Habitat amount and connectivity in forest planning models: Consequences for profitability and compensation schemes.

Adjacency relationships are pervasive in forest planning problems, especially the ones related to the selection of habitat networks for biodiversity conservation. Two main approaches are applied in the planning of these conservation actions: i) selection grounded on the island biogeography theory, where connected habitats are preferred and ii) selection grounded in the habitat amount hypothesis, where the amount of habitat is enforced in local landscapes, regardless of their spatial distribution. Because the presence of connectivity requirements in the creation of habitat networks impose more stringent limitations on the search for optimal solutions, they are expected to cascade to the total benefit from harvesting revenues and, consequently, to the costs of the habitat networks. The ecological implications of these approaches have been investigated, whereas the economic consequences of imposing connectivity remain unclear. Here, I address this issue and investigate the costs of selecting habitat networks in multiple forest landscapes in central Europe, applying these two approaches. To this end, a conic optimization model is proposed, to find minimum cost allocations of forest reserves. Furthermore, a sensitivity analysis on the optimal allocation is conducted, regarding the size of the habitat network required and the level of heterogeneity in forest profitability within the landscapes. The results show that habitat networks amounting to 10% of the forest area may be created with up to 5.5% reduction in the total Net Present Value (NPV), with a higher cost when connectivity is imposed (6.5%). The cost of connectivity, however, may increase in landscapes with high heterogeneity in forest profitability and with the minimum amount of habitat required. In conclusion, habitat selection must be tailored to local conditions and weight the additional costs of imposing connectivity against the requirements of the target species and the expected ecological benefits.

Climate change and the provision of biodiversity in public temperate forests - A mechanism design approach for the implementation of biodiversity conservation policies.

The provision of forest biodiversity remains a major challenge in the management of forest resources. Biodiversity is mostly considered a public good and the fact that societal benefits from biodiversity are private information, hinders its supply at adequate levels. Here we investigate how the government, as a forest owner, may increase the biodiversity supply in publicly-owned forests. We employ a mechanism design approach to find the biodiversity provision choices, which take into account agents' strategic behavior and values towards biodiversity. We applied our framework to a forest landscape in Southwestern Germany, using forest birds as biodiversity indicators and evaluating the impacts of climate change on forest dynamics and on the costs of biodiversity provision. Our results show that climate change has important implications to the opportunity cost of biodiversity and the provision levels (ranging from 10 to 12.5% increase of the bird indicator abundance). In general, biodiversity valuations needed to surpass the opportunity cost by more than 18% to cope with the private information held by the agents. Moreover, higher costs under more intense climate change (e.g. Representative Concentration Pathway 8.5) reduced the attainable bird abundance increase from 12.5 to 10%. We conclude that mechanism design may provide key information for planning conservation policies and identify conditions for a successful implementation of biodiversity-oriented forest management.

Retention as an integrated biodiversity conservation approach for continuous-cover forestry in Europe.

Retention forestry implies that biological legacies like dead and living trees are deliberately selected and retained beyond harvesting cycles to benefit biodiversity and ecosystem functioning. This model has been applied for several decades in even-aged, clearcutting (CC) systems but less so in uneven-aged, continuous-cover forestry (CCF). We provide an overview of retention in CCF in temperate regions of Europe, currently largely focused on habitat trees and dead wood. The relevance of current meta-analyses and many other studies on retention in CC is limited since they emphasize larger patches in open surroundings. Therefore, we reflect here on the ecological foundations and socio-economic frameworks of retention approaches in CCF, and highlight several areas with development potential for the future. Conclusions from this perspective paper, based on both research and current practice on several continents, although highlighting Europe, are also relevant to other temperate regions of the world using continuous-cover forest management approaches.

Diversification of forest management regimes secures tree microhabitats and bird abundance under climate change.

The loss of biodiversity in temperate forests due to combined effect of climate change and forest management poses a major threat to the functioning of these ecosystems in the future. Climate change is expected to modify ecological processes and amplify disturbances, compromising the provisioning of multiple ecosystem services. Here we investigate the impacts of climate change and forest management on the abundance of tree microhabitats and forest birds as biodiversity proxies, using an integrated modelling approach. To perform our analysis, we calibrated tree microhabitat and bird abundance in a forest landscape in Southwestern Germany, and coupled them with a climate sensitive forest growth model. Our results show generally positive impacts of climate warming and higher harvesting intensity on bird abundance, with up to 30% increase. Conversely, climate change and wood removals above 5% of the standing volume led to a loss of tree microhabitats. A diversified set of management regimes with different harvesting intensities applied in a landscape scale was required to balance this trade-off. For example, to maximize the expected bird abundance (up to 11%) and to avoid tree microhabitat abundance loss of >20% necessitates setting aside 10.2% of the forest area aside and application of harvesting intensities < 10.4% of the standing volume. We conclude that promoting forest structural complexity by diversifying management regimes across the landscape will be key to maintain forest biodiversity in temperate forests under climate change.

Realizing Mitigation Efficiency of European Commercial Forests by Climate Smart Forestry.

European temperate and boreal forests sequester up to 12% of Europe's annual carbon emissions. Forest carbon density can be manipulated through management to maximize its climate mitigation potential, and fast-growing tree species may contribute the most to Climate Smart Forestry (CSF) compared to slow-growing hardwoods. This type of CSF takes into account not only forest resource potentials in sequestering carbon, but also the economic impact of regional forest products and discounts both variables over time. We used the process-based forest model 4 C to simulate European commercial forests' growth conditions and coupled it with an optimization algorithm to simulate the implementation of CSF for 18 European countries encompassing 68.3 million ha of forest (42.4% of total EU-28 forest area). We found a European CSF policy that could sequester 7.3-11.1 billion tons of carbon, projected to be worth 103 to 141 billion euros in the 21st century. An efficient CSF policy would allocate carbon sequestration to European countries with a lower wood price, lower labor costs, high harvest costs, or a mixture thereof to increase its economic efficiency. This policy prioritized the allocation of mitigation efforts to northern, eastern and central European countries and favored fast growing conifers Picea abies and Pinus sylvestris to broadleaves Fagus sylvatica and Quercus species.