Forest Basal Area Research Articles

Pinus banksiana Lamb. Regeneration Patterns in a Lacustrine Dune System

Successional patterns in lacustrine sand dunes along Lake Superior begin with grass-dominated plant communities leading to the establishment of Pinus banksiana Lamb. as initial forests. Using maximum entropy models, we predicted P. banksiana seedling and sapling patterns within the Grand Sable Dunes, Pictured Rocks National Lakeshore, USA, based on slope, aspect, forest basal area, and vegetation types. Across the different vegetation types, there were variable probabilities of seedling and sapling occurrence. For both seedlings and saplings, the higher likelihoods of occurrence were observed in coastal pine barrens vegetation types. P. banksiana regeneration is occurring in the Grand Sable Dunes in the absence of fire, with seedlings establishing and saplings being recruited in a variety of vegetation types. With the greatest probabilities in barrens, there is likely a relationship with seed source and canopy density. Understanding regeneration patterns in dune ecosystems is necessary to predict the future forest arrangement and colonization of P. banksiana into the dunes. These results contribute insights into the dynamics of plant communities in lacustrine dune systems, specifically the establishment of P. banksiana seedlings in various vegetation types. Continued forest establishment and increasing P. banksiana density will influence endangered species and non-native species management strategies for Pictured Rocks National Lakeshore.

Evaluating the predictors of habitat use and successful reproduction in a model bird species using a large‐scale automated acoustic array

The emergence of continental to global scale biodiversity data has led to growing understanding of patterns in species distributions, and the determinants of these distributions, at large spatial scales. However, identifying the specific mechanisms, including demographic processes, determining species distributions remains difficult, as large‐scale data are typically restricted to observations of only species presence. New remote automated approaches for collecting data, such as automated recording units (ARUs), provide a promising avenue towards direct measurement of demographic processes, such as reproduction, that cannot feasibly be measured at scale by traditional survey methods. In this study, we analyze data collected by ARUs from 452 survey points across an approximately 1500 km long study region to compare patterns in adult and juvenile distributions in great horned owl Bubo virginianus. We specifically examine whether habitat associated with successful reproduction is the same as that associated with adult presence. We postulated that congruence between these two distributions would suggest that all areas of the species' range contribute equally to maintenance of the population, whereas significant differences would suggest more specificity in the species' requirements for successful reproduction. We filtered adult and juvenile calls of the species for manual review using automated classification and constructed single season occupancy models to compare land cover and vegetation covariates which significantly predicted presence of each life stage. We found that habitat use by adults was significantly predicted by increasing amounts of forest cover, reduced forest basal area, and lower elevations; whereas juvenile presence was significantly predicted only by decreasing amounts of forest cover, a pattern opposite that of adults. These results show that presence of adult great horned owls is not a sufficient proxy for locations at which reproduction occurs, and also demonstrate a highly scalable workflow that could be used for similar analyses in other sound‐producing species.

Optimizing E-commerce Inventory to prevent Stock Outs using the Random Forest Algorithm Approach

This research investigates the effectiveness of the Random Forest algorithm in optimizing e-commerce inventory management. In a digital business that continues to grow, inventory management is crucial for smooth operations and customer satisfaction. The Random Forest algorithm, a development of the CART method by applying bagging techniques and random feature selection, was tested to predict inventory. An experimental design is used to test the algorithm's performance algorithms performance, using data relevant to the observed inventory variables. The analysis involves evaluating the performance of algorithms in predicting and preventing stockouts. The results show that the Random Forest algorithm provides more accurate inventory predictions than traditional methods. Comparison with linear and rule-based regression reveals higher accuracy, making this algorithm a promising choice for e-commerce inventory management. These findings imply that the Random Forest Algorithm can be an effective solution in overcoming the complexity and fluctuations of digital markets. Practical recommendations include a deep understanding of the data, engagement of trained human resources, and training strategies for optimal use of these algorithms. This research also contributes to the literature by expanding understanding of the application of the Random Forest algorithm in various contexts, including forest basal area prediction, supply chain management, and backorder prediction. In conclusion, the Random Forest algorithm has great potential to improve e-commerce inventory management, opening up opportunities for broader application in the digital business world. Proactive adoption of these algorithms can have a positive impact on operational efficiency, customer satisfaction, and a company's competitiveness in an ever-evolving market.

Distribution of logjams in relation to lateral connectivity in the River Corridor

We examine the redistribution of logjams from the channel to the floodplain during a large flood following a wildfire in a forested montane catchment, conceptualizing redistribution with respect to changes in connectivity within the river corridor during and after the flood. A 2020 wildfire burned much of the 40 km2 Little Beaver Creek catchment at high severity. A flash flood in July 2022 completely inundated the river corridor and moved substantial amounts of large wood from the channel onto the floodplain. Floodplain logjams were largely absent prior to the flood. Forty-two channel-spanning logjams remained in the channel after the July 2022 flood, compared to 91 before the flood, and only 4 of these created backwater at base flow. Most of the large wood present in the river corridor was redistributed into 700 floodplain logjams, most of which were pinned against tree trunks. Multivariate linear models indicate that floodplain jam distribution density (number of logjams/ha surface area) correlates most strongly with floodplain forest basal area and floodplain/channel width ratio. Prior to the July 2022 flood, channel-spanning logjams limited longitudinal connectivity within the active channel but enhanced vertical connectivity via hyporheic exchange and lateral connectivity via formation of secondary channels and obstruction-inducing overbank flows. The enhanced transport capacity of the flood removed or altered most of these logjams, increasing longitudinal connectivity. Complete inundation of the floodplain during the July 2022 flood represented a transient increase in lateral connectivity. The formation of floodplain logjams and secondary channels, along with localized floodplain erosion and deposition, created more persistent alterations in lateral connectivity. Our observations suggest that logjams can increase lateral connectivity within the river corridor by deflecting flow in a manner that creates persistent secondary channels. Although secondary channels might have formed in Little Beaver Creek during the 2022 flood without the presence of logjams, the flow obstructions created by even relatively transient logjams likely increased the formation of a multichannel planform and the associated persistent lateral connectivity.

Sensitive tree species remain at risk despite improved air quality benefits to US forests.

Atmospheric nitrogen (N) and sulfur (S) deposition can significantly affect forest biodiversity and production by altering the growth and survival of trees. Three decades of air quality regulations in the United States (U.S.) have led to large reductions in oxides of N (44-81%) and S (50-99%) emissions and associated deposition. Here, we evaluated the magnitude and extent of effects over 20 years from atmospheric N and S deposition on the growth and survival of 94 tree species - representing 96.4 billion trees and an average of 88% of forest basal area across the contiguous U.S. (CONUS). Overall, species' growth and survival rates have responded positively to declining deposition, but we find that decreases of at least 2.5 kg N ha-1 yr-1 are needed across 19.8% (growth) and 59.5% (survival) of the CONUS to prevent detrimental effects to sensitive species. Reduced forms of N (NHx = NH3 + NH4 +) are now the dominant form of N deposition in 45.4% of the CONUS - notably in agricultural regions - and exclusively need to be reduced by ≥ 5.0 kg N ha-1 yr-1 in some areas. Further S deposition decreases of ≥ 1.0 kg S ha-1 yr-1 are needed in 50.4% (growth) and 56.2% (survival) of the CONUS to protect sensitive species and notably, evergreen trees. Total basal area is increasing in much of the country (85.2%) because of N fertilizing effects, but these growth increases could result in biodiversity loss. Our findings can be used to evaluate past successes of air quality policies and the future benefits of air pollution reductions to terrestrial ecosystems.

Important role of a few large-diameter tree species in basal area and its increase in an old-growth deciduous broadleaf forest in Japan

Because of their large diameter and biomass, old-growth forests provide valuable wood and high levels of ecosystem services (e.g., carbon sinks). Most of the aboveground biomass or basal area (BA) in old-growth forests is provided by small numbers of large-diameter trees. If the diversity of these trees is lower in temperate forests than in tropical forests, then the BA of temperate forests should be dominated by small numbers of large-diameter species. To explore how and to what extent BA and increase in BA (ΔBA) are determined by species with large diameters in temperate old-growth forests, we examined changes in the size structure and demographic parameters of large-diameter tree species based on 11 years of diameter at breast height (DBH, ≥ 5 cm) records for a 6-ha plot in an old-growth deciduous broadleaf forest in Japan. To estimate the extent to which difference in the successional status affect future ΔBA, we compared demographic parameters between them. Individuals with DBH ≥ 50 cm represented only 4.2% of all trees; however, their relative BA (rBA, ratio of BA of individual trees to the BA of entire forest) and relative increase in BA (rΔBA, ratio of increase in BA of individual trees to increase in BA of entire forest) were 36.4% and 25.1%, respectively, indicating that both BA and ΔBA were dominated by a small number of large trees. The rBA and rΔBA of the four species with the highest maximum DBH (DBHmax) were 71.1% and 61.4%, respectively, indicating that BA and ΔBA were also dominated by a very small number of species with exceptionally high DBHmax. Even among individuals with DBH ≥ 50 cm, the top four species in terms of DBHmax represented 90.0% and 80.6% of the total BA and ΔBA, respectively, confirming that both BA and ΔBA are highly dependent on species with high DBHmax values irrespective of the successional status. Most of the top 10 species in terms of DBHmax also showed increasing diameter growth rates and survival rates with increases in DBH class. Although the species with the second-highest DBHmax value had relatively low BA and ΔBA, BA gain exceeded BA loss for 11 years, thereby increasing the overall BA of the forest. These findings suggest that small numbers of large-diameter tree species play an important role in the sustainable increase in biomass among temperate old-growth forests in Japan. However, late successional species have higher rates of gain in BA, lower mortality, and higher recruitment rates than mid successional and early succesional species, indicating that their populations are increasing strongly. It is expected that the late successional species will eventually become more dominant than the mid and early successional species, unless there occurs some large-scale disturbance.

Future climate change effects on US forest composition may offset benefits of reduced atmospheric deposition of N and S.

Climate change and atmospheric deposition of nitrogen (N) and sulfur (S) are important drivers of forest demography. Here we apply previously derived growth and survival responses for 94 tree species, representing >90% of the contiguous US forest basal area, to project how changes in mean annual temperature, precipitation, and N and S deposition from 20 different future scenarios may affect forest composition to 2100. We find that under the low climate change scenario (RCP 4.5), reductions in aboveground tree biomass from higher temperatures are roughly offset by increases in aboveground tree biomass from reductions in N and S deposition. However, under the higher climate change scenario (RCP 8.5) the decreases from climate change overwhelm increases from reductions in N and S deposition. These broad trends underlie wide variation among species. We found averaged across temperature scenarios the relative abundance of 60 species were projected to decrease more than 5% and 20 species were projected to increase more than 5%; and reductions of N and S deposition led to a decrease for 13 species and an increase for 40 species. This suggests large shifts in the composition of US forests in the future. Negative climate effects were mostly from elevated temperature and were not offset by scenarios with wetter conditions. We found that by 2100 an estimated 1 billion trees under the RCP 4.5 scenario and 20 billion trees under the RCP 8.5 scenario may be pushed outside the temperature record upon which these relationships were derived. These results may not fully capture future changes in forest composition as several other factors were not included. Overall efforts to reduce atmospheric deposition of N and S will likely be insufficient to overcome climate change impacts on forest demography across much of the United States unless we adhere to the low climate change scenario.

Adaptation and mitigation capacity of wildland forests in the northeastern United States

Managing forests to mitigate climate change and increase their capacity to adapt to future climate-related disturbances and conditions typically involves protecting and enhancing forest carbon stocks and sequestration capacity while promoting structural diversity. While the focus has been on comparing active management approaches for meeting these objectives, there are few empirical assessments of passive management. Here we used quasi-experimental methods to compare carbon and structural complexity within “wildlands,” where harvesting and other land uses are prohibited, to environmentally comparable forests without protection from timber harvesting. Using USDA Forest Inventory and Analysis (FIA) plots from the Adirondack-New England region of the Northeastern U.S., we compared aboveground carbon, total forest basal area increment (our proxy for carbon sequestration), and six forest-level structural variables in forests. To help explain observed differences, we examined (1) the recent history of harvesting within unprotected forests, (2) stand age in wildland and unprotected forests, and (3) the carbon and structural attributes of protected and unprotected plots at the initiation of wildlands protection. Aboveground carbon was 20% higher in wildlands overall (P < 0.0001), with differences greatest in wildlands of New York (+32%; P = 0.0001) and in Maine (+34%; P = 0.01) where recent harvesting intensity and differences in stand age between protection categories were highest. Basal area increment did not differ between protected areas at the regional and sub-regional scale, but was 37% higher in wildlands (P = 0.03) than in recently harvested areas. Structural complexity was generally higher in wildlands, with four structural variables – large live (>60 cm DBH) and large dead (>45 cm DBH) tree density, maximum tree height, and diversity of diameter size classes) – greater in wildlands than in unprotected forests. Two variables (adult tree species richness and standard deviation of tree height) did not differ between protection categories. Both carbon and structural differences were amplified by recent harvesting in unprotected plots. For the subset of plots that allowed for comparison, wildlands did not differ in carbon and structural attributes from unprotected plots at the onset of wildlands protection, suggesting that subsequent management rather than initial differences was the driver of carbon and structural differences between protection categories. Our results highlight the adaptation and mitigation benefits of allowing natural processes to predominate in strictly protected areas.

How have wildfires affected forest basal area in Northern and Southern California during the 21st century?

Wildfires are unplanned and dynamic fires that occur in areas of combustible vegetation. They can be natural or human-induced and play a vital role in ecosystem health. The severity and intensity of wildfires can change over time based on the weather, available fuel and topography. California is continuously experiencing longer wildfire seasons as a direct result of climate change, affecting the forest structure of the state’s forest. Forest basal area is used to determine forest stand density and is an indicator of annual growth potential (Nix, 2020). It is often used as the basis for making important forest management decisions. My research will determine how wildfire frequency and extent have affected the basal area of Northern and Southern California’s forests in 2000 and 2017. Fire perimeter and frequency data obtained from the United States Forest Service regional datasets website will be used to define fire characteristics in the regions. Tree basal area data obtained from the United States Forest Service regional-level datasets website will be used to quantify the basal area of critical forest types. Percent change in basal area, fire frequency and acres burned each year will be determined to compare the burn regimes of the two regions during the two years to see how that has impacted the forest’s basal area. The findings will give an idea of how the rate of wildfires has changed in the last two decades and its subsequent impacts, which can help us better prepare for the future of forests in an ongoing climate crisis.

Too hot, too cold, or just right: Can wildfire restore dry forests of the interior Pacific Northwest?

As contemporary wildfire activity intensifies across the western United States, there is increasing recognition that a variety of forest management activities are necessary to restore ecosystem function and reduce wildfire hazard in dry forests. However, the pace and scale of current, active forest management is insufficient to address restoration needs. Managed wildfire and landscape-scale prescribed burns hold potential to achieve broad-scale goals but may not achieve desired outcomes where fire severity is too high or too low. To explore the potential for fire alone to restore dry forests, we developed a novel method to predict the range of fire severities most likely to restore historical forest basal area, density, and species composition in forests across eastern Oregon. First, we developed probabilistic tree mortality models for 24 species based on tree characteristics and remotely sensed fire severity from burned field plots. We applied these estimates to unburned stands in four national forests to predict post-fire conditions using multi-scale modeling in a Monte Carlo framework. We compared these results to historical reconstructions to identify fire severities with the highest restoration potential. Generally, we found basal area and density targets could be achieved by a relatively narrow range of moderate-severity fire (roughly 365-560 RdNBR). However, single fire events did not restore species composition in forests that were historically maintained by frequent, low-severity fire. Restorative fire severity ranges for stand basal area and density were strikingly similar for ponderosa pine (Pinus ponderosa) and dry mixed-conifer forests across a broad geographic range, in part due to relatively high fire tolerance of large grand (Abies grandis) and white fir (Abies concolor). Our results suggest historical forest conditions created by recurrent fire are not readily restored by single fires and landscapes have likely passed thresholds that preclude the effectiveness of managed wildfire alone as a restoration tool.

The Zoʻé perspective on what scientists call “forest management” and its implications for floristic diversity and biocultural conservation

Indigenous perspectives on forest management are grounded in traditional ecological knowledge (TEK), so that socioculture influences the ways Indigenous Peoples transform their landscapes. However, how socioculture structures Indigenous perspectives on forest management is unclear. Moreover, little is known about the influence of Indigenous landscape transformations on forest succession and floristic diversity. Here, we test hypotheses from biocultural and ecological theories suggesting that: (i) key social-ecological relationships with specific taxa structure Indigenous perspectives on forest management; (ii) such relationships guide sustainable management that generates resilient forest regrowth; and (iii) this management promotes floristic diversity by acting as an intermediate disturbance. We collected information about cosmology, occupation history and management among the Zoʻé, in Brazilian Amazonia. We also carried out floristic inventories in old-growth forests and in old Zoʻé swidden-fallow areas to analyze forest structure and alpha- and beta-diversity along a gradient of forest successional stages. We show that the Zoʻé perspective on forest management is structured by an ethical principle involving a social-ecological relationship with different beings, especially the spider monkey (<em>Ateles</em> sp.). This relationship generates mobility among the Zoʻé that allows forest regrowth in their fallow areas, so that in 28 years, forest basal area may equal that of old-growth forests. Also, Zoʻé forest management has increased alpha- and beta-diversity by increasing species richness and diversity in intermediate secondary forests and promoting floristic turnover at the landscape-level. These results show that some aspects of Zoʻé cosmology influence forest disturbance regimes that generate a sustainable social-ecological system, therefore being key for Zoʻé well-being and local biodiversity conservation. We believe that Indigenous perspectives about forest management should be included in forest conservation efforts aimed at protecting Amazonian biocultural diversity, thus valuing TEK and engendering sustainable social-ecological systems.

Tree growth response to drought partially explains regional-scale growth and mortality patterns in Iberian forests.

Tree-ring data has been widely used to inform about tree growth responses to drought at the individual scale, but less is known about how tree growth sensitivity to drought scales up driving changes in forest dynamics. Here, we related tree-ring growth chronologies and stand-level forest changes in basal area from two independent data sets to test if tree-ring responses to drought match stand forest dynamics (stand basal area growth, ingrowth, and mortality). We assessed if tree growth and changes in forest basal area covary as a function of spatial scale and tree taxa (gymnosperm or angiosperm). To this end, we compared a tree-ring network with stand data from the Spanish National Forest Inventory. We focused on the cumulative impact of drought on tree growth and demography in the period 1981-2005. Drought years were identified by the Standardized Precipitation Evapotranspiration Index, and their impacts on tree growth by quantifying tree-ring width reductions. We hypothesized that forests with greater drought impacts on tree growth will also show reduced stand basal area growth and ingrowth and enhanced mortality. This is expected to occur in forests dominated by gymnosperms on drought-prone regions. Cumulative growth reductions during dry years were higher in forests dominated by gymnosperms and presented a greater magnitude and spatial autocorrelation than for angiosperms. Cumulative drought-induced tree growth reductions and changes in forest basal area were related, but initial stand density and basal area were the main factors driving changes in basal area. In drought-prone gymnosperm forests, we observed that sites with greater growth reductions had lower stand basal area growth and greater mortality. Consequently, stand basal area, forest growth, and ingrowth in regions with large drought impacts was significantly lower than in regions less impacted by drought. Tree growth sensitivity to drought can be used as a predictor of gymnosperm demographic rates in terms of stand basal area growth and ingrowth at regional scales, but further studies may try to disentangle how initial stand density modulates such relationships. Drought-induced growth reductions and their cumulative impacts have strong potential to be used as early-warning indicators of regional forest vulnerability.

Environmental Effects among Differently Located and Fertile Sites on Forest Basal-Area Increment in Temperate Zone

Environmental properties differently influence the growth of forest tree species. The antagonistic effects of variable environmental properties classify the forest response according to various tree compositions among different sites. The division of the forest response was assessed in 52 stands arranged into 26 types of 13 site management populations (MPs) in 5 areas in the Czech Republic territory. The assessment was performed using time-series multiple regressions of basal-area increment from pure immature stands of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), oaks (Quercus sp.), ash (Fraxinus excelsior) and willows (Salix sp.) dependent on the interpolated average temperatures, annual precipitation, atmospheric concentrations of SO2, NOx and O3 and soil properties over the period 1971–2008 at p &lt; 0.05. Site MPs differentiated the forest response to a greater extent than tree species. The response of the forests was significantly distributed by means of the montane, upland and waterlogged sites. The multiple determination index (r2) ≥ 0.6 indicated an adaptable tree increment but an interval of r2 between 0.80–0.92 implied forest sensitivity to variability in environmental properties on non-waterlogged sites. The index r2 &lt; 0.6 suggested a fluctuating forest increment that reflects environmental variability inconsistently. The fluctuating increment most affected the spruce and pine stands grown from upland to submontane locations. Montane spruce stands, as well as rock pines, appeared to be one of the most sensitive ones to environmental change. Floodplain forests seemed as adaptable to variable environmental properties.

Phytogeographical origin determines Tropical Montane Cloud Forest hydraulic trait composition

Abstract Tropical montane cloud forests (TMCF) have unique climatic conditions, which allow the coexistence of plant lineages with different phytogeographical origins from tropical versus temperate climates. Future climate projections suggest TMCFs will be subjected to increasing drought stress due to fog uplift and higher temperatures, possibly leading to tree mortality and local extinctions, and consequently changes in forest composition and functioning. Characterizing community functional composition, trade‐offs among traits and the drivers of community assembly is of utmost importance to improve our capacity to predict the response of montane plant communities to forecast climate change. Here, we aimed to test whether species from different phytogeographical origins (i.e. tropical – evergreen × deciduous − and temperate) differ in drought vulnerability and how the coexistence of these groups change the hydraulic composition of TMCFs. We used a framework based on measurements of key hydraulic traits (i.e. xylem embolism resistance, hydraulic safety margin, stomata control, turgor loss point, minimum water potential) of 16 dominant species (&gt;70% of the forest basal area) within a TMCF in the Atlantic Rain Forest Domain in southeast Brazil. We used community‐weighted means to model whether removing each species group would change the community hydraulic functional composition. Temperate, tropical deciduous and tropical evergreen groups differ in their hydraulic functioning and these differences explain forest functional composition and taxa dominance. Temperate and tropical deciduous taxa were consistently more vulnerable hydraulically (i.e. lower safety margins and embolism resistance). The coexistence of different phytogeographical lineages is a key determinant of TMCF hydraulic composition. We also used models including phylogeny to evaluate the variation of hydraulic traits across phytogeographical groups, and the results suggest some niche conservatism associated with plant hydraulic functioning. Our results provide evidence of the importance of species phytogeographical origin on TMCF functioning, and niche conservatism in the evolution of hydraulic traits. The higher drought vulnerability observed in temperate group might be a mechanistic explanation for the restriction of temperate taxa distribution to wetter places during past colder and drier climate. Thus, we suggest hydraulic functional traits may be useful to predict future dynamics of TMCFs under changing climatic conditions.

River Distance, Forest Basal Area, and Climatic Conditions are the Main Drivers Influencing Lying Deadwood in Riparian Forests

River Distance, Forest Basal Area, and Climatic Conditions are the Main Drivers Influencing Lying Deadwood in Riparian Forests

Tree mortality response to drought‐density interactions suggests opportunities to enhance drought resistance

AbstractThe future of dry forests around the world is uncertain given predictions that rising temperatures and enhanced aridity will increase drought‐induced tree mortality. Using forest management and ecological restoration to reduce density and competition for water offers one of the few pathways that forests managers can potentially minimize drought‐induced tree mortality. Competition for water during drought leads to elevated tree mortality in dense stands, although the influence of density on heat‐induced stress and the durations of hot or dry conditions that most impact mortality remain unclear.Understanding how competition interacts with hot‐drought stress is essential to recognize how, where and how much reducing density can help sustain dry forests in a rapidly changing world. Here, we integrated repeat measurements of 28,881 ponderosa pine trees across the western US (2000–2017) with soil moisture estimates from a water balance model to examine how annual mortality responds to competition, temperature and soil moisture conditions.Tree mortality responded most strongly to basal area, and was elevated in places with high mean temperatures, unusually hot 7‐year high temperature anomalies, and unusually dry 8‐year low soil moisture anomalies. Mortality was also lower in places that experienced unusually wet 3‐year soil moisture anomalies between measurements. Importantly, we found that basal area interacts with temperature and soil moisture, exacerbating mortality during times of stress imposed by high temperature or low moisture.Synthesis and applications. Our results imply that a 50% reduction in forest basal area could reduce drought‐driven tree mortality by 20%–80%. The largest impacts of density reduction are seen in areas with high current basal area and places that experience high temperatures and/or severe multiyear droughts. These interactions between competition and drought are critical to understand past and future patterns of tree mortality in the context of climate change, and provide information for resource managers seeking to enhance dry forest drought resistance.

Legacies of forest harvesting on plant diversity and plant community composition in temperate deciduous forest

AbstractAimsTo conserve forest natural heritage, sustainable forest harvesting requires the recovery of plant diversity and ecosystem functions following management. There is a need to clarify the temporal dynamics of plant diversity following harvesting, for both even‐aged and uneven‐aged silvicultural systems. To achieve this goal, the temporal dynamics of plant diversity in the herb layer were measured in unmanaged forests (control) and along a chronosequence (&lt;5 years, 15 years and 30 years after harvesting) for even‐aged and uneven‐aged managed forests.LocationHardwood forest of southern Quebec, Canada.MethodsPlant diversity, plant community composition and ecosystem functioning were investigated using metrics exploring richness, evenness and disparity diversity components, and included two scales of diversity partitioning (alpha and beta). Shrub–canopy layer, forest tree species composition and structure, and total forest basal area were also measured.ResultsIn both uneven‐aged and even‐aged managed forest stands, we found: (a) a substantial decrease in mean plant phylogenetic diversity compared with unmanaged forest, even 30 years after harvesting (i.e., decrease of 16% and 22%, respectively); and (b) lowest plant alpha‐diversity in the herb layer 15 years after harvesting. Modification of community composition based upon dissimilarity (beta‐diversity) metrics demonstrated more numerous effects of even‐aged management than uneven‐aged management. For forest composition and structure, plant community and plant traits, dissimilarity relative to the unmanaged control was highest 5 years after even‐aged management. Trait‐based communities were more similar to unmanaged forest at the intermediate levels of forest density (i.e., ~20 m2/ha) that were found 5 years after uneven‐aged management.ConclusionsForest management clearly affected diversity, community composition and ecosystem functions along the chronosequence, highlighting the strongest effects of more intensive management (i.e., even‐aged) and the need to improve the sustainability of forest management.

Data-Driven Analysis of Forest–Climate Interactions in the Conterminous United States

A predictive understanding of interactions between vegetation and climate has been a grand challenge in terrestrial ecology for over 200 years. Developed in recent decades, continental-scale monitoring of climate and forest dynamics enables quantitative examination of vegetation–climate relationships through a data-driven paradigm. Here, we apply a data-intensive approach to investigate forest–climate interactions across the conterminous USA. We apply multivariate statistical methods (stepwise regression, principal component analysis) including machine learning to infer significant climatic drivers of standing forest basal area. We focus our analysis on the ecoregional scale. For most ecoregions analyzed, both stepwise regression and random forests indicate that factors related to precipitation are the most significant predictors of forest basal area. In almost half of US ecoregions, precipitation of the coldest quarter is the single most important driver of basal area. The demonstrated data-driven approach may be used to inform forest-climate envelope modeling and the forecasting of large-scale forest dynamics under climate change scenarios. These results have important implications for climate, biodiversity, industrial forestry, and indigenous communities in a changing world.

Potential Hurricane Wind Risk to US Rural and Urban Forests

Abstract Hurricanes cause billions of dollars in damage annually in the United States and are projected to increase in intensity in the coming years. By exploring historical patterns of hurricanes and exposure of these hurricane-force winds across the landscape, areas of potentially high threat to future hurricane winds can be revealed. Combining potential threats from hurricane winds with forest data reveal the areas with the greatest potential threats to this important resource. Not surprisingly, most of the threats to forests occur in the Southeast, but the greatest threats to urban forests overall occur along the Northeast coast and in metropolitan centers in the Southeast. Overall, 4.6% of the nation’s rural forest basal area is within zones of the highest risk from hurricane winds. Information on regional and local scale variations in hurricane risk can be used to aid policies and local forest management to improve forest health and sustainability.

Modeling of aboveground tree stand-level biomass in Erukot Forest of Oban Division, Cross River National Park, Nigeria

This research estimated aboveground tree stand level Biomass in Erukot Forest of Oban Division, Cross River National Park. A total of 872 individual trees were identified and measured for diameter at breast height and total height (dbh ≥ 5cm). The 872 individual trees spread across 51 species belonging to 25 different tree families. Simple random sampling was used with sampling intensity of 0.3% to lay 15 nested plots (7m x 7m, 25m x 25m and 35m x 35m). Diameter at breast height, total height and specific density of each wood species were used to determine aboveground biomass for each tree. Conversion factors were applied to estimate stand level green and dry biomass, sequestered carbon and carbon dioxide (CO2) emission in the study area. Simple linear regression models were fitted into the stand level growth data for the forest (basal area and volume). The mean diameter at breast height and mean total height were 38.5cm and 18.5m respectively. Mean basal area of 39.8 m2 ha-1 was obtained with a mean volume of 177.3 m3 ha-1 . Average green biomass, dry biomass, carbon stock and carbon-dioxide emission of 521.8113 ton ha-1 , 341.5880 ton ha-1 , 183.196 ton ha-1 and 694.2067 ton ha-1 respectively were obtained in the study area. Stand level biomass model developed for the forest showed that common logarithm of volume per hectare is significantly related to common logarithm of stand biomass (R2 = 58%). The actual and predicted biomasses were not significantly different (Paired T-test at p ˂ 0.05). Estimated bias of 0.10% for the stand biomass model means that the developed model can be used to predict the aboveground biomass of the study area without any adjustment. The research has provided easy to use regression model for determining aboveground biomass at stand level. This is very useful for carbon trade and assessment of carbon-dioxide emissions through deforestation in the study area. The model is also a tool for assessing the wood productivity of the study area and for better management of the park.&#x0D; Keyword: Sequestered carbon, aboveground biomass, dry biomass, conversion factor