Download 2 Forest soil functions

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SP0538 Climate change and soil function
Appendix
1 Specific findings from reviewed research projects
1.1 Specific findings from Defra research projects
CC0242 developed a modelling tool for estimating changes in soil carbon stocks due to
changes in land use and management for the National Carbon Dioxide Inventory,
although the system was also applied to possible climate impacts using UKCIP02 and
HadCM3 scenario data. This showed that, assuming constant residue inputs from
vegetation, increased temperatures would lead to considerable losses of soil carbon,
which were generally more marked in the South and East of England since temperature
increases were predicted to be greatest in this region.
CC0333 looked at the timescales of potential farm-level responses and adaptation to
climate change in England and Wales. The majority of crops investigated showed an
increase in yield under climate change, which would potentially mean increased crop
residue inputs to agricultural soils. It was generally concluded that radical adaptations to
climate change would not be necessary. The main exception was winter oilseed rape
which showed yield declines in Southern and Eastern England. Unirrigated root crops
showed small yield increases or decreases on light soils or in Southern England. Warmer
conditions increased the availability of grass on farms in spring, although grazing yields
declined in summer on farms on light land in the South and East. Grain maize generally
gave low yields; yields of sunflower were improved under climate change, which became
competitive with oilseed rape in East Anglia. On arable farms, there were generally less
available work days in spring and autumn, although western locations had increased
autumn workdays. Dry summers in the South and East meant it could become more
profitable to increase irrigation of root crops, and could lead to reduced livestock
production (with a small move from livestock production to arable). Increased irrigation
demands could have implications for regional water management policies. Wetter springs
and drier summers could lead to an earlier end to autumn field work, and have
implications for grassland management and control of herbicide-resistant weeds. The
main adaptations needed would include maximising machinery efficiency, increasing the
areas of spring barley or setaside where winter root crop establishment could become
limiting, and improved shepherding on hill farms to minimize damage to upland pastures.
CC0336 assessed drought risks for UK crops under future climate change. Increased soil
moisture deficit (because of increased evapotranspiration) for winter wheat was
predicted, especially on shallow soils but despite this 15-23% yield increases by the
2050s could be expected due increases in radiation use efficiency because of elevated
CO2 concentrations. Similarly for sugar beet, increases of up to 10% in drought stress
could be expected especially on sandy and shallow soils, but the CO2 effect still led to
increased yields. However, sowing dates could affect achievable yields because of wet
springs which could lead to late sowing and large yield reductions.
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CC0337 developed regional climate change impact studies for East Anglia and Northwest
England, covering several sectors. The impact of climate change depended upon the
region and climate scenario considered. Under the ‘regional enterprise’ scenario in East
Anglia, a reduced area of land was available for agriculture due to increased flooding
risks and urban area, although there was an increase in crop production from sugar beet
and potatoes which needed greater irrigation. There was also increased specialisation in
cereal and root crops. Changes in coastal grazing marsh and freshwater habitats could
occur depending on management and abandonment. Decreased water resources were
predicted as a result of increased domestic and agricultural demands, along with
increased winter flooding and changes in spatial nitrate concentrations. Under the ‘global
sustainability’ scenario, increasing sugar beet and potato production were also predicted,
along with greater irrigation needs, more break crops, decreased water resources and
slight improvements in nitrate concentrations. In the Northwest, the ‘regional enterprise’
scenario led to increasing sugar beet and potato production with little need for irrigation,
and some conversion of grassland to arable, most marked in the uplands. The ‘global
sustainability’ scenario would lead to a reduction in permanent grass and conversion to
arable crops, such as peas, beans, rape, sugar beet, and linseed with little need for
irrigation. Overall, the project highlighted the importance of socio-economic trends in
determining cropping patterns.
CC0339 looked at the effects of climate change on agricultural land use in England and
Wales. The project predicted that growing seasons would remain insufficient for
considerable production of either sunflowers or maize. CC0357 aimed to identify and
cost adaptive responses of agriculture under different climate change scenarios. Important
yield effects were shown for wheat, which could be offset by introduction of new
cultivars, and irrigation was unlikely to be cost effective unless already installed.
Substitution of grain maize for wheat was unlikely unless yields changed a lot. Potato
yield losses could be offset by new cultivars, although Cornwall, providing the earliest
crops, may not be able to adapt to the longer growing season. Cauliflower yields
increased in Northern England and might require more spraying for aphids. A general
increase in grass yields was expected, with a reduction in N inputs and an increase in
legume usage.
CC0372 investigated the implications of the wet autumn of 2000 for agriculture. Wet
autumns affected root crop harvests, winter vegetables and the establishment of later
crops. A smaller area of winter crops were sown, compensated by spring crops, although
weed control was difficult and greater than normal spring herbicide use resulted. Poor
and damaged soil structure resulted from the need to work in wet conditions, when it was
difficult to use minimal cultivation techniques. Increased erosion risks resulted in flood
sensitive areas, especially after autumn cultivations, with knock-on impacts on P loss on
suspended particles. Phosphorus, nitrogen, sulphur and pesticide leaching losses also
resulted from high rainfall, whilst warm and wet soils resulted in greater nitrous oxide
losses. CC0378 conducted a scoping study on the potential impacts of climate change on
nutrient pollution of water from agriculture. Increases in the crop growing season were
most marked in the Southeast of the country, and changing rainfall patterns were
predicted to lead to increased nutrient losses in winter. However, there was potential for
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greater N uptake by certain crops, which could reduce the nitrate available for leaching.
Changes in vegetation cover could have implications for P losses via changes in runoff
and soil detachment by rainsplash.
PS2208 assessed the impacts of climate change on the fate and behaviour of pesticides in
the environment. The project suggested that climate change could have very variable
effects on pesticide fate and transport as a result of uncertainties in climate projections,
the complexity of the environment and competing climate-controlled processes which
influence fate and transport. Land use change could have more significant effects on
pesticide fate and transport than the direct effects of climate change. Increased pests,
disease and weed prevalence could lead to wider and more frequent pesticide
applications, although climatic changes could possibly lead to more rapid degradation
rates. Increased winter rainfall would likely lead to more rapid pesticide movement, more
bypass and drain flow, and surface waters receiving more pesticides from surface runoff,
erosion and sediment. Changes in soil water content could lead to changes in degradation
rates and residues. For instance, higher winter soil water contents could cause increased
degradation. Dryer warmer summers might lead to increased cracking of shrink-swell
clays and therefore greater bypass flow in winter. However, dryer summer soils might
result in lower biodegradation potential and thus longer pesticide persistence. More
intense and frequent storms might lead to more flushing of pesticides to groundwater,
whilst higher groundwater levels particularly in winter, could result enhanced transfer to
groundwater. Further work, including modelling, was recommended.
WT01001 revisited the impact of climate change on the demand for water, predicting
likely increases in water demands in the agricultural, domestic and commercial sectors.
Within agriculture, this was a result of changes in plant physiology, soil water balances,
cropping mixes, cropping patterns (making use of longer growing seasons), and changes
in food demands. Increased demands for irrigation were notable in Eastern, Southern and
Central England, of the order of 20% and 30% by the 2020s and 2050s respectively.
SP0511 developed a UK soils database for modelling soil C fluxes due to land use
change for the national carbon dioxide inventory, which was further used in CC0242,
discussed earlier. SP0306 investigated whether there were critical levels of soil organic
matter for maintaining soil functions. Declines of around 5% in cereal yields had been
observed if SOC declined to around 1%, and this decline could not be corrected by
adding fertilisers. Soil structure (aggregate stability) could deteriorate unacceptably if
SOC concentrations fell much below 2%. In the soils databases from England and Wales,
SOC explained around 10% in the variability of water holding capacity of topsoils, and
made no contribution to the water holding capacity of subsoils. Soil structure was shown
to be affected by reduced levels of SOC – there was a marked decrease in the
dispersibility of aggregates for soils under arable cultivation where SOC was below
around 1.5% SOC. SOC made little contribution to the plastic limit of soils (how readily
soils deform) and none to the soil liquid limit (the point above which soils lose their
mechanical strength). SOM was shown to be a considerable source of nutrients,
especially on sandy, clayey and chalk soils. Use of the RothC soil C model with the
UKCIP Medium-high scenario indicated that equilibrium SOC could decline by about
0.5% - and Eastern England could experience considerable declines in SOC.
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SP0519 assessed critical levels of soil organic matter in surface soils in relation to soil
stability, function and infiltration. This suggested that there was a critical level of SOC
to maintain aggregate stability. Intense rainfall was found to displace, entrain and
transport soil containing a greater proportion of SOC and fine particles than bulk soil.
Thus the particle and stability conferring parts of soil were bring eroded and transported
away. Grassland soils were found to be relatively stable to rainfall. Silt-rich soils, low
in SOC, were found to be susceptible to damage, loss of sediment and surface runoff of
rain, with conventional tillage having an additional negative impact. In light of this, the
project recommended that SOC should be increased and maintained by land management.
SP0523 developed economically and environmentally sustainable methods of C
sequestration in agricultural soils. In conclusion, the best scenarios of land management
for C sequestration involved converting arable land and marginal grassland to woods.
Arable land management (set aside, field margins, residue returns, manures and tillage)
was also found to be of merit. CC0375 aims to develop a soil properties database for
England and Wales for climate impact studies.
1.2 Specific findings from NERC research projects
Specific findings are not reported since final/interim research reports were not available
from the internet.
1.3 Specific findings from BBSRC research projects
Specific findings are not reported since final/interim research reports were not available
from the internet.
1.4 Specific findings from Environment Agency research
projects
Specific findings are not reported since final/interim research reports were not available
from the internet.
1.5 Specific findings from EPSRC research projects
Specific findings are not reported since final/interim research reports were not available
from the internet.
1.6 Specific findings from ESRC research projects
The project ‘Environmental and distributional impacts of climate change in Scotland’
included land cover effects, biodiversity and a modelling strategy. This utilised UKCIP
climatic scenarios, a crop yield estimator and a farm management decision model. This
showed that both elevated CO2 and climate change had positive effects on crop yields
with the exception of the site in south east Scotland which suffered from water stress.
Land use changes were likely to include a move towards spring crop varieties although
some more significant changes were predicted to occur. There were variable effects on
biodiversity, depending on the implied changes in land management, although effects
were generally not large. Increased fertiliser inputs were needed under climate change in
some sites.
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1.7 Specific findings from NAW research projects
NAW conducted a scoping study on the impacts of climate change in Wales to 2080
involving the University of Bangor, CEH, CRU-UEA and ECOTEC. Key biodiversity
effects included a northwards migration of sensitive species and possible losses of coastal
and lowland zones by increased storms and sea level rise. It was considered possible that
bogs would dry out unless artificially managed; upland ecosystems could be particularly
vulnerable, especially in artic-alpine systems where soils play a crucial role.
Archaeological sites in low-lying regions could suffer from flooding, subsidence and
severe storms. In agriculture, increased crop growth from elevated CO2 concentrations
might be offset by yield reductions from increased temperatures although grass yields
were likely to increase. Agriculture might be able to adapt by changing crops or varieties
(e.g. fodder maize), and by conversion of livestock to arable farming, although increased
irrigation needs were likely in summer. Difficulties in getting machinery on to land in
autumn and winter might be encountered. Land use is likely to be affected by market
forces, with small projected impacts on upland systems but significant increases in arable
land areas in East Wales. Reduced water supply and increased demands would put
pressure on increasing needs for irrigation. Flooding could also lead to some loss of
arable land in coastal zones. Forests could be damaged by storms and high winds, and
more frequent fires in dry summers. Land use changes were likely to lead to losses in
biodiversity and some terrestrial and freshwater habitats. In particular, coastal
floodplains and grazing marshes could be lost due to sea level rise and storm damage
although this loss could be mitigated by managed retreat elsewhere; montane habitats
could suffer from increased summer temperatures and droughts and warmer winters
making the environment less suitable for arctic-alpine species; lowland raised bogs could
be damaged by warmer summers and droughts; blanket bogs could suffer minor or
considerable impacts depending on the severity of climate change – possibly irreversible
changes in shallow peats could occur if they dried out and oxidised with knock on
impacts on wetlands, aquatic habitats and climate feedbacks from GHG fluxes. The
historic environment might suffer from lower or fluctuating water tables and pH changes
which could have a significant impact on the preservation of artefacts. Climate change
could also impact wetland and waterlogged habitats which are notable areas of
archaeological preservation. The projected increase in arable agriculture might increase
destruction of archaeological remains and new woodlands could also have a negative
impact. However, whilst drier conditions in summer might improve reconnaissance and
excavation the benefits of this would probably be outweighed by negative impacts.
Increased rainfall patterns could also have an impact on land stability and landslips.
1.8 Specific findings from SEERAD research projects
SEERAD commissioned a scoping study on the implications of climate change on
Scotland. The project discussed direct impacts (as a result of changes in climatic
variables) and indirect impacts (as a result of measures to reduce GHG emissions). This
suggested that climate change might be beneficial to forestry due to increased tree growth
under higher temperatures, increased afforestation, and biomass fuel usage although
excess wind could have a negative impact and moisture stress might be an issue in
Southeast Scotland. Subsidy changes were likely to be more important that direct climate
impacts on agriculture although more diverse and valuable crops (sugar beet, fodder
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maize, oilseed rape) may be grown in the future. Climate change might result in lower
fertiliser usage although water stress could affect cropping in Southeast Scotland and
high water demand crops such as potatoes. Water logging could cause problems with
fieldwork and harvesting. Increased demands for water from house building and
irrigation for horticulture and agriculture (especially in East Lothian and Fife) were
likely. The scoping study was one of the few projects reviewed to have a section
specifically covering climate impacts on soils. This noted that increased temperatures
could increase organic matter decomposition and nutrient release from soils, possibly
increasing plant growth, whilst increased rainfall could increase atmospheric N
deposition and elevated CO2 concentrations would enhance plant growth. The vegetation
of heather moorlands and high-altitude heaths are adapted to nutrient-poor soil conditions
and enhanced soil fertility under climate change could result in invasion from competitive
species. Predicted changes in climate were unlikely to have large effects on erosion in
Scotland although in high altitude soils where freeze-thaw driven solifluction could
decrease, this could increase competition between low productivity plant species and
more vigorous species. Increases in temperature could increase both the rates of peat
formation and decay, and thus changes in rainfall could have important effects on the fate
of peatlands under climate change. Lower rainfall would likely lead to peat loss and CO2
release; wetter conditions would result in more peat formation and CH4 emissions.
Afforestation could dry peats and offset the benefits of carbon uptake in trees. The
transport sector could be affected by increased landslides, and flooding and drainage
problems.
A further scoping study was developed to identify potential adaptation strategies for
climate change in Scotland. This suggested that agricultural crop ranges might spread
northwards; high-quality horticultural crops might be susceptible to negative impacts; the
potential for soils to support agriculture was strongly depended on changes in soil water;
increased soil erosion and leaching could result from greater winter rainfall; problems of
vehicular access to agricultural land were likely due to waterlogged soils in autumn and
winter; greater crop yields might result from longer growing seasons and reduced frost
days although increasing rainfall could limit these benefits and those of increased
temperatures and CO2 levels.
SEERAD also commissioned a review of the contribution of organic soils under different
land uses to climate change. This focussed on GHG fluxes historically rather than likely
future impacts, but recommended development of a process-based model for future work.
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Table 1 Effects of climate change on soils for agriculture and forestry
Increasing summer
temperature
Increasing winter temperature
More extreme high
temperature
Less extreme low temperature
Higher winter rainfall
Less summer rainfall
Loss of soil organic matter
Decreased moisture retention
Increased mineralization
Loss of structural stability
Reduced tilth mellowing
Increased pest and disease persistence in soil
Earlier start to growing season
More extreme high temperatures
Livestock heat stress
(Forest fires)
Crop failure
No significant effect
Decreasing tilth mellowing-freeze-thaw
Decreased access for forestry
More persistent pests and diseases in soil, therefore
increase use of pesticides or management
Longer growing season leads to higher moisture deficits
No significant effect
Reduced machinery work days/stocking capacity,
leading to soil structural damage.
Reduced farm waste disposal opportunities.
Surface runoff and erosion – control with catchment
sensitive farming and single farm payment.
Nutrient leaching, and methane and N2O flux
More compaction, smearing, poaching
Increased nutrient/chemical leaching
Decreased opportunity for farm waste disposal
Increased waterlogging – reduced stability
Yield reduction and harvest timing.
Loss of soil organic matter (mineralization and N2O
flux)
Potential for loss of rainfall surfeit leading to salinisation
Fire risk for woodland and peats
Crop failure – increased litter input
Reduced yield – reduced litter input
Timing issues
Abstraction license issues
Earlier harvest leading to increased erosion
Re-cropping in autumn – problems with germination
Lower methane and higher N2O
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More intense downpours
Sea level rise and increased
coastal flood risk
Possibly more winter storms
Rainfall runoff lost to crop available water.
Increased frequency/severity of large erosion events (rill
and gully formation).
Direct crop damage and lodging.
Difficulty timing machinery.
Less infiltration – confound drought
Pesticide/herbicide application – ease of application
Compaction
Smearing
Poaching
Direct loss of soils on Best and Most Versatile
agricultural land.
Rising water table and encroachment of salt water
Limits scope for woodland thinning and pushes
management towards clear felling.
Erosion and crop damage
Over-turning – soil damage
Soil sealing/crusting
Reduced forestry rotation height
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Table 2 Effects of climate change impacts on soil, air and water interactions
Increasing summer
Increased GHG fluxes?
temperature
Reduced soil moisture, aquifer recharge
Increased water demands
Reduced OM and CEC
Increased autumn flush of pollutants
Increased pesticide applications (arable and livestock?)
Erosion from upland cultivation?
Increasing winter temperature Increased GHG fluxes?
Reduced OM and CEC
Increased pesticide applications?
Nutrient pool exhaustion
Farming operations/livestock – soil structure
More extreme high
temperature
Water stress/demands
Wind erosion
Cracking clays – bypass flow
Less extreme low temperature Freeze-thaw / tillage
Increased N2O flux
Increased pesticide loadings (arable and livestock)
Higher winter rainfall
Increased runoff, erosion, flooding
Diffuse pollution
Forest wind-throw
Inundation of sewage works
Increased N2O fluxes
Less summer rainfall
Urban first flush pollution events
Water demand stress, aquifers
Pollutant build up in soils
Less N2O, CO2 mineral soils
Less CH4, more CO2 organic soils
Wind erosion, cracking
Fires: erosion risk, GHG
More intense downpours
Pollutant flushing
Extreme erosion, flooding, flash floods
Reduced aquifer recharge, surface runoff
Sediment loss
Capping – gaseous exchange
Sea level rise, coastal flood
Saline intrusion, irrigation, drinking water
risk
Nutrient flushing e.g. Norfolk Broads
Damage to soil structure (salt)
Increased N2O and CH4 fluxes
More winter storms
As extreme rainfall
Soil disturbance plus windthrow in forests
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Table 3 Effects of climate change impacts on soil biodiversity
Increasing summer
Deeper burrowing by worms,
temperature and less summer
More flushes in activity as a result of an enhanced
rainfall
“priming effect” leading to potential increases in ground
and surface water eutrophication,
Changes in competitive advantage leads to change in
species composition – will this still support the
existence of conservation target assemblages?
Changes in structure will lead to changes in gaseous
exchange and physical access
Changes in the “workable window”.
Increasing winter temperature Increasing anaerobicity, increases in methane,
higher winter rainfall and less ammonium and nitrogen emissions
extreme low temperature
Loss of vernalisation leading to loss of vernal species
Increases in survival of pathogens/herbivorous pests
More extreme high
Potential population crashes
temperature
Skewed gender profile of offspring?
More intense downpours and
thunderstorms
Sea level rise, coastal flood
risk
Bursts of “anaerobicity”
Increasing erosion leading to soil loss and
eutrophication of surface waters
Increasing tree strikes and fires
Increasing flooding events
Loss of water storage for human use
Changes in run-off
Salinisation
Managed realignment vs. conservation of habitats
adjacent to sea walls
Loss of species
Migration inland of habitats
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Table 4 Effects of climate change impacts on soils in the landscape and cultural
heritage
Increasing summer
temperature
Increasing winter temperature
General effects on landscape and vegetation due to
climate change and effects through the soil.
More extreme high
temperature
Significant changes to appearance of landscape due to
changing land-use and farming practices, including
changes to crop types; more areas affected by fires
(forest/brush/scrub)
Less extreme low temperature
Higher winter rainfall
Less summer rainfall
More intense downpours
Sea level rise, coastal flood
risk
More winter storms
Flooding more common and widespread; greater risk of
soil erosion and loss of artefacts
Significant changes to appearance of landscape due to
changing land-use and farming practices, including
changes to crop types; more areas affected by fires
(forest/brush/scrub)
Greater risk of soil erosion and loss of artefacts
Loss of coastal land and landscape; loss of
archaeological opportunity
Risk of windthrow and disturbance to archaeological
evidence under woodland; greater risk of catastrophic
landscape change, e.g. after 1987 storm in south-east
England
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Table 5 Effects of climate change impacts on soils in mineral extraction,
construction and the built environment
Increasing summer
temperature
Increasing winter temperature
More extreme high
temperature
Changes in organic matter in materials added as
amendment to soil-forming materials
Increase the rates of gas emissions and volatilisation of
some organic pollutants and mercury
Increase autumn flush of pollutants
Changes in the rate of organic matter mineralisation for
added materials
Soil materials used for construction purposes may
change, which may affect the availability of certain
construction materials, notably quality hardstones and
the location of extraction sites
Increased GHG fluxes
Higher chance of prolong leaching of pollutants
Reduction of the use of de-icing salts, and subsequent
salt contamination of roadside soils
Possible disturbance to building foundations due to
increase likelihood of shrink-swell in soils with shrinkswell clay minerals
Vegetation may be discouraged on clay soils in urban
areas due to compaction
Potential risk of engineered structures based on clay caps
Cracking clays – bypass flow
Effects of soil compaction are likely to be greater in
restored soils
Less extreme low temperature
Higher winter rainfall
Less summer rainfall
Potential increase in leachate generation and release in
landfill gases
Increase release of metals and pollutants into soil and
stream water
Unpredictability of high rainfall events pose the need to
reconsider the risk of geomorphic phenomena (e.g.
landslips, slope failure).
Better planning and factoring unpredictable rainfall
events into surface drainage system on mineral sites
Raised water tables with consequent effect on drainage,
flooding, cesspit and sewage treatment
Increased methane emissions from landfill sites
Possible disturbance to building foundations due to
increase likelihood of shrink-swell in soils with shrinkswell clay minerals
Vegetation may be discouraged on clay soils in urban
areas due to compaction
Potential risk of engineered structures based on clay caps
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More intense downpours
Urban first flush pollution events
Pollutants build up
Window to establish vegetation on newly placed soil
may narrow due to early summer drought and increased
soil strength and root penetration resistance
The risk of erosion may be greater
The provision of irrigation to establish vegetation may
become essential in drier south-east
Pollutant flushing
Elevated risk of soil erosion, with greatest danger on
brownfield land where soil materials may be
contaminated and soil erosion could lead to pollution of
surface waters
Increased risk of flooding, flash floods and surface
runoff again leading to potential risk of surface and
ground water contamination
Capping – gaseous exchange
Sea level rise, coastal flood
risk
More winter storms
2 Forest soil functions – research gaps and needs
The main issues in the research gaps and needs on climate change impacts on forest soil
function are to:
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Integrate intensive woodland ecosystem monitoring in the UK to monitor climate
change impacts and drive model development.
Investigate interactions between climate change and pollutant deposition and
exposure, particularly critical loads (levels) and critical loads exceedance for
woodland in relation to issues of acidification/recovery and eutrophication.
Enhance inventories of carbon stocks and stock changes in woodland soils, and in
particular focus on vulnerable soils.
Promote model development for organic and woodland soils, including the collection
of data required for parameterisation and verification.
Improve estimates of non-CO2 GHG balance (primarily N2O and CH4) of forest soils,
including predictions of the impacts of climate change and the effects of forest
management; extension to broadleaf woodland and deforestation activities is
important.
Investigate the effects of climate change (principally soil moisture content and
temperature) on mycorrhizal associations.
Assess the effects of climate change on soil erosion and interactions with forest
management practices.
Collate information on the likely effects of climate change on soil chemical and
physical properties and how archaeological remains may be affected.
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The research carried out in the UK on the effects of climate change on forest soil function
is limited. However, the growing interest in forests and the potential of forest soils for
carbon mitigation necessitates immediate action for further research in this area. The
research areas highlighted in this section deal specifically with soil function. However,
the response of soil function to climate change is also dependent, both directly and
indirectly, on the response of vegetation to climate change. Uncertainty in vegetation
responses (as outlined below) should therefore be considered in future assessments of the
impacts of climate change on soil function, while future research into these areas of
uncertainty should include an assessment of implications for soil function:
 The response of trees beyond the sapling stage to rising CO2 levels.
 Interactions between rising CO2 levels, air pollution and a changing climate.
 The response of woodland to climatic extremes as compared to mean climate.
 Changes in the incidence of insect pest and pathogen outbreaks.
Long-term monitoring is an essential component of research into the effects of climate
change on soil function; without monitoring data, models cannot be adequately validated
or verified and their predictions must be viewed with caution. Soil inventories may not be
able to provide the required level of detail, in isolation, and their ability to identify
change may be compromised by changes in other environmental or land use related
factors. Only intensive monitoring at the ecosystem level (ie including aboveground
components and processes) can provide this level of detail, including signals warning of
the early stages of climate change induced changes to soil function. At present, long-term
monitoring at this level of detail is primarily undertaken through the Environmental
Change Network (ECN) and the EU/UNECE ICP-Forests Intensive Forest Monitoring
Network (Level II). Woodland land cover is limited in the former, while the latter is
largely restricted to managed forests. Ensuring compatibility across the two networks,
with commonality of protocols developed specifically for woodland ecosystems would
provide a more robust data-set, while targeted monitoring of natural ecosystems thought
to be most at risk to climate change should be considered. There is some uncertainty over
the future of both Level II and ECN. In the case of Level II, European Union co-funding
is uncertain beyond 2006 while the voluntary basis of the funding of ECN by
participating organisations cannot be guaranteed in the long-term. Long-term monitoring
at these sites should not be discontinued for financial reasons without due consideration
of additional funding streams.
Interactions between climate change and the impacts of pollutant deposition are
uncertain. When the effects of climate change on critical loads (of pollutants) are
considered, sensitivity analyses of key parameters indicate that further research should be
focussed on the effects of nitrogen in the forest environment. Changing rainfall patterns
and their potential to enhance nitrate leaching, together with the effects of rising
temperature on mineralisation rates are areas of particular concern and uncertainty.
The role that soils plays in diffuse pollution is an area of particular concern to regulatory
agencies and directives.
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The greenhouse gas balance of forest soils is a key area of uncertainty in predictions of
future GHG emissions scenarios. While forest inventories can provide detailed
information on changes in above-ground carbon stocks, assessment of carbon stocks and
stock changes in forest soils is extremely limited, not only in the UK, but across Europe
in general. An enhanced inventory of carbon stock changes in forest soils therefore
warrants consideration. However, future predictions can only be made on the basis of
robust models which, at present, represent forest soils poorly. The collection of
appropriate data for parameterising and validating these models, including inputs (eg
litter, root exudates), outputs (DOC, gaseous emissions) and the chemical
characterisation of soil organic matter, is an essential component of model development.
These data should not be restricted to surface horizons, but include the entire soil profile.
A key issue is the widespread evidence of rising DOC levels in waters which is directly
related to water quality. Another particular area of concern is the effect of forest
harvesting and deforestation on soil C storage. To date, research has concentrated on
conifer woodland and upland soils; there is a need for these studies to be extended to
include native woodland expansion, especially on organic soils.
The effects of climate change on the balance of non-CO2 GHGs represents an even
greater area of uncertainty than for carbon dioxide. Although for both N2O and CH4,
exchange in forest soils is limited relative to other sources (and sinks) at a national scale,
it is important that the non-CO2 GHG balance of forest soils is better quantified,
particularly in the context of changes in forest and land management including
deforestation.
Mycorrhizal associations enhance the ability of trees to extract nutrients from soils, while
there is also limited evidence that they may confer some protection against soil-borne
pathogens. Although research effort into elucidating the effects of both pollutant
deposition and atmospheric CO2 levels on mycorrhizae is continuing, knowledge of how
mycorrhizal associations vary in response to other environmental factors is more limited.
The same considerations apply more generally to the wider soil microflora.
There is little or no direct research relating specifically to climate change and the
implications for archaeological resources. Although some inferences may be drawn from
predictions of changes in soil chemistry that may derive from other studies, there is an
urgent need to draw this information together.
15
Appendix
SP0538 Climate change and soil function
Table 6. Summarised peer-reviewed literature on the effects of climate change on forest soil functions in the UK.
Reference
Soil type,
Objectives and
Experimental set up
Naden, P.S. and Watts,
C.D. (2001). Estimating
climate-induced change
in soil moisture to five
areas of ecological
interest in the U.K.
Climate change 49,
411-440.
Five soil types were
identified:
1) clay soils on an
impermeable or
slowly permeable
substrate;
2) well-drained loams
on a macroporous
substrate (e.g. chalk
or limestone)
3) sandy soils on a
macroporous
substrate
4) soil types developed
on hard impermeable
rocks (e.g. lithosol);
5) peat.
Bridget, A.E., Beier, C.,
Estiarte, M., Tietema,
Modelled climate-induced
changes on soil moisture
at the landscape level
(100-250 km2) are
assessed using the UK
Hadley Centre Transient
(UKTR) model (with 20302040 and 2060-2070
scenarios). This is
expressed in terms of
distribution of monthly
mean soil moisture values
on a 50 m grid, which
include the lateral
movement of water and
the effects of typography
and soil type.
Four soil types were
studied under dominant
Effects on soil
chemistry
Effects on soil physics,
hydrology
The modelling results show:
1) Decrease in modelled PE and
relatively small increase in rainfall
between nowadays and the two
climate change scenarios
contributed to the significant
increase in soil moisture deficit in
northern, middle and southern
England in comparison with
Scotland where a slight decrease in
soil moisture deficit is modelled.
2) There is a seasonal pattern of soil
moisture change depending on soil
type. The largest amount of
modelled changes is for the three
more southerly sites in England in
the clay soils (type 1).
3) Substantial drying does occur under
the above climate change scenario
and the moisture levels in April and
September suggest that clay soils
are more vulnerable in comparison
to loams and sandy soils.
4) Critical soil moisture threshold for
different plant communities are also
discussed and the modelled results
suggest that there may a risk of
reduction in suitable habitat for wetloving plant communities under the
climatic scenario used.
The results indicate:
1) Strong seasonal trends
16
Effects on soil
biology
Uncertainties,
questions and
research gaps
identified
Appendix
SP0538 Climate change and soil function
Kristensen, H.L.,
Williams, D., Peňuelas,
J., Schmidt, I. and
Sowerby, A. (2004).
The responses of soil
processes to climate
change: Results from
manipulated studies of
shrublands across an
environmental gradient.
Ecosystems 7, 625637.
vegetation of ericaceous
shrub Calluna vulgaris:
1)
2)
3)
4)
Sandy podzol (DK)
Peaty podzol (UK)
Sandy podzol (NL)
and
Petrocalcic
calcixerepts (ES)
The effects of soil warming
and drought on soil
respiration net nitrogen
mineralisation and litter
decomposition were
assessed in experiments
in the UK (North Wales),
DK, NL and ES.
2)
3)
4)
5)
6)
in soil respiration rates
were observed, which
closely followed
seasonal patterns of soil
temperature.
There was a trend of
reduced soil respiration
rates of 3%-29% in
response to drought
relative to the control
and 0%-19% increase in
response to warming.
A linear model of soil
respiration dependence
on temperature and soil
moisture which
explained 73% of the
variation is proposed for
the soil at 5-10 cm
depth.
Net N mineralisation
rates were significantly
related to soil moisture
content across the sites,
with positive rates
generally recorded in
soils with moisture
content between 2060%.
Within the soil moisture
range (20%-60%), a
significant linear
response to temperature
was observed. No
significant relationship
with moisture was
observed within this
range.
In the UK site, net N
immobilisation (negative
values) was often
recorded, possibly as a
result as a combination
of wetter and colder
conditions and the low
availability of other
17
Appendix
SP0538 Climate change and soil function
nutrients.
The effect of climate
gradient and effect of
experimental treatments
on litter decomposition
were assessed.
8) Across the
environmental gradient,
mass loss rates were
positively related to air
temperature (explained
81% of the variance).
Rhizosphere respiration
increases significantly at
elevated temperature.
7)
VanHees, P.A.W.,
Jones, D.L., Finlay, R.,
Godbold, D.L. and
Lundström, U. (2004).
The carbon we do not
see – the impact of low
molecular weight
compounds on carbon
dynamics and
respiration in forest
soils: a review. Soil
Biology & Biochemistry
37, 1-13.
Lukas, M., Calfapietra,
C. and Godbold, D.L.
2003. Production,
turnover and
mycorrhizal
colonisation of root
systems of three
Populus species grown
under elevated CO2
(POPFACE). Global
Change Biology 9, 838848.
Thornley, J.H.M. and
Cannel, M.G.R. (2001).
Soil carbon storage
response to
temperature: a
hypothesis. Annals of
Botany 87, 591-598.
CO2
increase
and
subsequent warming effect
on soil carbon dynamics
were assessed.
Below-ground biomass and
fine root turnover increased
and thus total C flux to the
soil.
In this paper, an
alternative to the additional
hypothesis is proposed to
explain the apparent
insensitivity of soil carbon
stocks to temperature
under some
circumstances. The
Both a simple analytical
model and a more complex
model demonstrate that if this
hypothesis is true, warming
may cause little decrease in
total soil carbon in the longterm and would cause an
increase in soil carbon if
18
Appendix
SP0538 Climate change and soil function
Norby, R.J., Cotrufo,
M.F., Ineson, P.,
O’Neill,E.G. and
Canadell, J.G. (2001).
Elevated CO2, litter
chemistry, and
decomposition: a
synthesis.
Zerva, A., Ball. T.,
Smith, K.A. and
hypothesis is that warming
may increase the rate of
physico-chemical
processes which transfer
organic carbon to
“protected”, more stable,
soil carbon pools. Indeed,
physico-chemical
“stabilisation” reactions
may respond more to
warming than microbial
‘decomposition/respiration’
reactions. If this is true,
soil carbon stocks may
remain relatively
unchanged, or even
increase, with increase in
temperature, without
invoking low temperature
sensitivity for microbial
respiration in the older
mineral pools. It is
proposed that soil physicochemical reactions, which
stabilise soil carbon and
protect it from microbial
respiration, may be
accelerated by warming.
A review on different soil
types.
The results of published
and unpublished
experiments investigating
the impacts of elevated
[CO2] on the chemistry of
leaf litter and
decomposition of plant
tissues are summarised.
physico-chemical stabilisation
reactions were over 50%
more sensitive to temperature
than microbial reactions. It
should be stressed that shifts
between soil carbon pools
can be slow and that the
hypothesis refers to
equilibrium carbon storage
which may not be reached for
decades or centuries.
Research has been shown
that soil respiration may be
greatly increased with little
loss of soil carbon shortly
after a step-wise increase in
temperature, but after some
time, both respiration and soil
carbon decrease and at
equilibrium, respiration will
equal net primary production
and total soil carbon may
have actually increased. It is
clearly not adequate to draw
conclusions about real world
conditions from short-terms
warming experiments.
Peaty gley
The soil carbon stock of the
first rotation stands was 140 t
It is concluded that any
changes in decomposition
rates resulting from
exposure of plants to
elevated [CO2] are small
when compared to other
potential impacts of
elevated [CO2] on carbon
and N cycling. An
indication of potential
decline in litter N and
increase in plant litter
lignin which will slow the
litter decomposition rate
was suggested for CO2
enriched litter.
Soil respiration was the
highest at the grassland
19
Appendix
SP0538 Climate change and soil function
Mencuccini, M. (2004).
Soil carbon dynaimcs in
a Sitka spruce (Picea
sitchensis (Bong.)
Carr.) chronosequence
on a peaty gley. Forest
Ecology and
Management (in press).
Dewar, R.C. and
Cannell, M.G.R. (1992)
Carbon sequestration in
the trees, products and
soils of forest
plantations: an analysis
using UK examples.
Tree Physiology 11, 4971.
Heath, J., Ayres, E.,
Rossell, M., Bardgett,
R.D., Black, H.I.J.,
Ineson, P., Stott, A. and
Kerstiens, G. (2005)
Rising atmospheric CO2
reduces soil carbon
sequestration. To be
submitted.
Karjalainen, T.,
Pussinen, A., Liski, J.,
The impact of planting
forests on organic
grassland soils on the
losses of soil carbon due
to the site preparation for
the planting of trees and
other disturbances has
been investigated. Soil
respiration, soil carbon
stocks and annual litterfall
were also measured while
allometric equations were
used for the estimation of
the above and
belowground biomass.
The sites chosen were:
40-year-old first rotation
stands, 12, 20 and 30
year-old second rotation
stands, one 18-month-old
clearfelled site and
unplanted natural
grassland sites.
The soil was a fine
montmorillonitic, mesic
udertic Paleustoll with
texture of silt loam or silty
clay loam and a range of
clay content from 26 to
34%.
The soil was imported
from the USA but it is
inoculated in the UK.
Analysis of the impacts of
two forest management
C ha-1, far lower than in the
surrounding unplanted
grasslands with 274 t C ha-1,
while clearfelling cause a
further decline to 100 t C ha-1.
Soil carbon accumulated
again as the forest grew
during the second rotation.
site (14.2 t C ha-1 year-1),
after the forest
establishment the
respiration was 2.3, 2,2,
5,4 and 5.0 t C ha-1 at the
age of 12, 20, 30 and 40
years, while in the
clearfelled site soil
respiration was 5.6.
CO2 enrichment, while
causing short-term growth
stimulation in a range of
European tree species,
also lead to an increase
in microbial respiration,
resulting in a marked
decline in sequestration
of root derived carbon in
the soil.
Carbon stocks in tree
biomass, soil and wood
20
Appendix
SP0538 Climate change and soil function
Nabuurs, G., Eggers,
T., Lapvetelainen, T.
and Kaipainen, T.
(2003) Scenario
analysis of the impact
of forest management
and climate change on
the European forest
sector carbon budget.
Forest Policy and
Economics 5, 141-155.
(felling increased 0.5-1%
per year until 2020 and
forest management paid
more attention to current
trends towards more
nature oriented
management) and two
climate change scenarios
(mean annual temperature
increased with 2.5 C and
annual precipitation 5-15%
between 1990 and 2050)
on the European forest
sector carbon budget
between 1990 and 2050
have been carried out in
this study.
Sanger, L.J., Anderson,
J.M., Little, D. and
Bolger, T. (1997)
Phenolic and
carbohydrate
signatures of organic
matter in soils
developed under grass
and forest plantations
following changes in
land use. European
Journal of Soil Science
48, 311-317.
Comparisons were made
between phenolic and
carbohydrate signatures
of soil profiles developed
under grass, spruce and
ash stands. Samples were
collected from a brown
earth soil which was
originally under the same
land use, but over the past
43 years has supported
different monocultures.
Jo M. Anderson,
Professor of Ecology,
Biological Sciences
Department, Exeter
University (personal
Discussion on the above
research (paper N 11)
includes the use of lignin
signature to track SOM
following changes in
vegetation cover. They
products increased in all
applied management and
climate scenarios, but slower
after 2010-2020 than that
before. This was due to
ageing of forests and higher
carbon densities per unit of
forest land. Differences in
carbon sequestration were
very small between applied
management scenarios,
implying that forest
management should be
changed more than in this
study if aim is to influence
carbon sequestration. Applied
climate scenarios increase
carbon stocks and net carbon
sequestration compared to
current climatic conditions.
A relatively undecomposed
phenolic fraction from the
lignin and hydrolysable
carbohydrate fractions from
plants had accumulated in
the soil under spruce and ash
which largely reflected the
quantity and quality of the
litter inputs from the ash and
spruce compared to the
grass. The phenolic and
hydrolisable carbohydrate
fractions accounted for as
much as 60% of the total
organic carbon concentration
in the deep soil horizons. The
conclusions are that the
decay rate of these fractions
are function of vegetation
type.
From his experience,
Prof.. Anderson conclude
that
21
Appendix
SP0538 Climate change and soil function
communication).
Dewar, R. C. and
Cannell, M.G.R. (1992)
Carbon sequestration in
the trees, products and
soils of forest
plantations: an analysis
using UK examples.
have shown that a conifer,
even on a fertile soil, has a
very shallow signature of
SOM compared to the
broad leaf species.
Whether the deep
signature under ash was
due to DOC as well as
roots they were unable to
determine.
A carbon-flow model for
managed forest
plantations was used to
estimate carbon storage in
UK plantations differing in
Yield Class, thinning
regime and species
characteristics.
A sensitive
analysis revealed
the following
processes to be
both uncertain and
critical: the fraction
of total woody
biomass in
branches and
roots; litter and soil
organic matter
decomposition
rates; and rates of
fine root turnover.
Results showed that:
1) Increasing the Yield
Class from 6 to 24 m3
ha-1 year-1 increased the
rate of carbon storage in
the first rotation from 2.5
to 5.6 Mg C ha-1 year-1 in
unthinned plantations.
Thinning reduced total
carbon storage in P.
sitchensis plantations by
15%, and it is likely to
reduce the carbon
storage in all plantation
types.
2) If the objective is to
store carbon rapidly in
the short term and
achieve high carbon
storage in the long term,
Populus plantations
growing on fertile land
(2.7 m spacing, 26-year
rotation, YC 12) were
the best option
examined.
3) If the objectives is to
achieve carbon storage
in the medium term (50
years) without regards
to the initial rate of
storage, then plantations
of conifers of any
species with aboveaverage yield class
would suffice. In the
22
Appendix
SP0538 Climate change and soil function
Ineson, P., Benham,
D.G., Poskitt, J.,
Harrison, F., Taylor, K.
and Woods, C. (1998)
Effects of climate
change on nitrogen
dynamics in upland
soils 2. A soil warming
study. Global Change
Biology 4, 153-161.
A warming technique was
developed and
demonstrated in this study,
together with the
consequences for the
release of nitrate from
lysimeters due to increase
soil temperature. Three
soil types were under
investigation: Brown earth,
Micropodzol and peaty
gley.
Jones, D.L., Hodge, A.
and Kuzyakov, Y.
(2004) Plant and
mycorrhizal regulation
of rhizodeposition. New
Phytologist, 163: 459480.
The paper summarising
the C flows in and from the
rhizosphere and
underlined the importance
of the better understanding
the complexity of the
rhizosphere in order to
fully engaged with key
scientific ideas such as
development of
sustainable agricultural
systems and the response
of ecosystems to climate
change.
In this study, carried out
within the cross- European
research project
CLIMOOR, the effect of
climate change, resulting
from imposed
manipulations, on carbon
dynamics in shrubland
Gorissen, A. et al.
(2004) Climate change
affects carbon
allocation to the soil in
shrublands.
Ecosystems 7, 650661.
long term (100 years),
broadleaved plantations
of oak and beech store
as much carbon as
conifer plantations. Minirotations (10 years) do
not achieve high carbon
storage.
The response of the soil
solution concentration of
nitrate to increase of soil T up
to 3C more than the control
varied markedly between soil
types, but showed a
significant decrease in the
brown earth during the first 5
months of additional heating.
This suggests that increased
nitrogen release is masked
by plant uptake in this soil,
but the responses of the
other two soils were less
marked.
Drought clearly reduced
carbon flow from the roots
to the soil compartments.
The fraction of the 14C
fixed by plants and
allocated into the soluble
carbon fraction in the soil
and to soil microbial
23
Differences in
climate, soil, and
plant
characteristics
resulted in a
gradient in the
severity of the
drought effects on
Appendix
SP0538 Climate change and soil function
ecosystems was
examined. The
experiments performed
were 14C – labelling
experiment to probe
changes in net carbon
uptake and allocation to
the roots and soil
compartments as affected
by a higher temperature
during the year and a
drought period in the
growing season.
Lenton, T.M. and
Huntingford, C. (2003).
Global terrestrial
carbon storage and
uncertainties in its
temperature sensitivity
examined with a simple
model. Global Change
Biology 9, 1333-1352.
Chapman, S.J.,
Thurlow, M. (1996).
The influence of climate
on CO2 and CH4
emissions from organic
soils. Agricultural and
Forest Meteorology 79,
205-217.
biomass in Denmark and
the UK decreased by
more than 60%. The
effects of warming were
not significant, but, as
with the drought
treatments, a negative
effect on carbon
allocation to soil microbial
biomass was found. The
changes in carbon
allocation to soil microbial
biomass at the northern
sites in this study indicate
that soil microbial
biomass is a sensitive,
early indicator of drought
or temperature-initiated
changes in these
shrubland ecosystems.
In this paper, key controls
on global terrestrial carbon
storage are examined
using a simple model of
vegetation and soil.
CO2 and CH4 emissions
from two peat sites in
Scotland were monitored
and related to temperature
and moisture. One site is a
deep Sphagnum bog and
the other is planted with
Sitka spruce and
Lodgepole pine.
CO2 emissions rates at both
sites showed a marked
seasonal pattern and
paralleled the ambient soil
temperature. Values ranged
from 10 mg C m-2 h-1 in the
bog area in March to 190 mg
C m-2 h-1 in the adjoining
forest area in July. Values in
the dry area tended to be
about 40% greater than those
in the wet area while those in
the forest plantation were on
average 90% greater than
24
net carbon uptake
by plants with the
impact being most
severe in Spain,
followed by
Denmark, with the
UK showing few
negative effects at
significance levels
of p< or = 0.10.
The reduced
supply of substrate
to the soil and the
response of the
soil microbial
biomass may help
to explain the
observed
acclimation of CO2
exchange in other
ecosystems.
Land carbon sink
is a significant
uncertainties in
global change
projections.
Appendix
SP0538 Climate change and soil function
those in the indigenous bog
area. The effect of
temperature was modelled by
Arrhenius equation (linear
regression of the log of the
CO2 flux against the
reciprocal of the absolute
temperature should give a
straight line). This model
showed that 57-70% of the
CO2 variations could be
explained by temperatures.
Q10 values were estimated
as 3.3. and 6.1 respectively,
which seemed to be greater
than many published values
for minerals soils. Significant
CH4 emissions were found
only for the bog area and
only 23 % of their variations
were explained by
temperatures by the model
used. Using the responses to
temperature as determined
above it was possible to
estimate the increase in
carbon dioxide emission from
these sites for any given rise
in annual mean temperature.
For delta T = 2.5 C, the
increase in CO2 emission
was 36% and 59% for the
bog and wet areas
respectively. For delta T = 4.5
C, a doubling of CO2
emissions was predicted,
which extended over the
global range of peat and
organic soils, could have a
significant effect on the
contributions of soil carbon to
atmospheric CO2. Repeating
the above calculations for
methane gave an increase
605 for delta T = 4.5C.
However, the main effect on
25
Appendix
SP0538 Climate change and soil function
methane would be due future
changes to the moisture
content. Land use changes
such as drainage and
afforestation can have a
major effect in reducing
methane emissions.
Smith, P., Smith, J.U.,
Powlson, D.S. etc…
(1997). A comparison
of the performance of
nine soil organic matter
models using datasets
from seven long-term
experiments.
Geoderma 81, 153225..
Nine organic models were
evaluated using twelve
datasets from seven longterm experiments.
Datasets represent three
different land-uses
(grassland, arable
cropping and woodland)
and a range of climatic
conditions within the
temperature region.
Different treatments
(inorganic fertilisers ,
organic manures and
different rotations) at the
site allowed the effect of
different land management
to be explored. Model
evaluation were evaluated
against the measured data
and the performance of
the models was compared
both qualitatively and
quantitatively.
Hargreaves, K.J.,
Milne, R. and Cannell,
M.G.R. (2003). Carbon
Balance of afforested
peatland in Scotland.
Forestry, 76 (3), 299-
The annual net CO2
exchange over
undisturbed deep peatland
in Scotland was measured
continuously for 22 months
using eddy covariance.
Annual CO2 exchange
Not all models
were able to
simulate all
datasets. No one
model performed
better than all
others across all
datasets. A
comparison of
overall
performance of
models across all
datasets reveals
that the model
errors of one group
of model (RothC,
CANDY, DNDC,
CENTURY, DAISY
and NCSOIL) did
not differ
significantly from
each other.
Another group
(SOMM, ITE and
Verberne) did not
differ significantly
from each other
but showed
significantly larger
model errors than
did models in the
first group.
Assuming that the
trees accumulated
carbon at rates
commensurate
with yield class 10
m3 ha-1 a-1, the
peat beneath the
The undisturbed peat
accumulated approx. 2.5 t C
ha-1 a-1. Newly drained
peatland (2-4 years after
ploughing) emitted between 2
and 4 t C ha-1 a –1, but when
ground vegetation
26
Appendix
SP0538 Climate change and soil function
317.
over peatlands that had
been drained, ploughed
and afforested with
conifers 1, 2, 3, 4, 8, 9 and
26 years previously were
estimated by extrapolating
two to four weekly
measurements, using
relationships between
daytime fluxes and solar
radiation and night-time
fluxes and air
temperatures.
Pilling, C. and Jones,
J.A.A. (1999). High
resolution climate
change scenarios:
implications for British
runoff. Hydrological
processes 13, 28772895.
Nationwide changes in
spatially well-resolved
patterns of British runoff
were investigated under
two climate change
scenarios derived from
general circulation model
(GCM) output. A physical
process-based
hydrological model
(HYSIM) was used to
simulate effective runoff
across a 10 x 10 km
British grid under baseline
and future climate
conditions. A gridded
baseline climatology for
precipitation and Penman
variables was used to
validate HYSIM across
Britain using grid cellspecific parameters
derived from land use and
soil type. The climate
change scenarios were
constructed from the
Hadley Centre’s high
recolonised, the peatland
became a sink again,
adsorbing approx. 3 t C ha-1
a-1, 4-8 years after tree
planting. Thereafter, the
trees dominated the budget
and afforested peatland
adsorbed up to 5 t C ha-1 a-1.
Annual effective runoff is shown to
increase throughout
most of Britain
under the UKHI scenario for 2050, whilst
it decreases over much of England and
Wales under the UKTR scenario for
2065. Both scenarios show an increasing
gradient in runoff between a wetter
northern Britain and a drier south-eastern
Britain. This gradient is more pronounced
under the UKTR scenario. Changes in
effective runoff for winter and summer
show an increase in seasonality under
both scenarios. Winter runoff is shown to
increase most in northern Britain under
both scenarios, whilst summer runoff is
shown to experience major reductions
over much of England and Wales under
the UKTR scenario.
27
trees after canopy
closure was
estimated to be
decomposing at
only approx. 1 t C
ha-1 a –1 or lee.
This is slower than
previously though
and suggested that
afforested
peatlands in
Scotland
accumulate more
carbon in trees,
litter, forest soil
and products than
is lost from the
peat for 90-190
years.
If these
simulations are
realised, Britain
may expect an
accentuated north
to south-east
imbalance in
available water
resources. If this is
combined with a
temporal
imbalance
suggested by the
increased
seasonality, there
could be problems
of the future
management of
British water
resources.
Appendix
SP0538 Climate change and soil function
Grogan, P. and
Matthews, R. (2002). A
modelling analysis of
the potential for soil
carbon sequestration
under short rotation
coppice willow
bioenergy plantations.
Soil Use and
Management 18, 175183.
Falloon, P., Smith, P.,
Szabo, J. and Pasztor,
L. (2002). Comparison
of approaches for
estimating carbon
sequestration at
regional scale. Soil Use
and Management 18,
164-174.
Thornley, J.H.M. and
Cannell, M.G.R. (2000)
Managing forests for
wood yield and carbon
storage: a theoretical
study. Tree Physiology
20(7), 477-484.
resolution equilibrium
GCM (UKHI) for 2050 and
transient GCM (UKTR) for
2065. Future effective
runoff was simulated
under both scenarios.
The paper describes a
process-based model
specifically designed to
evaluate the potential for
soil carbon sequestration
in short rotation coppice
(SRC) willow plantations in
the UK.
A mechanistic forest
ecosystem simulator,
which couples carbon,
nitrogen and water
(Edinburgh Forest Model),
was calibrated to mimic
the growth of a pine
plantation in a Scottish
climate. The model was
run to equilibrium 1) as an
undisturbed forest, 2)
removing 2.5, 10, 20 or
40% of the woody biomass
each year, 3) removing
According to the model
predictions, the conclusions
were that the potential for soil
carbon sequestration in these
plantations is comparable to,
or even greater than, that of
naturally regenerating
woodland. Our preliminary,
site –specific model output
suggest that soil carbon
sequestration may constitute
about 5% of the overall
carbon mitigation benefit
arising from SRC plantations.
Their results
suggest that
carbon
sequestration
potential is
greatest in soils
whose carbon
content has been
depleted to
relatively low
levels due to
agricultural land
use practices such
as annual deep
ploughing of
agricultural soils.
More carbon was stored in
the undisturbed forest (35.2
kg C m-2) than in any regime
in which wood was
harvested. Plantation
management gave moderate
carbon storage (14.3 kg C m2
) and timber yield 915.6 m3
ha-1 year-1). Notably, annual
removal of 10 or 20% of
woody biomass per year
gave both a high timber yield
(25 m3 ha-1 year-1) and high
carbon storage (20-24 kg C
There was no
simple inverse
relationship
between the
amount of timber
harvested from a
forest and the
amount of carbon
stored.
Management
regime that
maintain a
continuous canopy
cover and mimic,
28
Appendix
SP0538 Climate change and soil function
50% of the woody biomass
every 20 years, and 4)
clear-felling and replanting
every 60 years as in
conventional plantations in
this climate.
m-2). The efficiency of the
latter regime could be
attributed (in the model) to
high light interception and net
primary productivity, but less
evapotranspiration and
summer water stress than in
the undisturbed forest, high
litter input to the soil giving
high soil carbon and N2
fixation, low maintenance
respiration and low N
leaching owing to soil mineral
pool depletion.
to some extent,
regular natural
forest disturbance
are likely to
achieve the best
combination of
high wood yield
and carbon
storage.
29
Appendix
SP0538 Climate change and soil function
Table 7 Summary of email feedback and web search on the projects associated with the effects of climate change on forest soil
functions in the UK.
Research
Contact
Professor
Paul Jarvis
Department
Project
Ecology and
Resource
Management.
University of
Edinburgh.
Centre for
Ecology and
Hydrology,
Edinburgh
IMP Forest
Focus (EU
funded)
Grid ENabled
Integrated
Earth system
model
(GENIE)
Global Atmosphere Division includes modules on:
1. Development of plant biomass components for the RothC
soil carbon model (with Pete Smith, Aberdeen University),
2. Incorporating effects of changes in climate, nitrogen
deposition and CO2 in projections of forest carbon budgets,
3. Development of soil process modelling for the UK national
GHG Inventory (with Rothamsted Research),
4. Demonstration and evaluation of Forest Carbon Monitoring
Network (with Mark Broadmeadow, Forest Research).
Assessment of the relative importance of N-deposition, climate
change and forest management on C-sequestration at intensive
monitoring plots in Europe
Dr Pete
Smith
www.ierm.ed.ac.uk/people/academic/jarvis.htm
[email protected]
www.ceh.ac.uk
A modular, distributed and scaleable Earth System Model for
long-term and paleo-climate studies (NERC funded)
1.
Department of
Plant and Soil
Science.
Aberdeen
University
Further Information
C sequestration and water evaporation in relation to global
environmental change in the boreal forest in Saskatchewan,
temperate forest in Scotland and Mediterranean oak forest in
Portugal.
Preparation of
annual
Greenhouse
Gas Inventory
for Land Use
Change and
Forestry in UK
- funded by
DEFRA
Dr Ronnie
Milne,
Details
Intercomparison of Dynamic Global Vegetation Models
(CEH funded)
Application of Bayesian methods of parameterisation,
updating and testing to CEH ecosystem models (CEH
funded).
CEH
2.
Research
consortium SEERAD/NAW
funded
Developing a model to simulate carbon and nitrogen dynamics
in organic soils and predict the response of these soils to landuse and climate change.
30
www.abdn.ac.uk/pss/petesmith.hti
Appendix
SP0538 Climate change and soil function
Professor
JM
Anderson
University of
Exeter Dept
Biological
Sciences
Dr David
Viner
Climatic
Research Unit,
University of
East Anglia
DEFRA funded
Climate
Impacts LINK
project
Professor
Richard
Bardgett
Department of
Biological
Sciences,
University of
Lancaster
NERC
Opinion based on tropical forest research:

Roots are the major sources of carbon in mineral soils;

Root material is deposited within the mineral matrix and
therefore has a high potential for C stabilisation;

Root carbon can be deposited deep in the soil profile where
it is relatively unaffected by climate change compared to
surface pools;

Distribution and amount of root carbon vary with species
management;

With global warming there will be an increase in the active
depth of soils leading to greater root deposition in mineral
soils and the potential for C stabilisation, particularly if there
is a shift from conifer to broadleaf forests.
• Soil erosion and the interactions with land-management and
climate. Collaboration with Anglia Polytechnic University and
local (Norfolk) land managers.
• Climate Change Impacts, Options, Strategies and Solutions for
Rural Estate and Land-Use Management in the European
Union. Collaboration with EU partners, the European Land
Owners Organisation and the Country Land and Business
Association.
Just completed a project looking at C sequestration under
various tree species under elevated CO2. The studies showed
that C sequestration is actually reduced, due to priming of soil C.
31
Sanger et al. (1997)
Haron et al. (1998).
http://www.cru.uea.ac.uk/link/dave/dave.html
Not specified the links with forestry
Publication in press
Appendix
SP0538 Climate change and soil function
Professor
Douglas
Godbold
University of
Wales, Bangor
Free Air
Carbon
Enrichment
(FACE)
experiment
Determining the influence of elevated CO2 on forest ecosystem
C fluxes (Birch, Alder and Beech). Planted in March 2004, will
run for at least 6 years. The design of the BangorFACE site
allows for:

Investigations of competition between tree species under
current and future atmospheres;

C and N dynamics of afforestation, in particular whole
ecosystem C budgets,

Changes in greenhouse gas emissions

Investigation ectomycorrhizal succession and of nitrogen
fixation under the influence of elevated CO2.
[email protected]
Reference: D. Godbold “BangorFACE – investigating global
climate change” Information Sheet, unpublished.
Work is currently concentrating on the influence of elevated
atmospheric CO2 on C balance and C sequestration of old field
afforestation. Determining whether elevated CO2 increases C
sequestration of afforestation and to establishing the fate of old
C stored in the soil prior to afforestation.
Dr Andreas
Heinemeyer
University of
York
Professor
John Grace
Atmospheric
and
Environmental
Science,
University of
Edinburgh
Carboage
project
His research areas include: Improving understanding of soil
carbon responses to environmental factors (e.g. temperature)
and assessing the importance of separating soil microbial from
root respiration; a main focus will be on forest soils and northern
peatlands. A new approach is the York based mobile
continuous-flow mass-spectrometer unit, enabling monitoring
and partition of carbon fluxes under labelled and natural
abundance levels in connection with treatments such as soil
trenching and soil warming (e.g. infra-red light). We will also
attempt to use this approach to link soil carbon fluxes to
changes in the canopy environment via natural (photosynthetic)
discrimination against 13C within the canopy.
1. Measure stocks of carbon at five sites over Europe,
including carbon in biomass and soil;
2. Measure CO2 fluxes using eddy covariance in the 'roving
tower' approach, over a chronosequence which will include
existing EUROFLUX sites;
3. Measure soil respiration over time, also in the
chronosequence;
4. Model the age-related changes in net primary production
(NPP) and net ecosystem production (NEP), so that these
models can be used as a management tool;
5. Develop products for users and stakeholders, so that such
people can estimate the likely uptake of carbon by forests.
32
www.shef.ac.uk/ctcd/heinemeyer.html
www.ierm.ed.ac.uk/lab101/annex1.doc
www.geos.ed.ac.uk/abs/research/carboage
Appendix
SP0538 Climate change and soil function
Dr Tom Nisbet (Forest
Research), Professor Ian Reid
(Loughborough University) and
Professor Ian Calder
(University of Newcastle Upon
Tyne)
Trees and
Drought
project of
Lowland
England
(TaDPoLE)
consortium
Objectives of TaDPoLE include:
Study soil moisture deficits under a range of landuses (conifer or
broadleaf woodland, heath and grass).
Understand evaporative moisture losses and groundwater
recharge in woodlands overlying sandy soils.
To generate quantitative information for input into national
modelling
http://www.lboro.ac.uk/departments/gy/tadpole/index.html
Feedback from Professor Reid:
“Our modelling of forest hydrology was very successful and gave
us hope that this could be extended to include climate change
scenarios”.
“TaDPole already has the expertise, a massive database and
the ability to resurrect the experimental set-up”.
Sanger LJ, Anderson JM, Little D and Bolger T (1997) “Phenolic and carbohydrate signatures of organic matter in soils developed
under grass and forest plantations following changes in land use” European Journal of soil science, 48 311-317
Haron K, Brookes PC, Anderson JM and Zakaria ZZ (1998) “Microbial Biomass and Soil Organic Matter Dynamics in Oil Palm
Plantations, West Malaysia” Soil Biology and Biochemistry 30(5) 547-552
33
Appendix
SP0538 Climate change and soil function
Table 8. DEFRA – funded projects in the UK related to the effects of climate change on forest soil functions
Research
project/project
code/time
period
Review of the
potential for soil
carbon sequestration
under bioenergy
crops in the U.K
(NF0418), 01/02/0110/04/01
UK Emissions by
Source & Removals
by Sinks due to Land
Use, Land Use
Change & Forest
Activities (GA01054),
02/06/03 – 31/05/06
Contractor
organisation and
location
Project details
Uncertainties, questions
and research gaps
identified
Institute of Water and
Environment, Cranfield
University at Silsoe,
Bedfordshire, MK 45
2PA
At present, the experimental data suggested that soil carbon sequestration rates under short
rotation coppice plantations can range from 0-1.6 Mg C ha-1 y-1. Of all available models,
CENTURY seemed to be the best potential for adaptation to bioenergy crop systems
because of its integrated plant-soil approach. A simple model using a carbon mass balance
approach to predict soil carbon sequestration was also developed, which is site specific
model, calibrated to soil data from natural woodland regeneration site in the U.K. According
to the model output, there is a potential for a significant soil carbon sequestration in shortrotation coppice plantations in the U.K. The model identified the following factors of being
major controls on rates and amounts of soil carbon sequestration under willow coppices: 1)
carbon inputs (net primary production), 2) decomposition rates of the major soil carbon pools,
3) initial soil carbon content, 4) crop/plantation management practice, 5) depth of soil being
influenced by the bioenergy crop. Carbon sequestration is most likely on soil whose carbon
content has been depleted relatively low levels due to previous management practices.
Carbon sequestration in soils is likely to occur until the original climatically-controlled
equilibrium point between soil carbon inputs and outputs is reached.
Considerable further research
would be required to develop a
general model that could
incorporate climatic and soil-type
variation, as well as hydrological
interactions associated with the
relatively high water demand of
bioenergy crops, to accurately
predict the potential for soil
carbon sequestration in
bioenergy plantations across the
U.K.
Centre for Ecology and
Hydrology
Projects aims are to provide estimates of greenhouse emissions by sources and removals by
sinks associated with land use, land use change, forestry (LULUCF) in the U.K. and
Devolved Administrations. The project will:
1. ensure that UK can meet its annual inventory reporting requirements on emissions by
sources and removals by sinks associated with LULUCF
2. project UK emissions by sources and removals by sinks associated with LULUCF
3. ensure that UK’s inventory in these areas is significantly defensible, meets international
reporting requirements, including IPCC guidelines and any Good Practice Guidance
agreed by the UNFCCC COP, and uses the full range of available relevant information.
The project is ongoing
Department of Plant and
Soil Science. Aberdeen
University
Developing a model to simulate carbon and nitrogen dynamics in organic soils and predict
the response of these soils to land-use and climate change.
www.abdn.ac.uk/pss/petesmith.hti
34