Northeastern Forest Research Articles

Estimation of Vegetation Carbon Sinks and Their Response to Land Use Intensity in the Example of the Beijing–Tianjin–Hebei Region

Accurate regional carbon sequestration estimates are essential for China’s emission reduction and carbon sink enhancement efforts to address climate change. Enhancing the spatial precision of vegetation carbon sink estimates is crucial for a deeper understanding of the underlying response mechanisms, yet this remains a significant challenge. In this study, the Beijing–Tianjin–Hebei (BTH) region was selected as the study area. We employed the GF-SG (Gap filling and Savitzky–Golay filtering) model to fuse Landsat and MODIS data, generating high-resolution imagery to enhance the accuracy of NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) estimates for this region. Subsequently, the Sen+MK model was used to analyze the spatiotemporal variations in carbon sinks. Finally, the land use intensity index, which reflects human activity disturbances, was applied, and the bivariate Moran’s spatial autocorrelation method was used to analyze the response mechanisms of carbon sinks. The results indicate that the fused GF-SG NDVI (Normalized Difference Vegetation Index) data provided highly accurate 30 m resolution imagery for estimating NPP and NEP. The spatial distribution of carbon sinks in the study area showed higher values in the northeastern forest regions, relatively high values in the southeastern plains, and lower values in the northwestern plateau and central urban areas. Additionally, 58.71% of the area exhibited an increasing trend, with 11.73% showing significant or strongly significant growth. A generally negative spatial correlation was observed between land use intensity and carbon sinks, with the impact of land use intensity on carbon sinks exceeding 0.3 in 2010. This study provides methodological insights for obtaining vegetation monitoring data and estimating carbon sinks in large urban agglomerations and offers scientific support for developing ecological and carbon reduction strategies in the BTH region.

Comparison of Foraging Strategies and Effects of the Wapiti and Siberian Roe Deer on Japanese Yew.

The foraging strategies of sympatric ungulates with similar ecological niches are important for understanding ecological niche differentiation, resource utilization, competition, and coexistence and for understanding the ecological impacts on plant communities in the ecosystem. The behavior of the wapiti (Cervus elaphus) and Siberian roe deer (Capreolus pygargus) foraging on Japanese yew (Taxus cuspidata) has affected its succession and renewal in the northeastern forests of China, which has become an urgent problem for the relevant departments. This study analyzed the foraging strategies of the wapiti and Siberian roe deer on Japanese yew from July 2021 to January 2024 using field investigations and infrared camera monitoring in the Muling National Nature Reserve, Heilongjiang Province, China. It was found that the wapiti and Siberian roe deer have different foraging strategies in terms of time, space, and behavior. Temporally, they both preferred to forage for the saplings of the Japanese yew during the winter season, the degree of overlap in foraging rhythms was medium (Dhat1 = 0.67), and the diurnal foraging activity index (D RAI) of the wapiti was larger than that of the Siberian roe deer. Spatially, the suitable foraging habitat of the Siberian roe deer was twice that of the wapiti, and their overlap was low in the location and direction of saplings and the distance of the seed tree. Behaviorally, the foraging intensity of the wapiti was high, and that of Siberian roe deer was low. Foraging reduced the average primary branch height, number of new branches, and length of lateral branches of saplings, and the influence of the wapiti was significantly greater than that of the Siberian roe deer. This study provides a scientific basis for solving the conservation and management problems of the deer animals foraging on Japanese yew and contributes to further understanding of the competition-coexistence mechanism of sympatric species.

Mapping Characteristics in Vaccinium uliginosum Populations Predicted Using Filtered Machine Learning Modeling

Bog bilberry (Vaccinium uliginosum L.) is considered a highly valued non-wood forest product (NWFP) species with edible and medicinal uses in East Asia. It grows in the northeastern forests of China, where stand attributes and structure jointly determine its population characteristics and individuals’ growth. Mapping the regional distributions of its population characteristics can be beneficial in the management of its natural resources, and this mapping should be predicted using machine learning modeling to obtain accurate results. In this study, a total of 60 stands were randomly chosen and screened to investigate natural bog bilberry populations in the eastern mountains of Heilongjiang and Jilin provinces in northeastern China. Individual height, canopy cover area, and fresh weight all increased in stands at higher latitudes, and shoot height was also higher in the eastern stands. The rootstock grove density showed a polynomial quadratic distribution pattern along increasing topographical gradients, resulting in a minimum density of 0.43–0.52 groves m−2 in stands in the southern part (44.3016° N, 129.4558° E) of Heilongjiang. Multivariate linear regression indicated that the bog bilberry density was depressed by host forest tree species diversity; this was assessed using both the Simpson and Shannon–Wiener indices, which also showed polynomial quadratic distribution patterns (with a modeling minimum of 0.27 and a maximum of 1.21, respectively) in response to the increase in latitude. Structural equation models identified positive contributions of tree diameter at breast height and latitude to shoot height and a negative contribution of longitude to the bog bilberry canopy area. Random forest modeling indicated that dense populations with heavy individuals were distributed in eastern Heilongjiang, and large-canopy individuals were distributed in Mudanjiang and Tonghua. In conclusion, bog bilberry populations showed better attributes in northeastern stands where host forest trees had low species diversity, but the dominant species had strong trunks.

Agrotechnical methods of increasing the realization of the genetic potential of buckwheat varieties for the conditions of the North Eastern Forest Steppe of Ukraine

Agrotechnical methods of increasing the realization of the genetic potential of buckwheat varieties for the conditions of the North Eastern Forest Steppe of Ukraine

Effectiveness of application of microbial preparations and physiologically active substances on soybean productivity indicators in the conditions of the Northeastern Forest Steppe of Ukraine

Effectiveness of application of microbial preparations and physiologically active substances on soybean productivity indicators in the conditions of the Northeastern Forest Steppe of Ukraine

The influence of varietal characteristics on the formation of elements of productivity of winter wheat in the conditions of the North-Eastern Forest Steppe of Ukraine

The influence of varietal characteristics on the formation of elements of productivity of winter wheat in the conditions of the North-Eastern Forest Steppe of Ukraine

Field similarity and survival of buckwheat plants depends on elements of technology in the conditions of the Northeastern Forest Steppe of Ukraine

Field similarity and survival of buckwheat plants depends on elements of technology in the conditions of the Northeastern Forest Steppe of Ukraine

How are nature-based solutions contributing to the improvement of ecosystem quality in China: A systematic review

Nature-based solutions (NbS), an upgraded version of ecological restoration concept, has developed as an integrated approach to encompass a broad range of actions that protect, restore, or sustainably manage ecosystems to provide benefits to people. However, it is challenging to obtain a thorough understanding of the effectiveness of NbS because of the uncertainty of the assessment in different regions based on ecosystem services. Here, we conduct a synthesis analysis of the effects of ecological interventions on ecosystem quality within China. We systematically analyze 76 studies selected from 275 peer-reviewed papers, which were undertaken at regional scale and published between 2011 and 2022. Average values of ecosystem services before and after the ecological interventions are extracted to quantify the ecosystem changes. Results show that ecological restoration purposefully contributes to the improvements of ecosystem services with an increase in Net Primary Productivity (NPP) of 31% and an increase in soil conservation (SC) of 21%. Effects on water yield (WY), carbon storage (CS) and habitat quality (HQ) are all not significant. Restoration interventions have a mixed effect on ecosystem service trade-offs which may vary by regions. Trade-offs primarily exist between WY and other ecosystem services on the Northeastern Forest Belt and the Southwestern Karst, while synergies mainly exist among NPP, SC and CS on the Loess Plateau and the Qinghai-Tibet Plateau. Moreover, utilizing grey correlation analysis methods, factor analysis reveals that temperature and precipitation are highly correlated with the changes of the five ecosystem services. Natural factors contribute more to the changes of NPP, SC and WY than the human factors. This research is aimed at obtaining an overall perception of the effectiveness of ecological restoration programmes implementation in different regions across China, which will provide references for reducing ecosystem services trade-offs and adjusting the layouts of regional ecological restoration programmes.

Forest floor and Na azide effect on elements in leachate from contrasting New Hampshire and Virginia forest soils

AbstractAs northeastern forests experience increased temperatures and fluctuations in precipitation patterns, montane soils will lose forest floor (Oi, Oe, Oa horizons) formation and their associated ecosystem services. Here, we conducted comparative laboratory soil column experiments to examine the effects of forest floor on sourcing and weathering of macroelements (Al, Si), macronutrients (Ca, Mg, P), and micronutrients (Cu and Zn) from two contrasting soils: a supraglacial‐till Inceptisol (Mt. Moosilauke, NH) and colluvium Ultisol (Lesesne State Forest, VA). Forest floor addition caused a significant increase in the leaching of Ca, Mg, and Mn in the two soils. The forest floor only control leachate indicates the two mineral soils were net accumulators of Al, Si, P, Cu, and Zn from the forest floor. Using partition coefficient, Kd, values, leachate Ca and Mg could be sourced directly from the forest floor traversing the soil column. We aimed to assess the biotic influence on element release from soil using a Na azide treatment to suppress microbial activities. Under Na azide treatments, Al, Ca, Mg, Mn, and Cu leachate decreased significantly for both soils, but Na azide also did not affect or increased leachate Si, P, Cu, and Zn for the Lesesne soil. We attribute the effects from Na azide to changes in pH, dissolved organic carbon, and oxidation‐reduction potential as opposed to suppression of microbes. Thus, our results suggest that the loss of the forest floor will reduce the storage of nutrients in the mineral soil, even across varying parent materials.

Southern Red-backed Vole (Myodes gapperi) habitat associations in northern New England forests

Abstract Understanding habitat selection is fundamental to addressing the response of a species to disturbance. Because resources are unevenly distributed across the landscape, habitat selection occurs at multiple scales. We used capture–mark–recapture and radiotelemetry techniques to quantify the macrohabitat and microhabitat associations that define space use of the Southern Red-backed Vole (Myodes gapperi) in northeastern forests. Macrohabitat characteristics were evaluated at the scale of the forest stand by comparing conditions between visited and unvisited trap stations and suggest red-backed voles have an affinity for locations with higher basal area of Eastern Hemlock (Tsuga canadensis) and more coarse woody material. For microhabitat characteristics we modeled the influence of forest structure, ground cover, and geographic features on home range, specifically core area placement. We found that Southern Red-backed Vole core areas were associated with higher Red Maple (Acer rubrum) basal area, deeper leaf litter, greater density of hemlock stems, and closer proximity to water. The affinity of southern red-backed voles for eastern hemlock raises questions about population persistence and shifts in distribution as eastern hemlock stands are replaced by hardwood stands following infestation by Hemlock Woolly Adelgid.

Influence of forest infrastructure on the responses of ecosystem services to climate extremes in the Midwest and Northeast United States from 1980 to 2019

Forests provide several critical ecosystem services that help to support human society. Alteration of forest infrastructure by changes in land use, atmospheric chemistry, and climate change influence the ability of forests to provide these ecosystem services and their sensitivity to existing and future extreme climate events. Here, we explore how the evolving forest infrastructure of the Midwest and Northeast United States influences carbon sequestration, biomass increment (i.e., change in vegetation carbon), biomass burning associated with fuelwood and slash removal, the creation of wood products, and runoff between 1980 and 2019 within the context of changing environmental conditions and extreme climate events using a coupled modeling and assessment framework. For the 40-year study period, the region’s forests functioned as a net atmospheric carbon sink of 687 Tg C with similar amounts of carbon sequestered in the Midwest and the Northeast. Most of the carbon has been sequestered in vegetation (+771 Tg C) with more carbon stored in Midwestern trees than in Northeastern trees to provide a larger resource for potential wood products in the future. Runoff from forests has also provided 4,651 billion m3of water for potential use by humans during the study period with the Northeastern forests providing about 2.4 times more water than the Midwestern forests. Our analyses indicate that climate variability, as particularly influenced by heat waves, has the dominant effect on the ability of forest ecosystems to sequester atmospheric CO2to mitigate climate change, create new wood biomass for future fuel and wood products, and provide runoff for potential human use. Forest carbon sequestration and biomass increment appear to be more sensitive to heat waves in the Midwest than the Northeast while forest runoff appears to be more sensitive in the Northeast than the Midwest. Land-use change, driven by expanding suburban areas and cropland abandonment, has enhanced the detrimental heat-wave effects in Midwestern forests over time, but moderated these effects in Northeastern forests. When developing climate stabilization, energy production and water security policies, it will be important to consider how evolving forest infrastructure modifies ecosystem services and their responses to extreme climate events over time.

Small Mammals Perceive Most Fruits of Invasive Plants as Low-Quality Forage in a Pennsylvanian Forest and Meadow

Invasive plants often drastically alter food webs. Small-mammal assemblages may be greatly impacted by invasive plants, which often provide cover from predators. In addition, a less-studied potential impact is the possibility that small mammals use invasive plants as a food resource. We quantified small mammal giving-up densities (GUDs) by offering fruits of 5 common invasive shrubs and 1 native shrub in adjacent meadow and forest habitats in Pennsylvania. The study ran for two 48-hour sessions in November in 2 consecutive years with different combinations of shrub fruits available to small mammals within buckets that also contained Panicum miliaceum (Proso Millet), and sand. While some degree of differences in foraging activity could be accredited to annual variation, significant differences in GUDs among fruit species and between habitats were detected. The fruits of the invasive shrubs Berberis thunbergia (Japanese Barberry), Ligustrum vulgare (Eurasian Privet), and Rhodotypos scandens (Jetbead) did not appear to be significantly foraged on by small mammals in either habitat. However, the woody liana Celastrus orbiculatus (Oriental Bittersweet) was readily consumed in both the forest and meadow. Fruits of the invasive shrub Eleagnus umbellata (Autumn Olive) was favored but only in meadow habitat, while fruits of the native shrub Lindera benzoin (Spicebush) were moderately foraged in the forest. Through this experiment, we were able to conclude that most woody plants included in this study offer fruits with limited perceived benefit. However, Oriental Bittersweet and Autumn Olive may represent important exceptions that could be influencing small-mammal foraging patterns in northeastern forest and meadow ecosystems.

Harvesting wind damaged trees: a study of prediction of windthrow damage in mixed-broadleaf stands via a machine learning model

ABSTRACT Due to climate change, windstorms are becoming increasingly common resulting in the destruction not only of extensive forest areas but, quite often, of small-sized and scattered forest lands, thereby adversely affecting both the productivity and the safety of workers employed in the harvest of windblown trees. In the present study, an attempt is made to identify and record areas in the northeastern forests of Greece covered by mixed stands of conifers and broadleaves that experienced massive windthrow following local storms. Our results reveal that where Pinus sylvestris was mixed either with Quercus sp. or with Fagus sylvatica, it had been substantially protected, while in plots where it stood on its own it had been extensively uprooted. On the other hand, Picea abies, even if it was mixed with Fagus sylvatica and Pinus sylvestris, had been blown down to a large extent. Based on tree-level data, local topographic features, forest characteristics, and the mechanical properties of green wood, a reliable model, to be used for the prediction of similar disturbances in the future, has been selected after a thorough comparative study of the most well-known intelligent Machine Learning (ML) algorithms. Specifically, Random Forest Classifier, k-Neighbors Classifier, Decision Tree Classifier, Light Gradient Boosting Machine, Gradient Boosting Classifier, Ada Boost Classifier, Ridge Classifier, Linear Discriminant Analysis, Logistic Regression, Naive Bayes, SVM – Linear Kernel, and Quadratic Discriminant Analysis were evaluated and compared using six performance measures (confusion matrix, accuracy, precision, recall, F1-score, and ROC).

Research of modern varieties of winter wheat according to productivity depending on growing conditions

The creation of modern varieties of winter wheat has become an impetus to the intensification of cultivation technologies, which was directed to revealing the genetic potential of the latter, which is possible only provided the implementation of the entire complex of agrotechnological measures and hard technology of growing seeds. The productivity of varieties which are dif-ferent by genotype depends to a large extent on predecessors, sowing terms and weather conditions during the vegetation period. The purpose of our research was to determine the potential crop capacity of new winter wheat varieties by Myronivka selection depending on predecessors and terms of sowing in the conditions of the North-Eastern Forest-Steppe of Ukraine. The research was conducted in the fields of the Pravdynske State Enterprise of Experimental Farming (SEEF "Pravdynske"), the V.M. Remeslo Myronivka institute of wheat of National academy of agrarian sciences of Ukraine (MIW) in vegetation years 2018/19–2020/21 (factor – A (year)), located in the conditions of the North-Eastern Forest Steppe of Ukraine. The objects of research were five new varieties of winter wheat by Myronivka selection (MIP Fortuna, MIP Lada, MIP Yuvileina, Aurora Myronivska, MIP Lakomka) compared to the standard of Podolyanka (factor B). Experi-ments were laid after two predecessors – sunflower, soy (factor C); sowing was carried out on September, 25 and October, 5, a deviation of 1–3 days (factor D). The level of materiality coefficients of air temperature deviations (°С) and amount of precipitation (mm) were determined according to the gradation methods by Ped D. A. (1975) and Kalenska S.V. (2018). The weather conditions during the years of research differed significantly, which made it possible to evaluate the material objectively. The crop capacity of new winter wheat verities by Myronivka selection was examined depending on predecessors and sowing terms. Among the examined predecessors, soy was identified as the best one, and the sowing date – October 5, which on average over the years of study helped to obtain the maximum level of productivity of new crop varieties. The variety differences research determined that the largest crop capacity in general according to the experiment for two sowing dates (September, 25 and October, 5) had varieties the MIP Yuvileyna (6.38 and 6.82 t/ha, respectively) and MIP Fortuna (6.78 and 6.60 t/ha, respectively). Key words: winter wheat, variety, yield, weather conditions, predecessor, sowing time.

A COMPARATIVE ANALYSIS OF PIXEL-BASED AND OBJECT-BASED APPROACHES FOR FOREST ABOVE-GROUND BIOMASS ESTIMATION USING RANDOM FOREST MODEL

Abstract. Providing an accurate above-ground biomass (AGB) map is of paramount importance for carbon stock and climate change monitoring. The main objective of this study is to compare the performance of pixel-based and object-based approaches for AGB estimation of temperate forests in north-eastern of New York State. Second, the capabilities of optical, SAR, and optical + SAR data were investigated. To achieve the goals, the random forest (RF) regression algorithm was used to model and predict the AGB values. Optical (i.e. Landsat 5TM, Landsat 8 OLI, and Sentinel-2), synthetic aperture radar (SAR) (Sentinel-1 and global phased array type L-band SAR (PALSAR/PALSAR-2)), and their integration have been used to estimate the AGB. It is worth mentioning that the airborne light detection and ranging (LiDAR) AGB raster has been used as a reference data for training/testing purposes. The results demonstrate that the OBIA approach enhanced the RMSE of AGB estimation about 5.32 Mg/ha, 8.9 Mg/ha, and 5.29 Mg/ha for optical, SAR, and optical + SAR data, respectively. Moreover, optical + SAR data with the RMSE of 42.63 Mg/ha and R2 of 0.72 for pixel-based and RMSE of 37.31 Mg/ha and R2 of 0.77 for object-based approach provided the best results.

A Static Pulling Test Is a Suitable Method for Comparison of the Loading Resistance of Silver Birch (Betula pendula Roth.) between Urban and Peri-Urban Forests

In urbanized areas, wind disturbances can be intensified by anthropogenic stresses under which trees may become hazardous, creating serious threats and damages to nearby targets. Therefore, species with notably lower both wood mechanical properties and compartmentalization, such as pioneers, are considered to have higher wind damage risk if subjected to unfavorable growing conditions. Eurasian aspen (Populus tremula L.) and silver birch (Betula pendula Roth.), are frequently found in both urban and peri-urban forests in Northeastern and Central parts of Europe, which strengthen the necessity for the evaluation of mechanical stability of such species. Therefore, static pulling tests were performed to compare the mechanical stability of the studied species in both urban and peri-urban forests. The loading resistance of the studied species differed, with birch being more stable than aspen, indicating aspen to be more prone to wind damage. Additionally, the mechanical stability of birch did not differ between trees growing in urban and peri-urban forests, suggesting static pulling tests are a suitable method for comparing trees from completely different growing conditions.

The influence of plant growth regulators on the quality of mustard seeds in the conditions of the north-eastern Forest Steppe of Ukraine

The influence of plant growth regulators on the quality of mustard seeds in the conditions of the north-eastern Forest Steppe of Ukraine

The dependence of the yield of winter wheat on the time of sowing in the conditions of climate change in the Northeastern Forest Steppe of Ukraine

The dependence of the yield of winter wheat on the time of sowing in the conditions of climate change in the Northeastern Forest Steppe of Ukraine

Ecological and typological features of forest vegetation of the emerald network object “Tsirkunivskyi forest” in the North-Eastern Forest Steppe of Ukraine

Forest typological and ecological properties of natural complexes of the Emerald Network object of Ukraine “Tsyrkunivskyi forest” (UA0000290 Tsyrkunivskyi forest) in the Kharkiv region, with a total area of 9948.6 hectares are presented. This object is located in Lipetsk and Southern forest division of the State Forest Enterprise “Kharkiv Forest Research Station” in the north-western part of the Kharkiv region. The territory of the studied object is an undulating plain with a wellrepresented valley-beam relief and a fairly branched ravine-beam network. Forest areas are represented by stands of 35 tree species. The main forest-forming tree species is Quercus robur (8830.3 ha, 88.75 %), a much smaller area is Pinus sylvestris (392.1 ha, 3.94 %). Other tree species occupy small areas: Betula pendula (119.9 ha, 1.21 %), Robinia pseudoacacia (88.5 ha, 0.89 %), Acer platanoides (80.7 ha, 0.81 %), Acer campestre (80.3 ha, 0.81 %), Tilia cordata (75.4 ha, 0.76 %), Populus tremula (66.4 ha, 0.67 %), Fraxinus excelsior (52.4 ha, 0, 53 %) and others. The studied forest areas are represented by 13 edatopes, covering all trophic groups and moisture levels. The most common types of forest vegetation conditions are fresh (7040.2 ha; 70.77 %) and dry (2242.3 ha, 22.54 %) oak dibrova. 19 types of forests were identified in the study area, the most common of which are fresh maple-linden dibrova (7040.2 ha, 70.78 %), a slightly smaller area is dry maple-linden dibrova (2242.3 ha, 22.54 %); much smaller is fresh oak-pine subir (354.1 ha, 3.56 %). Quercus robur grows in 5 forest types, the most common of which are fresh (6552.8 ha, 74.21 %) and dry (2102.0 ha, 23.80 %) maple-linden dibrova.

Ocelot density and habitat use in Tamaulipan thornshrub and tropical deciduous forests in Northeastern México

AbstractNortheastern México is one of the most diverse regions in the country with high mammal richness. This region also sits on the northern periphery of the geographic distribution of ocelots (Leopardus pardalis), which are listed as endangered in México. Ocelot ecology in northeastern México is poorly known at local and landscape levels, especially in the ecologically rich temperate sierras, a perceived stronghold for ocelots. We used an occupancy approach to estimate ocelot-habitat use in Tamaulipan thornshrub and tropical deciduous forests and a spatially explicit capture–recapture (SECR) framework to estimate density of ocelots in the northern edge of the Sierra Tamaulipas, México. From May to December 2009, we conducted two camera trap surveys (summer: 20 camera stations; fall: 58 camera stations) on Rancho Caracol and Rancho Camotal, north of the Rio Soto de La Marina. We found ocelot detections were higher in areas with increasing patch density of tropical deciduous forest and habitat use was greater in Tamaulipan thornshrub and tropical deciduous forests with lower edge densities. Ocelot densities varied by sex, with females achieving greater densities (7.88 ocelots/100 km2 [95% CI: 4.85–12.81]) than males (3.81 ocelots/100 km2 [95% CI: 1.96–7.43]). Ocelots were averse to areas with high densities of edge cover in each woody community, supporting the notion of a forest patch interior species. Despite the study occurring 11 years ago, population densities were also among the highest reported in México using spatially explicit capture–recapture methods, The high ecological integrity of the habitat within the Sierra de Tamaulipas, recent protection as a Biosphere Reserve, and remote rugged terrain suggest long-term security of the ocelot population in this region.