Evergreen Broad-leaved Tree Species Research Articles

Sound Absorption Property of the Leaves of Two Evergreen Broad-Leaved Tree Species, Dendropanax morbiferus and Fatsia japonica

In this study, the effect of specimen size and layer thickness on the sound absorption of the leaves of two evergreen broad-leaved tree species, Dendropanax morbiferus and Fatsia japonica, was investigated. The specimen sizes of 0.5 × 0.5, 1.0 × 1.0, and 2.0 × 2.0 cm2 and layer thicknesses of 1.00, 1.75, and 2.50 cm were considered. At the layer thickness of 2.5 cm, the leaf of the D. morbiferus showed no significant difference in sound absorption coefficients (SACs) as the sample size varied, however, a significant change in SACs was recorded in that of the F. japonica. At 1.0-cm thickness, the SACs of the F. japonica leaf varied more remarkably with the sample size. The 2.50-cm-thick F. japonica leaf with the specimen size 0.5 × 0.5 cm2 exhibited the highest sound absorption effect among all samples investigated.

Intraspecific variation in spring leaf phenology and duration of leaf expansion in relation to leaf habit and leaf size of temperate tree species

Spring leaf phenology has been intensively studied in temperate deciduous broad-leaved tree species, but the phenology of evergreen broad-leaved tree species has seldom been focused on. Evaluation of the difference in spring leaf phenology between coexisting deciduous and evergreen species is essential to predict their responses to climate change. In this study, spring leaf phenology was investigated for the 12 deciduous and 12 evergreen broad-leaved species coexisting in a warm-temperate forest in Japan, based on the predictions that selection pressure for earlier leaf production in spring results in less intraspecific variation in phenology at a given timing (SDmax) and a shorter duration of leaf expansion in deciduous than in evergreen species. In contrast to this prediction, SDmax did not differ between deciduous and evergreen species and was not related to leaf area or LMA. On the other hand, the duration of leaf expansion was longer in evergreen than in deciduous species, and was positively correlated with LMA. The leaves of greater LMA required longer periods of leaf expansion, probably due to a higher cost of and/or more conservative leaf development in the face of herbivory. As a consequence, the timing of full leaf expansion was delayed not only by later budburst (approximately two weeks) but also by a longer duration of leaf expansion (approximately two weeks) in evergreen than in deciduous broad-leaved species, which would probably influence the productivity of newly emerging leaves in spring.

An atmospheric pollutant (inorganic nitrogen) alters the response of evergreen broad-leaved tree species to extreme drought

Drought and nitrogen (N) deposition are important components of global climate and environmental change. In this greenhouse study, we investigated the ecophysiological responses of the seedlings of three subtropical forest plant species (Schima superba, Castanopsis fissa, and Michelia macclurei) to short-term experimental drought stress, N addition, and their interaction. The results showed that drought stress reduced the activities of antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)] and total antioxidant capacity (T-AOC), but increased the malondialdehyde (MDA), abscisic acid (ABA), and proline (PRO) contents in plants. The PRO content, T-AOC, and antioxidant enzyme activities were increased, and ABA and MDA contents were decreased by N addition alone. Furthermore, N addition under drought stress increased antioxidant enzymes activities, PRO content, and T-AOC. The treatments, however, did not significantly affect the chlorophyll fluorescence parameters of the species. T-AOC was positively correlated with antioxidant enzyme activities in each species, indicating that antioxidant enzymes were important for plant resistance to oxidative stress. MDA content increased with the increase of ABA content, indicating that ABA may help regulate stomatal movement and drought-induced oxidative injury in plants. T-AOC was positively correlated with PRO content, probably because PRO participated in osmotic regulation of cells and increased osmotic stress resistance. These results indicate that N addition can reduce drought stress of subtropical forest plants and will help researchers predict how evergreen broad-leaved forests will respond to global change in the future.

Changes of Cinnamomum camphora root characteristics and soil properties under ozone stress in South China.

High O3 exposure affects the forest growth and soil characteristics. Although there is substantial evidence that O3 does impose a stress on forest trees, the effects of O3 on roots and soil of evergreen broad-leaved tree species in South China remain unknown. The effects of ozone (O3) fumigation on the root biomass, root morphology, root nutrient, soil physical, and chemical properties were examined in Cinnamomum camphora seedlings grown under four O3 treatments (charcoal-filtered air (CF) or O3 at 1×, 2× and 4× ambient concentration). O3 significantly decreased root biomass and root carbon (C). Regardless of O3 level, elevated O3 significantly resulted in reduced root surface area, volume, number of forks, and specific root length (SRL). The percentages of fine to total root in terms of root surface area and root volume of seedlings under the CF and 1 × O3 treatments were significantly higher than those of seedlings under the 4 × O3 treatment, indicating that high O3 level impaired the growth performance of fine roots. O3 affected root growth and structures, which increased soil bulk density and reduced soil total porosity and void ratio. The soil pH under all O3 fumigation treatments significantly increased compared with CF treatment, whereas the organic matter significantly decreased. In conclusion, although the increased O3 level enhanced root N and P under 2 and 4 × O3 treatments compared with 1 × O3 treatment as compensation mechanisms to prevent O3-induced decrease in root C gain and root functions, O3 still decreased the root biomass and root tips, and changed the soil physical and chemical properties.

Photosynthesis of three evergreen broad-leaved tree species, Castanopsis sieboldii, Quercus glauca, and Q. myrsinaefolia, under elevated ozone

Abstract: The main goal of this study was to obtain detailed information on photosynthetic responses of evergreen broad-leaved tree species to ozone (O3). For this, two-year-old seedlings of Castanopsis sieboldii, Quercus glauca, and Q. myrsinaefolia were grown for one growing season, from 15 May to 27 October 2014 under three levels of gas treatments, charcoal-filtered air and 1.0 time and 1.5 times ambient O3 concentrations. We analysed the intercellular CO2 concentration-response curve of the net photosynthetic rate, i.e., the A/Ci curve, in July and October, and growth measurement was carried out at the end of the experiment in October. We observed a difference in O3 susceptibility among the species. Negative effects of O3 were observed on the growth and photosynthetic traits of C. sieboldii, while no significant effects on these traits were noted in the two Quercus species. The decrease in light-saturated net photosynthetic rate (Asat) of C. sieboldii under elevated O3 was accompanied with a significant decrease in the maximum rate of carboxylation (Vcmax). Decreases of leaf nitrogen content and nitrogen use efficiency to Rubisco are considered as factors contributing to lower Vcmax in C. sieboldii seedlings under elevated O3. In addition to the decrease in Vcmax, O3 exposure induced marginal increase of stomatal limitation of photosynthesis. These results indicate that both biochemical and diffusion processes in photosynthesis are responsible for the decrease in Asat of C. sieboldii under elevated O3.

A paradox of latitudinal leaf defense strategies in deciduous and evergreen broadleaved trees

The classical “low latitude–high defense” hypothesis is seldom supported by empirical evidence. In this context, we tested latitudinal patterns in the leaf defense traits of deciduous broadleaved (DB) and evergreen broadleaved (EGB) tree species, which are expected to affect herbivore diversity. We examined the co-occurrence of leaf defense traits (tannin and phenol content, leaf mechanical strength, leaf dry matter content, leaf mass per area, and leaf thickness) in 741 broadleaved tree species and their correlations with species geographical range in East Asian island flora. We discovered contrasting latitudinal defense strategy gradients in DB and EGB tree species. DB species employed chemical defenses (increasing tannin and phenol content) at higher latitudes and physical defenses (softer and thinner leaves) at lower latitudes, whereas EGB tree species exhibited opposite latitudinal defense patterns. The “low latitude high defense” hypothesis included a paradoxical aspect in chemical and physical defense traits across broadleaved tree species. To reconcile paradoxical defense strategies along the latitudinal gradient, we conclude that interactive correlations among leaf traits are controlled by leaf longevity, which differs between DB and EGB tree species.

Plant community type and site conditions of coastal forests consisting of evergreen broad-leaved tree species in warm temperate zone in south-west Japan

Plant community type and site conditions of coastal forests consisting of evergreen broad-leaved tree species in warm temperate zone in south-west Japan

Impact of environmental factors on the decoupling coefficient and the estimation of canopy stomatal conductance for ever-green broad-leaved tree species

Impact of environmental factors on the decoupling coefficient and the estimation of canopy stomatal conductance for ever-green broad-leaved tree species

Evaluation of Photosynthetic Ability in Two Representative Evergreen Broad-leaved Tree Species in Korea

Evaluation of Photosynthetic Ability in Two Representative Evergreen Broad-leaved Tree Species in Korea

Leaf habit of tree species does not strongly predict leaf litter decomposition but alters climate-decomposition relationships

Leaf habit of tree species (evergreen versus deciduous) is proposed to be an important determinant of leaf litter decomposition, but it remains largely understudied as to how climatic regulation of litter decomposition differs between leaf habits. We isolated the relative role of climate and leaf habit in leaf litter decomposition by investigating the latitudinal pattern of leaf litter decomposition for Chinese broad-leaved tree species. Litter decomposition rate decreased with latitude, which was largely driven by mean annual temperature (MAT). Evergreen and deciduous broad-leaved tree species shared similar decomposition rate where they coexisted. Leaf litter decomposition of evergreen broad-leaved tree species was more sensitive to MAT than that of the deciduous species, whereas leaf litter decomposition of the deciduous trees was more sensitive than that of the evergreen to mean annual precipitation. Climatic variables explained more variation in leaf litter decomposition than did leaf habit alone. Our findings support the conventional paradigm that climate is a dominant regulator of leaf litter decomposition over broad geographical scales, notwithstanding recent studies calling into question this paradigm. While leaf habit alone does not predict leaf litter decomposition very well where both evergreen and deciduous species coexisted, the direction and strength of shift in leaf litter decomposition diverged between leaf habits across the climatic gradient. These findings underscore the urgent need to consider the impacts of changes in leaf habits when predicting leaf litter decomposition in response to climate change.

Geographical and climatic gradients of evergreen versus deciduous broad-leaved tree species in subtropical China: Implications for the definition of the mixed forest.

Understanding climatic influences on the proportion of evergreen versus deciduous broad‐leaved tree species in forests is of crucial importance when predicting the impact of climate change on broad‐leaved forests. Here, we quantified the geographical distribution of evergreen versus deciduous broad‐leaved tree species in subtropical China. The Relative Importance Value index (RIV) was used to examine regional patterns in tree species dominance and was related to three key climatic variables: mean annual temperature (MAT), minimum temperature of the coldest month (MinT), and mean annual precipitation (MAP). We found the RIV of evergreen species to decrease with latitude at a lapse rate of 10% per degree between 23.5 and 25°N, 1% per degree at 25–29.1°N, and 15% per degree at 29.1–34°N. The RIV of evergreen species increased with: MinT at a lapse rate of 10% per °C between −4.5 and 2.5°C and 2% per °C at 2.5–10.5°C; MAP at a lapse rate of 10% per 100 mm between 900 and 1,600 mm and 4% per 100 mm between 1,600 and 2,250 mm. All selected climatic variables cumulatively explained 71% of the geographical variation in dominance of evergreen and deciduous broad‐leaved tree species and the climatic variables, ranked in order of decreasing effects were as follows: MinT > MAP > MAT. We further proposed that the latitudinal limit of evergreen and deciduous broad‐leaved mixed forests was 29.1–32°N, corresponding with MAT of 11–18.1°C, MinT of −2.5 to 2.51°C, and MAP of 1,000–1,630 mm. This study is the first quantitative assessment of climatic correlates with the evergreenness and deciduousness of broad‐leaved forests in subtropical China and underscores that extreme cold temperature is the most important climatic determinant of evergreen and deciduous broad‐leaved tree species’ distributions, a finding that confirms earlier qualitative studies. Our findings also offer new insight into the definition and distribution of the mixed forest and an accurate assessment of vulnerability of mixed forests to future climate change.

Latitudinal Patterns and Climatic Drivers of Leaf Litter Multiple Nutrients in Chinese Broad-Leaved Tree Species: Does Leaf Habit Matter?

Leaf litter nutrients play a key role in nutrient cycling in forest ecosystems, yet our current knowledge of the ways in which climate controls leaf litter nutrients remains uncertain, especially for broad-leaved tree species in China. We performed a meta-analysis of geographic patterns of leaf litter nutrients of Chinese broad-leaved tree species in relation to climatic variables and leaf habit (as a discrete classification of tree species). We found that mean leaf litter carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were 458.36, 10.11, 0.72, 6.37, 14.22 and 2.59 mg−1 g, respectively. Leaf litter nutrients did not diverge between leaf habits where they coexisted. These leaf litter nutrients displayed significant latitudinal trends, partly driven by climatic factors and a shift in leaf habit. Mean annual precipitation explained the largest amount of total variation in leaf litter C, N, P and K, and mean annual temperature was the most important predictor for leaf litter Mg, whereas leaf habit was the largest contributor to total variation in leaf litter Ca. We further found that the relationships between climate and leaf litter nutrients were distinguishable for evergreen and deciduous broad-leaved tree species. Collectively, our study differed from previous studies that evaluated leaf litter nutrients and only focused on N and P, and substantiated that leaf litter nutrients in forest ecosystems were affected by climate and leaf habit, but the strengths of the influences of these factors were strongly contingent on leaf litter nutrient identity. Therefore, alteration of climate would directly and indirectly (via a shift in species composition) affect latitudinal patterns of leaf litter nutrients and thus the associated nutrient flux and ecosystem functioning. Our study also underlined the need to include multiple nutrients to explore the influence of climate on leaf litter nutrient stoichiometry.

Cold resistance of four evergreen broad-leaved tree species

The leaves of four evergreen plants, i.e., Fatsia japonica, Nerium indicum, Mahonia bealei and Acer cinnamomifolium were used as the experimental materials. By measuring the changes of in vitro leaf in soluble sugar, soluble protein, free proline, POD activity, chlorophyll content and relative electrolytic conductivity under aritificial simulated low temperature, combining the measurements of SPAD, leaf surface features and anatomical changes in organizational structure in the process of natural wintering, the cold resistance of four evergreen tree species was evaluated comprehensively. The results showed that in the process of artificial low temperature stress, the chlorophyll content of the leaves of four evergreen species decreased, the content of soluble protein pea-ked at -20 ℃, and the soluble sugar, free proline, POD activity and relative electrolytic conductivity showed an overall upward trend. The semilethal temperatures of four species were -8.0, -13.4, -19.4 and -14.8 ℃, respectively. During the winter, the leaf SPAD of the four species changed markedly, reflecting that the change of relative chlorophyll content was related to the change of temperature. Meanwhile, the leaf thickness, cutin layer thickness, stockade tissue thickness and tightness of four species increased and the plasmolysis occurred thereafter. Also the content of starch grains and calcium oxalate cluster crystal increased. The typical stomatal pits and the intensive non-glandular trichome within the pits of N. indicum and the sclerenchyma of M. Bealei could improve the cold resistance of plants to some extent. In addition, the phenomena like the breakage of wax layer in leaf surface, the fracture of epidermal hair and the deformation of palisade tissue indicated that plants were damaged to a certain extent by low temperature.

Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest.

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as βNRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.

Disentangling long- and short-term changes in perennial organ functions in seasonal environments: A model of foliar chlorophyll and nitrogen in saplings of four evergreen broad-leaved trees

Perennial organ functions of trees living in seasonal environments exhibit temporal changes that can be classified as long-term interannual changes and seasonal fluctuations within single years. However, few studies have separately quantified these changes from longitudinal measurement data or analyzed the relationships between them. We developed a hierarchical Bayesian statistical model consisting of three parts: a long-term interannual change expressed by consecutive annual linear trends, seasonal fluctuations with 26 values for two-week periods in a year, and a random effect for repeated measurements. The model can extract long-term interannual changes and seasonal fluctuations from longitudinal repeated measure data. The pattern of seasonal fluctuation, the amount of seasonal fluctuation, and the net annual change are expressed by the estimated model parameters. We applied our model to foliar chlorophyll (Chl) and nitrogen (N) content measured repeatedly on more than 1-year-old leaves of saplings in four evergreen broad-leaved tree species using nondestructive optical methods. The model successfully explained large variations in the Chl and N content. In general, seasonal fluctuations corresponded to the phenology of current-year leaves; Chl and N tended to decrease from the opening to maturation of new leaves and increased during the rest period. The magnitude of the decrease in the Chl and N content in the growth period of current-year leaves (Δγ) did not decrease noticeably as leaves aged. For the Chl content, Δγ was positively correlated with the maximum value before leaf opening across species. For the N content, Δγ and the maximum value before leaf opening were not clearly correlated across species, but were positively correlated within some species. A model parameter for annual linear trends in Chl and N varied from positive (indicating increasing trends) to negative values (indicating decrease) depending on species and leaf age in years.

Architectural differences among shaded saplings of four evergreen broad-leaved tree species in Japan.

Architectural differences among shaded saplings of four evergreen broad-leaved tree species in Japan.

Leaf morphology of 40 evergreen and deciduous broadleaved subtropical tree species and relationships to functional ecophysiological traits.

We explored potential of morphological and anatomical leaf traits for predicting ecophysiological key functions in subtropical trees. We asked whether the ecophysiological parameters stomatal conductance and xylem cavitation vulnerability could be predicted from microscopy leaf traits. We investigated 21 deciduous and 19 evergreen subtropical tree species, using individuals of the same age and from the same environment in the Biodiversity-Ecosystem Functioning experiment at Jiangxi (BEF-China). Information-theoretic linear model selection was used to identify the best combination of morphological and anatomical predictors for ecophysiological functions. Leaf anatomy and morphology strongly depended on leaf habit. Evergreen species tended to have thicker leaves, thicker spongy and palisade mesophyll, more palisade mesophyll layers and a thicker subepidermis. Over 50% of all evergreen species had leaves with multi-layered palisade parenchyma, while only one deciduous species (Koelreuteria bipinnata) had this. Interactions with leaf habit were also included in best multi-predictor models for stomatal conductance (gs ) and xylem cavitation vulnerability. In addition, maximum gs was positively related to log ratio of palisade to spongy mesophyll thickness. Vapour pressure deficit (vpd) for maximum gs increased with the log ratio of palisade to spongy mesophyll thickness in species having leaves with papillae. In contrast, maximum specific hydraulic conductivity and xylem pressure at which 50% loss of maximum specific xylem hydraulic conductivity occurred (Ψ50 ) were best predicted by leaf habit and density of spongy parenchyma. Evergreen species had lower Ψ50 values and lower maximum xylem hydraulic conductivities. As hydraulic leaf and wood characteristics were reflected in structural leaf traits, there is high potential for identifying further linkages between morphological and anatomical leaf traits and ecophysiological responses.

Modeling qualitative and quantitative elements of branch growth in saplings of four evergreen broad-leaved tree species growing in a temperate Japanese forest

Factors influencing branch growth differed between a qualitative element (whether a branch grows) and a quantitative element (the amount of biomass accretion). We measured branch growth in saplings of four evergreen broad-leaved tree species growing in a temperate Japanese forest. A hierarchical Bayesian approach was used to model two elements of branch growth: a qualitative component [whether branches produce new annual shoots (ASn)] and a quantitative component (total ASn mass). The two components were influenced by somewhat different factors. The probability that a branch would produce ASn was affected by the total mass of previous-year annual shoots (total ASn–1 mass), branch age, relative branch height, canopy openness measured at the branch tip, maximum canopy openness within a single sapling, and the interaction between canopy openness and maximum canopy openness. The total ASn mass was influenced by the total ASn–1 mass, relative branch height, branch inclination, and maximum canopy openness. These two components of branch growth should be considered separately when tree architecture is modeled. In addition, we detected interactive responses among branches within individual saplings. The relative importance of interactive modular response and branch autonomy may differ depending on the status of plants, such as individual age, environmental conditions, and the timing of the measurements. We found considerable similarities in the responses of branch growth to the internal and environmental factors among the species studied. We also found some among-species differences in branch growth responses to the explanatory variables measured.

Changes in the potential habitats of 10 dominant evergreen broad-leaved tree species in the Taiwan-Japan archipelago

Ecosystem vulnerability to climate change remains elusive in the species-rich Taiwan-Japan archipelago. We predicted potential habitats (PHs) of ten dominant evergreen broad-leaved tree species by using the current and twenty potential climate change scenarios using generalised additive models. The presence/absence records of each species, extracted from vegetation database, were used as response variables. Four climatic and one spatial variables were used as explanatory variables. The results showed that the interaction terms of spatial variable, indicating historical range shifts or species interactions, restricted the distribution of all the target species as much as that by the each climatic variable. The PHs of all the target species were predicted to consistently increase, and in particular, to expand northward and upward to the cool temperate zone. However, the PHs were predicted to decrease within the range of 23.6–38.1 % in the Ryukyu Islands for Castanopsis sieboldii and Elaeocarpus japonica, respectively, and within the range of 32.4–42.3 % in Taiwan for Camellia japonica and Distylium racemosum, respectively. These findings suggest that the four species will be vulnerable at the southern range limits; however, the remaining six species will potentially increase within the PH areas in the future at all regions.

Transpiration and stomatal control: a cross-species study of leaf traits in 39 evergreen and deciduous broadleaved subtropical tree species

Key message Using an extensive dataset for 39 subtropical broadleaved tree species, we found traits of the leaf economics spectrum to be linked to mean stomatal conductance but not to stomatal regulation.