Understorey Vegetation Research Articles

Three decades of understorey vegetation change in Quercus‐dominated forests as a result of increasing canopy mortality and global change symptoms

Three decades of understorey vegetation change in <i>Quercus</i>‐dominated forests as a result of increasing canopy mortality and global change symptoms

Seed rain as a propagule source for restoration of semi‐arid floodplain old fields

AbstractAimsRevegetation of the world's abandoned agricultural land (old fields) is vital to promote biodiversity and restore ecosystem services. Natural regeneration, whereby vegetation regrows on its own via the propagules already within the landscape, is a cost‐effective restoration approach for old fields. It is vital that we understand how different seed sources contribute to the regenerative capacity of old fields to make informed management decisions. Little is known about seed rain as a propagule source for restoration within semi‐arid floodplains of eastern Australia.LocationWithin this study, we examined seed rain and extant vegetation in old fields and paired remnant sites across four regions in the northern Murray–Darling Basin, eastern Australia.MethodsSeed rain was surveyed using seed traps that were then subjected to a seedling emergence experiment.ResultsMinimal differences in seed rain composition, species richness, abundance, and plant functional groups were observed between old‐field and remnant sites, indicating similarities in seed dispersal within both land use histories. Larger distances to remnant patches and mean annual rainfall were found to drive the composition of old field's seed rain. The study found few emerged Eucalyptus seedlings despite seed traps being placed during peak seed release periods, which may be due to poor tree conditions from drought, interference with seed traps and the episodic germination requirements of Eucalyptus coolabah.ConclusionsThis study demonstrates that seed rain can contribute to the natural regeneration of understorey vegetation, with low abundances of exotic species, unlike other seed bank types. However, seed rain composition resembled little of the extant vegetation, suggesting a species pool facing barriers to germination and establishment, but likely linked to bet‐hedging strategies. Moving forward to promote natural regeneration via seed rain in old fields, protecting existing patches of vegetation within the landscape is vital to enable biotic connectivity.

Potential processes leading to winter reddening of young Douglas-fir Pseudotsuga menziesii Mirb. Franco. in Europe

Key messageWinter reddening of young Douglas-fir (Pseudotsuga menziesii Mirb. Franco), triggered by large thermal fluctuations in late winter, is a critical problem for European forestry. A literature review identified certain climatic conditions that are characteristic of ‘reddening’ years, including warm daily temperatures, high daily temperature amplitude, low relative humidity, moderate wind speeds, as well as the occurrence of freeze-thaw cycles with cold night temperatures.By describing the triggering environmental and stand factors, we propose three hypotheses for the physiological processes leading to winter reddening, namely (i) hydraulic failure due to winter drought stress, (ii) photo-oxidative stress in shade-acclimated trees, and (iii) early cold deacclimation during warm periods.i) Low soil temperature, by reducing root water uptake, combined with anticyclonic conditions, by increasing water losses, can induce hydraulic failure in the xylem. Hydraulic failure may be further accelerated by night frosts.ii) Winter reddening can occur when low temperature and high irradiance coincide, disrupting photostasis. Overwhelming of winter photo-protection may lead to photodamage and subsequent reddening.iii) Warm periods, by inducing cold deacclimation, make trees susceptible to frost damage.Finally, the three processes may interact under atypical anticyclonic conditions in late winter (e.g. cold or dry soils, warm days, high irradiance and/or freezing nights). Indeed, trees under water stress would develop a higher sensitivity to freezing night and photooxidative stress. We therefore proposed mitigation actions to avoid exposing trees to stressful conditions based on e.g. stand characteristics, understorey vegetation and planting.

Strategies for falcata (Falcataria falcata (L.) Greuter and R.Rankin) farmers to mitigate gall rust severity across elevations

The extent of gall rust severity in Falcata plantations across various elevations and locations in the country is insufficiently documented, posing challenges for developing an integrated disease management strategy. This study aimed to assess the conditions favorable for gall rust severity in Falcata plantations at different elevations in Mindanao. Our survey revealed that gall rust severity is significantly higher at elevations exceeding 400 m above sea level (asl), with potential yield losses estimated between 23% and 52% of the total log volume per hectare. Factors contributing to increased severity, regardless of elevation, include low stand density (&lt;1000 trees/ha), extended distances from natural vegetation (&gt;1000 m), low understorey species diversity, and low average temperatures (&lt;24°C). These factors interact significantly with elevation, as higher severity was observed in plantations with greater understorey vegetation diversity and elevated temperatures (&gt;24°C), particularly at elevations over 600 m (asl). Based on our findings, it is recommended to avoid planting Falcata in areas with elevations exceeding 400 m (asl). However, if planting at higher elevations is unavoidable, adequate tree spacing (3 m x 3 m or 3 m x 4 m) should be maintained to achieve a moderate stand density (1000-1500 trees/ha). This practice can help regulate air circulation within the plantation, mitigate pathogen spread, and control understory vegetation growth and temperature impacts. Additionally, establishing and maintaining native vegetation or forest within 1000 m around Falcata plantations is advisable to create a protective buffer zone, thereby reducing gall rust severity.

Changes in plant diversity of European lowland forests: Increased homogenization and expansion of shade-tolerant trees

European lowland forests have undergone significant transformations over the past century due to increased canopy closure, eutrophication and plant invasions. The new millennium has brought plant invasions, alien fungal pathogens, and extreme weather conditions, all contributing to forest diebacks. However, the response of plant diversity remains poorly understood. We examined changes in understorey vegetation following a decade (2012–2021) of severe drought in four temperate lowland forest types (dominated by oaks, hornbeams, ashes, and willows) to understand how water availability, canopy openness, and alien fungal pathogens altered diversity in interaction with climate change. Following an exceptionally warm decade, the vegetation exhibited increased homogeneity, with denser shrub and herb layers, likely resulting from diminished tree canopy, particularly in hornbeam and ash forests. Homogenization was manifested by the colonization of plants with conservative life-history strategies (higher leaf dry matter content) to cope with increased drought. Consequently, communities with fewer species increased their species richness, while species-rich communities experienced impoverishment. Conversely, herbaceous species with higher specific leaf area were declining. Compositional changes were particularly prominent in hornbeam and oakwoods at the drier end of moisture gradient where the understorey became dominated by woody plants. Ashwoods were opening up due to ash dieback by fungal pathogens, causing replacement of wetland forbs by nitrophilous forbs and woody saplings. The overall number of species decreased in oakwoods but increased in hornbeam and ashwoods due to increased cover of grasses and shade-tolerant woody species, mostly Acer campestre. Conversely, willow understorey vegetation at the wetter end of the moisture gradient remained relatively stable. Our findings suggest shifts towards more homogeneous vegetation. Conservation plans for managing the remnants of species-rich lowland forests should consider the accelerated environmental changes linked to canopy alterations, biological invasions, and extreme climate events.

Predicting trajectories of temperate forest understorey vegetation responses to global change

Predicting forest understorey community responses to global change and forest management is vital given the importance of the understorey for biodiversity conservation and forest functioning. Though substantial effort has gone into disentangling the impact of global change on understorey communities, scarcity of information on site-specific environmental drivers across large temporal-spatial scales has limited our ability to predict global change effects at specific forest sites. In this study, using vegetation resurvey and soil data from 1363 plots across temperate Europe, we applied a machine learning approach (gradient boosting regression, GBR) to model and predict site-specific responses of four understorey properties to global change. We applied our final GBR models at 8 forest sites in Austria to validate the model performance, predict understorey trajectories, and evaluate the effect of alternative scenarios for future nitrogen(N) deposition, climate change and forest management on the projected trajectories. Our results showed that the R² value of the four final GBR models on the independent testing dataset ranged between 0.611 and 0.723 and the most important environmental drivers in predicting the trajectory of understorey properties at specific forest sites were soil pH, soil total carbon-to-nitrogen ratio, overstorey shade-casting ability and regional-scale mean annual precipitation. The out-of-sample R2 value of the four final GBR models on the Austrian data ranged between 0.224 and 0.561. The forecasted trajectories for the Austrian forest sites showed that site-specific understorey responses to near-future climate warming were expected to be weak. Under N deposition decreases, the proportion of woody species was predicted to increase, while species richness and total vegetation cover were predicted to decrease. Furthermore, under a closed canopy, the understorey community was predicted to shift towards more woody species and more forest specialists, albeit with reduced species richness and vegetation cover. Given expected warming and declining N pollution pressures, our presented GBR models allow the prediction of trajectories of understorey vegetation responses to global change and management interventions at specific forest sites. Such projections could aid forest management in addressing challenges posed by global change.

Floristic diversity of Naungan mangrove ecosystem in Ormoc, the largest port city in Leyte, Philippines

Abstract. Pasa AE, Solano VJD, Figueroa SMS, Valenzona EO, Buhay AFV, Buot Jr IE. 2024. Floristic diversity of Naungan mangrove ecosystem in Ormoc, the largest port city in Leyte, Philippines. Biodiversitas 25: 2093-2103. Assessing the floristic diversity of the Naungan mangrove ecosystem in Ormoc, the largest port city in Leyte and a highly susceptible area to geologic and natural hazards, extreme weather events and human disturbances, is vital to determine available resources and ecosystem services for communities. This study aimed to evaluate the present state of the mangrove ecosystem in Naungan by analyzing its floristic diversity, composition, and structural characteristics. A total of 55 nested quadrats were established as observation points, measuring 10 m x 10 m and 5 m x 5 m to document the upper canopy and understorey vegetation, respectively. Mangroves with a diameter of 10 cm and above were recorded for the upper canopy while plants with diameter below 10 cm were recorded for the understorey. Results showed that the upper canopy vegetation has a total of 331 individuals of which are 10 tree species belonging to 8 families while the understorey canopy has a total of 1,310 individuals of which are 23 species belonging to 15 families. The diversity of upper canopy vegetation, as measured by the Shannon index, is notably low at 1.492. Similarly, the understorey diversity, with a value of 2.198, falls into the low category. When considering the combined diversity of both upper and lower canopies, the overall score remains low at 2.176. Avicennia marina is the most dominant upperstorey species with a relative abundance of 0.39275 followed by Sonneratia alba with 0.27492 and Avicennia officinalis with 0.16012. The understorey is also dominated by Avicennia marina with a relative abundance of 0.352672 followed by Nypa fruticans with 0.118321 and Rhizophora apiculata with 0.10229. Aegiceras floridum and Ceriops decandra are “nearly threatened” while the other species are under the “least concern” category. The area is managed by a people’s organization but threats such as fishpond establishment, road construction, and subsistence farming remain and are expected to affect mangrove diversity and ecosystem services. A mangrove ecosystem conservation framework is proposed, incorporating the importance of policy intervention and local participation in realizing sustainable mangrove ecosystems and stable provisions of the ecosystem services.

Light thinning effectively improves forest soil water replenishment in water-limited areas: Observational evidence from Robinia pseudoacacia plantations on the Loess Plateau, China

Soil water plays a key role in vegetation growth and recovery, mainly replenished by rainfall in the water-limited areas. Thinning is an important practice for forest reconstruction and soil water regulation. However, the effects of different thinning intensities on the dynamics of soil water and its replenishment by rainfall have been inadequately quantified, which could provide a guide for reasonable thinning intensity determination for in high-density forests from a hydrological perspective. In this study, one nonthinning plot and 5 plots with different thinning intensities, i.e., 35 % (light), 45 % (medium), 55 % (moderate), 65 % (heavy) and 80 % (extremely heavy) in Robinia pseudoacacia plantations, which are widely planted on the Loess Plateau, were set up. The volumetric soil water content (SWC) at 0–200 cm depths and rainfall were observed simultaneously and continuously for up to two years. The soil properties and vegetation structure in each plot were also measured regularly. The results showed that (1) the SWC in all the thinning plots was significantly greater than that in the nonthining plot (P < 0.05). (2) The replenishment increased with increasing thinning intensity, and then decreased after reaching a maximum at T35 % under most rainfall events except for light events. (3) The variations in the soil water response characteristics among the plots with different thinning intensities were mainly significantly correlated with the initial soil water content (ISWC), leaf area index (LAI) and understorey vegetation characteristics (P < 0.05). (4) Based on the relationship between soil water replenishment and retention with thinning intensity and stand density, quantitative equations were fitted to determine the reasonable thinning intensity (22–28 %) and retained stand density (1019–1091 trees/ha), respectively. Our study concluded that thinning could effectively improve soil water, especially light thinning, which could obviously enhance the replenishment of soil water by rainfall in Robinia pseudoacacia plantations. This study can provide a reference for determining forest thinning intensity or stand retention density, which is beneficial for water and reforestation management in water-limited regions.

Contrasting responses of forest phenological guilds to complex floodplain change

Abstract Understanding the seasonal dynamics of the forest herb layer and the factors that influence it is essential for predicting how the forest ecosystem, including mutualistic interactions, will respond to global change. However, to date, no research has investigated how understorey phenological guilds respond to major environmental threats and forest interventions. We showed the marked changes in the phenological structure of floodplain forest plant communities over half a century at a multi‐regional scale in Central Europe. Unlike previous studies focusing on individual species' responses to climate change, we examined shifts in species richness, frequency and abundance between phenological guilds within the plant community. We examined the effects of temporal variation in climate, hydrology, soil conditions and canopy structure, and assessed the effects of non‐intervention and intervention management on phenological guild responses. Our results show a significant loss of local species richness and a decline in species frequency in the forest understorey vegetation, associated with species exhibiting summer phenology. In contrast, an increase in abundance and richness of spring flowering species was observed, attributed to high nutrient loads and reduced flooding, respectively. The abundance of spring species increased only in stands where canopy cover increased over time, probably due to the suppression of summer flowering species, allowing spring flowering species to spread on open, bare ground. The community experienced a shift in maximum flowering plant richness from June to May. Despite management interventions such as clearcutting and tree planting, our data show similar temporal trajectories in intervention and non‐intervention forests, indicating that changes in phenological structure are largely independent of recent management activities. Synthesis. We propose that a complex interplay of environmental factors, rather than climate change alone, is shaping shifts towards earlier phenological guilds in floodplain forests. This study highlights the importance of considering a comprehensive view of phenological guild dynamics and the impact of environmental factors on forest plant community structure in the face of global change.

How do management decisions impact butterfly assemblages in smallholding oil palm plantations in Peninsular Malaysia?

Abstract In the world's leading palm oil‐producing countries (Indonesia and Malaysia), smallholders make up about 40 per cent of total oil palm plantation area. Management in smallholdings can be highly variable, ranging from intensive monoculture to polyculture systems, especially in the earlier years of cultivation when open canopies allow a variety of understorey crop types to be grown alongside oil palm. Currently, many plantations in the region are mature and due to be replanted, which is likely to have substantial impacts on the ecosystems within them, but studies investigating the impacts of alternative post‐replanting management strategies in smallholder plantations are lacking. We investigated the impacts of replanting and choice of crop management following replanting (growing oil palm as a monoculture or polyculture) on habitat structure and complexity, and on the abundance, richness and composition of butterfly assemblages in smallholding oil palm plantations in Banting, Selangor, Malaysia. We also assessed the direct effects of habitat structure and complexity on butterfly assemblages. Butterflies are likely to be a valuable indicator group for monitoring the impacts of management practices on biodiversity as butterfly species also show a range of sensitivities to habitat disturbance, with some being vulnerable to change, but others being common in plantations. They are also a functionally important group that pollinate wild plants, are prey for larger species and are common in tropical systems. Across 27 plantations, we recorded 1227 butterflies from 5 families, 46 genera and 56 species. Habitat structure and complexity differed between management decisions (mature monoculture, immature monoculture, immature polyculture), although many environmental parameters overlapped. We found no significant differences in species richness, density and assemblage composition of butterflies between management decisions. However, changes in local environmental conditions, such as an increase in the coverage of understorey vegetation, increased the abundance of butterflies. Synthesis and applications. Our findings suggest that replanting oil palm and choice of mono or polyculture have relatively few effects on butterflies, but management for specific features in plantations could benefit butterfly assemblages.

A case study on the early stage of Pinus nigra invasion and its impact on species composition and pattern in Pannonic sand grassland

Alien woody species are successful invaders, frequently used for afforestation in regions like semi-arid lands. Shrubs and trees create important microhabitats in arid areas. Understorey vegetation in these habitats has unique species composition and coexistence. However, the impact of solitary woody species on understorey vegetation is less understood. This study evaluated the effect of native (Juniperus communis) and invasive solitary conifers (Pinus nigra) on surrounding vegetation, where individuals were relatively isolated (referred to as solitary conifers). The field study conducted in Pannonic dry sand grassland in 2018 recorded plant and lichen species presence around six selected solitary conifers. Composition and pattern of understorey vegetation were assessed using 26 m belt transects with 520 units of 5 cm × 5 cm contiguous microquadrats. Compositional diversity (CD) and the number of realized species combinations (NRC) were calculated from the circular transects. Results showed native conifer J. communis created more complex, organized microhabitats compared to alien P. nigra. CD and NRC values were significantly higher under native conifers than invasive ones (p = 0.045 and p = 0.026, respectively). Native species also had more species with a homogeneous pattern than the alien species. Alien conifers negatively affected understorey vegetation composition and pattern: some species exhibited significant gaps and clusters of occurrences along the transects under P. nigra. Based on our study, the removal of invasive woody species is necessary to sustain habitat diversity.

Impact of coppicing on microclimate and understorey vegetation diversity in an ancient Mediterranean oak forest

Coppicing is one of the oldest silvicultural practices and is still widely applied to produce renewable energy from broadleaf forests. However, the consequences on microclimate and understorey vegetation are still poorly understood, especially in Mediterranean oak forests. With the ongoing changes in the climate system and global biodiversity loss, a better understanding of how the forest temperature buffering capacity and below-canopy plant community are impacted by coppicing is crucial. Here we quantify microclimate and understorey vegetation changes in adjacent ancient coppice-with-standards and high forest stands dominated by oaks in Italy, where these systems have been applied for a long time. Air and soil temperatures were recorded for 2.5 years, and nested vegetation plots were used to analyse coppicing effects on species composition, taxonomic, phylogenetic, and functional diversity. Coppicing significantly reduced the forest temperature buffering capacity. The mean of the daily maximum temperatures over the entire period was 1.45 °C higher in the coppiced sites, whereas the mean of the daily minimum temperatures was 0.62 °C lower than in the high forest. Coppicing increased understorey species richness by favouring generalist taxa, but significantly decreased the proportion of forest specialists. The understorey community in coppiced forests consisted of more warm-adapted species. Moreover, coppicing also led to a loss of phylogenetic evenness and to shifts in diversity and community weighted mean Leaf Dry Matter content, pointing to habitat filtering and acclimation processes. In sum, we show that coppicing affects microclimate and understory vegetation in a direction that can exacerbate the effects of climate change, negatively affecting the oak forest specialist flora and its phylogenetic evenness.

Species Diversity of Understorey Vegetation in Pinewood (Pinus merkusii) Forest in RPH Sempor, BKPH North Gombong

Understorey plant is a type of basic vegetation under forest stands except for saplings. Understorey vegetation includes grasses, herbs, shrubs, and ferns. The presence of understorey vegetation can be used as an indicator of forest conditions and is expected to reduce disturbances to the forest. The purpose of this research is to determine the diversity and the dominance of understorey species under the pinewood stands based on pine ages in RPH Sempor, BKPH North Gombong. This research was conducted using a survey method and systematic sampling techniques at two different age groups pinewood forest of RPH Sempor, BKPH North Gombong. The result showed that the total understorey species found were 34 species from 21 families. The understorey species number found at the 25 years of pine forest was 22 species found and at the 45 years, there were 17 species. Based on the research that has been done, it can be concluded that the younger the age of pine stand, the more understorey species number. Evenness of the understorey species at two different ages of pine stand in RPH Sempor is evenly distributed, so there are no dominant species. The physicochemical factors measurement result showed that the canopy cover affected the temperature and humidity level, thus affecting the number of understorey individuals and the species number in each stand.

Tree species replacement from birch to spruce affects eukaryome in boreal forest soil

Large-scale replacements of native birch with spruce have been carried out in Western Norway for economic reasons. This tree species shift potentially affects biotic components such as the eucaryome, consisting of microscopic animals (Metazoa), protists and fungi, which are key players in the functioning of forest ecosystem. The impact on the belowground eukaryome and its interactions with vegetation and soil properties is not well assessed. We examined the impact of replacing native birch with Norway spruce plantations on the eukaryome of the boreal forest floor in Western Norway using 18S rDNA metabarcoding. The tree species shift from birch to spruce had significant impacts on the eukaryome at both taxonomic (Metazoa) and functional categories (phagotrophs, phototrophs, parasites and osmotrophs). The distinct differences in eukaryome communities were related to changes in understorey vegetation biomass and soil chemistry following the tree species shift. This had a negative effect on eukaryome richness, particularly affecting phagotrophs and parasites, while the opposite was observed for osmotroph richness. Our results indicated that the spruce plantations altered the eukaryome communities and their food-web patterns compared to what was found in the native birch forest soil. This information should be taken into consideration in forest management planning.

Nutrient‐demanding and thermophilous plants dominate urban forest‐edge vegetation across temperate Europe

AbstractQuestionsForests are highly fragmented across the globe. For urban forests in particular, fragmentation increases the exposure to local warming caused by the urban heat island (UHI) effect. We here aim to quantify edge effects on herbaceous understorey vegetation in urban forests, and test whether these effects interact with forest structural complexity.LocationWe set up a pan‐European study at the continental scale including six urban forests in Zurich, Paris, Katowice, Brussels, Bremen, and Stockholm.MethodsWe recorded understorey plant communities from the edge towards the interior of urban forests. Within each urban forest, we studied edge‐to‐interior gradients in paired stands with differing forest structural complexity. Community composition was analysed based on species specialism, life form, light, nutrient, acidity and disturbance indicator values and species' thermal niches.ResultsWe found that herbaceous communities at urban forest edges supported more generalists and forbs but fewer ferns than in forests' interiors. A buffered summer microclimate proved crucial for the presence of fern species. The edge communities contained more thermophilous, disturbance‐tolerant, nutrient‐demanding and basiphilous plant species, a pattern strongly confirmed by corresponding edge‐to‐interior gradients in microclimate, soil and light conditions in the understorey. Additionally, plots with a lower canopy cover and higher light availability supported higher numbers of both generalists and forest specialists. Even though no significant interactions were found between the edge distance and forest structural complexity, opposing additive effects indicated that a dense canopy can be used to buffer negative edge effects.ConclusionThe urban environment poses a multifaceted filter on understorey plant communities which contributes to significant differences in community composition between urban forest edges and interiors. For urban biodiversity conservation and the buffering of edge effects, it will be key to maintain dense canopies near urban forest edges.

The impact of drying on the structure and photosynthesis of boreal peatland vegetation

Boreal peatlands harbour large stores of carbon as peat below their surfaces. Climate change is expected to cause drying in northern peatlands, which will in turn impact the carbon balance of these ecosystems that is maintained by high water tables and the hydrologically sensitive plants growing there. This study aims to quantify how vegetation will be structured (I) and photosynthesize (II, III) in a future climate as emulated by long-term water level drawdown (WLD). To do this, changes in the vegetation and its photosynthesis after WLD are linked, and the response of Sphagnum mosses to periodic drought is investigated. Field measurements were done at a long-term WLD field experiment that contained a rich (mesotrophic) fen, a poor (oligotrophic) fen and a bog (ombrotrophic) site. Measurements included vegetation surveys from existing permanent sample plots and leaf-level carbon dioxide exchange measurements. For an experiment in controlled conditions peatland surface cores from this field experiment were transported to a greenhouse where the photosynthesis of lawn Sphagna during and after an experimental periodic drought was measured. The field study revealed that the response of peatland vegetation to WLD depend on peatland type. The species composition in the rich fen was the most impacted by WLD, while the bog vegetation demonstrated stability. Similarly, large increases in photosynthesis occurred following WLD on the vascular plant-covered rich fen, while changes were negligible on the Sphagnum-carpeted bog. The vegetation on the two fens shifted from an open sedge-, or sedge and Sphagnum-dominated ecosystem, to a tree-dominated ecosystem. Canopy development following WLD further accelerated vegetation changes by shading and sheltering the understorey vegetation. Vascular plants were the most likely to increase productivity from WLD as they are best suited to utilize the nutrients made available by peat mineralization, while Sphagnum moss photosynthesis was impacted little. The greenhouse study revealed that lawn Sphagnum mosses exposed to long-term WLD were more vulnerable to drought compared to those from wet sites. Large capitula typical to fen Sphagnum species appeared to be beneficial for surviving periodic drought. This work demonstrated that climate change as emulated by long-term WLD will have a large impact on the vegetation composition of northern peatlands and increase photosynthetic function of these ecosystems, fens in particular. To better predict climate feedbacks from these changes, carbon dynamics including peatland vegetation dynamics should be updated in global process models. Future research to better understand the tipping point of different peatland types after WLD in different climatic regions will help us to predict changes in these diverse and globally important systems.

Assessing the measuring time of forest plots

Forests provide a wide range of ecosystem services and information requirements on forests have grown considerably. Nevertheless, collecting information in the forest is expensive and for this reason assessment of forest resources strongly relies on statistical sampling. However, plot measurement remains essential even when remote-sensing data are used, and field assessments are still among the costliest components of forest inventories. Studies on the costs for plots survey are limited and usually based on expert evaluation rather than on data. This article analysed the relationship between the time needed for measuring forest plots and their site-related characteristics (slope, terrain roughness), stand features (number of trees, subsample trees, stumps, coarse woody debris, understorey vegetation) and protocol-related procedures, by means of univariate and multivariate analyses. Analyses showed that the time needed for measuring plots depends on the workload or the intensity of fieldwork. Especially, the number of variables surveyed matters, because the variables explained the measuring time variation by an additive effect, suggesting that within a complex field protocol the total number of measurements taken may not represent properly the overall intensity of work. Marking in an effective way permanent plots is recommendable because the retrieval success of the pins buried into the ground was the most important explanatory variable. Presence of understorey vegetation was more important than the number of individuals measured. The results obtained are consistent and logical, but the variance explained was limited, suggesting that predictability of the measuring time under complex field protocols might be intrinsically limited by the interactions among factors with opposite effects and especially by the adaptation of the surveyors to specific circumstances. For example, effects of physical tiredness were not detected in the days when two plots were measured; conversely, measuring a second plot reduced the measuring time of the first, an event most likely dependent on the surveyors’ behaviour. Under the conclusion that predictability is low by nature, the inference of studies based on simulation

Impact of different silvipastoral systems on understorey vegetation and soil properties

The present investigation was carried out in seven different silvipastoral systems . T -TvizCedrus deodara, - 12Robinia pseudoacacia, - Cupressus torulosa, - Prunus armeniaca, - Ailanthus altissimaTTT, T - mixed 3456plantations and T - grassland (control) of Sindh range, Ganderbal Forest Division, Kashmir Province. It aimed 7to assess floristic composition of different plantations and their impact on understorey vegetation and soil nutrients. The results revealed that 12 shrub and 43 herb species were found in all these systems. Cyanodon dactylon Ailanthus altissima Cupressus torulosa was the dominating species under grassland (control), and plantations. was dominating under plantations.was Oxalis acetosella Cedrus deodara Lolium perenne dominating species under mixed stand, and plantations. Maximum Robinia pseudoacacia Prunus armeniaca available nitrogen was recorded in T - plantation (363.76 kg ha ), whereas the highest 2Robinia pseudoacacia-1values for phosphorus and potassium (23.44 kg ha and 312 kg ha respectively) were recorded in T --1-15Ailanthus altissima plantation. Maximum soil organic carbon and electrical conductivity (2.14% and 0.51 dSm , -1respectively) was recorded in T -plantation. pH in different plantation types followed the 5 Ailanthus altissima trend of T &gt;T T T T &gt;T T plantations.

Динамика нижних ярусов растительного покрова в антропогенно нарушенных сосновых ценозах Красноярской лесостепи

The dynamics of the understorey vegetation cover in anthropogenically transformed cenoses of common pine (Pinus sylvestris L.) in the period 2017–2020 was studied. The studies were conducted in a diverse herbaceous group of forest types of natural origin in the Krasnoyarsk forest-steppe zone. The forest stands are characterized by I–IV classes of bonitet, density 0.5–0.9 and IV–VII class of age. Vegetation cover was studied at each monitoring site on 30 (1 m2) survey plots: species composition, projective cover, species occurrence, horizontal and vertical structure of phytocenosis. The intensity of change in species composition over a 4-year period was identified using the Serensen-Chekanovsky coefficient. Species diversity was assessed using Shannon index, recreational transformation of living ground cover – synanthropization index. Based on the results of the study, the species composition of the undergrowth and living ground cover was determined, and the features of its change in the period 2017–2020 were described. Based on the analysis of changes in species diversity, composition and projective cover of dominants and co-dominants, quantitative ratio of ecological and cenotic groups, the stages of recreational transformation of the ground cover were determined. As a result of the increased recreational load, the stage of recreational transformation of the vegetation cover changed: in sample area 1 from undisturbed to the 1st (initial) phase I stage (weak transformation), in sample area 3 – from the 1st to the 2nd (final) phase I stage. Due to the absence of anthropogenic influence, the undisturbed vegetation cover was preserved in sample area 4, whereas in sample areas 2 and 5, due to the constant recreational load, the 2nd phase I stage of vegetation cover transformation observed in 2017 remained. To reduce the impact on the lower tiers of vegetation under the canopy of pine plantations (sample areas 1–3) and to preserve its species diversity, it is possible to recommend the arrangement of a specific road-trail network. For citation: Goncharova I.A., Skripalschikova L.N., Barchenkov A.P. Dynamics of Understory Vegetation Cover in Anthropogenically Disturbed Pine Cenoses of Krasnoyarsk Forest-Steppe. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 204–214. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-204-214

Understorey vegetation moderates climate in open forests: The role of the skirt‐forming grass tree Xanthorrhoea semiplana F.Muell

AbstractMicrosites are created by abiotic and biotic features of the landscape and may provide essential habitats for the persistence of biota. Forest canopies and understorey plants may moderate wind and solar radiation to create microclimatic conditions that differ considerably from regional climates. Skirt‐forming plants, where senescent leaves create hut‐like cavities around the stem, create microsites that are sheltered from ambient conditions and extreme weather events, constituting potential refuges for wildlife. We investigate day and night temperatures and humidity for four locations (grass tree cavities, soil, 20 cm above‐ground, 1 m above‐ground) in a South Australian forest with relatively open canopy of stringybark eucalypts (Eucalyptus baxteri, E. obliqua) and an understorey of skirt‐forming grass trees (Xanthorrhoea semiplana) at 5, 10, 20, and 40 m from the forest edge. We also measured the percentage of canopy and understorey covers. Generally, temperature and humidity differed significantly between more sheltered (grass tree cavities, soil) and open‐air microsites, with the former being cooler during the day and warmer and more humid during the night. Furthermore, our results suggest that canopy cover tends to decrease, and understorey cover tends to increase, the temperature of microsites. Distance to the edge was not significantly related to temperature for any microsite, suggesting that the edge effect did not extend beyond 10 m from the edge. Overall, grass trees influenced microclimatic conditions by forming a dense understorey and providing cavities that are relatively insulated. The capacity of grass tree cavities to buffer external conditions increased linearly with ambient temperatures, by 0.46°C per degree increase in maximum and 0.25°C per degree decrease in minimum temperatures, potentially offsetting climate warming and enabling persistence of fauna within their thermal limits. These climate moderation properties will make grass trees increasingly important refuges as extreme weather events become more common under anthropogenic climate change.