Fire season matters for midstory hardwood control: Impacts of fire season and firing technique on plant communities.

In the southeastern USA, lack of historical fire regimes often leads to hardwood encroachment into early successional plant communities and managed pine stands, reducing wildlife value and timber yields. Land managers lack information on how firing technique interacts with fire season to influence plant communities. We designed an experiment to quantify these interactions in east-central Mississippi with pairs of 4 m × 8 m plots randomly assigned a backing and heading fire in each of three seasons: February (Feb), May-June (May/Jun), and September-October (Sep/Oct). We used thermocouples to monitor fire temperature and tagged midstory trees to monitor response. We lit heading fires with an 18-25 kph wind generated by a backpack blower and backing fires into the ambient wind. Despite backing fires producing longer residence times than heading fires and raising temperature above the lethal threshold of 60 °C an average of 54 s longer, firing technique did not influence midstory response one growing season post-fire. Backing and heading fires produced similar maximum temperatures. For both firing techniques, May/Jun resulted in the highest midstory mortality rates which were 3-fold greater than Sep/Oct and 4-fold greater than Feb. Among all three fire seasons, trees with a 2.5 cm diameter at breast height (DBH) had approximately a 75% chance of top-kill which decreased to <20% as trees approached 6.5 cm DBH. We found no effects of fire season on fire temperature, rate of spread, flame height, or percent crown scorch. We found no significant interactions between fire season and firing technique. Understory analysis revealed Sep/Oct produced the greatest increase in forb coverage, May/Jun resulted in the most grass coverage, and Feb produced the most brambles (Rubus spp.). On sites with similar species, weather, and fuel conditions to ours, land managers should emphasize fire season over firing technique for midstory control and understory manipulation. Where midstory hardwood control with fire is a priority, fire return intervals should be frequent enough to prevent trees from exceeding 2.5 cm DBH to avoid trees escaping fire's reach. These data can help managers reduce midstory competition with crop trees and promote understory development for wildlife.

The effects of thinning on carbon and nutrient fluxes input into forest floor via litterfall in black pine afforestation sites.

As a component of the biogeochemical cycle, litterfall contributes carbon and nutrients to forest ecosystems by transferring organic material to mineral soil. Litterfall therefore serves as an important indicator for soil fertility and ecosystem health. This study aimed to determine the impact of different levels of thinning (light, moderate, and heavy) on litterfall quantity (needles, branches, bark, cones, and miscellaneous parts) and on the amount of carbon and nutrients entering the ecosystem in black pine afforestation areas. Three levels of low thinning, namely light, moderate, and heavy thinning (15%, 25%, and 35% of breast height area, respectively), were applied as treatments. Additionally, a control plot was included in the experiment. Litterfall samples were collected four times per year (once per season) from 12 treatment plots for three years. In the laboratory, dry weight measurements and analyses of carbon and macro-micro nutrient elements (N, P, K, Ca, Mg, S, Na, Fe, Cu, Zn, and Mn) were performed on litterfall samples taken from the field. Differences between treatments in terms of litterfall and the amount of carbon and nutrient elements entering the ecosystem were evaluated through variance analysis and the Duncan test. According to the findings, the quantity of litterfall input into the forest floor was highest in the control treatment, at 6,543 kg ha-1 year-1 and lowest in the heavy treatment, at 4,378 kg ha-1 year-1, showing a significant variation in litterfall quantity. The input of C to the soil ranged between 2,233 kg ha-1 year-1 and 3,347 kg ha-1 year-1 depending on thinning treatment. Although thinning treatment reduced C input to the soil, there was no significant difference among treatments. This also applied to nutrient elements such as N, P, K, Mg, and S. Needles constituted the majority of litterfall components (60%) and had the highest C density among all components, at 51.2%. The weighted carbon ratio for litterfall was calculated at 50.8%. Considering carbon-focused planning, performing moderate thinning interventions in the study area or similar pine-afforested areas may be a suitable option for maintaining the sustainability and health of the forest.

Characterizing heterogeneous forest structure in ponderosa pine forests via UAS-derived structure from motion.

Increasingly, dry conifer forest restoration has focused on reestablishing horizontal and vertical complexity and ecological functions associated with frequent, low-intensity fires that characterize these systems. However, most forest inventory approaches lack the resolution, extent, or spatial explicitness for describing tree-level spatial aggregation and openings that were characteristic of historical forests. Uncrewed aerial system (UAS) structure from motion (SfM) remote sensing has potential for creating spatially explicit forest inventory data. This study evaluates the accuracy of SfM-estimated tree, clump, and stand structural attributes across 11 ponderosa pine-dominated stands treated with four different silvicultural prescriptions. Specifically, UAS-estimated tree height and diameter-at-breast-height (DBH) and stand-level canopy cover, density, and metrics of individual trees, tree clumps, and canopy openings were compared to forest survey data. Overall, tree detection success was high in all stands (F-scores of 0.64 to 0.89), with average F-scores > 0.81 for all size classes except understory trees (< 5.0 m tall). We observed average height and DBH errors of 0.34 m and - 0.04 cm, respectively. The UAS stand density was overestimated by 53 trees ha-1 (27.9%) on average, with most errors associated with understory trees. Focusing on trees > 5.0 m tall, reduced error to an underestimation of 10 trees ha-1 (5.7%). Mean absolute errors of bole basal area, bole quadratic mean diameter, and canopy cover were 11.4%, 16.6%, and 13.8%, respectively. While no differences were found between stem-mapped and UAS-derived metrics of individual trees, clumps of trees, canopy openings, and inter-clump tree characteristics, the UAS method overestimated crown area in two of the five comparisons. Results indicate that in ponderosa pine forests, UAS can reliably describe large- and small-grained forest structures to effectively inform spatially explicit management objectives.

Cascading impacts of overstory structure in managed forests on understory structure, microclimate conditions, and Ixodes scapularis (Acari: Ixodidae) densities.

Forest management practices designed to meet varied landowner objectives affect wildlife habitat and may interrupt the life-cycle stages of disease vectors, including the black-legged tick, Ixodes scapularis Say (Acari: Ixodidae). Ixodes scapularis transmits multiple pathogens including Borrelia burgdorferi, the causative agent of Lyme disease, which is the most common tick-borne disease in the United States. There is evidence that a range of active forest management practices (e.g., invasive plant removal, prescribed burning) can alter tick densities and pathogen transmission. However, few studies have investigated relationships between forest stand structural variables commonly manipulated by timber harvesting and tick ecology. Foresters may harvest timber to create certain forest structural conditions like the mean number of trees, or basal area, per hectare. This study used a spatially replicated experiment in a blocked design to compare forest stands with a range of overstory structures and document variations in the midstory, understory, and forest floor, as well as microclimate conditions within tick off-host habitat. Greater numbers of trees or basal area per hectare correlated with greater canopy closure but less understory cover, stabilized microclimate temperature, higher microclimate humidity, and greater I. scapularis nymph densities. A random forest model identified understory forest structure as the strongest predictor of nymph densities. There was no relationship between the number of trees or basal area per hectare and daily deer (Odocoileus virginianus Zimmermann) activity or nymphal infection prevalence. These findings provide a deeper understanding of tick-habitat associations within a forest stand and have the potential to inform forest management decisions.

Invasion by Cedrela odorata threatens long distance migration of Galapagos tortoises.

Invasive alien species are among the most pervasive threats to biodiversity. Invasive species can cause catastrophic reductions in populations of native and endemic species and the collapse of ecosystem function. A second major global conservation concern is the extirpation of large-bodied mobile animals, including long-distance migrants, which often have keystone ecological roles over extensive spatial extents. Here, we report on a potentially catastrophic synergy between these phenomena that threatens the endemic biota of the Galapagos Archipelago. We used GPS telemetry to track 140 migratory journeys by 25 Western Santa Cruz Island Galapagos tortoises. We plotted the spatial interaction between tortoise migrations and recently established non-native forest dominated by the invasive tree Cedrela odorata (Cedrela forest). We qualified (a) the proportion of migratory journeys that traversed Cedrela forest, and (b) the probability that this observed pattern occurred by chance. Tortoise migrations were overwhelmingly restricted to small corridors between Cedrela forest blocks, indicating clear avoidance of those blocks. Just eight of 140 migrations traversed extensive Cedrela stands. Tortoises avoid Cedrela forest during their migrations. Further expansion of Cedrela forest threatens long-distance migration and population viability of critically endangered Galapagos tortoises. Applied research to determine effective management solutions to mitigate Cedrela invasion is a high priority.

Private land management is more important than public land in sustaining oaks in temperate forests in the eastern U.S.

Preserving the abundance and stocking of oaks (Quercus spp.) has become increasingly challenging in temperate hardwood forests of the eastern US in recent decades due to a remarkable shift in dominance to mesophytic species (e.g., red maple Acer rubrum). Studies have shown that efforts to sustain oaks while restraining maples yield limited success. Given that a significant portion of forestlands in the eastern U.S. are privately owned, it is critical to assess whether current forest management on cross-ownership forests can achieve those objectives. However, such assessments are rare. In this study, we employed a landscape modeling approach to investigate the long-term outcomes (i.e., 150-year forest composition and structure) of business-as-usual management and alternative management in a large, temperate hardwood forest landscape in Ohio, US. The business-as-usual management continues the current existing management practices, whereas the alternative management increases the pace and scale of forest management on both private and public lands to favor oaks. We compared the basal area and relative dominance for oaks (including Q. alba, Q. coccinea, Q. prinus, Q. rubra, and Q. velutina) and maples (including A. rubrum, A. saccharinum, and A. saccharum). Our results demonstrate that the implementation of business-as-usual management practices on both private and public lands may not effectively ensure the long-term sustainability of oak populations, but instead promote the proliferation of maple species over time. By contrast, alternative management on both private and public lands can effectively sustain oaks across a range of diameter classes while mitigating the growth of large, dominant maples. Our study emphasizes the influential role of private lands in driving oak-maple dynamics at the regional scale, as they can generate significant regional effects even when public lands continue with their business-as-usual management practices. Starting conditions based on landownership are crucial considerations for understanding these dynamics over time.

Tree-ring δ15N as an indicator of nitrogen dynamics in stands with N2-fixing Alnus rubra.

Tree-ring δ15N may depict site-specific, long-term patterns in nitrogen (N) dynamics under N2-fixing species, but field trials with N2-fixing tree species are lacking and the relationship of temporal patterns in tree-ring δ15N to soil N dynamics is controversial. We examined whether the tree-ring δ15N of N2-fixing red alder (Alnus rubra Bong.) would mirror N accretion rates and δ15N of soils and whether the influence of alder-fixed N could be observed in the wood of a neighboring conifer. We sampled a 27-year-old replacement series trial on south-eastern Vancouver Island, with red alder and coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) planted in five proportions (0/100, 11/89, 25/75, 50/50 and 100/0) at a uniform stem density. An escalation in forest floor N content was evident with an increasing proportion of red alder, equivalent to a difference of ~750 kg N ha-1 between 100% Douglas-fir versus 100% alder. The forest floor horizon also had high δ15N values in treatments with more red alder. Red alder had a consistent quadratic fit in tree-ring δ15N over time, with a net increase of $\sim$1.5‰, on average, from initial values, followed by a plateau or slight decline. Douglas-fir tree-ring δ15N, in contrast, was largely unchanged over time (in three of four plots) but was significantly higher in the 50/50 mix. The minor differences in current leaf litter N content and δ15N between alder and Douglas-fir, coupled with declining growth in red alder, suggests the plateau or declining trend in alder tree-ring δ15N could coincide with lower N2-fixation rates, potentially by loss in alder vigor at canopy closure, or down-regulation via nitrate availability.

A new non-destructive method for the estimation of annual height increment in standing trees.

Measurement of tree growth is needed in many scientific and production sectors, especially in forestry for wood and biomass production. The assessment of annual height increment in standing living trees, under ambient field conditions, is challenging or even impossible. This study develops a new simple non-destructive method for the estimation of annual height increment in standing trees, based on sampling two increment cores for each targeted tree.,. Τhe method combines the tree annual ring-analysis and trigonometry. The extracted data by the method application can be widely used in many forest disciplines, such as forest ecology, silviculture, and forest management.•Annual height increment in standing trees is a valuable parameter needed in biology, ecology, and forestry.•Measurement of annual height increment in standing trees is a very difficult tusk.•This study develops a new non-destructive and simple method for the estimation of annual height increment in standing trees.

Low detection of glyphosate in rivers following application in forestry.

BACKGROUND: Glyphosate is the most commonly used herbicide in the world, and is used in agriculture, forestry, and urban settings. In regions with high glyphosate use, such as agricultural, glyphosate and its' major derivative aminomethylphosphonic acid (AMPA) are frequently detected in surface waters. In Canadian forestry glyphosate-based herbicides are used to control vegetation that competes with conifer trees and are applied one to two times during a rotation, leading to infrequent application to the same area. Forestry occurs over a large spatial extent, and the cumulative application in space can lead to a large percentage of the land base receiving an application through time. To assess the frequency and concentration of glyphosate and AMPA in surface waters of a region where forestry is the dominant use sector, we conducted three monitoring programs targeting: (i) immediately after application, (ii) after rainfall, and (iii) cumulative application over a large spatial extent. RESULTS: Across all monitoring programs we collected 296 water samples between August and October from eight river systems over two years and detected glyphosate in one sample at 17 ppb. CONCLUSION: Glyphosate is not likely present in surface waters during baseflow conditions as a result of applications in forestry. Lack of detection is likely because soil capacity to bind glyphosate remains high due to infrequent applications to the same area, and factors that limit sediment transport to surface waters such as buffers. Additional sampling is needed during other stream conditions, ideally spring freshet, to determine peak concentrations. © 2023 National Research Council Canada. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Reproduced with the permission of the Minister of Innovation, Science, and Economic Development.

Future supply of boreal forest ecosystem services is driven by management rather than by climate change.

Forests provide a wide variety of ecosystem services (ES) to society. The boreal biome is experiencing the highest rates of warming on the planet and increasing demand for forest products. To foresee how to maximize the adaptation of boreal forests to future warmer conditions and growing demands of forest products, we need a better understanding of the relative importance of forest management and climate change on the supply of ecosystem services. Here, using Finland as a boreal forest case study, we assessed the potential supply of a wide range of ES (timber, bilberry, cowberry, mushrooms, carbon storage, scenic beauty, species habitat availability and deadwood) given seven management regimes and four climate change scenarios. We used the forest simulator SIMO to project forest dynamics for 100 years into the future (2016-2116) and estimate the potential supply of each service using published models. Then, we tested the relative importance of management and climate change as drivers of the future supply of these services using generalized linear mixed models. Our results show that the effects of management on the future supply of these ES were, on average, 11 times higher than the effects of climate change across all services, but greatly differed among them (from 0.53 to 24 times higher for timber and cowberry, respectively). Notably, the importance of these drivers substantially differed among biogeographical zones within the boreal biome. The effects of climate change were 1.6 times higher in northern Finland than in southern Finland, whereas the effects of management were the opposite-they were three times higher in the south compared to the north. We conclude that new guidelines for adapting forests to global change should account for regional differences and the variation in the effects of climate change and management on different forest ES.

Global effects of forest modification on herpetofauna communities.

As the area covered by human-modified environments grows, it is increasingly important to understand the responses of communities to the novel habitats created, especially for sensitive and threatened taxa. We aimed to improve understanding of the major evolutionary and ecological processes that shape the assemblage of amphibian and reptile communities to forest modifications. To this end, we compiled a global data set of amphibian and reptile surveys in natural, disturbed (burned, logged), and transformed (monocultures, polyspecific plantations) forest communities to assess the richness, phylogenetic diversity, and composition of those communities, as well as the morphological disparity among taxa between natural and modified forest habitats. Forest transformations led to a diversity reduction of 15.46% relative to the statistically nonsignificant effect of disturbances. Transformations also led to a community composition that was 39.4% dissimilar to that on natural forests, compared with 16.1% difference in disturbances. Modifications did not affect the morphological disparity of communities (p = 0.167 and 0.744), and we found little evidence of taxon-specific responses to anthropic impacts. Monocultures and polyspecific plantations detrimentally affected the conservation and ecological value of both amphibian and reptile communities and altered the evolutionary processes shaping these communities, whereas forests with lower impact disturbances might, to some extent, serve as reservoirs of species. Although different mechanisms might buffer the collapse of herpetological communities, preserving remaining natural forests is necessary for conserving communities in the face of future anthropic pressures.

Con el aumento del área cubierta por entornos modificados por el humano, cada vez es más importante entender las respuestas que tienen las comunidades a los nuevos hábitats creados, especialmente en los taxones sensibles y amenazados. El objetivo de este estudio es mejorar el conocimiento sobre los principales procesos evolutivos y ecológicos que condicionan el ensamblado de las comunidades de anfibios y reptiles ante las modificaciones forestales. Con este fin, compilamos un conjunto de datos globales de los censos de anfibios y reptiles en las comunidades forestales naturales, perturbadas (taladas, incendiadas) y transformadas (monocultivos, plantaciones poliespecíficas) para valorar la riqueza, diversidad filogenética y composición de aquellas comunidades, así como la disparidad morfológica entre los taxones entre los hábitats forestales naturales y modificados. Las transformaciones forestales llevaron a una reducción de 15.46% de la diversidad en relación al efecto sin significancia estadística de las perturbaciones. Las transformaciones también derivaron en una composición comunitaria que fue 39.4% diferente a la de los bosques naturales, en comparación con el 16.1% de diferencia en las perturbaciones. Las modificaciones no afectaron la disparidad morfológica de las comunidades (p = 0.167 y 0.744) y no encontramos suficiente evidencia de respuestas específicas por taxón a los impactos antrópicos. Los monocultivos y las plantaciones poliespecíficas afectaron negativamente a la conservación y al valor ecológico de las comunidades de anfibios y reptiles y alteraron los procesos evolutivos que condicionan a estas comunidades, mientras que los bosques menos impactados podrían, hasta cierto punto, actuar como reservorios de especies. Sin embargo, mientras que diferentes mecanismos pueden amortiguar el colapso de las comunidades herpetológicas, se requiere la conservación de los bosques naturales para preservar las comunidades que se enfrentarán a presiones antrópicas.

Growth and functional leaf traits of coppice regrowth of Bertholletia excelsa during an El Niño event in the central Amazon / Crescimento e características funcionais foliares de rebrotas de Bertholletia excelsa durante um evento de El Niño na Amazônia Central

The most severe drought of this century in the Amazon rainforest, which was caused by El Niño, occurred from 2015 to 2016. With a focus on the ecophysiology of the regrowth of the Brazil nut tree, Bertholletia excelsa, it was investigated how the progression of the drought of 2015-2016 affected the physiological traits of the coppice regrowth of B. excelsa. The experiment was carried out in a ten-year-old plantation of Brazil nut trees, which had been subjected to thinning and coppice regrowth two years earlier. In the sprouts grown on the stumps of cut trees, the following treatments were applied: (T1) thinning to one sprout per stump; (T2) thinning to two sprouts per stump, and (T3) maintenance of three sprouts per stump. Thinning treatments did not alter the growth and ecophysiological traits of the Brazil nut tree sprouts, though the phosphorus content of the leaves was higher in T1. However, the progression of the drought in 2015-2016 negatively affected the growth (height) and gas exchange of sprouts of all treatments. In addition, an increase of around 37% was observed in the intrinsic wateruse efficiency. Concerning photochemical performance, no alterations were observed. Therefore, drought stress promoted a negative effect on sprout growth and affected traits related to the photosynthesis of the B. excelsa sprouts independently of the number of sprouts per stump.(AU)

A seca mais severa deste século na floresta amazônica, causada por El Niño, ocorreu de 2015 a 2016. Com foco na ecofisiologia da rebrota da castanheira da Amazônia, foi investigado como a progressão da seca de 2015-2016 afetou as características fisiológicas das rebrotas de uma talhadia de B. excelsa. O experimento foi realizado em uma plantação de castanheiras com dez anos, a qual havia sido submetida a um desbaste e rebrota de talhadia dois anos antes. Nas rebrotas crescidas sobre os tocos das árvores cortadas foram aplicados os seguintes tratamentos: (T1) desbrota para manter um broto por cepa; (T2) desbrota para manter dois brotos por cepa; e (T3) manutenção de três brotos por cepa. Os tratamentos de desbrota não alteraram o crescimento e as características ecofisiológicas dos brotos da castanheira, exceto para o teor foliar de fósforo, que foi maior em T1. Porém, a progressão da seca em 2015-2016 afetou negativamente o crescimento em altura e as trocas gasosas dos brotos de todos os tratamentos. Além disso, foi observado um aumento de cerca de 37% na eficiência intrínseca do uso da água. Quanto ao desempenho fotoquímico, não foram observadas alterações. Portanto, o estresse hídrico promoveu efeito negativo no crescimento da brotação e afetou características relacionadas à fotossíntese das brotações de B. excelsa, independentemente do número de brotações por cepa.(AU)

Spatial variability of soil fertility under agroforestry system and native forest in eastern Amazonia, Brazil

The usage of spatial tools might be helpful in the optimization of decision-making regarding soil management, with technologies that assist in the interpretation of information related to soil fertility. Therefore, the present study evaluated the spatial variability of chemical attributes of the soil under an agroforestry system compared to a native forest in the municipality of Tomé-açu, Eastern Amazon, Brazil. Soil samples were performed at 36 points arranged in a 55 x 55 m grid. The soils were prepared and submitted to analysis in order to determine pH in H2O, exchangeable calcium, magnesium, potassium and aluminium, available phosphorus, potential acidity, organic matter, bases saturation and aluminium saturation. For each soil attribute, the spherical, gaussian and exponential models were adjusted. After the semivariograms fitting, data interpolation for assessment of spatial variability of the variables was performed through ordinary kriging. The spherical and gaussian models were the most efficient models in estimation of soil attributes spatial variability, in most cases. Most of variables presented a regular spatial variability in their respective kriging maps, with some exceptions. In general, the kriging maps can be used, and we can take them as logistical maps for management and intervention practices in order to improve the soil fertility in the study areas. The results principal components indicate the need for integrated management of soil chemical attributes, with localized application of acidity correctors, fertilizers and other types of incomes, using the spatial variability of these fertility variables.

Silvicultural Practices for Diversity Conservation and Invasive Species Suppression in Forest Ecosystems of the Bundala National Park, Sri Lanka.

Forest ecosystems in Sri Lanka are under pressure from intensive human activity and climate change. Invasive species are one of the greatest threats to autochthonous species and ecosystems. In Bundala National Park of Sri Lanka, there are efforts to control and limit the spreading of unwanted invasive Prosopis juliflora (Sw.) DC. and Opuntia dillenii (Ker-Gawl.) Haw., which poses a significant risk to natural ecosystem conservation. Nine different treatment variants (four replications) were used to test which management approach provides the control of Prosopis juliflora. This research is based on nine repeated measurements from 2017 to 2021 on 36 permanent research plots (each 625 m2) with 27 observed plant species and a total of 90,651 recorded plant individuals. The results confirmed that the dynamics of species richness, heterogeneity, and evenness showed significant differences between treatments during the five years of dynamics. The lowest species diversity was found in the control variant, followed by treatments based on the hard pruning and thinning of Prosopis juliflora trees. In contrast, strategies emphasizing the complete uprooting of Prosopis juliflora trees, replanting, and support of the natural regeneration of native species showed high species diversity and a high overall number of plant species. Generally, treatments had a significant effect on species diversity and the number of individuals of Prosopis juliflora, while changes in the overall number of plant species were more affected by time and succession. Silvicultural treatments including pruning, uprooting, and thinning have proven to be essential tools for nature conservation across various sites, aimed at enhancing habitat diversity in the face of ongoing climate change.

Effects of stand types on recreational preferences of society in the Sub-Alpine Zone, northern Turkey.

The main objective of this study was to examine how different stand types influenced the tendency of visitors for varying recreational activities (i.e., hiking, trekking, camping and hunting) from 1993 to 2018 in the surrounding areas of Uluyayla Natural Recreation Site in Bartin, northern Turkey. A total of 627 visitors were selected on a voluntary basis, and questioned in the form of questionnaire. Most of the participants were in the age of 21-40 years old, and they were mostly (62.4%) male. Most of the participants (82.7%) lived in cities, while 62.8% of them were tourists when visiting the site. In determining the preferences of the visitors regarding the stand types for different recreational activities, several images of each stand were shared with them, and they were asked which stand type they would prefer for a given recreation activity (i.e., hiking, tracking, camping and hunting). A range of options from 1 to 5 in Likert's scale was used in evaluating the given responses. The degree of positive and negative effects was examined via trend analysis. It was found that stand type had influence on the preferences of visitors regarding the recreational activities. In general, unmanaged and moderately treated stands were more preferred by visitors for the recreational purposes, compared to the previously managed stands. On the other hand, visitors' preference for the activities were different during two periods (i.e., 1993-2005 and 2006-2018). For each recreational activity, there was an increasing trend from 1993 to 2018. There had been a continuous increase for hunting since 1996, and for trekking and camping after 1999. The increases between 1993-1996 and 1996-1999 were likely due to the increasing awareness of the society as a result of the training and consciousness raising activities for nature conservation. The demand on the recreational activities continuously increased in unmanaged and moderately treated stands, while no significant changes were examined in the previously managed stands. The study points out that forest planning and management should consider different needs of visitors for recreational infrastructure.

Effects of Forest Management on the Insect Assemblage of Black Cherry (Prunus serotina) in the Allegheny National Forest.

Over the last decade, the Allegheny National Forest (ANF) in the USA has experienced issues with the regeneration of black cherry (Prunus serotina). This study was conducted to investigate the effects of silvicultural treatment on the insect communities that may affect black cherry pollination and regeneration. We conducted a 2-year study to compare the abundance, richness, and diversity of insects in unmanaged, shelterwood seed-tree, and shelterwood clear-cut stands. Using pan traps, we sampled insects at the ground level and in the canopies of flowering mature black cherry trees. The results of this study showed significant increases in the abundance of insects captured in shelterwood seed-tree stands and in species richness and diversity of insects captured in the canopy of black cherry in shelterwood removal stands, indicating that silvicultural treatment affected the insect community significantly. The dominant insect order was Diptera (true flies, 72.91%, n = 12,668), and Anthalia bulbosa (Diptera: Hybotidae) was the dominant species comprising 33% of all insects found in the canopy of flowering black cherry. The findings in this study could help land managers in managing black cherry for its pollination and natural regeneration.

Datasets of productivity and vegetation composition of boreal stands from an experiment comparing silviculture scenarios of increasing intensity after 20 years.

This data article describes datasets of plant community composition, dendrometric measurements, quantity and quality of snags of humid boreal stands (Quebec, Canada) from an experiment comparing silviculture scenarios of increasing intensity: (i) careful logging around advance growth (CLAAG); (ii) CLAAG followed by pre-commercial thinning; (iii) plantation followed by mechanical release; and (iv) plantation followed by chemical release and within five naturally disturbed sites. These data enable researchers to examine vegetation biodiversity recovery, ecosystem variables such as dead wood, and boreal stand productivity 20 years following the start of increasing-intensity silviculture scenarios. As a result, these data can be used to investigate the trade-off between keeping important ecosystem aspects of natural forests and maintaining and/or growing merchantable wood production at the stand level. This trade-off is the paradigm of forest ecosystem-based management, which aims to reduce the ecological distance between natural and managed forests in order to balance ecological challenges with the provision of socioeconomic services.

A low-cost open-source handheld LiDAR-based automated understory timber stand surveying device.

Timber stand inventories are critical for making management decisions in both commercial and conservation related forestry applications. When taking these inventories, the most critical characteristics to record are diameter at breast height (DBH), stand density, tree height and tree species. As discovered in prior research, a relatively inexpensive device, which hereby will be referred to as AutoTSI (short for Automatic Timber Stand Inventory), can be assembled and deployed in the field to take accurate measurements of diameter at breast height (DBH) for timber stand sample plots in a short amount of time compared to the traditional method of manually measuring these trees. The specified range and angle of resolution of the sensor allows for estimation of stand density and basal area. Each element of both the hardware and software is modular by design allowing the user to customize according to whatever sensors may be readily available to the user. In silviculture research, methodical collection, and analysis of geometric measurements of trees is essential for developing land management plans that optimize biomass production, biodiversity, and other desired characteristics in a forest environment making this device useful to both tree farmers and researchers.

Restoration and fuel hazard reduction result in equivalent reductions in crown fire behavior in dry conifer forests.

Over the past several decades, the management of historically frequent-fire forests in the western United States has received significant attention due to the linked ecological and social risks posed by the increased occurrence of large, contiguous patches of high-severity fire. As a result, efforts are underway to simultaneously reduce potential fire and fuel hazards and restore characteristics indicative of historical forest structures and ecological processes that enhance the diversity and quality of wildlife habitat across landscapes. Despite widespread agreement on the need for action, there is a perceived tension among scientists concerning silvicultural treatments that modify stands to optimally reduce potential fire behavior (fuel hazard reduction) versus those that aim to emulate historical forest structures and create structurally complex stands (restoration). In this work, we evaluated thinning treatments in the Black Hills National Forest that exemplify the extremes of a treatment continuum that ranges from fuel hazard reduction to restoration. The goal of this work was to understand how the differing three-dimensional stand structures created by these treatment approaches altered potential fire behavior. Our results indicate that restoration treatments created higher levels of vertical and horizontal structural complexity than the fuel hazard reduction treatments but resulted in similar reductions to potential crown fire behavior. There were some trade-offs identified as the restoration treatments created larger openings, which generated faster mean rates of fire spread; however, these increased spread rates did not translate to higher levels of canopy consumption. Overall, our results suggest that treatments can create vertical and horizontal complexity desired for restoration and wildlife habitat management while reducing fire hazard and that they can be used in concert with traditional fuel hazard reduction treatments to reduce landscape scale fire risk. We also provide some suggestions to land managers seeking to design and implement prescriptions that emulate historical structures and enhance forest complexity.

Gaining Insights about Forest Health Prescriptions from Loggers and Foresters: Understudied Voices in the Human Dimensions of Forest Health.

Maintaining healthy forests requires multiple individuals, including foresters who develop timber sale silvicultural prescriptions and loggers who implement those prescriptions, resulting in the transplantation of forest health science into workable management plans. However, data on the experiences, attitudes, and opinions of these two groups are often missing when developing or refining forest health treatment strategies. To explore the role that these groups play in sustaining forest health, we examined timber sale administrators' and loggers' perspectives on treatment approaches for eastern spruce dwarf mistletoe (Arceuthobium pusillum) (ESDM), a parasitic plant native to Minnesota that increases mortality and reduces growth rate and regeneration success of black spruce (Picea mariana). While ESDM has been managed for decades in black spruce stands in Minnesota, little is known about the effectiveness of the management approaches. Data were gathered through interviews and focus groups with loggers, as well as an online survey and focus groups with foresters who administer timber sales. Study participants identified a range of field-based barriers, knowledge gaps, and uncertainties that hamper the ability to effectively implement ESDM treatment strategies as designed, including financial, administrative, informational, policy-related, and environmental factors. These factors have a significant bearing on the ability to effectively implement ESDM treatment approaches; yet may be factors that were not known or considered when developing treatment strategies. This case study underscores the value of nurturing a science-management partnership to ensure that a broad set of voices are considered when developing or revising forest health treatment strategies.