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Plant stoichiometry and nutrient allocation can reflect a plant's adaptation to environmental nutrient changes. However, the allocation strategies of carbon (C), nitrogen (N), and phosphorus (P) between leaf and fine root in response to wildfire have been poorly studied. Our primary objective was to elucidate the trade-off of elemental allocation between above- and belowground parts in response to the soil nutrient changes after a wildfire. We explored the allocation sloping exponents of C, N, and P between leaf and fine root at the species and community levels at four recovery periods (year 2, 10, 20, and 30) after moderately severe wildfire and one unburned treatment in boreal forests in Great Xing'an Mountains, northeast China. Compared with the unburned treatment, leaf C concentration decreased and fine root C increased at year 2 after recovery. The leaf N concentration at year 10 after recovery was higher than that of unburned treatment. Plant growth tended to be limited by P concentration at year 10 after recovery. Nutrient allocation between leaf and fine root differed between species and community levels, especially in the early recovery periods (i.e., 2 and 10 years). At the community level, the nutrient concentrations of the leaf changed more as compared to that of the fine root at year 2 after recovery when the fine root nutrients changed more than those of the leaf. The different C, N, and P allocation strategies advanced the understanding of plant adaptation to soil nutrient changes during the postfire ecosystem restoration. [ABSTRACT FROM AUTHOR]

Wildfire is crucial in the regulation of nutrient allocation during the succession of boreal forests. However, the allocation strategies of carbon (C), nitrogen (N) and phosphorus (P) between leaves and fine roots in response to wildfire severities remain poorly studied. We aimed to explore the allocation strategies of C, N and P between leaves and fine roots among different fire severities. We selected four wildfire severities (unburned, low, moderate and high severity) after 10 years recovery in the Great Xing'an Mountains, northeast China, and compared C, N and P concentrations in leaves and fine roots of all species among fire severities using stoichiometry theory and allometric growth equations. Compared with unburned treatment, C concentrations in leaves and fine roots increased at low severity, and leaf N concentration was the greatest at high severity, but the lowest fine root N concentration occurred at high severity. Plant nutrient utilization tended to be P-limited at high fire severity according to the mean value of N:P ratio > 16. More importantly, C, N and P allocation strategies between fine roots and leaves changed from allometry to isometry with increasing fire severities, which showed more elements allocated to leaves than to fine roots with increasing fire severities. These changes in patterns suggest that the allocation strategies of elements between leaves and fine roots are of imbalance with the wildfire severity. This study deepens our understanding of nutrient dynamics between plant and soil in ecosystem succession. [ABSTRACT FROM AUTHOR]

The relationship between plants and the environment is a core area of research in ecology. Owing to differences in plant sensitivity to the environment at different life history stages, the adaptive strategies of plants are a cumulative result of both their life history and environment. Previous research on plant adaptation strategies has focused on adult plants, neglecting saplings or seedlings, which are more sensitive to the environment and largely affect the growth strategy of subsequent life stages. We compared leaf N and P stoichiometric traits of the seedlings, saplings, and adult trees of Acer mono Maxim and different altitudes and found significant linear trends for both life history stages and altitude. Leaf N and P content by unit mass were greatly affected by environmental change, and the leaf N and P content by unit area varied greatly by life history stage. Acer mono leaf N‐P utilization showed a significant allometric growth trend in all life history stages and at low altitudes. The adult stage had higher N‐use efficiency than the seedling stage and exhibited an isometric growth trend at high altitudes. The N‐P utilization strategies of A. mono leaves are affected by changing environmental conditions, but their response is further dependent upon the life history stage of the plant. Thus, this study provides novel insights into the nutrient use strategies of A. mono and how they respond to the environmental temperature, soil moisture content along altitude and how these changes differ among different life history stages, which further provide the scientific basis for the study of plant nutrient utilization strategy on regional scale. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wildfires change plant nutrient homeostasis (H- value) in different functional groups. • Woody plants exhibited strong H N (or H P) under nutrient limitation conditions. • H N and H P in woody plants jointly dominate community biomass accumulation after wildfire. As an essential part of the stoichiometric flexibility in regulating the relative tissue contents of nitrogen (N) or phosphorus (P), their homeostasis (H) could determine plant growth under changing nutrient environments, such as under wildfire disturbance. Although a growing number of studies have suggested a coupling relationship between plant nutrient H and species abundance, how leaf N and P homeostasis (H N and H P) regulates the accumulation of community biomass remains unclear, especially in nutrient-fluctuating burned areas. We measured leaf N and P concentrations and total biomass of all species and the soil N and P concentrations across 15 forest plots at four recovery periods (2, 10, 20, and 30 years after burning) with low-severity wildfire and one unburned treatment (>80 years after burning) in boreal forests and associated the community-level H N and H P with biomass accumulation in the Great Xing'an Mountains, China. We found that the H N of trees peaked 20 years after burning under N limitation conditions, and the H P of shrubs approached a maximum at 10 years after burning due to P limitation. It is worth noting that the biomass of trees and herbs was significantly positively correlated with H N , while negative relationships between H P and biomass were shown in trees. Nutrient H explained 59% of the total variation in community biomass, and the joint effect of H N and H P mainly contributed to the biomass accumulation of trees (43.5%) and shrubs (68.5%), respectively. These findings greatly improve the theoretical foundation for understanding how plant nutrient H is associated with biomass accumulation after wildfire. Flexible nutrient H in woody plants highlights the vital role of understory woody species in postfire forest management. Therefore, clearly understanding the relationship between nutrient H and carbon sequestration is essential for a thorough assessment of postfire forest sustainability. [ABSTRACT FROM AUTHOR]

Wildfire is the primary natural disturbance in boreal forest ecosystems. It substantially changes soil nutrient conditions and plant nutrient dynamics. After a wildfire, various plant strategies of nutrient utilization are fundamental to ecosystem recovery processes. Stability of plant nutrients reflects the ability of plants possessing relatively constant elemental concentrations in the face of nutrient changes, which can be calculated by the value of "nutrient homeostasis". However, the mechanism of how nutrient homeostasis mediates plant community recovery in post-fire ecosystems remains unknown. The dominant tree species that survived after fire and the new emergence of regenerated tree species are the important components of a plant community during the recovery process. Our primary objective was to elucidate the nutrient homeostasis trade-off between dominant and regenerated species over years after recovery. Five treatments, namely, 2 year, 10 year, 20 year, 30 years after moderate burning severity, and unburned forests, were designed in the boreal forests of Great Xing'an Mountains, Northeast China. Compared with unburned forests, wildfire lowered the average value of homeostasis of plant nutrients (N and P). Moreover, the mean homeostasis value of the dominant species (i.e., Larix gmelinii) was higher than that of the regenerated species (i.e., Betula platyphylla). The slope of relationship between nutrient homeostasis and recovery years of the regenerated species was higher than that of the dominant species, suggesting that the nutrient homeostasis in the regenerated species recovered more quickly than dominant species after recovery. Compared with the dominant species, changes in the regenerated species' homeostasis can explained more to the changes of species diversity during the years after recovery. This study revealed plant nutrient adaptation in different species and different plant organs with years after wildfire and highlighted the importance of nutrient homeostasis in plant adaptation strategies and the recovery of plant community. • 'Homeostasis' shows as an ability of plant to maintain relatively constant elemental content when soil nutrient changes. • Wildfire lowered the average value of plant nutrient homeostasis. • Nutrient homeostasis of regenerated species recovered more quickly than that of dominant species. • Changes in nutrient homeostasis of regenerated species contributed more to diversity recovery than that of dominant species. [ABSTRACT FROM AUTHOR]

Competition between plants has an important role during the natural succession of forest communities. Niche separation between plants can reduce such interspecific competition and enable multispecies plant to achieve coexistence, although this proposition has rarely been supported in experiments. Plant competition can be captured by spatial segregation of the competing species to avoid fierce direct conflicts for nutrients and light. We investigated a site of 400 m × 1000 m in Beijing Pine Mountain National Nature Reserve that was established for protecting Chinese pine and some rare fungi. Six dominant tree species (Fraxinus chinensis Roxb., Syringa reticulata (Blume) H. Hara var. amurensis (Rupr.) J. S. Pringle, Quercus mongolica Fisch. ex Ledeb., Armeniaca sibirica (L.) Lam., Pinus tabuliformis Carrière, and Ulmus pumila L.) were individually marked. Metrics of spatial segregation, based on the theory of spatial point process, were calculated to detect spatial competition. The corresponding type (species)-specific probabilities and the p-values from a spatially implicit test revealed significant overall spatial segregation between the six tree species. We further used the cross-type L-function to check the spatial correlation between Chinese pine and the other tree species, and detected a significant spatial repulsion relationship with four other tree species. Our study shows that each of the six dominant tree species occupies a different subarea in the landscape to effectively reduce direct spatial competition. We thus argue that patchy distributions of different tree species could be common in late forest community succession, and the coexistence of plants could be maintained over a large spatial scale. Management intervention, such as thinning the densities of dominant tree species, could be used to foster species coexistence and ensure the productivity of commercial stands. [ABSTRACT FROM AUTHOR]