Assume that current management (BAU) is continued: Is it possible to achieve current goals also under climate change conditions?

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).

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

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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.

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

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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

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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.

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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).

Forest ecosystem function 

2020-2050

2050-2100

Timber production and supply 

++

Protection of erosion 

~

Landscape improving 

~

Carbon sequestration 

Biodiversity 

~