There are few options available to adapt the forest management in the Panagyurishte to a changing climate.
One is to support the increasing of the share of more drought tolerant species as Turkey oak, despite the less valuable timber production of it.
Another potential measure is to implement more intensive regeneration treatments on mature coppice stands. This would respond to two important management goals – to convert coppice oaks stands in to high ones and to establish young, high forests stands, which theoretically would be more flexible to environmental changes.
From the other side, the competition of new stumping sprouts after the regeneration felling is an important ecological and economic obstacle, which might frustrate the transformation. We may expect that more stands in the future will own mixed origin. The problem with the total timber productivity of the future stands should not be underestimated as well.
Reducing the fire risk means more intensive thinning, as well as diminishing the share of pure conifer plantations. These measures could meet some economic obstacles, since many of them are not profitable.
Finally, the strictly even age structure of the current existing stands favors its occurrence again in to next generations. Generally pure, even age stands with simple (homogeneous) spatial structure are less resilient to different stress factors. The establishing of a more heterogeneous stands structure needs longer time and additional financial and human resources, which will reduce the implementation of these treatments.
The adaptive management scenario (AM) includes silvicultural treatments which are convenient, well-known and possible according to both the expert opinions and legal management conceptions. They include shortening the rotation age of the coppice stands for conversion in to high and relatively intensive tending and thinning in to young stands.

Fig. BG-11. Species and origin dynamics of forest stands in case study Panagyuristhe by moderate climate scenario A1B and AM management (2010)

Fig. BG-12. Species and origin dynamics of forest stands in case study Panagyuristhe by moderate climate scenario A1B and AM management (2100)

What do the AM projections predict about?

1. Tree species composition and stands origin;
2. Stands growth and potential timber harvest;
3. Volume stock per hectare of the stands.

Tree species composition and stands origin: In all climate scenarios, adaptive management scenarios determine higher share of high forests in the case study area in comparison with current practice (BAU). More intensive regeneration felling according to AM will lead to increasing the areas of young stands dominated by trees of seed origin in short to mid-term outlooks. Long-term projections predict back-turn to coppice dominate origin of the existing stands. The share of the most adaptive Turkey oak increase faster in short-term run replacing more often Sessile oak and pine. Important conclusion of the long-term projection is that the conception of total conversion of the coppice oak stands will not be fulfilled, never than the less AM scenario promotes higher future share of high forests, than BAU.

Stands growth and potential timber harvest: 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. AM management require urgent, short-term harvest in all coppice stands, which will decrease considerably after 2020. This rises the potential problem concerning the lack of ability of the stands to supply the timber demand in mid and long-term outlook, if assumed that it will keep the current level. From the other hand the risk of men-caused fires will diminish since less human activities will be possible in more dense young forests.

Volume stock per hectare of the stands: 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. This connects to the more intensive regeneration felling in the short-term run for oaks stands. The total area of the pure pine stand decreases since native species (oaks) become dominants. In the long term perspective the AM scenario supports higher volume stock in comparison with the BAU for all oaks stands. The projections represent volume per hectare in the end of the century equal to the current one.  In a few words, the AM promotes ability of the future coppice oaks stands to produce and support aboveground biomass, like coppice forest today. This mean that the stands will be similar to the current ones and will consist from closed forests and they could guarantee their protective and other environmental services, despite the low timber production and supply.

see also this FAQ (especially the figures).

For a summary of the results and differences between the AM and the BAU scenarios  see Table BG-3.

Table BG-3.Comparison between the AM and the BAU management concerning legal management goals, related to different forest ecosystem functions in the Panagyurishte case-study (+ positive impacts, – negative impacts, ~ indifferent).

 Some additional conclusions:

The AM scenario provides higher species diversity and performs a steady share of coniferous;

No significant differences in BAU and AM in terms of yield, growth and other stand characteristics (density, composition, origin) are observed;

The potential room for adaptation in terms of traditional silvicultural aims for all coppice forests is narrow;

The AM scenario moderates potential harm concerning timber supply and forest diversity;

These should lead to changes in long-term goals and traditional expectations from these forests.

Entry tagged as: Panagyurishte (Bulgaria)

The typical stands in the case study area are composed of Norway spruce and beech, often in mixture. The tree species are sensitive to drought, windfall and insect attack.

The typical stands in the case study area are composed by Norway spruce, silver fir and beech, often in mixture. Beech, followed by silver fir is sensitive to drought and the Norway spruce is the most sensitive to windfall and insect attack.

Although there is much empirical evidence of frequent drought episodes, there are no studies available to quantify and detail droughts in this region. The discussions with the forest management authorities in the case study area identified drought as being an increasingly important factor for tree stress, potentially leading to dieback. Beech is widely known as a drought-sensitive species, and would likely respond to more frequent or intense droughts by reducing its productivity. The Norway spruce growing in mixture with other coniferous species in the region had the strongest reaction to drought. The consequences could be a drop in productivity but also an increase in trees’ susceptibility to insect attacks.

The stands can be regenerated naturally or with some planting complements. However, a shift in species composition could be observed in the future, as beech tends to gain space to the detriment of Norway spruce, but there are not enough evidences to put this shift to the climate change.

The Norway spruce and larch are sensible to the insect attack moth Lymantria monacha. Attacks on Norway spruce during an outbreak can lead to total defoliation. Trees with defoliation exceeding 30% are unlikely to recover. Total or partial defoliation weakens trees and promotes secondary pest attacks (e.g. from bark beetles). Major bark beetle attacks (in the last 10 years) have been reported since 2003, when outbreaks of insect populations followed the existence of a large quantity of breeding material from the 2002 windfall. A high level of bark beetle population persisted until now, with a large number of healthy spruce trees being attacked annually. The damage can potentially be considerable, with several thousands m³ of wood to be cut.

Entry tagged as: Carpathians (Romania)

The distribution of forest tree species is expected to be affected by climate change which may have severe economic consequences (Hanewinkel et al. 2012). For example, the growth of Norway spruce is expected to suffer from water stress especially in south-eastern Sweden on sites with low water-holding capacity.[ 1]  Studies assuming that the same tree species as today will be used in forestry indicate that the tree growth in Kronoberg County will in general increase under a warmer climate. Results from our simulations in the MOTIVE case study area, where we have applied business as usual forest management under both current climate and a warmer climate (A1B scenario), indicate that tree growth will increase by approximately 15% during the period 2001-2100 due to a warmer climate. The increase in growth is indicated to affect average standing volume (5%) and harvest volumes (15%) and to increase net incomes from forest operations. Due to increased growth, rotation periods will be shorter and forestry in general more intensive in terms of the number of forest operation activities per unit of time. The average number of activities per stand and year is indicated to increase by 6%, mainly in terms of final fellings and regenerations. For Norway spruce the average age at final felling under a warmer climate is indicated to reduce by seven years until the period 2071-2100. The effects of the changing climate on the forest will increase gradually which might affect also the provisioning of opportunities for hunting and recreation. Our simulation results show only small effects, however, on average moose habitat suitability index (Kurtilla et  al. 2002) and recreation index (Lindhagen 2005) during the period 2001-2100.

At the same time climate change is expected to lead to increasing disturbances from extreme weather events, insect outbreaks, fungi etc. with consequences on services and benefits from the forest. While increasing growth might lead to higher financial return, the quality and or the quantity of the wood, and indeed the financial return, will reduce should insect outbreaks, wind damage or some other risk materialize. Furthermore, a changing climate might lead to effects that so far remain unidentified.

Wind damage to forests in southern Sweden has increased during recent decades (Gardiner et al., 2010). This is because of changes in the state of the forest as well as form a changing climate. Kronoberg County was the most extensively damaged county in a major wind damage event on 8 January, 2005, when damage occurred on 14.1% of its forest area (SFA 2006) (Figures SE-1 and SE-1). The wind damage was mainly done to Norway spruce (SFA 2006). More than a fourth of the forest area used for the MOTIVE simulation study was damaged during the 2005 wind damage event (based on data from the Swedish Forest Agency) (see Figure SE-1). Pervasive wind-related reduction in growth of the remaining forest during three years after the storm has recently been shown (Seidl & Blennow 2012). The growth reduction is of a magnitude similar to the total secondary damage incurred by spruce bark beetles during the corresponding period of time after the storm.

Figure SE-1: Case study area and surroundings in Kronoberg County. Forests damaged by wind on 8 January 2005 in purple (source: classified satellite imagery by the Swedish Forest Agency) © Lantmäteriet, i2012/901

Figure SE-2: Kronoberg County was the most extensively damaged county in a major wind damage event on 8 January, 2005. The fallen trees resulted in extensive secondary effects straining civil security to its limits. Photo Kristina Blennow.

Entry tagged as: Kronoberg (Sweden)

The simulated tree species distribution in 2110 (Figure VE-1) shows clear differences between current climate and moderate climate change on the one hand, and the more extreme climate change scenario on the other hand. Under current conditions or moderate climate change, beech is expected to increase in large parts of the area. However, increased drought under climate change leads to a loss of beech, in favour of drought-resistant, coniferous species, mostly Scots pine on the poor soils and Douglas fir on the somewhat richer soils. Broadleaved, drought-sensitive species like oak and beech can only maintain dominance in the south part of the area with higher water availability. The climate effect on the tree species distribution in the more extreme W+ scenario will have a larger influence on the future tree species composition than adaptive management can compensate for. Research has shown that different provenances of Douglas fir have different tolerance to drought. It is likely that such provenances have been used in our case study in the past. In the simulations we have assumed that also in future drought-tolerant varieties are used.

Figure VE-1. Dominant tree species in 1981 (left) and in 2110 under the 9 simulations.

Entry tagged as: South-East Veluwe (Netherlands)

Most tree species occurring in the area are typical Mediterranean tree species which are medium to extremely drought resistant. It means that they have low risk of cavitation due to drought. The most serious threat of climate change in the area is the increased occurrence of long dry spells.  Even Mediterranean species can suffer carbon starvation due to these dry spell, as they need to consume their mobile carbon reserves to overcome such periods. If too recurrent, mobile carbon reserves cannot be replenished in time, with vitality loss as a consequence. This may be the case for holm oak. Eurosiberian species like Scots pine, who find some of their southernmost distribution areas in these mountains are directly threatened by climate change. Scots pine has no possibility to migrate to higher elevations given that they occupy already the highest zone of this geographically isolated mountain.

Entry tagged as: Prades (Spain)

The assessment of tree species sensitivity to climatic changes in the case study distinguishes three key ecosystem processes (a) growth, (b) regeneration and (c) mortality of trees with regard to three time horizons: (i) short-term (up to 2020), (ii) mid-term (2020 to 2050) and (iii) longterm (2050 to 2100).

1) Growth

All tree species in the region will actually physiologically fall out because of the drier climate and the water supply on most sites is a limiting factor (current precipitation levels will decrease up to 120 mm per year and T will rise up to 3.5 degree C which increases the evapotranspiration). The droughts and less favorable growing conditions during the growing seasons cause substantial decrease of the mean annual increment of the forest stands (fig. BG-1).

Fig BG-1. Average annual increment (cub.m/ha/year) simulation data for the forest case-study area Panagyurishte, by two climate scenarios (A1B& BL) and both BAU and AM management scenarios

2) Regeneration

In the short-term scale, not severe changes are expected. Mid-term seed regeneration will be still possible for most of the oak coppice stands (which is the important management goal). In long-term, the ecological conditions will worsen seed regeneration since the mature oak trees need favorable climatic condition to produce vital acorns. Young seedlings of seed origin will be more sensitive to drought stress and will be shifted by the young sprouts, which ability to provide more water through their old and well developed root system is higher (fig.BG-2).

Fig.BG-2. Distribution of forest stands in case study by origin for the two climatic scenarios (A1B & BL) following BAU management scenario.

3) Mortality

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. More valuable, but mesophyte Sessile oak (Q.petrea) will be most affected by long lasting, dry conditions. Warmer and open winter could provoke earlier blossoming of trees’ buds which could cause damage from later frosts. Constant short vegetation period will lead to a decrease of growth of the existing trees and a reduced stand’s canopy. These will increase the risk of epidemic outbreaks caused by insects, fungies and forest fires as well.

The Hungarian oak (Q.frainetto) is the most drought-resistant species in the case study area, followed by Turkey oak (Q.cerris). An important difference between them is that H.oak has a relatively slower growth in the beginning (lag in mixed stands) and reaches a mature phase at least 15-20 years later than Turkey oak.These leads to a permanent increase of the share of the more drought-tolerant and adaptive Turkey oak, which gradually replaces Sessile and Hungarian oaks during all periods of time (fig.BG-3 and BG-4).

For pine plantations the risk of forest fires will increase substantially. Reduced precipitation and warmer temperatures may positively affect the conditions for Thaumetopoea pityocampa Schiff. and thus deteriorate the growing conditions for pines. From the other side, the Austrian pine (Pinus nigra) is competitive in dry soils.

Fig BG-3. Species and origin dynamics of forest stands in the the case study Panagyurishte by moderate climate scenario A1B and BAU management (Year 2010).

Fig BG-4. Species and origin dynamics of forest stands in the the case study Panagyurishte by moderate climate scenario A1B and BAU management (Year 2100).

More of the pine stands should be harvested in mid-term run and pine will regenerate successfully together with some oaks. Looking long-term, about half of these future mixed stands will not be dominated by pine.

Flowering ash (Fraxinusornus) and Eastern hornbeam(Carpinusorientalis) will be more often a part of the tree species composition as provisional species.

For a summary of the tree species’ sensitivities please see Table BG-1.

Table BG-1: Mid- to longterm tree species’ sensitivities towards projected climate change for the three forest ecosystem processes. (+ increase, ~ no change, – decrease)

Entry tagged as: Panagyurishte (Bulgaria)

Climate change is expected to affect the growth and survival of forest trees through increased mean annual temperature and rainfall, while increasing the risks from storms, summer drought, pests and diseases. Towards the end of the century some variants of the A1B scenario indicate much drier conditions in the region. This would be expected to cause previously high yielding sites to be constrained by drought, so yield would drop. Tree species in these forests have different sensitivities to climate change with some expected to become more suitable and others expected to become less suitable (see species maps below). Pines and broadleaves can sustain their current output levels in the context of the drier A1B variants studied, while Spruce is only expected to do so where the climate projections suggest little or no decline in summer precipitation.

Fig. EN-1. Clocaenog species composition change by 2080 with Species Diversity storyline. Comparison of species composition between the baseline and five contrasting variants of the HadRM3 A1B 11 member ensemble. The maps on the left are for baseline and for variants with a warmer climate and reduced summer rainfall, and maps on the right show outcome for variants with warmer climate and little or no change to rainfall.

Entry tagged as: Wales (UK)

Growth

All the tree species in the case study area will physiologically (e.g. net primary production, NPP) benefit from warmer climate during the next 30 years as shown in Table JO-1 for Norway spruce (Climatic Zone II). The average annual NPP under CC is expected to be 5–15 % higher than that under current climate (CUR) until 2030 regardless of the climate zone.  In the middle period, 2030– 2060,  the average annual NPP under climate change (CC) will decrease again to the level of CUR in the Zones I and II,  and further on below CUR during the period 2060–2099. The decrease rate of net primary production in the Zone I will be greater than that in Zone II. In the Zones III and IV, the average annual NPP under CC is higher than under CUR over the whole 100-year simulation period. In southern Finland, Scots pine on the medium-fertile site and birches on high-fertile sites become more preferable than Norway spruce.

Table JO-1. Periodic (2000–2030, 2030–2060 and 2060–2099) annual net primary production (NPP) of Norway spruce under the current (CUR) and changing climate (CC) in different climatic zones (I–IV) and site types (OMT and MT) over Finland. The values in parentheses are the percentage change (%) from that under the current climate. Climatic zones are separated based on the temperature sum (Ts): Zone I, Ts > 1200 d.d.; Zone II, Ts, 1000 -1200 d.d.; Zone III, Ts 750 – 1000 d.d.; Zone IV, Ts 600 – 750. The case study area is the representative of the climatic Zone II.

Regeneration

In the period 2000-2030, the success of natural regeneration of all tree species will be enhanced in the case study area due to the warming climate, which enhances flowering and maturing of seeds. Furthermore, the germination of seeds and establishment of seedlings will be improved. Also establishment of seedlings based on direct seeding (in Scots pine) and planting (in all species) will be improved. However, later on, natural regeneration (or direct seeding) may no more be that successful due to reduced soil moisture, which is likely to reduce the germination of seeds and establishment of seedlings. Low soil moisture on less fertile sites may also reduce the success of planting regardless of tree species.

Mortality

In the case study area, the changing climate may in general enhance tree mortality due to high wind speeds and/or heavy snow loading with shorter duration of soil frost from late autumn to early spring.  In summer storms, especially Norway spruce but also Scots pine and birch (in leaf) are vulnerable to wind damage, whereas in winter time Norway spruce with shallow rooting is the most vulnerable (Figure JO-1). The mortality may also increase due to drought episodes and especially in Norway spruce with shallow rooting on sites with relatively low water-holding capacity. This has been found also nowadays in summers with exceptional high temperatures and long drought periods. Table JO-2 summarizes the sensitivity of growth, mortality and success of regeneration for different tree species to changing climate.

Figure JO-1. Under warming climate, the risk of wind damages in forests will increase regardless of any change in windiness.

Table JO-2. Mid- and long-term sensitivies of different tree species in the case study area. Legend: + increase, – reduction.

Entry tagged as: North Karelia (Finland)

The main goal of management in the case study area is the sustainable and profitable use of the forest resources for all possible demands of society. This includes, in particular, the production of timber (for revenues), but also the maintenance of landscape beauty, attractive recreation environment including sustainable crops of berries and mushrooms, sequestration and storing carbon and providing habitats for wildlife. In short term (until the year 2020), a continuation of BAU will not affect the planned provisioning of ecosystem services (Table JO-3). In long term, the preference of Norway spruce on the sites of medium fertility (32% of forest area) or even on sites with lower fertility (44% of forest soils) due to moose problem in Scots pine and birch may reduce the capacity to produce timber and energy biomass, and sequestrate and store carbon in the ecosystem.  This may also increase the risk of abiotic and biotic damages (e.g. bark beetle), which will further reduce the possibility to maintain the potentials to achieve the current goals under warming climate.

Table JO-3. Impacts of expected climate change on different forest ecosystem functions in the Finnish case study area. Legend: + positive impact, – negative impact, ~ indifferent.

Entry tagged as: North Karelia (Finland)

Current management is in many cases already well adapted to the sites and climatic conditions, and already takes into account natural developments. A mild climate change scenario can be easily dealt with in the current management schedules and is not expected to lead to problems in relation to the goals set. Most forest functions are not much affected by the climate change scenarios. However, part of the current Natura2000-labelled old-growth oak and oak-beech sites would convert to coniferous forest under the more extreme climate scenario.

Entry tagged as: South-East Veluwe (Netherlands)

In Poblet forest just like in most Mediterranean forests in southern Europe, BAU practices is no stand tending and a clearcut or a destruction by fire at variable age. Simulations show that the BAU management under climate change leads to a decrease in biomass production.  The reason is that the high stand density of a BAU management in combination with increased drought stress leads to increased competition and mortality. The BAU leads also to a serious decrease in water use efficiency (table 1). This example shows the huge potential of management to keep ecosystem services on an aceptable level under climate change. These large differences in management outcome were also observed for other ecosystem services.

Entry tagged as: Prades (Spain)

The formal overall goal of the State forest enterprise “Panagyurishte” is the sustainable and profitable use of the forest resources for all possible demands of society. Operationally, this includes the fullfilment of fuel-wood demands and the production of timber to create revenues. The maintenance of the water catchments of the forest areas, the protective services against erosion, and the protection of the woody, and green landscapes of the slopes around the settlements and agricultural lands, is part of the present management aims and responsibilities of the local forest department.

The current management practices (business as usual; BAU) rely on the conception of converting existing coppice stands into high trough natural regeneration, which will increase the quality of producing timber and will ensure higher productivity in a long-term view.Since these stands are planned for seed regeneration, regular thinning is required until they reach maturity.Regeneration felling is shelter-wood implemented in two or three phases. Mandatory tending should be done after the final stage to suppress competition from new sprouts from the stumps of felled trees. If the latter tendings and thinings are not done (for example, because of lack of funds), then the future young stand will remain with a mixed origin and more sprouts will appear. Traditionally, the forests practitioners look at the man-made pine plantations as  temporally stands which will produce some construction wood and after they reach rotation age of 60 to 80 years, will be partially or fully replaced by native trees (oaks, hornbeams).

The examination of the BAU scenario through the stand development modelling and simulation (PICUS model has been used) gives the following:

In short-term run all oak stands will not change vastly their silvicultural records. The pine plantation will be harvested more intensively, which will continue at some period after 2020 (fig. BG-7&BG-8).

Mid-term projections suggest an intensive timber harvest from the coppice stands, reaching double quantity of the present level (fig.BG-6). If this will not be done many uncertainties concerning future existence of all over-mature coppice stands will occur. The natural tree dyeback will be a precondition of fires or insect calamities.There will not be available timber from conifers (fig.BG-8). The average timber volume per hectare will considerably decrease .The trees’ cover will be more sparse and open, and individuals will be younger and smaller. Thus, some other ecosystem services as erosion protection and landscape improvement will become more vulnerable.

The long-term outlook is even worse .The stands will grow very slowly and both oaks and pine stands will be able to supply small amount of timber. The main goal to increase coppice transformation will not be reached. The area of the coppice stands remains the same as the current one (fig BG-5) and the main annual increment of the high oaks (fig.BG-9) keeps lower than the coppice ones (fig.BG-10), according to all climate scenarios.

The Carbon sequestration regime may also have a negative impact caused by a higher fire danger and the slow growth of the trees. However, due to a higher share of the standing deadwood caused by natural die-back and more open tree cover,  the habitat and biodiversity functions for different mammal species (rodents, foxes, some wild boars) are expected to improve. On the other hand younger forests will not receive hospitality to endangered (late successional) species, which depend from old and heterogeneous forest stands (table BG-2).

Fig BG-5. Current and projected average volume per ha of the coppice oak stands under moderate climate scenario A1B, AM and BAU management

Fig.BG-6. Current and projected 10 years average removed timber volume per ha from the coppice oak stands under moderate climate scenario A1B, AM and BAU management.

Fig.BG-7. Current and projected average volume per ha of the pine stands under moderate climate scenario A1B, AM and BAU management

Fig.BG-8. Current and projected 10 years average removed timber volume per ha from the pine stands under moderate climate scenario A1B , AM and BAU management

Fig.BG-9. Average annual increment (cub.m/ha/year) simulation data for the high oak stands by climate scenarios (A1B, B1, BL) and BAU management scenario.

Fig BG-10. Average annual increment (cub.m/ha/year) simulation data for the copiice oak stands by climate scenarios (A1B, B1, BL) and BAU management scenario

Table BG-2. Impacts of expected climate change on different forest ecosystem functions in the Panagyurishte case-study (+ positive impacts, – negative impacts, ~ indifferent).

Entry tagged as: Panagyurishte (Bulgaria)

The Frasin forest managers consider that stands are not particularly vulnerable to climate change. However some stands are more exposed to illegal logging, some other to forest fire, or other to grazing, which act as man-related disturbances able to amplify the negative effect of the climate change. Also, the uncertainty of the ownership created and will still create pressure on the forest management, e.g. attempt to harvest more than allowed.

The managers listed some additional risks that are related with the forest management practiced today. For example:

• the current management of the stands density: the stands are too dense;
• the production-oriented goals today do not meet anymore the economic demand or the ecological requirements: the stands are managed in long rotations and large tree sizes that is inducing a risk for unstable stands (too old) in the future, and are not satisfying neither the demand of the timber processing industry.
• The managers have started to have difficulties in regenerating the forests and in controlling the insects development, e.g. the bureaucracy of timber harvesting make impossible a fast intervention to cut infested trees and quickly stop insects development.

Thus, if there are not stands particularly vulnerable today, a combination between the current management risks and man-induced disturbances and the effect of the climate change may have serious consequences in the future. Then the natural drivers will make improbable the achievement of the current management goals. On the one hand, the economic difficulties encountered already today by the managers (they called the forestry practiced as being “subsistence forestry”) will increase with increasing disturbances, costs to fight attack insects and costs to regenerate the forests. On the other hand, the protective functions of the forests can not be achieved anymore if, for example, wind throw will happen on larger scale. The frequency and the quantity of timber extracted as salvage operations will increase and that will affect the planned harvest schedules. Nevertheless, the biodiversity is expected to increase following the different disturbances that are likely to occur (Table RO-1). Larger scale of windthrow will benefit to the regeneration of tree species that are now rare, e.g. birch, larch, horn bean, even oak, supplying then richer conditions for different animal species. In the BAU management, the biomass volume is quite similar to the current situation. The managers will have to face the reduction/disappearing of the Norway spruce and the apparition of pioneer species (Betula pendula, Salix) that will represent almost half of the biomass produced. Thus, due to the new species composition, there will be a significant decrease in the supply of wood for the market.

Figure RO-1. BAU management will lead to an decrease of the timber production, but an increase of the biodiversity

Figure RO-2. BAU management will lead to an decrease of the timber production, but an increase of the biodiversity

A particular problem comes from the age structure of the stands today in the Frasin forests (Figure RO-3). The current age class distribution is particularly unbalanced: at the beginning of the simulation (2000), half of the stands are more than 70 years old and a third more than 90 years. The excess of the over-mature stands will impose to the forest manager to progressively harvest the stands in order to distribute the harvesting of the old stands in tree-four decades.  If climate change happen, the forest manager will not be able anymore to decide which stands to harvest, because he will be obliged to harvest according to the disturbances occurred. Current goals such regeneration after final cutting or spatial optimisation of cuttings for better soil protection may become impossible to achieve. The present old stands may remain un-harvested, therefore more vulnerable to new disturbances, also due to the accessibility of the stands, which is quite low (Figure RO-4).

Figure RO-3. The excess of the over-mature stands – in yellow – over 80, in orange-red stands over 100 years old.

Figure RO-4. The low accessibility of the stands (particularly of the old stands) will impede the intervention with forestry works in case of disturbances.

Entry tagged as: Carpathians (Romania)

Business as usual provides opportunities to achieve current goals under some future climate scenarios. However, Diversification as an adaptation strategy is expected to lead to less uncertainty, with projected standing biomass for all variants being between the highest and lowest projections for Business as Usual. Therefore although BAU has a possibility of higher returns, it also has a possibility of much lower returns than Diversification.

Studies of Business as Usual management assuming no climate change suggest that the current species choice is appropriate for conditions based on the period 1960-1990.

Entry tagged as: Wales (UK)

The landscape model LandClim is used to investigate large-scale effects of climate change on forest stand development and to develop and evaluate adaptive forest management strategies. The model was developed to assess the importance of climatic effects, wildfire and management on historical and future forest dynamics.

We simulated in total 9 scenarios (3 climate x 3 management scenarios). The forest was initialised with data from 1980. The period 1980-2010 was simulated with management as close as possible to real management, in consultation with stakeholders/owners/managers, and by applying observed weather over this period. All scenarios are simulated for the period 2010-2110.

Entry tagged as: South-East Veluwe (Netherlands)

The scenarios and recommendation for the Panagyurishte case-study area are defined on the basis of expert opinions of the foresters involved in different management levels, as well as the present legal framework and stakeholder preferences.

The dynamic forest ecosystem model PICUS v1.5 has been employed for the scenario simulations.  An additional new module for simulation the stumps sprouting after felling has been developed. A set of indicators representing the demanded ecosystem services (an examples are given in Tables 1 and 3) was fed by model output and subsequently used to analyse the interrelationships of initial forest state, management concepts including assumptions about management intensity and climate conditions.

Entry tagged as: Panagyurishte (Bulgaria)

Landscape level model LandClim was used to simulate forest ecosystem dynamic. Adaptative management were explored using the harvest module by defining potential management scenarios for each management unit within the forest district studied following the silvicultural trends. The simulations was run on the forest district landscapes designed from a digital elevation model, stand and soil information, climate data and forest ownership maps.

The data from the management plans produced before 1989 were used to initialize the private stands. A first run enabled to simulate the current starting state of these stands, after they had been aged for 2 decades by the model.

The model did not deal specifically with the uncertainties.

Entry tagged as: Carpathians (Romania)

A suite of decision support tools and models were used to examine case study outcomes to 2080 based on differing management strategies: Business as Usual, Species Diversification, Short-rotation forestry and Low-impact silvicultural systems (LISS) that is essentially conversion to continuous cover.

Management strategies

1. Business as usual (BAU). This was the ‘Conservative’ trajectory (see D4.4), replacing forest stands ‘like for like’ with the same species and maintaining forest management alternatives as they are over the simulation period.
2. Species Diversification (DIVERSE). This followed a ‘Progressive’ trajectory for species mix. Species suitability was modelled at each 10-year period and species were changed at scheduled interventions (usually clearfell, replant) to maximize species diversification whilst also maximizing production. Other species diversification rules from the Welsh policy guidance document “Species Diversification” were used to accelerate diversification where possible, but these also restricted diversification in places due to the need to maintain populations of some species such as Scots pine and Norway spruce for other objectives. When a stand is restocked, ESC selects a replacement species based on highest yielding suitable species.
3. Transformation to a Low Impact Silvicultural System (LISS). This followed a ‘Progressive’ trajectory aspiration for FMA change. It applied continuous cover forestry (CCF) as widely as possible, constrained by wind exposure to lower elevation sites. In practice this would be further constrained by operational considerations.
4. Conversion to short rotation forestry for biomass production (SRF). Stands reaching the end of their FMA4 management were subsequently replanted with the same species on a 25 year rotation. Norway Spruce and Scots Pine in those areas would be retained on 100 year rotations to support habitats for rare species (e.g. red squirrels).

 Models

These were run with data from five variants of the HadRM3 A1B climate model. The models run were a species suitability model (Ecological Site Classification, ‘ESC’), growth and yield models (various); assortment models (ASORT, BSORT, CSORT); wind risk model (ForestGALES). The method for each management strategy and climate model variant was as follows, for each decadal time period and with each climate scenario:

1. Use growth models to grow each stand
2. Assess which stands to fell based on whether they have reached their rotation length for given management regime.
3. Thin remaining stands as appropriate
4. Perform log and biomass assortments on thinnings and fellings
5. For each felled stand, decide which species and management system to replace it with (under Diversification storyline)
6. Update database with changes and repeat process.

 Outputs

Models provided outputs as a range of ecosystem service indicators, including: Timber outturn volume; Standing Carbon; Recreation index; Biodiversity index and Wind damage risk status. The ESC suitability score gave a measure of the suitability of the species for a given site under prevailing climatic/soil conditions at a particular time.

Entry tagged as: Wales (UK)

The conclusions are mainly based on ecosystem model based analyses carried out in Finnish conditions. In these studies, the basic question has been: how is the climate change affecting the dynamics of managed boreal forest ecosystems and the consequent growth and development of managed boreal forests, and how the boreal forests should be managed under the climate change in order to sustain the production of goods and services obtainable in forest management. The main focus in these studies has been on the production of timber and biomass for energy and the sequestration and storing carbon in the forest ecosystem. However, also previous experimental studies on the climate change impacts (e.g. elevated CO₂, temperature, availability of water and nitrogen) have provided data for modeling, which utilized the basic physiological mechanisms to introduce the climate change impacts into the dynamics of the forest ecosystems. On the other hand, some of these models (e.g. FinnFor/Sima models) include also the effects of management (e.g. regeneration, tending of seedling stands, thinning, rotation length, nitrogen fertilization, provenance effects on growth) on the structure and the consequent dynamics of the forest ecosystem. Large-scale and multiple applications of the models in scenario analyses and the analyses of the current functioning and structure of forests throughout Finland have given a comprehensive insight on how the managed boreal forests may growth and develop under changing climate change and how these changes should be considered in formulating management rule to fit the situation due the changing climate. The findings have been widely discussed also in seminars with other researches, forest practitioners, administrators and policy-makers. In this context, the future management options are scaled to meet the needs and possibilities set by economy, forest policy, legislation and perception among public.

Entry tagged as: North Karelia (Finland)

Our results are based on simulations of forest development with the Forest Time Machine (FTM) model and assessments of wind damage probabilities for the projected forest states using the WINDA-GALES model.

The FTM model is a forest management-unit simulator developed to support evaluation of forest management strategies at a landscape level (Andersson et al. 2005). The model uses empirical stand growth functions and different stand management programs can be assigned to the individual stands. The stand growth response to climate change is mediated by adjusting the site index according to modeling results from the FinnFor model (Kellomäki & Väisänen 1997; Matala et al. 2005). FTM outputs variables describing periodical states of the forest as well as flows of harvested wood and money.

In our FTM simulations we have applied stand management programs reflecting today’s management in terms of choice of tree species, initial spacing, thinning regime and rotation periods (business as usual management). We have applied adaptive stand management programs including shorter rotation periods and adjusted thinning regimes in combination with a species change at wind exposed locations. At these locations conifer tree species have been replaced with Silver and Downy Birch using natural regeneration at first regeneration occasion. The use of other deciduous tree species is expected to require additional game management and/or use of fencing at regeneration to mitigate browsing by moose and deer.

The WINDA-GALES model is an integrated system of models for assessing the probability of wind damage to forest stands building on the WINDA model (Blennow & Sallnäs 2004) and the GALES model (Gardiner et al. 2000). It provides a geographically explicit environment for standwise calculation of the probability of exceeding critical windspeeds for wind damage in a landscape. The calculations are sensitive to the stability of the forest as well as to the local wind climate and uses extreme value theory for the statistical calculations.

Entry tagged as: Kronoberg (Sweden)

Table JO-4 summarizes some approaches available to adapt to the changing climate in short and long term. The case study area is located in the mid-boreal zone, where the warming is generally increasing the forest growth, if the availability of water is not reduced too much due to enhanced evaporation. In any case the changing climate is clearly increasing the frequency and duration of drought episodes, which occur even under the current conditions.  Drought risk is likely reduced in northern boreal (and partly mid-boreal boreal) forests, but increased in southern boreal (and partly mid-boreal) forests, including the case study area.

In general, existing tree species (either native or exotic) are probably growing faster, with more rapid life cycle and enhanced turnover of tree populations. However, later in this century, the use of Norway spruce should be preferred only on the fertile and moist sites in order to avoid the likely reduction of growth and increase of drought caused mortality and damages due to bark beetles. The consequent reduction of area occupied by Norway spruce will reduce the wind-induced damages in winter. However, in summer time all tree species may suffer equally summer storms. Any increase in breeding material will increase the risk of damages due to bark beetle,  due to a rapid growth of bark beetle populations (if not harvesting timber soon enough).

Regarding regeneration, the preference of coniferous species in planting may require careful site specific choice of tree provenance and species with more optimal response to the changing climate (Table JO-4). This seems to allow more southern and more productive provenances of Scots pine and Norway spruce to be used in forestry. However, the properties of photoperiod may limit the provenance transfers northwards to be less than 200 km even in short term. In long term, the tree improvement programmes may be launched in order to increase the genetic potentials of tree plantations to adapt to higher temperatures with low risk to be damaged by spring and autumn frosts. However, the preference of natural regeneration, and especially in Scots pine on less fertile sites (44% of forest soils in case study area), provides huge genetic potentials to adapt forest to the climate change in the region represented by the case study area. This choice is realistic, since natural regeneration is a common practise in forestry along with direct seeding in Scots pine.

Natural deciduous regrowth in coniferous plantations may require more tending of seedling stands in favour of coniferous species (Table JO-4).  Later, more frequent and/or intensive thinnings may be needed to maintain the growth of trees and reduce risks of abiotic and biotic damages. The regular thinnings will also increase the stability of trees due to the enhanced radial growth, and thus reduce the risk of abiotic damages. Regular thinnings and shorter rotations are also needed to avoid biotic damages (e.g. due to lower growth rate of maturing trees and drought episodes), however, the need depending on the subarea of boreal zone and site fertility.  Regular thinnings reduce the evaporation, thus increase soil moisture and reduce the risk of drought on the areas and soils, where the summer-time evaporation is likely to exceed the summer-time precipitation. In this regard, regular thinnings of Norway spruce stands may reduce substantially the effects of drought on growth and mortality.

Entry tagged as: North Karelia (Finland)

We have analysed three management scenarios. Business as usual is a continuation of the current management. Intensified management (IM) anticipates at increased productivity of the forest due to climate change by intensifying the management. In IM, in some reserves wood harvest is resumed, while some heathlands are allowed to convert naturally to forest. Thinnings are aimed at increasing production of remaining trees or to stimulate regeneration of more productive/economically attractive species, sometimes assisted by planting. Precautinary management (PM) aims at decreasing risks associated with climate change. PM is more careful than IM, with more small-scale thinnings and more care to maintain tree cover. In PM managers influence tree species distribution to decrease vulnerability. Some choose for Castanea sativa and Tilia cordata, sometimes in combination with oak, beech and birch. Other managers stimulate Scots pine and Douglas fir. All management scenarios were discussed with the managers, and the adaptive scenarios thus differ in implementation and risks/chances that are dealt with.

In general, both IM and PM have a tendency to negatively influence the forest services and risk level, although at different rates under different climate scenarios. Some trade-offs are visible, for example PM negatively affects biodiversity in the area, but has a positive effect on the standing stock and increment. IM has a smaller negative impact on biodiversity goals, but is decreasing production indicators. Overall, continuing the current management seems the best option to maintain the current levels of service provisioning. Early and strong changes in management strategy as response to an expected extreme climate change might lead to irreversible losses of especially biodiversity values if climate is less extreme as expected. However, only in another 50 years starts the W+ scenario to be really different from the G scenario, which gives ample time to adapt management to observed climate change as time progresses.

Continuation of current management is therefore the best choice for the time being, but it is recommended to monitor the forest development and the climate closely in order to be able to adapt the management if necessary. However, individual owners may decide differently for their own properties, based on different preferences.

Entry tagged as: South-East Veluwe (Netherlands)

Adaption of forests and forest ecosystems to the climate change can be improved by proper management. In fact, regular and timely management and harvest make it possible to modify the growing conditions and properties of tree populations and communities to allow easier adaption than that possible when excluding intentional management disturbances. Adaptation is nothing to occur in the future but actions are needed now in anticipation to the future conditions. In this regard, a major problem is that development and human acceptance of necessary actions is highly speculative and susceptible to uncertainties in the development of future climate. Furthermore, the future socio-economic context is unknown, with a need of adaptive forests policy, which is responsive to a wide variety of economic, social, political and environmental circumstance.  This implies that the adaption is a long-term process from now onwards, including monitoring of stage of forest ecosystem and analysis of observations for planning and action in short-term time perspective (e.g. ten years) set by the management planning.

Entry tagged as: North Karelia (Finland)

A major obstacle limiting the implementation of adaptive management is the forest owners’ personal perceptions of local effects of climate change. When forest owners believe in and see the effects of climate change, they are more likely to have taken adaptive measures. These two personal factors almost completely explain and predict forest owners´ adaptation to climate change (Blennow et al. 2012) The forest owners who have taken measures to adapt their forest management to climate change often see wind damage as the climate-change risk that increases the most (Blennow, 2012).

Entry tagged as: Kronoberg (Sweden)

For the introduction of new broad-leaves species there are currently two contradictory trends, and therefore two kind of obstacles. In one hand it seems that broadleaves are coming back and are replacing Norway spruce, at least in clear cut areas formerly composed by Norway spruce stands. The preliminary results of on-going sociological inquiries in the area show that forest managers tend to prefer the Norway spruce in the regeneration and to neglect/eliminate if possible in prunning/cleaning/thinning the other species. On the other hand, it seems that under the shelter-wood cutting system, largely practiced and prescribed in the management plan, the broadleaves species (excepting beech) do not succeed to regenerate, a recent phenomenon (about ten years). One explanation that may be provided is the existing  browsing/grazing that concentrate on the patches of broadleaves resulted after the regeneration works (Schultze, personal communication). Thus we may underline that for the changes in the species composition the main obstacle are: 1) the forest managers (and owners) preference for Norway spruce, more income-promising than beech-based stands, and 2) the high browsing/grazing pressure that can not be easily solved.

The obstacles are different when the solution proposed concerns the reduction of the harvesting age (rotation length) or the increase of the thinning intensity. The harvesting age is determined in the forest management plan as implementation of very strict rules with law force. The harvesting age is established according to the type of the stand (composition, productivity) and the forest ecosystem functions. Therefore there is a legal obstacle for modifying the harvesting age, because it is established by law, compulsory for all forest owners, and can not be modified locally according the forest managers’ experience or owners’ needs in terms of wood assortments. The same obstacle applies for the thinning intensity which is not as strictly imposed by the technical norms as the rotation age but rather it is a consequence of practitioners’ fear to act by their experience (they prefer to use some average values recommended by norms). Another obstacle related to thinning is the low value of wood that make the works unattractive for the harvesting companies, particularly if the thinning has to be done in stands with low accessibility or strong slopes. We expect that the problem of too low thinning intensity and frequency will not be solved soon.

Finally, several obstacles may affect the forest managers capacity to react and to adapt, e.g. too long and bureaucratic process for obtaining the permit to harvest the infested trees and stands in case of insect attacks;  lack of forest road infrastructure (national average is 5.6 m of forest road per ha) that limit the forest managers capacity to intervene in case of disturbances; unbalanced age structure that offers little room to adapt the management once the harvesting is done.

Entry tagged as: Carpathians (Romania)

Our previously limited experience of some of the species that appear useful for climate change adaptation is being improved with new species trials that are now underway. However, where site quality is poor (due to exposure and/or soil nutrient status), the range of species available for planting will remain limited.

Conversion to continuous cover forestry (CCF) is constrained by wind exposure to lower elevation sites, and implementation rates of all adaptation options are constrained by operational restrictions, i.e. less than 1% of the forest can be converted each year.

Entry tagged as: Wales (UK)

Even the adaptive management activities are not able to fullfil some of the negative consequences of the predicted by climate scenarios changes. This could raise negativism between the stakeholders, which have to implement some restrictions or nonprofitable measures. The possible unpredictable behavior of the great number of small private forest owners as well as the relatively weak capacity of the municipal forest managers could lead to short term interventions in some stands (clear cuts, overgrazing, over thinning, planting of non adequate species and so on.), with long-term negative impact. The existing standards of the forest inventory and planning have also to be adjusted to the recommended adaption measures.

The dissemination of knowledge, as well as the active information flows to all potential stakeholders (mainly the local citizens) and decision makers should be disposed to overcome these possible obstacles.

Entry tagged as: Panagyurishte (Bulgaria)

Wind throw is expected to have an increasing impact in the disturbances regime, and to affect larger area (to have an increased frequency of the catastrophic events). There is a significant risk that the areas affected by the wind throw would be difficult to regenerate with the main tree species, if climate is warmer (risk of drought). We have in the site examples from private forests cut down ten years ago, and still not regenerated, or regenerated with pioneer species like birch, aspen or willow.

For   Norway   spruce   there   will   be   an   increasing   bark   beetle   infestation risk. Fire risk will increase on Norway spruce stands in a warmer and drier climate. Fire starts usually in the spring time when the landowners are cleaning the arable/grazing lands by fire and it happens that the fire spread out in the forests nearby.

The temperature increase considered by the climatic scenario becomes a handicap for Norway spruce which will suffer or lose the competition with the other species naturally regenerated.

Entry tagged as: Carpathians (Romania)

Due to warmer conditions Fagus sylvatica and Acer Pseudoplatanus as well as Fraxinus excelsior will be less affected by winter frost. However the future development of early and late frosts remains uncertain. Another important abiotic factor with large uncertainties with regard to the future development is the snowpack on the steep slopes of the Montafon which causes mortality in seedlings due to snow creeping and gliding. If future conditions feature more frequent wet snow precipitation events damages from snow breakage will increase. Wind throw is currently playing only a minor role in the disturbance regime. This is not expected to change in the future.  Given the current and projected climatic conditions forest fires are not a concern in the case study region.

For Norway spruce there will be an increasing bark beetle infestation risk due to better development conditions for poikilothermal insects. Figure MO-1 shows simulated salvage from bark beetle infestations in a warmer climate for the Montafon. Especially during the second half of the 21^st century a strong increase in bark beetle (Ips typographus) induced mortality can be expected for Norway spruce. For silver fir the bark beetle risk in the future remains uncertain. There has been less research on insects feeding on Silver fir compared to Norway spruce and the knowledge base is still limited. For ash future development is uncertain because of current severe dieback symptoms caused by the fungus Chalara fraxinea. Reduced precipitation and warmer temperatures may negatively affect conditions for Lachnellula willkommii (larch cancer) and thus improve the growing conditions for European larch.

Figure MO-1: Simulated future bark beetle damages for two climate change scenarios under continuation of current management practices (BAU management) in relation to the long term average damage under current climatic conditions.

Entry tagged as: Montafon Valley (Austria)

Risk profile of different tree species will change along with warming climate in such a way that towards end of this century Norway spruce becomes more vulnerable than Scots pine and birch.  High wind speeds and/or heavy snow loading accompanied with shorter duration of soil frost and, thus, reduced tree anchorage may increase the risk of damages regardless of tree species, but especially in Norway spruce with shallow rooting. Uprooted and/or broken trees are also suitable breeding material, e.g. for bark beetles, if not being harvested immediately. In addition, Norway spruce is expected to suffer drought the most and especially in the southern Finland on sites with relatively low water-holding capacity, making it also more vulnerable to insect outbreaks under warmer climate.  On the other hand, if the share of Norway spruce may reduce opposite to Scots pine and birch in forests, the mortality of trees due to wind may in general decrease from late autumn to early spring (as birch is leafless) unlike in summer when Scots pine and birch are also vulnerable to wind damage (Figure JO-2).

Figure JO-2. Predicted occurrence of different threshold (critical) wind speeds for uprooting of trees in Finland from late autumn to early spring towards end of this century (birch nor consider as being leafless). The decrease of share of lower critical wind speeds is related to possible decrease in the success and share of Norway spruce in tree species composition (opposite to birch and Scots pine), especially in southern Finland, due to increasing drought episodes increase. In the North, higher average dbh/h-ratio of trees and low share of Norway spruce explains the high resistance of forests to wind force. However, in summer the map would look different as in addition to Norway spruce also birch (in leaf) and Scots pine are vulnerable to damage.

Entry tagged as: North Karelia (Finland)

Although forest fires are relatively rare, it is considered an important risk in the area. The area is used intensively for recreation purposes and borders several densely populated urban areas. The concern with fires is thus mostly focussed on safety and economic assets rather than the forest itself. Developments towards more broadleaved tree species as found in current and moderate climate change under BAU and IM are considered as helpful to decrease the risk of fire ignition and rapid fire spread. A more extreme climate change would lead to both increased frequency of periods with high-risk weather conditions and a more vulnerable, conifer-dominated vegetation. Under the W+ scenario, maintaining a high share of broadleaves is only possible in the southern zone of the area, and management should thus focus more on managing the continuity and build-up of the fuel in the landscape. A fire risk assessment showed increased fire risk in the heathland, especially at the borders with existing forest, where natural regeneration of coniferous species (mostly Scots pine) occurs.

It is still unclear if storm frequency and intensity will change under changing climate. It is thus mostly changes in the forest structure that will influence future storm risk. The scenarios with gradual increase of broadleaves can be considered as having equal or less risk than nowadays. An increase in dominance of especially Douglas fir might lead to somewhat increased storm risk, since Douglas fir can generally attain higher heights. This is mostly in the W+ climate scenarios and the IM management scenarios. The business as usual management shows an increase in storm risk due to a relatively low management level. Insect risk is deemed highest in the W+ climate due to more drought stress on the trees.

Entry tagged as: South-East Veluwe (Netherlands)

Tree species like holm oak that were perfectly adapted to the area in former time show decrease in vitality and even mortality due to recent long drought periods, which probably causes carbon starvation in the trees. Other species that were already at the edge of their distribution range, like Pinus sylvestris increasingly suffer from dieback due to drought stress. The general risk profile of all species changes because of increased fire risk.

Entry tagged as: Prades (Spain)

Overall, forest growth models run with the climate projections indicate that the dominant species in these forests, Sitka spruce, is at risk of declining in productivity after 2050 if conditions become drier, while other main species should maintain their productivity. In the event of moisture deficits only changing slightly, Sitka spruce yields might increase substantially where temperature has hitherto been a limiting factor. However in Clocaenog, increased growth rates will also expose trees to higher risk of storm damage earlier than might have been otherwise expected.

Entry tagged as: Wales (UK)