Old-growth forest structures in small-scale private forests are strongly shaped by landscape context and can be reliably predicted using freely available spatial data. Remnant forest patches within mixed cultural landscapes act as important reservoirs and connectivity elements for forest biodiversity and should be prioritized in conservation and management planning. Many forest species of high conservation concern depend on old-growth structures, which are often rare in contemporary production forests. In small-scale private forests, these structures are fostered by inactive owners and influenced by parcel topography. We attempt to quantify the abundance of old-growth structures in small-scale private forests in Lower Saxony, Germany. Landscape-related predictors are employed to model spatial distribution patterns. The Parcel Index of Conservation Attributes (PICA) was calculated from forest structural data and modeled using a gradient boosting tree model. Independent survey data was used to evaluate its performance externally. The predictions are shown in the form of a spatial distribution map. The prediction identified parcels with a high abundance of old-growth structures. These were mostly found outside of large, more intensively managed forest regions and consisted of stands rich in broadleaf trees situated in semi-open, mixed-use cultural landscapes. Predictions about the spatial distribution of valuable habitats can be made using freely available landscape-scale data. Verifying these predictions using small samples increases the trustworthiness of the model. Forest patches in fragmented agricultural landscapes can act as islands of old-growth structures. These patches are vital for rare forest species and must be urgently protected.

When analyzing management behaviors of small-scale private forest owners, demographic variables such as income, age, or profession, and land characteristics such as forest holding size often emerge as important drivers. However, gender is frequently used in targeted outreach, even though the other variables regularly show higher predictive power. To shed light on this discussion, we examined the influences of a broad set of predictors including both land characteristics and sociodemographic factors such as gender on management activities, owner goals, perceived obstacles, and conservation attitudes as response variables. We used a questionnaire survey to collect quantitative data from 1268 small-scale private forest owners in northwestern Germany. Random forest models were used to predict the responses and to rank the predictors according to their variable importance. We found that the size of forest holdings often had a strong influence on economic activities, while the amount of broadleaf forest was important for conservation-oriented management decisions. While genderspecific outreach is a strong tool to empower formerly marginalized forest owner groups, gender was not found to be an important predictor of forest management activities in our analyses. We advocate considering other characteristics when conceiving communication with forest owners. In order to design carefully targeted policy instruments and outreach to forest owners, we propose a set of easily accessible owner parameters and land characteristics. These factors can guide more individualized conservation outreach strategies in small-scale private forests that are embedded in the overall livelihood systems of their owners.

Context: Many forest species of high conservation concern depend on old-growth structures, which are often rare in contemporary production forests. In small private forests, these structures are fostered by inactive owners and influenced by parcel topography. Aims: We attempt to quantify the abundance of old-growth structures in small-scale private forests in Lower Saxony, Germany. Topographic predictors are employed to model spatial distribution patterns. Methods: The parcel index of conservation attributes (PICA) was calculated from forest structural data and modeled using a gradient boosting tree model. Independent survey data was used to evaluate its performance externally. The predictions are shown in the form of a spatial distribution map. Results: The prediction identified parcels with an abundance of old-growth structures. These were mostly found outside of large, traditionally managed forest regions, and consisted of stands rich in broadleaf trees situated in open, mixed landscapes. Conclusion: Freely available topographic data can be used to make predictions about the landscape-scale spatial distribution of valuable habitats. Verifying these predictions with small samples increases the modelʼs trustworthiness. Forest patches in fragmented agricultural landscapes can act as islands of old-growth structures. These patches are vital for rare forest species and must be urgently protected.

Abstract Balancing societal demands on forests is a major challenge in current forest management. Small‐scale private forest owners are an important ownership group that is rarely addressed directly in this discussion. Our study aims to identify and differentiate between private forest owner groups. Based on this, we take a systemic approach and determine leverage points that can be used to foster transformative change towards integrative conservation‐oriented forest management. We conducted a survey of 1656 small‐scale private forest owners in northwest Germany within a typical European multi‐ownership landscape and formed three clusters based on their activities. While all groups generally perceived nature conservation as important, they differed with regard to their forest management activities. Multiple‐use‐oriented forest owners (45%) were most active, including in terms of conservation measures. Conservation‐oriented owners (25%) mainly focused on passive measures, and conventional owners (30%) showed only a little engagement with conservation‐related activities. Despite the differences, common instruments promoting conservation activities were identified. They included, for example on‐site consultation, information about legal regulations and financial incentives. Based on four system characteristics (parameters, feedback, design and intent), we identified leverage points towards transformative change. The deep and thus effective leverage points are changing the discourse, accounting for the heterogeneity of private forest owners as well as for uncertainty related to climate change and adapting measures to local contexts. Furthermore, working towards increasing awareness, knowledge and interest as well as accounting for the desire for autonomy and control are promising pathways for change. A holistic transformation of forest policy and management towards integrative conservation is urgently needed to meet the current challenges of climate change, biodiversity loss and timber demand. This transformation has to go beyond the adaptation of existing policy instruments and instead focus on systematic and cross‐sectoral changes in the underlying policy orientation, its design and its implementation. Read the free Plain Language Summary for this article on the Journal blog.

Small-scale private forests cover large areas in Europe and often contain structures and habitats of high nature conservation value that are increasingly put under pressure due to a rising interest in fuelwood and wood products. We investigate the distribution of variables like living tree and deadwood volumes, management intensity, diversity and density of tree-related microhabitats recorded in 81 small-scale private forest parcels in the Lower Saxon Hills (northwest Germany). We provide an assessment of the influence of predictors like the individual forest owners’ goals and activities, as stated by them in a quantitative survey, as well as landscape parameters like parcel size, slope, landscape fragmentation and forest continuity. Our results indicate that there are two types of structures of conservation value in small-scale private forests: slowly evolving structures (type A) like large-diameter living trees and tree-related microhabitats which mostly depend on landscape parameters that act on longer time scales, and fast evolving structures (type B) like deadwood that are influenced by both owner attitudes and landscape parameters. The resulting implications for integrative forest and conservation management are discussed. When considering the conservation of the slowly evolving type A structures, long-term commitments to conservation legislation, financial incentives and generation-spanning education of forest owners are necessary. Efforts to promote the faster evolving type B structures might prove particularly advantageous in small-scale private forests given the structural diversity of the stands, but also the often strong identification of owners with their land. Graphical abstract

A prominent approach to implementing ontology-mediated queries (OMQs) is to rewrite into a first-order query, which is then executed using a conventional SQL database system. We consider the case where the ontology is formulated in the description logic EL and the actual query is a conjunctive query and show that rewritings of such OMQs can be efficiently computed in practice, in a sound and complete way. Our approach combines a reduction with a decomposed backwards chaining algorithm for OMQs that are based on the simpler atomic queries, also illuminating the relationship between first-order rewritings of OMQs based on conjunctive and on atomic queries. Experiments with real-world ontologies show promising results.

We study FO-rewritability of conjunctive queries in the presence of ontologies formulated in a description logic between EL and Horn-SHIF, along with related query containment problems. Apart from providing characterizations, we establish complexity results ranging from ExpTime via NExpTime to 2ExpTime, pointing out several interesting effects. In particular, FO-rewriting is more complex for conjunctive queries than for atomic queries when inverse roles are present, but not otherwise.

We propose a new type of algorithm for computing first-order (FO) rewritings of concept queries under ELHdr-TBoxes. The algorithm is tailored towards efficient implementation, yet complete. It outputs a succinct non-recursive datalog rewriting if the input is FO-rewritable and otherwise reports non-FO-rewritability. We carry out experiments with realworld ontologies which demonstrate excellent performance in practice and show that TBoxes originating from applications admit FO-rewritings of reasonable size in almost all cases, even when in theory such rewritings are not guaranteed to exist.

We propose a new type of algorithm for computing firstorder (FO) rewritings of concept queries under EL-TBoxes that is tailored towards efficient implementation. The algorithm outputs a non-recursive datalog rewriting if the input is FO-rewritable and otherwise reports non-FO-rewritability. We carry out experiments with ontologies from practical applications which show that our algorithm performs very well in practice, and that EL-TBoxes originating from real-world applications admit FO-rewritings (of reasonable size) in almost all cases, even when in theory such rewritings are not guaranteed to exist.