Supplementary material nr. 3
Table 1. Summary of the climate scenarios impacts and management interventions
Case study / Climate changes scenarios / Simulated impact of climate changes / “business as usual” management(BAU) / Adaptive management 1 (AM1) / Adaptive management 2 (AM2) / Adaptive management 3
3 (AM3)
FI / Mean annual temperature increases from + 2.3oC to 6.2oC
Mean annual precipitation increases by 28% (from 493 mm to 635 mm) / The growth increases regardless of species
- Scots pine: 0.41%/year on mesic sites and 0.52%/year on subxeric sites
- Norway spruce: 0.27%/year on herb-rich sites and 0.29%/year on mesic sites
- Birch: 0.33%/year on herb-rich sites and 0.33%/year on mesic sites
- Planting density
- Norway spruce: 1800 seedlings/ha
- Silver birch: 1600 seedlings/ha
- Thinning based on the dominant height/basal area thresholds specific for tree species and site fertility
- Rotation
SE / Change in climatic parameters in the period 2070-2099 compared with the period 1961-1990: Mean annual temperature increases, according to the scenarios, with +2oC, +3oC up to +4.1oC. Mean precipitation increase with 6.5% up to 30.2% in two scenarios, but decrease with -24.8% in the third scenario. / The growth is expected to increase significantly unless biotic and abiotic damages, including windthrow,increase.Norway spruce may suffer from water stress in sites with low water holding capacity. / The clear-felling sylviculture is applied on almost all productive stands. Planting or measures for natural regeneration should be completed by the end of the third year after felling. / Management regimes using at reducing wind damages were defined in consultation with stakeholders and applied at the half of the simulation period and half way through. “Adaptive regimes resulted in generally increased yield, increased hunting potential and a higher number of forest management operations to be carried out, although other aspects of recreation services were reduced. The net return remained unaffected by most of the adaptive forest management regimes”(Andersson et al. 2014).
GB / Change in climate parameters at decadal intervals from 2010 to 2080 from 11 RCMs variants of equal likelihood from AR5 HadRM3 to assess the uncertainty of climate change drivers. / Impacts:
Reduction in spruce suitability below the minimum production threshold throughout the 21st century for nine of the eleven RCM variants, due to increasing moisture deficit. Two most extreme model variants render the average species suitability score unsuitable for both case study forests. / BAU – is replacing like-with-like at the rotation age – at the stage of maximum mean annual increment (MMAI). Clocaenog forest is mainly spruce (86%), Gwydyr forest is largely spruce (55%) but with greater species diversity. / AM1 Increasing species diversity (DIV). In Gwydyr forest a greater range of species could be introduced than in Clocaenog forest – due differences in site type. In both forests AM1 maintained timber production volume and carbon sequestration levels at a level comparable to the period between 1970 and 2010.
AM2 Low Impact Silviculture System (LISS). Transformation to LISS produced biodiversity and recreation gains in both forests through the 21st century. Production, biomass and carbon sequestration performed well compared to BAU.
AM3 Short rotation forestry (SRF). Decline in recreation and biodiversity through the 21st century.
NL / Dutch climate scenarios G and W+ to have climate scenarios tailored to the local situation:
G: 30yrs: + 0.7⁰C, Precipitation: +10%, Drought index: -12%
100yrs: + 1.6⁰C, Precipitation: +7%, Drought index: +3%
W+: 30yrs: + 2⁰C, Precipitation: -4%, Drought index: +70%
100yrs: + 4.7⁰C, Precipitation: -9%, Drought index: +140% / The G scenario is quite similar to current climate. As a result, changes in ecosystem services provided and species composition are minor.
The W+ scenario has quite severe changes in the species composition (shift towards drought-resistant conifers)
Harvest, standing biomass, fire safety and biodiversity are decreased while the landscape amenity indicator increases. / BAU scenarios are based on interviews with local forest owners and validation on historical data.
Current management is mainly multi-functional management, with owner-specific focus on production for state forestry and private-estates.
The largest owner does (intentionally) not intervene with forest succession in the centre of the case study area.
Heathlands and a small pocket of driftsand are maintained. / AM scenarios are based on in-depth discussion with local forest owners.
The management paradigm in the area of no-intervention is maintained.
AM1: Intensify diversification by increasing thinning and application of group cuts within the first decades for reducing storm and fire risk
AM2: Increase thinning intensity to promote growth; either accompanied by planting production species, incl. Douglas fir, Scots pine, oak or by natural regeneration.
In some areas more drought tolerant species are selected for.
For heathlands a managed succession into forest.
DE / Changes in annual temperature and precipitation between 1950-2000 and 2081-2100 averages:
CCSM3: +2.2°C, -4.1% precipitation, ECHAM5: +3.6°C, -6.9% precipitation, HadCM3: +4.6°C, -4.1% precipitation
All climate scenarios project decreasing summer (-14%, -18% and -17%, respectively) and increasing winter precipitation (Temperli et al. 2012). / Impacts:
Short term (<2050): Increased bark beetle disturbance risk under all climate change scenarios. Increased proportion of deciduous species in natural regeneration. Forest biomass (growing stock) is stable and dominated by Norway spruce, beech and silver fir.
Long term (>2050): Increased drought- and bark beetle-induced mortality in Norway spruce results in a partial (CCSM3) or complete (HadCM3) removal of Norway spruce from the species composition. Increased establishment of drought adapted species such as oaks, lime-tree or Douglas-fir. General increase in biodiversity indicators, and increasing opportunities for timber production with deciduous species or Douglas-fir. / BAU scenarios are based on report, literature, forest inventory data that describe most common management regimes and forest management prescriptions of Baden-Wuerttemberg (SW Germany).
Initial status: three different stand types (all 10-20 years old):
1) Norway spruce of high altitude (90% spruce, 10% beech)
2) Mixed fir-spruce-beech of low altitude
3) Mixed Douglas fir (70%) and beech (30%)
Two different BAU-management strategies according to the modeling approach used:
BAU 1 (process-based model): Even-aged spruce at higher elevations (>800 m a.s.l): Clear cut of stands of 0.5 to several hectares at a dominant diameter of 45 cm at breast height (dbh). Replanting with spruce. Thinning from below.
Uneven-aged mixed forests (<800 m a.s.l.): Target diameter harvest of trees > 48 cm dbh, natural regeneration, thinning from below in favor of spruce and fir.
BAU 2 (empirical growth model) : -management (close-to-nature forestry without clearcutting):
-Future-crop tree (FCT) selection (number of FCT depending on stand type between 50 and 150)
-High thinning to release FCTs
-Target diameter harvest (TDH) over an extended period for natural regeneration (TDH according to tree species) / AM options are based on recommendations of the local forestry administration (MLR, 1999) and on one workshop with stakeholders and an intensive workshop with local decision makers (head foresters and local forest rangers) where details of the management strategies to be simulated were fixed. AM4 was entirely suggested by the practitioners. AM are mainly designed to increase stability of single trees by reducing tree height as the most important factor for vulnerability towards storm damage and to reduce tree density to enhance individual growth and improve stability of trees (described in Temperli et. al. 2012, Temperli et al. 2013)
Two different sets of AM strategies according to the modeling approach used: AM1-3 – process based model, AM 4-5: empirical growth model
AM1: Conversion of even-aged spruce forests to uneven-aged mixed forests by harvesting spruce at a target diameter of 48 cm dbh and increasing the proportion of deciduous species through thinning.
AM2: Promotion of natural vegetation. Harvest of planted spruce at 48 cm dbh, No management after the removal spruce.
AM3: Conversion to uneven-aged Douglas-fir: Harvest of spruce at 48 cm dbh and promotion of Douglas-fir through thinning.
AM 4: Storm adaptive management – final felling of crop trees defined by tree height (30m for Douglas fir and beech, 25m for Norway spruce)
AM 5: Selection of final crop trees (FCTs), when FCTs have reached a branch-free bole of 6m, all remaining competitors were removed to accelerate growth and increase stability of the remaining crop trees – crop trees are harvested following target diameter prescriptions
AT / Mean annual temperature increases from + 2.5oC to +4.5oC (period 2080-2100 compared to baseline);
Mean annual summer season precipitation may decrease up to -19%; / General: rising temperatures will increase forest productivity; decrease in precipitation will not have major impacts as baseline precipitation is high (up to 1600mm/year); damages by bark beetles will likely increase due to warmer temperatures and thus favorable conditions for insect development; / BAU management is based on interviews with forest manager.
Current management practices rely on long-distance cable yarding with skyline systems. The skyline tracks are set up diagonal along the slopes over distances of up to 1000 m. Along the skyline tracks irregularly shaped slit and patch cuts of appr. 1500m2 size are implemented in order to initiate and favour natural regeneration (mainly Norway spruce; other species are heavily browsed by ungulates). No additional thinning operations are done; harvesting is done motor-manually, harvested trees are cut to length (4-6 m logs) on site. The current management intensity translates into a virtual rotation length of 200-250 years. / AM have been designed based on interviews with forest managers.
Adaptive management strategies feature the introduction of European larch on 25% of all cut areas (AM1) in combination with an increased game management which decreases browsing pressure by ruminant game species by 50% (AM2). Additionally a management regime featuring an increased harvesting intensity in combination with spatially smaller structured cuts (horizontal slit cuts) and planting of 25% European larch under 50% browsing pressure has been implemented (AM3).
The management scenario AM3 is the most productive management alternative in terms of timber harvests and mitigates further increases in growing stock. Larix decidua requires a strong reduction in browsing pressure for successful establishment. With regard to the protective functions against snow avalanches and landslides the management scenario AM3 provided the best results, due to the smaller openings created by slit cuts along slope contour lines.
ES / Temperature increase: Scenario B1: 3.6 (in June, July and August) is projected by the end of this century (2081-2100)
Scenario A2: 5.4 ºC
Precipitation reduced by 67%(June, July and August) in Scenario A2 and by 48% (June, July and August) in scenario B1 (Barrera-Escoda and Cunillera, 2010). / Severe dieback of some species especially soils with low soil water holding capacity.
Dieback episodes already observed in Pinus sylvestris, Quercus ilex and other species in shallow soils. / BAU based on local expert knowledge and historical management regimes. / Given that drought is the main driver, the recommendation to face these problems is to reduce the tree density. The recommendation is based on field experiments carried out in the area which have proved to be effective so far.
PT / A1B scenario with regional climate model developed by the Hadley Centre, data set HadRM3Q0:
Precipitation - reduction of 33% in the growing season (May-September)
Temperature - overall increase between 9 and 25% with 13% in the growing season / Cork oak: 1) increasing tree mortality, 2) decreasing tree growth, 3) decreasing cork growth, 4) increased vulnerability to pests
Eucalyptus: 1) decrease in productivity, 2) increased vulnerability to pests / Cork oak: Cork debarking rotation periods of 9 years, cork debarking heights equal to 2, 2.2 and 2.5 for 1st, 2nd and the following cork extractions, maintaining, for each stand, the crown cover percentage encountered in 2010 in the forest inventory data
Eucalyptus: a typical eucalypt rotation may include up to 2 or 3 coppice cuts, each coppice cut being followed by a stool thinning in year 3 of the coppice cycle that may leave an average number of 1.5 sprouts per stool and final harvest age of 9. / In both the cork oak and eucalyptus case studies, a similar methodology was used. Rather than prescribing à priori an adaptive strategy applicable to all the stands of a landscape, based on expert knowledge, the research approach was to simulate different management alternatives for each stand and use optimization techniques to find the best combination of management alternatives for each objective.
The results point out for the following adaptations to climate change in forest management:
Cork oak: adaptive management alternatives included cork debarking rotation periods of 9, 10 or 11 years, cork debarking coefficients equal to 2, 2.2 and 2.2 meters for 1st, 2nd and the following cork extractions respectively. The decrease in the debarking coefficient was a tentative of decreasing the stress undertaken by the trees that are already being challenged by climate change. The adaptive management also includedtree density increase in order to reach 300 trees ha-1 (crown cover around 58%) in forest stands and 120 trees ha-1 (crown cover around 40%) in silvopastoral systems. The major recommendation to minimize the impact of climate change on growth is to increase stand density by artificial or natural regeneration. In addition, forest managers can also consider extending the debarking rotation period to more than 9 years, in order to allow the increase of cork thickness of the extracted cork that may be affected by the dryer climate in the climate change scenario.
Eucalyptus: in the adaptive management alternatives a rotation may include up to 2 or 3 coppice cuts, each coppice cut being followed by a stool thinning in year 3 of the coppice cycle that may leave an average number of sprouts per stool ranging from 1.4 to 1.6. Harvest ages range from 9 to 16. The optimized solution selected the longer rotations.
BG / The expected climate change features a distinct increase in temperature: from 1.5 °C to 3.5°C (mean annual at the present – 10,7 °C),during the second part of the 21st century. Major changes are expected for precipitation, whose amount will lightly decrease between 60 up to 120 mm (annual at the present 600mm).Periods of drought lasting over 20 days during the second part of the vegetation period will enhance up to 60 days on the end of the period of simulation. / The most expected impacts of climate change on this region are drought stress to trees and an increased risk of fire.
Due to the warmer and drier conditions some shortening of the current vegetation period will occur and the more xerophytes tree species will be less vulnerable. Young seedlings of seed origin will be more sensitive to drought stress and will be shifted by the young sprouts. The droughts and less favorable growing conditions during the growing seasons cause substantial decrease of the mean annual increment of the forest stands. / BAU scenario is based on today’s legislative norms. The concept of a longer rotation period for the coppice stands to promote seed regeneration is dominant sylvicultural system for these forests.This means:
For oaks (Q.sessiliflora, Q.frainetto, Q.cerris) – regeneration felling after age of 50 years based on natural seed and sprout regeneration; random tendings and economically efficient thinnings.
More of the black pine (P.nigra) plantations will be transformed in to mixed stands with different share of local species (oaks) depending of the site type. / AM scenario is following the hand-book recommendations (state of the art of the scientific knowledge concerning oak coppice stands dynamic).
These mean that all regeneration fellings as well thinnings are happen in appropriate time, despite their economic efficiency. Rotation period is shorter for the coppice generation.AM promotes the relatively intensive and steady decrease of the standing volume per hectare of the existing forests in short and middle term period for all stands.
Black pine plantations is transformed to mixed stands dominate of pines thanks to regular thinnings.
In all climate scenarios, adaptive management scenarios determine higher share of high forests in the case study area in comparison with current practice (BAU). Potential timber harvest will decrease during the projection time, since the main annual increment decreases for both AM and BAU scenarios and both coppice and high stands. In the long term perspective the AM scenario supports higher volume stock in comparison with the BAU for all oaks stands.
RO / Changed annual parameters in 2100 compared with 2000 (Bouriaud et al., 2014):
CCSM3: +1.9°C, -21% precipitation
ECHAM5: +3.2°C, - 23% precipitation
HadCM3: +4.6°C, -37% precipitation / Impacts:
On long term: increased biomass under CCSM3, decreased biomass by 50% under ECHAM5 and by 80% under HadCM3.
Substitution of coniferous species by broadleaves.
Mid term (30 years): biomass remains the same under CCSM3 and ECHAM5, slightly decrease in biomass under HadCM3.
Fir and beech stable in the stands composition, but Norway spruce is strongly decreasing.
Species composition changed radically in low elevation stands that are subject to harvests. / BAU is based on Romanian legal compulsory norms for forestry.
Spruce monocultures: harvested at 110 or 120 years old, by clear-cutting small areas, 3ha maximum, followed by planting with spruce (5000 saplings per ha).
Beech-based stands: harvested by shelterwood cuts at 140 years old, one third of tree removed at once.
Mixed species stands: harvested by shelterwood cuts at 100 or 120 years old, one third of trees removed at once, followed by natural regeneration and complementary planting if need (2500 spruce saplings and 2500 beech plants per ha).Thinnings are scheduled in each stand type with respect to species composition and stand age; less than 15% of the current volume is extracted. / AM options are based on interviews with forest managers and owners, aiming at slightly shortening the rotation and increasing the intensity of thinnings. No specific measures for species replacement are planned. The AM are continuing with the natural regeneration of stands and, if possible, with the current presence of spruce.
AM1: Rotation age reduced by 10 years for all types of stands.
Thinnings intensity: 20% of the standing volume.
AM2: Rotation age reduced by 20 years for all types of stands.
Thinnings intensity: 25% of the standing volume.
AM3 is a mixture of the others: BAU is kept until 2030, AM1 covers the period from 2040 to 2060 (decades 4 to 6), and AM2 covers the period from 2070 to 2100 (decades 7 to 10).
References