Stand Composition, Tree-Related Microhabitats and Birds—A Network of Relationships in a Managed Forest

Forest ecosystems contain many tree-related microhabitats (TreMs), which are used by various groups of organisms. Birds use TreMs for shelter, foraging and breeding. The abundance and variability of TreMs is related to tree stand composition and age. Over the last few centuries there has been a drastic decline in the structural and biological diversity of temperate forests over large areas of the Northern Hemisphere. These changes have reduced the diversity and quantity of TreMs. In this study we showed the relationships between stand composition, the abundance of TreMs, and the species richness of birds in a managed forest. We focused on TreMs that are important to birds: woodpecker breeding cavities, rot holes, dead branches, broken treetops, and perennial polypores. Our study was performed in a managed lowland temperate forest. In 94 plots (10 ha each) we made bird surveys and inventoried the stand composition and TreMs. Our results show that the tree stand composition of a managed forest affects the abundance of TreMs. The share of deciduous trees in the stand favors the occurrence of such TreMs as dead branches, rot holes and perennial polypores. The overall richness of bird species and the species richness of primary cavity nesters depended on the total basal area of oak, hornbeam and birch, whereas the species richness of secondary cavity nesters increased with the total basal area of birch and oak.

3D LiDAR Scanning of Urban Forest Structure Using a Consumer Tablet

Forest measurements using conventional methods may not capture all the important information required to properly characterize forest structure. The objective of this study was to develop a low-cost alternative method for forest inventory measurements and characterization of forest structure using handheld LiDAR technology. Three-dimensional (3D) maps of trees were obtained using an iPad Pro with a LiDAR sensor. Freely-available software programs, including 3D Forest Software and CloudCompare software, were used to determine tree diameter at breast height (DBH) and distance between trees. The 3D point cloud data obtained from the iPad Pro LiDAR sensor was able to estimate tree DBH accurately, with a residual error of 2.4 cm in an urban forest stand and 1.9 cm in an actively managed experimental forest stand. Distances between trees also were accurately estimated, with mean residual errors of 0.21 m for urban forest, and 0.38 m for managed forest stand. This study demonstrates that it is possible to use a low-cost consumer tablet with a LiDAR sensor to accurately measure certain forest attributes, which could enable the crowdsourcing of urban and other forest tree DBH and density data because of its integration into existing Apple devices and ease of use.

Impact of Disturbances on Species Diversity and Regeneration of Nepalese Sal (Shorea robusta) Forests Managed under Different Management Regimes

Sal (Shorea robusta) forests, a dominant forest type in Nepal, experience different disturbance intensities depending on management regimes. This study compares the impact of disturbance on Nepalese Sal forests, which are managed on three major management regimes: protected area, state-managed forest, and buffer zone community forest. Using a systematic sampling approach, we sampled 20 plots, each covering 500 square meters, and nested plots within each main plot to measure pole and regeneration for each management regime. We recorded forest characteristics including tree species, counts, diameter, height, crown cover, and disturbance indicators. We compared forest attributes such as diversity indices, species richness, and stand structure by management regime using analysis of variance and regression analysis. The forest management regimes were classified into three disturbance levels based on disturbance factor bundles, and the buffer zone community forest was found to have the highest disturbance while the protected forest had the lowest disturbance. Species richness, diversity, evenness, abundance, density and basal area were higher, but regeneration was lower in protected area and state-managed forest compared to the buffer zone community forests. This suggests positive impacts of moderate disturbance on regeneration. The management plan should prioritize the minimization of excessive disturbance to balance forest conservation and provide forest resources to local users.

Factors affecting the species richness and composition of bird species in a community managed forest of Nepal

There exists limited information on biodiversity including avifaunal diversity and habitat condition in community forests (CF) of Nepal; thus we aimed to fulfill such gaps in Tibrekot CF of Kaski district. We used the point count method for assessing bird diversity and laid out a circular plot size of radius 5-m within 15-m distance from each point count station for recording the biophysical habitat characteristics. Bird species’ diversity, richness and evenness were calculated using popular indexes and General Linear Model (GLM) was used to test the respective effect of various biophysical factors associated with the richness of bird species. In total, 166 (summer 122, winter 125) bird species were recorded in 46 sample plots. The Shannon-Wiener diversity index was calculated as 3.99 and 4.09, Margalef’s richness index as 16.84 and 17.53 and Pielou’s evenness index as 0.83 and 0.84 for summer and winter, respectively. The influencing factors for richness of bird species were season (χ21, 90= 112.21; P= 0.016) with higher richness in the summer season and low vegetation cover (χ21, 89= 113.88; P= 0.0064) with higher richness in lower percentage cover. Thus, community managed forest should be protected as it has a significant role in increasing bird diversity, which has potential for attracting avifaunal tourism for the benefit of the local communities.

Forest Restoration: Do Site Selection and Restoration Practices Follow Ecological Criteria? A Case Study in Sweden

The speed with which restoration will, or can, be accomplished depends on the initial state and location of the sites. However, many factors can undermine the process of choosing sites that are deemed the best ecological choice for restoration. Little attention has been paid to whether site selection follows ecological criteria and how this may affect restoration success. We used habitat inventory data to investigate whether ecological criteria for site selection and restoration have been followed, focusing on restoration for the white-backed woodpecker (Dendrocopos leucotos B.) in Sweden. In our study region, which is situated in an intensively managed forest landscape with dense and young stands dominated by two coniferous species, purely ecological criteria would entail that sites that are targeted for restoration would (1) initially be composed of older and more deciduous trees than the surrounding landscape, and (2) be at a scale relevant for the species. Furthermore, restoration should lead to sites becoming less dense and less dominated by coniferous trees after restoration, which we investigated as an assessment of restoration progress. To contextualize the results, we interviewed people involved in the restoration efforts on site. We show that although the first criterion for ecological site selection was largely met, the second was not. More research is needed to assess the motivations of actors taking part in restoration efforts, as well as how they interlink with public efforts. This would allow us to identify possible synergies that can benefit restoration efforts.

The Effect of Sanitation Felling on the Spread of the European Spruce Bark Beetle—An Individual-Based Modeling Approach

Sanitation felling is considered as the main measure to protect managed forests from damage due to outbreaks of the European Spruce Bark Beetle. In this study, we investigate the effectiveness of sanitation felling on stopping the spread of a bark beetle population from an un-managed to a managed forest area. For this, we advance an individual-based dispersion model of Ips typographus by adding the influence of wind on the beetle dispersion and by importing GIS data to simulate real world forests. To validate the new model version and to find reasonable parameter values, we conduct simulation experiments to reproduce infestation patterns that occurred in 2015, 2016, and 2017 within the national park Saxon Switzerland, Germany. With the then calibrated model IPS-SPREADS (Infestation Pattern Simulation Supporting PREdisposition Assessment DetailS), we investigate the impact of different factors such as the distance between beetle source trees and the forest border on the amount of damage within the managed forest stand and test the effectiveness of different levels of sanitation felling and its point of action on reducing the amount of damaged trees. As expected, the results of the model calibration show that the direction of wind plays an important role for the occurring infestation patterns and that bark beetle energy reserve is reduced during mass outbreaks. The results of the second experiment show that the main drivers for the amount of damaged trees are the primary attractiveness and the distance to beetle source trees. Sanitation felling effectiveness is highest when performed near the beetle source trees, with considerably high felling intensities and if there is at least some distance to the managed forest. IPS-SPREADS can be used in future studies as a tool for testing further management measures (e.g., pheromone traps) or to assess the risk for bark beetle infestations of forest areas near to wind-felled or already infested trees.