RESTORE · RESILIENCE AND STABILITY IN DEVELOPING TOOLS FOR SUSTAINABLE FOREST MANAGEMENT AND RESTORATION

RESILIENCE AND STABILITY IN DEVELOPING TOOLS FOR SUSTAINABLE FOREST MANAGEMENT AND RESTORATION

RESTORE combines the unique data set - a gradient from pristine forests in Russia to intensively managed forests in Finland. We assess ecosystem resilience, and consequently, ecosystem services. We aim to develop new tools for sustainable forest management in boreal regions based on the ecosystem resilience thresholds. We developed the concept of forest ecosystem stability. Stability was defined as complex phenomenon including: 1) resilience - returning to the reference state after a disturbance, 2) resistance - remaining essentially unchanged despite the presence of disturbances and 3) elasticity - speed of return to the reference state after a disturbance and 4) Successional resilience: intrinsic ecosystem property; moving towards ‘reference state’. New mathematical formulae and models developed allowed us calculating resilience, resistance, elasticity and successional resilience for different ecosystem parameters used as biodiversity indicators. This allowed us to define the reference or control in terms of basic research and restoration in European boreal forests and formulate short- and long-term restoration targets. We summarized stand-scale studies of pristine forest structures, disturbance regimes and successional patterns carried out in boreal Eurasia. The studies reviewed demonstrated multiple successional pathways in stand development in all types of pristine forests. Based on characteristics of forest stands and disturbance regime, four main types of pristine boreal forest stand dynamics can be distinguished: (1) even-aged, compositional change dynamics, (2) even-aged, mono-dominant dynamics, (3) cohort dynamics and (4) fine-scale gap dynamics. These types can be mimicked in developing scenarios of ecologically sustainable forest management in Eurasian boreal forests. We reviewed concepts of pristine, natural, primeval, virgin and old-growth forests, the prevalence and variability of old-growth forests across landscapes, and evaluated different stand scale dynamics at the old-growth stage across the circumboreal zone. An understanding of different dynamic features of old-growth forests is crucial both for old-growth management and conservation strategies. The message to managers is that the focus should not only be on setting aside remaining valuable old-growth forests or in restoring static old-growth forest attributes, but also in emulating natural disturbances and successional dynamics at landscape and regional scales to maintain natural variability in old-growth attributes through time. We studied carbon and nitrogen release and phosphorus and base cation accumulation and release patterns from decomposing Scots pine, Norway spruce and silver birch stumps in a chronosequence of clear-cut areas in southern Finland. The results indicate that decomposing stumps of the major tree species in Fennoscandian forests are long-term carbon and nutrient pools and they serve as N and P sinks, thus potentially diminishing N and P leaching into ground water and watercourses after harvesting. This suggests that the recently increased removal of stumps for bioenergy production may markedly affect the nutrient status and nutrient cycling of boreal forests. We investigated the immediate effects of two forest management treatment series producing timber and forest chips on the volume and decay classes of coarse woody debris (CWD) and epixylic species composition. The results revealed drastic effects of bioenergy removal (collecting logging residues and stump harvesting) on coarse woody debris and for example epixylic species. Especially the quality of CWD is remarkably changed due to stump harvesting. Mounding together with stump harvesting significantly decreased the total volume of CWD. The middle and highly decayed CWD were destroyed most easily in the treatments. Logging decreased the cover and species richness in all epixylic species groups. The soil preparation decreased the cover of macrolichens, while stump harvesting was significantly most devastating both for the cover and richness in bryophytes. Results from our restoration experiment on the other hand revealed that dead-wood creation (logs and logging residue) has a positive effect on the occurrence probability of many fungal species. Logs and ordinary logging residues (stumps and treetops) host different fungal assemblages. Hence, if increased harvesting of residues for use as biofuel is applied widely, it may remove important resources for many wood-inhabiting fungal species that still occur in managed forests. Controlled burning was also shown to have a positive effect on for example the diversity of wood-inhabiting fungi. Controlled burning diversifies the composition of the pioneer fungal communities. Ecological rehabilitation (here: controlled burning and dead-wood creation) seems a useful tool to recover and sustain biodiversity in managed boreal The management and restoration tools being developed represent combination of variable retention felling and prescribed burning, characteristics of which (e.g. the optimal number, spatial distribution and shape of retention tree groups, number of trees by tree species etc.) will be defined according to resilience, resistance and elasticity threshold of each ecosystem type. We evaluate the restoration success by comparing dynamics of ecosystem components after different management treatments. The relevancy of suggested management and restoration tools is ensured by the feedback from the RESTORE Advisory board, JRC, FAO, Finnish Ministry of Agriculture and Forestry, METSO biodiversity conservation programme and other end-users, such as forest management and conservation organizations.

Data: CORDIS, © European Union