are important in photosynthetic functioning. Photosynthetic p...
Preprint
Full-text available
In forests, air-parcel residence times – the inverse of first-order exchange rates – influence in-canopy chemistry and the exchanges of momentum, energy, and mass with the surrounding atmosphere. Accurate estimates are needed for chemical investigations of reactive trace species, such as volatile organic compounds, some of whose chemical lifetimes...
Article
Full-text available
Forest environments contain a wide variety of airborne biological particles (bioaerosols), including pollen, fungal spores, bacteria, viruses, plant detritus, and soil particles. Forest bioaerosol plays a number of important roles related to plant and livestock health, human disease and allergenicity, and forest and wider ecology and are thought to...
Article
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We outline the principles of the natural capital approach to decision making and apply these to the contemporary challenge of very significantly expanding woodlands as contribution to attaining net zero emissions of greenhouse gases. Drawing on the case of the UK, we argue that a single focus upon carbon storage alone is likely to overlook the othe...
Article
Studying the interactions between the atmosphere and forests is a key component of understanding forest ecosystems and the interplay between our atmosphere and the living world.
Article
Full-text available
Forests cover nearly a third of the Earth's land area and exchange mass, momentum, and energy with the atmosphere. Most studies of these exchanges, particularly using numerical models, consider forests whose structure has been heavily simplified. In many landscapes, these simplifications are unrealistic. Inhomogeneous landscapes and unsteady weathe...
Article
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The Amazon rainforest is the largest source of isoprene emissions to the atmosphere globally. Under low nitric oxide (NO) conditions (i.e. at NO mixing ratios less than about 40 pptv), isoprene reacts rapidly with hydroxyl (OH) to form isoprene-derived peroxy radicals (ISOPOO), which subsequently react with the hydroperoxyl radical (HO2) to form is...
Research
Urban design influences where air pollution is produced, how it disperses through streets and neighbourhoods, and where, when, and how much people are exposed. This guide explains how good urban design can improve air quality using simple principles that benefit air quality and providing practical guidance and illustrations outlining how to impleme...
Preprint
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Urban residents are frequently exposed to high levels of traffic-derived air pollution for short time periods, often (but not exclusively) during commuting. Although chronic air pollution exposure and health effects, including neurological effects on children and older adults, are known to be correlated, causal effects of acute pollution exposure o...
Article
Computational fluid dynamics models are resource-intensive, particularly when complex chemical schemes are implemented, and this computational expense limits their use in sensitivity analyses. We propose a flexible multi-box model that permits spatial disaggregation of sources and depositions to simulate the transportations and distributions of che...
Preprint
Full-text available
Current carbon cycle models attribute rising atmospheric CO 2 as the major driver of the increased terrestrial carbon sink, but with substantial uncertainties. The photosynthetic response of trees to elevated atmospheric CO2 is a necessary step, but not the only one, for sustaining the terrestrial carbon uptake, but can vary diurnally, seasonally a...
Preprint
Full-text available
Forest environments contain a wide variety of airborne biological particles (bioaerosols), including pollen, fungal spores, bacteria, viruses, plant detritus and soil particles. Forest bioaerosol plays a number of important roles related to plant and livestock health, human disease and allergenicity, forest and wider ecology, and are thought to inf...
Article
Full-text available
The development process at the site/building scale is a multi-objective process requiring the cooperation of many professions and other stakeholders. The addition of multiple sustainability objectives, often seemingly unrelated (economic versus environmental versus social) in a rapidly changing global urban context, further constrain and complicate...
Article
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The benefits of ‘green infrastructure’ are multi-faceted and well-documented, but estimating those of individual street-scale planting schemes at planning can be challenging. This is crucial to avoid undervaluing proposed schemes in cost–benefit analyses, and ensure they are resilient to ‘value engineering’ between planning and implementation. Here...
Article
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The uptake of aquatic nutrients can represent a major pathway for their removal from river ecosystems and is a key control on nitrogen and carbon export from watersheds. Our understanding of temporal variability in nutrient mass balance is incomplete as conventional methods for estimating uptake rates are suited to low-frequency analysis. Here, we...
Article
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Cities intimately intermingle people and air pollution. It is very difficult to monitor or model neighbourhood-scale pollutant transport explicitly. One computationally efficient way is to treat neighbourhoods as patches of porous media to which the flow adjusts. Here we use conceptual arguments and large-eddy simulation to formulate two flow regim...
Article
Full-text available
The ecosystem services provided by forests modulate runoff generation processes, nutrient cycling and water and energy exchange between soils, vegetation and atmosphere. Increasing atmospheric CO2 affects many linked aspects of forest and catchment function in ways we do not adequately understand. Global levels of atmospheric CO2 will be around 40%...
Presentation
Full-text available
Poster presentation describing a forthcoming systematic review and meta-analysis on volatile organic compounds (VOCs) released by plants under herbivory, and how those VOCs are moderated by elevated CO2 and ground level ozone.
Article
Full-text available
Iceland is a highly active source of natural dust. Icelandic dust has the potential to directly affect the climate via dust–radiation interaction and indirectly via dust–cloud interaction, the snow/ice albedo effect and impacts on biogeochemical cycles. The impacts of Icelandic dust depend on its mineralogical and chemical composition. However, a l...
Article
The demand for charcoal in Africa is growing rapidly, driven by urbanization and lack of access to electricity. Charcoal production and use, including plastic burning to initiate combustion, release large quantities of trace gases and particles that impact air quality and climate. Here, we develop an inventory of current (2014) and future (2030) em...
Article
Full-text available
Iceland is a highly active source of natural dust. Icelandic dust has the potential to affect directly the climate via dust-radiation interaction, and indirectly via dust-cloud interaction, snow/ice albedo effect and impacts on biogeochemical cycles. The impacts of Icelandic dust depend on its mineralogical and chemical composition. However, lack o...
Article
Traffic-generated ultrafine particles (UFPs) in the urban atmosphere have a high proportion of their composition comprised of semi-volatile compounds (SVOCs). The evaporation/condensation processes of these SVOCs can alter UFP number size distributions and play an important role in determining the fate of UFPs in urban areas. The neighbourhood-scal...
Article
Full-text available
This study proposes an approach for estimating the emission of soot, carbon monoxide (CO) and carbon-dioxide (CO) from a typical gas flare. The estimations depend on the quantity and varying composition of the 2 natural gas, flame dynamics (represented by the fire Froude number, Fr) and the equivalence ratio, f, of the fuel-f air mixture. Soot emis...
Article
Full-text available
As a result of differences in heat absorption and release between urban and rural landscapes, cities develop a climate different from their surroundings. The rise in global average surface temperature and high rates of urbanization, make it important to understand the energy balance of cities, including whether any energy-balance-related patterns e...
Poster
Full-text available
Proposed PhD research into chemical communication between trees (Populus nigra) and other ecosystem members (Operophtera brumata, Agrypon flaveolatum) under elevated CO2 and ground level ozone.
Article
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We present allometric-scaling relationships between non-point-source emissions of air pollutants and settlement population, using 3030 urban settlements in Great Britain (home to ca. 80% of the population of that region). Sub-linear scalings (slope < 1.0; standard error on slope ~ 0.01; r2 > 0.6) were found for the oxides of nitrogen (NOx) and micr...
Article
Traffic is the key source of ultrafine particles (UFPs, particulate matter with a diameter less than 0.1 μm or 100 nm) in most urban areas. The traffic-generated UFPs vented out from an urban street mix with overlying ‘urban background air’ and are diluted whilst also undergoing change due to condensation/evaporation and other aerosol microphysics....
Article
Full-text available
In 2017, the Birmingham Institute of Forest Research (BIFoR) began to conduct Free Air Carbon Dioxide Enrichment (FACE) within a mature broadleaf deciduous forest situated in the United Kingdom. BIFoR FACE employs large scale infrastructure, in the form of lattice towers, forming ‘arrays' which encircle a forest plot of ~30 m diameter. BIFoR FACE c...
Article
We present direct room-temperature vapour pressure measurements for eight semi-volatile n-alkanes of atmospheric importance. Measured vapour pressures range from 8.4 ± 1.6 × 10−3 Pa for C17, to 1.7 ± 0.6 × 10−8 Pa for C31. The new measurements for C17–C18 are in reasonable agreement but at the lower end of values in the literature; the new measurem...
Article
Full-text available
As evidence for the devastating impacts of air pollution on human health continues to increase, improving urban air quality has become one of the most pressing tasks facing policy makers world-wide. Increasingly, and very often on the basis of conflicting and/or weak evidence, the introduction of green infrastructure (GI) is seen as a win–win solut...
Article
Full-text available
Diesel engine emissions are by far the largest source of nanoparticles in many urban atmospheres, in which they dominate the particle number count, and may present a significant threat to public health. This paper reviews knowledge of the composition and atmospheric properties of diesel exhaust particles, and exemplifies research in this field thro...
Article
An understanding of the dispersion and level of emissions source of atmospheric pollutants; whether point, area or volume sources, is required to inform policies on air pollution and day-to-day predictions of pollution level. Very few studies have carried out simulations of the dispersion pattern and ground-level concentration of pollutants emitted...