Success Of Plants Research Articles

Deer browse deterrents and microsite selection influence Callitropsis nootkatensis and Thuja plicata planting success in Southeast Alaska

Deer browse deterrents and microsite selection influence Callitropsis nootkatensis and Thuja plicata planting success in Southeast Alaska

Когда кристаллизованный интеллект может быть профессионально «нежелательным» личностным качеством операторов

Purpose: To discuss the case of oppositely directed influences of the indicators of crystallized and fluid intelligence in the decisive rule designed to predict the professional success of the nuclear power plants (NPPs) operators. Material and methods: This paper analyzes the results of psychodiagnostic examinations of operators of main control rooms (MCR) of NPPs that functioned under normal conditions. All individuals were administered the J. Raven’s “Progressive matrices”, the Russian language adaptation of the Minnesota Multiphasic Personality Inventory (MMPI) and the Sixteen Personality Factor Questionnaire (16PF, form A). A cross-expert review using the ranking method revealed two groups of operators with relatively higher and lower levels of professional success. The method of canonical correlation analysis has been used to obtain the best linear discriminator for predicting the professional success of MCR operators based on indicators of psychodiagnostic tests. Results: Based on the results of the expert assessment, two groups of operators with the highest and lowest professional success were identified. Decisive rule were obtained that make it possible to predict the professional success of operators based on a system of signs (values of the psychodiagnostic tests scales multiplied by coefficients) after the data processing using canonical correlation analysis. Unexpected result was that the high values of 16PF factor «B» turned out to be «undesirable» for the prediction of professional success, that is, these values increased the probability of assigning the operator to the group of the lowest successful specialists. Conclusion: Factor «B» of 16PF was considered as a tool for assessing predominantly crystallized intelligence, and the Raven’s test – for the fluid one. At the same time, there are no methods that allow measuring these indicators in their purest form. Taking this fact into account, the author believes that the true role of factor B in the decisive rule did not reflect the undesirability of advanced crystallized intelligence among MCR operators. It is most likely that its opposition to the «desirable» indicator (the number of correctly solved tasks of the Raven’s test) made it possible to single out the role of fluid intelligence (or some of its lower-level aspects) as a professionally important quality for the particular operator activity.

Agarwood based agroforestry: a review

Agarwood is a resinous heartwood of various species of Thymelaeaceae primarily Aquilaria and Gyrinops with aromatic, cultural and medicinal uses. Owing to overexploitation in the wild the trees have become endangered, and cultivation has started all over the natural range and even outside under various agroforestry systems. The present review provides an overview of all the agroforestry systems based on agarwood worldwide and lists the species used in interplanting with agarwood. It also suggests means of raising successful plantations and the associated risks.

Effects of arbuscular mycorrhizal fungi on plant invasion success driven by nitrogen fluctuations

Abstract Both enemies and mutualists play crucial roles in shaping plant invasion processes. Recent studies have suggested that resource fluctuations could indirectly promote plant invasion through higher trophic levels, such as enemies. However, the influence of mutualists like arbuscular mycorrhizal fungi (AMF) on plant invasion under nitrogen fluctuations remains untested. We conducted a pot mesocosm experiment using a three‐factorial experimental design to assess the individual and interactive effects of nitrogen availability, nitrogen fluctuation and AMF on invasive success of alien plants. We grew nine invasive alien species alongside five different native communities in pot mesocosms. These were then subjected to varied nitrogen availabilities (low vs. high), nitrogen fluctuations (constant vs. pulsed) and AMF presence or absence within a sterile substrate. We found that pulsed nitrogen supply increased the dominance of invasive alien species in low nitrogen availability, regardless of the presence or absence of AMF inoculation. However, in high nitrogen availability, pulsed nitrogen supply only enhanced this dominance in pots without AMF inoculation. This was tentatively evidenced by the three‐way interaction among nitrogen‐availability, nitrogen‐fluctuation and AMF‐inoculation treatments. Furthermore, the dominance promotion by nitrogen addition was greater than that by AMF inoculation. Synthesis and applications. Our findings present, for the first time, evidence that AMF may play a crucial role in mediating the promotion effects of nitrogen fluctuations on alien plant invasion. To better understand the invasion process of alien plants and evaluate their impact on native communities, future research should integrate abiotic and biotic drivers into a single framework. Furthermore, our findings underscore the importance of prioritizing habitats with higher nutrient availability and variability for protection against alien plant invasions.

Germination ecology and seedling growth of invasive Ageratum species and allied native Adenostemma lavenia

AbstractThe success of invasive plants can be better understood by comparing their traits with closely related native species. This study compared germination ecology and seedling growth of invasive Ageratum houstonianum and Ageratum conyzoides with co‐occurring and allied native Adenostemma lavenia. Seeds were germinated under a different light (12 h photoperiod/complete dark), temperatures (low: 25°C/15°C day/night, and high: 30°C/20°C), and different levels of water stress (−0.1, −0.25, −0.5, −0.75, and −1 MPa). Seedlings were grown to determine biomass allocation, relative growth rate (RGR), plant height, and number of leaves. The seed mass and size of native A. lavenia were higher than those of invasive species. Seeds of all species were positively photoblastic. At low temperature and in all levels of water stress, all measured parameters except mean germination time were the highest in A. houstonianum. However, at high temperature, there was no significant difference in germination percentage between A. houstonianum and A. lavenia. No germination of A. conyzoides and A. lavenia was recorded beyond −0.5 MPa water potential, but seeds of A. houstonianum germinated up to −0.75 MPa. A. houstonianum had higher root mass fraction, root‐to‐shoot ratio, and number of leaves than the other two species. Stem mass fraction and the height of seedling were highest in A. conyzoides. The RGR was 1.6 times higher in invasive Ageratum species than the native species; it was slightly higher in A. houstonianum than in A. conyzoides. Overall, the results suggest that germination traits and seedling growth performance can be used as predictors of a species' invasiveness.

Plants at population edges enjoy longer mating distances: Implications for conservation practice

Habitat fragmentation and population declines have led to increased population edges, exposing higher proportions of plants to ecotones. However, it remains a challenging question how edge plants perform compared with interior ones, as they usually experience dissimilar abiotic and biotic interactions. To address this question, we performed experiments on a monoecious herb (Sagittaria trifolia) focusing on the reproductive fitness and mating patterns of individuals at the edge of two common gardens established under varied light conditions (open vs. understory) with natural pollination. Plant female fitness was determined by seed production, whereas male fitness and mating patterns were resolved by paternity analysis employing eight microsatellite markers. Results showed that edge plants had lower pollinator visitation frequency than interior ones in both gardens. However, there was no significant reduction in female or male reproductive success of edge plants. Instead, edge plants enjoyed longer distances of effective pollen dispersal when reproduced as males, as well as longer distances of sires when reproduced as females. This pattern was consistent across habitats and years. Together, the results indicate that edge plants not only maintained a comparable level of reproduction as interior ones but also enjoyed greater mating distances, which would likely bring about higher genetic diversity in their offspring. This further implies that edge effects may play an important role in promoting gene exchange and encouraging population recovery.

Alien plant fitness is limited by functional trade-offs rather than a long-term increase in competitive effects of native communities.

Alien plants experience novel abiotic conditions and interactions with native communities in the introduced area. Intra- and interspecific selection on functional traits in the new environment may lead to increased population growth with time since introduction (residence time). However, selection regimes might differ depending on the invaded habitat. Additionally, in high-competition habitats, a build-up of biotic resistance of native species due to accumulation of eco-evolutionary experience to aliens over time may limit invasion success. We tested if the effect of functional traits and the population dynamics of aliens depends on interspecific competition with native plant communities. We conducted a multi-species experiment with 40 annual Asteraceae that differ in residence time in Germany. We followed their population growth in monocultures and in interspecific competition with an experienced native community (varying co-existence times between focals and community). To more robustly test our findings, we used a naïve community that never co-existed with the focals. We found that high seed mass decreased population growth in monocultures but tended to increase population growth under high interspecific competition. We found no evidence for a build-up of competition-mediated biotic resistance by the experienced community over time. Instead, population growth of the focal species was similarly inhibited by the experienced and naïve community. By comparing the effect of experienced and naïve communities on population dynamics over 2 years across a large set of species with a high variation in functional traits and residence time, this study advances the understanding of the long-term dynamics of plant invasions. In our study system, population growth of alien species was not limited by an increase of competitive effects by native communities (one aspect of biotic resistance) over time. Instead, invasion success of alien plants may be limited because initial spread in low-competition habitats requires different traits than establishment in high-competition habitats.

Wood anatomical spectrum of co-occurring species in early and late-successional tropical dry forest communities

Key messageAnalysis of wood anatomical traits revealed that drought tolerance predominates in early-successional communities, and vessel variability is relevant for species’ ecological success in seasonally dry tropical environments.Successional tropical dry forests harbor a diverse array of species subjected to a strong seasonal precipitation regime. Considering that wood encompasses diverse functional properties related to stem hydraulics and mechanical support, in this study, we asked which quantitative anatomical traits are exhibited by co-occurring species in early (EC)- and late (LC)-successional communities. We used generalized linear mixed-effects models to estimate and compare means and standard deviations of wood traits (vessel area, vessel density, vessel grouping, and fiber dimensions) between eight EC and between 13 LC co-occurring species. Wood traits were highly heterogeneous. High vessel redundancy, a property associated with water safety involved in the prevention of hydraulic failure, prevails among species coexisting in EC but is maintained through succession by the same species in LC. Highly variable fiber dimensions indicate that species coexisting in LC possess different characteristics associated with mechanical resistance. Low wood density species typical of LC, which are absent from EC, displayed wood anatomical features associated with drought-evasion mechanisms. This result implies that deforestation not only reduces taxonomic but also functional diversity. Future research should adopt a standard deviation analysis approach, as this will allow confirming the high variability in vessel diameter, even in diffuse porous species, as a key feature for the ecological success of plants facing succession-driven changes in seasonally dry environments.

Assessment of understory vegetation in a plantation forest of the southeastern United States using terrestrial laser scanning

Forests of the southeastern United States are home to large timber industries with substantial contributions to global round wood production and paper products. Despite the success of plantations and the large timber industries in this area, pine growth remains constrained due to the competition between planted pine and the species in the understory. Moreover, effective control of this interspecies competition had shown a significant two- to four-times increase in stand productivity. Thus, this study aims to evaluate the use of laser scanning derived data from Terrestrial Laser Scanner (TLS) to assess understory vegetation biomass, as conventional methods utilizing optical imagery have yet to be effective in quantifying and mapping evergreen understory in the southeastern coastal forests of the United States. For this study, we utilized TLS to scan the entire forest profile within 60 sample plots of an operational loblolly pine plantation in Nassau County, Florida, and collected understory biomass data through destructive sampling. We compared three TLS-based volume estimation methods for predicting understory biomass and applied the Adaptive Least Absolute Shrinkage and Selection Operator (ALASSO) regression method to derive an optimal model by integrating the most efficient volume estimation methods and other TLS-derived standard metrics. Our study identifies the 20th percentile of the echo height and a 3D volume metric based on mean height and understory cover as the most significant explanatory variables for the optimal model. The model exhibits high accuracy, with Adjusted R-squared (Adj. R2) of 0.80 and Root Mean Square Error (RMSE) of 234.8 g per square meter (g/m2). Additionally, the mean height and understory-based volume estimation method outperformed other methods, such as voxel count and three dimensional (3D) alpha hall-based method, with Adj. R2 of 0.79, 0.47, and 0.57, and RMSE values of 288, 448.6, and 413 g/m2, respectively, when used as a single variable in the model. The resulting model successfully predicted and quantified understory vegetation, showcasing TLS's potential to accurately capture biomass variation, particularly in evergreen-dominated pine plantation forests in the southeastern United States coastal regions. As a tool for monitoring understory, TLS can be used to aid plantation forest managers in identifying areas that require control measures for enhanced management practices.

Thinning enhances success of enrichment planting with selected tree species under a pure stand of Leucaena leucocephala

Increasing the biodiversity of Leucaena leucocephala (hereafter leucaena) stands without losing the benefits provided by the forest structure is a challenge for adaptive management. Here, we report the survival and growth (height, stem, and canopy diameter) of five Atlantic Forest tree species planted underneath a pure stand of the exotic leucaena, which was broadcast sown 35 years before in a 0.6 ha area. Two treatments were compared: thinning (cutting all leucaena trees in 4‐m wide rows, where seedlings were planted) and control (seedlings planted under leucaena canopy), with four replicates each (20 seedlings per plot, four per species, 2‐m spaced). The five species selected were long‐lived emergent trees from seasonal forests, with broad canopy, evergreen, and shade‐tolerant. These traits were expected to allow their survival and growth, and, later on, to shade out the leucaena trees. Seven years after planting, survival was high for all species (around 80%), not differing between treatments or species. On average, stem diameter, height, and crown diameter were, respectively, 69, 44, and 36% higher in thinned than in control plots. Response to thinning differed between species in growth, with Gallesia integrifolia and Luehea divaricata standing out. Our results demonstrate that the species used for enrichment planting, selected by their suitable functional traits, can successfully survive under leucaena stands. Reducing competition by thinning, however, is crucial to enhance their growth. Despite the benefits from thinning, enrichment success strongly depends, therefore, on the abilities of the species selected to face the ecological filters acting on the target ecosystem.

Plant Dynamics and Growth in Forest and Land Rehabilitation Activities in Menamang Village, Muara Kaman District, Kutai Kartenegara Regency

This research was conducted in the planting area of ​​PT Kideco Jaya Agung, Muara Kaman District, Kutai Kartanegara Regency, East Kalimantan Province. The aim was to evaluate the growth success of plants planted 1 (one) year old. 2.5 hectares, plots are placed systematically representing a 25-hectare crop with a distance of 100 m between the centres of the plots. The results of research that has been done on 25 plots are 1830 plants with an average of 74 plants, and the average percentage of growth is 96.44%. The quality of plant growth is classified into 3 categories: healthy, languishing, and dead plants. Size plot 12 is the plot that has the worst plant conditions among the others, while the plot that has the best crop conditions is plot 19. The plot with the highest plant height is plot 20, with an average plant height of 76.98cm. In contrast, the plot with the lowest plant height was plot 7, with an average plant height of 68.01 cm. Overall, the average plant height is good, namely 73.84 cm.

Small genome size and variation in ploidy levels support the naturalization of vascular plants but constrain their invasive spread.

Karyological characteristics are among the traits underpinning the invasion success of vascular plants. Using 11 049 species, we tested the effects of genome size and ploidy levels on plant naturalization (species forming self-sustaining populations where they are not native) and invasion (naturalized species spreading rapidly and having environmental impact). The probability that a species naturalized anywhere in the world decreased with increasing monoploid genome size (DNA content of a single chromosome set). Naturalized or invasive species with intermediate monoploid genomes were reported from many regions, but those with either small or large genomes occurred in fewer regions. By contrast, large holoploid genome sizes (DNA content of the unreplicated gametic nucleus) constrained naturalization but favoured invasion. We suggest that a small genome is an advantage during naturalization, being linked to traits favouring adaptation to local conditions, but for invasive spread, traits associated with a large holoploid genome, where the impact of polyploidy may act, facilitate long-distance dispersal and competition with other species.

Invasive clonal plants possess greater capacity for division of labor than natives in high patch contrast environments.

Invasion success of clonal plants is closely related to their unique clonal life history, and clonal division of labor is a crucial clonal trait. However, so far, it is unclear whether invasive alien clonal species generally possess a greater capacity for division of labor than native species and whether this pattern is affected by environmental conditions. To test whether patch contrast affects the differences in the capacity for division of labor between invasive alien and native clonal plants, we selected five pairs of exotic invasive and native clonal plant species that are congeneric and co-occurring in China as experimental materials. We grew the clonal fragment pairs of these invasive and native plants under high, low, or no contrast of reciprocal patchiness of light and nutrient, respectively, with ramet connections either severed (division of labor prevented) or kept intact (division of labor allowed). The results showed that connection significantly decreased the proportion of biomass allocated to roots in distal (younger) ramets, whereas it increased in proximal (older) ramets of all studied plants under high -contrast treatments. This clear pattern strongly indicated the occurrence of division of labor. Furthermore, the connection had a more pronounced effect on the pattern of biomass allocation of invasive alien plants, resulting in a greater increase in biomass for invasive alien plants compared to native plants. These findings suggest that the invasive alien plants possess a greater capacity for division of labor, which may confer a competitive advantage to them over natives, thus facilitating their invasion success in some heterogeneous habitats such as forest edges where light and soil nutrients show a high negative correlation.

Reforestation of high elevation pines: Direct seeding success depends on seed source and sowing environment.

Forest persistence in regions impacted by increasing water and temperature stress will depend upon species' ability to either rapidly adjust to novel conditions or migrate to track ecological niches. Predicted, rapid climate change is likely to outpace the adaptive and migratory capacity of long-lived isolated tree species, and reforestation may be critical to species' persistence. Facilitating persistence both within and beyond a species' range requires identification of seed lots best adapted to the current and future conditions predicted with rapid climate change. We evaluate variation in emergent seedling performance that leads to differential survival among species and populations for three high elevation five-needle pines. We paired a fully reciprocal field common garden experiment with a greenhouse common garden study to (1) quantify variation in seedling emergence and functional traits, (2) ask how functional traits affect performance under different establishment conditions, and (3) evaluate whether trait and performance variation demonstrates local adaptation and plasticity. Among study species-limber, Great Basin bristlecone, and whitebark pines-we found divergence in emergence and functional traits, though soil moisture was the strongest driver of seedling emergence and abundance across all species. Generalist limber pine had a clear emergence advantage as well as traits associated with drought adaptation, while edaphic specialist bristlecone pine was characterized by low emergence yet high early survival once established. Despite evidence for edaphic specialization, soil characteristics alone did not explain bristlecone success. Across species, trait-environment relationships provided some evidence for local adaptation in drought-adapted traits, but we found no evidence of local adaptation in emergence or survival at this early life stage. For managers looking to promote persistence, sourcing seed from drier environments is likely to impart greater drought resistance into reforestation efforts through strategies such as greater root investment, increasing the probability of early seedling survival. This research demonstrates, through a rigorous reciprocal transplant experimental design, that it may be possible to select climate- and soil-appropriate seed sources for reforestation. However, planting success will ultimately rely on a suitable establishment environment, requiring careful consideration of interannual climate variability for management interventions in these climate and disturbance-impacted tree species.

Federal agency perspectives and funding opportunities for weed and invasive plant research

Weeds and invasive plants know no borders and have collectively impacted many ecosystems worldwide, including croplands, forests, grasslands, rangelands, wetlands, and riparian areas. Losses continue to mount, affecting yield and productivity, species diversity, and ecosystem services, with both short- and long-term repercussions on the sustainability of plant and animal communities and the livelihoods of many. New and emerging invasive plants, along with many of the most intractable weeds, have undermined even the best control efforts, serving as a reminder of the constant need for improvements in science, application, and technology. One of the main reasons for the success of weeds and invasive plants is their ability to adapt to abiotic and biotic conditions, and research suggests that this will continue with minimal change.

Determining the causal factors affecting the survival of young plantations in Udayapur, Nepal

Abstract. Ayer S, Bhandari Y, Gautam A, Gautam J. 2023. Determining the causal factors affecting the survival of young plantations in Udayapur, Nepal. Asian J For 7: 93-99. The plantation is a form of land management and rehabilitation to reverse land degradation, and the survival rate of seedlings is a critical factor for a successful plantation. This study aimed to investigate the survival rate of seedlings in ten plantation sites in Udayapur District, Nepal and identify the major causes of seedling mortality and stunted growth. Planting was done in April/May of 2020 and the total count of the seedlings was done in January/February 2021. Square plots of 5m x 5m each were used for inventory using systematic random sampling with 0.1% sampling intensity. Direct field observation and interviews with officials, heralu, and community forest users were conducted to identify reasons behind seedlings' mortality and stunted growth. The results showed that the overall survival rate of seedlings in the study site was 36.02%. However, site-wise survival rates varied significantly, with Paluwatar CF having the highest survival rate of 87.73% and Sunkoshi CF having the lowest survival rate of 10.76%. Species-wise survival rates also varied, with Syzygium cumini having the highest survival rate of 80% and Cassia siamea having the lowest survival rate of 5.55%. The major causes of seedling mortality were found to be soil composition and quality (38%), drought (27%), and plant diseases (12%). In addition, carelessness during handling, transportation, and after plantation (21%) were identified as the major causes of stunted growth. This study provides valuable insights into the factors affecting seedling survival and growth in a plantation site, which can be used to guide future plantation efforts. However, further research is needed to understand the complex interactions between different factors better and develop effective strategies for improving seedling survival and growth.

Assessment of farmers’ preferences for growing particular crops and the correlation with land suitability

The success of agricultural operations is highly dependent on the site selected, which affects sustainability, and it is important to solve problems associated with activities and efficient land use. However, many researchers have selected sites based solely on climate and soil characteristics and have ignored farmer preferences, which has resulted in the failure to meet sustainable agriculture goals, and a proper strategy is therefore required to anticipate related problems. This study was conducted to: (1) analyze plantation development priorities based on the hierarchy of farmers’ preferences, (2) identify the relationship between successful plantations, climate, and soil fertility. The attributes employed to assess farmers’ preferences included price, production, and price stability over the past five years, while annual rainfall, annual temperature, and soil fertility were used to assess land suitability. Farmers’ preferences were analyzed using the discrete choice experiment (DCE) method, and land suitability was analyzed using the fuzzy method. The farmer preference analysis showed that coffee was the priority crop of farmers in most of the research areas, and cocoa was the lowest cultivation priority. Coffee had a higher land suitability index than other plants, ranging from 0.62 to 0.92, and it was dominant within the optimal suitability class. Clove, pepper, and cocoa plants belonged to the moderate land suitability class with indexes of 0.6–0.91, 0.56–0.88, and 0.4–0.86 for pepper, clove, and cocoa, respectively. A regression analysis was conducted to determine the relationship between the priority of cultivated plants based on farmers’ preference and land suitability, and a positive relationship (moderate strength) was determined. These research results show that when selecting priority crops, 21% of farmers’ decisions are influenced by land suitability.

Contrasting responses to climate variability generate seasonal priority effects between native and invasive forest herbs

Abstract Invasive plants are often characterized by rapid germination and precocious phenology. Theory suggests that early germination may provide invaders with a competitive advantage over slower germinating natives, but the relative contribution of rapid germination versus other intrinsic competitive traits (e.g. rapid growth, high fecundity, broad environmental tolerance) to the success of invaders is poorly understood. Depending on the relationship between germination and competition, shifts in germination phenology due to climate change may increase the dominance of invaders or buffer communities against their impacts. We investigated the link between temperature variation, germination phenology and competitive interactions with a sequence of controlled environment experiments. First, we evaluated the relationships between temperature variation and germination phenology for two herbaceous species found in North American woodlands, the non‐native Hesperis matronalis and native Cryptotaenia canadensis. We then leveraged temperature‐response differences to manipulate the relative germination phenology of these taxa and quantified the effects of their phenological differences on competition. Seeds of the invasive H. matronalis germinated rapidly, reaching 50% germination in under 10 days in all treatment combinations. C. canadensis did not reach 50% germination with less than 7 weeks of cold stratification. However, with more than 10 weeks of cold stratification and low (20/10°C) incubation temperatures, the germination phenology of C. canadensis was well‐matched to that of H. matronalis. When grown together, we found that precocious germination phenology doubled the competitive impact of H. matronalis relative to its other intrinsic competitive traits. Phenological advantage of just 2–3 days relative to C. canadensis was enough to secure competitive dominance at the seedling stage. Synthesis. This study revealed that the mechanistic link between the germination phenology and competitive success of an invasive plant can be strongly mediated by climate sensitivity differences between introduced and native species. Climate change will likely exacerbate these differences, especially in regions where warming reduces cold stratification. Our findings suggest that phenological diversity in native plant communities is an important property of invasion resistance. The relationship between environmental variation, germination dynamics and competition provides a path forward for forecasting climate change impacts on seasonal community assembly and highlights the need to incorporate phenological diversity in restorations.

Synthesis of plant-soil feedback effects on eastern North American tree species: implications for climate-adaptive forestry

Climate change represents an existential threat to many forest ecosystems because tree populations are often adapted to local climate means and variability. If tree populations cannot migrate or adapt, they risk becoming increasingly maladapted with climate change. This emerging mismatch underscores the need for climate adaptive management techniques, such as assisted migration of tree species, to help mitigate climate change impacts on forest ecosystems. Although biotic and abiotic factors are known to constrain tree establishment success, the extent to which they may determine the success of assisted migration plantings is poorly understood. Thus, defining the extent to which trees affect—and in turn are affected by local soil environments and microbial communities (i.e., plant-soil feedbacks; hereafter PSFs) remains important for guiding effective climate-adaptive forest management. Our objectives were to synthesize the current state of knowledge about the direction and magnitude of PSF effects on temperate tree species of eastern North America, and to identify key hypotheses important for guiding future research. To accomplish these goals, we conducted a meta-analysis of 26 peer-reviewed publications that addressed our criteria. Our compiled database included 61 tree species and was composed primarily of short-term greenhouse experiments that studied PSF effects by manipulating the soil biota in three ways: (1) soil was previously inoculated by a conspecific or heterospecific tree species (i.e., home vs. away), (2) soil was live or sterilized, or (3) soil was untreated or treated with fungicide. We found that PSF had significant effects on tree growth, with the direction and magnitude of PSF strongly dependent on tree mycorrhizal guild. Arbuscular mycorrhizal tree species grown in live or home soils grew 13–33% less than those in sterile or away soils, while ectomycorrhizal tree species grew 11–44% more in live or home than sterile or away soils. PSF effects were associated with several plant functional traits, including specific leaf area, tissue nitrogen, and specific root length. We provide suggestions on incorporating PSFs into assisted migration trials and outline key knowledge gaps for future research. Our synthesis of context-dependent effects of PSFs on tree performance will help inform management decisions involving assisted migration.

The ever-tenuous success of plants engineered to kill insect foes

The ever-tenuous success of plants engineered to kill insect foes