Cypress Forest Research Articles

Impact of Thinning and Contour-Felled Logs on Overland Flow, Soil Erosion, and Litter Erosion in a Monoculture Japanese Cypress Forest Plantation

Impact of Thinning and Contour-Felled Logs on Overland Flow, Soil Erosion, and Litter Erosion in a Monoculture Japanese Cypress Forest Plantation

Relationship between changes in ground surface elevation and surface soil movement in areas around horizontal step works made from thin logs in a Japanese cypress forest

Relationship between changes in ground surface elevation and surface soil movement in areas around horizontal step works made from thin logs in a Japanese cypress forest

Wet canopy photosynthesis in a temperate Japanese cypress forest.

This study aimed to reveal the mechanism and significance of wet canopy photosynthesis during and after rainfall in temperate coniferous ecosystems by evaluating the influence of abaxial leaf interception on wet canopy photosynthesis. We used the eddy covariance method in conjunction with an enclosed-path gas analyser to conduct continuous ecosystem CO2 flux observations in a Japanese cypress forest within the temperate Asian monsoon area over 3years. The observation shows that wet-canopy CO2 uptake predominantly occurred during the post-rainfall canopy-wet period rather than the during-rainfall period. Then, the measured canopy-wet net ecosystem exchange was compared with the soil-vegetation-atmosphere transfer multilayer model simulations under different parameter settings of the abaxial (lower) leaf surface wet area ratio. The multilayer model predicted net ecosystem exchange most accurately when it assumed the wet area ratio of the abaxial surface was 50% both during and after rainfall. For the wet canopy both during and after rainfall, the model overestimated CO2 uptake when it assumed no abaxial interception in the simulation, but underestimated CO2 uptake when it assumed that the entire abaxial leaf surface was wet. These results suggest that the abaxial surface of the Japanese cypress leaf is only partly wet to maintain stomatal openness and a low level of photosynthesis. These results allow for an evaluation of the effect of rainfall on forest carbon circulation under a changing climate, facilitating an improvement of ecosystem carbon exchange models.

Microbiota associated with urban forests.

Urban forests are essential for maintaining urban ecological stability. As decomposers, soil microorganisms play an indispensable role in the stability of urban forest ecosystems, promoting the material cycle of the ecosystems. This study used high-throughput sequencing technology to explore the bacteria in six forest stands, including Phyllostachys edulis (ZL), Metasequoia glyptostroboides (SSL), Cornus officinalis (SZY), mixed broad-leaved shrub forest (ZKG), mixed pine and cypress forest (SBL), and mixed broad-leaved tree forest (ZKQ). Meanwhile, the differences in fungal communities were investigated. The results show that ZL has the highest alpha diversity of bacterial communities, while its fungal community is the lowest; Proteobacteria is the most abundant bacterial phylum in the six forest stands; ZKQ has the highest fungal diversity. In addition, soil microbial communities are affected by environmental factors. Soil pH, organic matter (SOM), and available phosphorus (AP) significantly influence the compositions of urban forest soil microbial communities. This study revealed the differences in bulk soil (BS) microbial community structures among six forest stands and the relationship between environmental factors and soil microbial communities, which has important guiding significance for creating healthy and stable urban forests with profound ecological benefits.

Seasonal Changes in the Soil Microbial Community Structure in Urban Forests.

Urban forests play a crucial role in the overall health and stability of urban ecosystems. Soil microorganisms are vital to the functioning of urban forest ecosystems as they facilitate material cycling and contribute to environmental stability. This study utilized high-throughput sequencing technology to examine the structural characteristics of bacterial and fungal communities in the bulk soil of six different forest stands: Phyllostachys pubescens (ZL), Metasequoia glyptostroboides (SSL), Cornus officinalis (SZY), mixed broad-leaved shrub forest (ZKG), mixed pine and cypress forest (SBL), and mixed broad-leaved tree forest (ZKQ). Soil samples were collected from each forest stand, including the corners, center, and edges of each plot, and a combined sample was created from the first five samples. The results revealed that among the bacterial communities, ZKG exhibited the highest alpha diversity in spring, while ZL demonstrated the highest alpha diversity in both summer and autumn. Proteobacteria was the most abundant bacterial phylum in all six forest stand soils. The dominant fungal phylum across the six forest stands was identified as Ascomycota. Notably, the microbial community diversity of SBL bulk soil exhibited significant seasonal changes. Although ZL exhibited lower bacterial community diversity in spring, its fungal community diversity was the highest. The bulk soil microbial diversity of ZL and SSL surpassed that of the other forest stands, suggesting their importance in maintaining the stability of the urban forest ecosystem in the Zhuyu Bay Scenic Area. Furthermore, the diversity of the bulk soil microbial communities was higher in all six stands during spring compared to summer and autumn. Overall, this study provides valuable insights into the seasonal variations of bulk soil microbial communities in urban forests and identifies dominant tree species, offering guidance for tree species' selection and preservation in urban forest management.

Modelling effects of immediate rainfall on sap flux of Cypress trees in the Southwest Hilly area of China

Background The hilly region of the central Sichuan basin is one of the most severely affected areas in China in terms of soil and water loss. For this reason, a large area of mixed alder and cypress forest has been established for protection. However, the uneven distribution of rainfall significantly impacts the stability of water usage in the plantations. Therefore, accurately understanding the response of trees to real-time rainfall is essential for effective forests management that optimizes hydrology and water resources. Aims To examine how the sap flux of the cypress forest responds to environmental factors and develop response models for two different conditions.

Impact of typical land use type on the stability and content of carbon and nitrogen of soil aggregates in western Hubei

AbstractIn order to investigate the characteristics of soil structural stability and the factors influencing it under typical land use types in the karst region of western Hubei, soil samples were collected from five land use types (natural mixed forest [NF], cypress forest [CF], stone dike terrace [ST], stone dike forest [SF], and abandoned land [AL]) in Xialaoxi to analyze the particle size distribution of aggregates, structural stability, and the distribution characteristics of carbon, nitrogen, and extracellular enzyme contents. The results showed that the aggregates of NF, CF, SF, and AL were dominated by >2‐mm aggregates, while ST showed mostly 2–0.25‐mm aggregates. The mean weight diameter (EMWD) and the geometric mean diameter (EGMD) of mechanical aggregates showed a trend of CF > NF > SF > AL > ST, whereas the erodibility factor K showed an opposite trend. The total organic carbon (TOC), labile organic carbon (LOC), and total nitrogen (TN) contents of aggregates of each particle size were significantly higher in NF and CF than in ST and AL under the five land types. The content of available nitrogen (AN) was highest in NF and ST. The content of carbon and nitrogen and extracellular hydrolases (β‐glucosidase [BG], cellulose disaccharide hydrolase [CBH], β‐N‐acetyl‐aminoglucosidase [NAG], and leucine aminopeptidase [LAP]) in soil aggregates were mainly concentrated in <0.25–0.053‐mm aggregates. The variation in carbon and nitrogen abundance of each particle size agglomerate mainly originated from the LAP content of that particle size agglomerate and showed significant correlation. The partial least squares path models (PLS‐PM) showed that the main influences on the stability of soil aggregates in small watersheds were land use types, soil physical properties, carbon and nitrogen abundance, and extracellular enzyme activity. In conclusion, the structural stability of soil aggregates in Xialaoxi watershed is the result of the interaction between human disturbance and soil nutrient self‐cycling. In general, NF and CF have better soil aggregate stability and are conducive to soil carbon and nitrogen accumulation, whereas for later development and management of SF, ST, and AL sample plots, scientific cultivation means should be adopted, and attention should be paid to long‐term carbon and nitrogen accumulation and conservation.

Estimating Canopy Resistance Using Machine Learning and Analytical Approaches

Canopy resistance is a key parameter in the Penman–Monteith (P–M) equation for calculating evapotranspiration (ET). In this study, we compared a machine learning algorithm–support vector machine (SVM) and an analytical solution (Todorovic, 1999) for estimating canopy resistances. Then, these estimated canopy resistances were applied to the P–M equation for estimating ET; as a benchmark, a constant (fixed) canopy resistance was also adopted for ET estimations. ET data were measured using the eddy-covariance method above three sites: a grassland (south Ireland), Cypress forest (north Taiwan), and Cryptomeria forest (central Taiwan) were used to test the accuracy of the above two methods. The observed canopy resistance was derived from rearranging the P–M equation. From the measurements, the average canopy resistances for the grassland, Cypress forest, and Cryptomeria forest were 163, 346, and 321 (s/m), respectively. Our results show that both methods tend to reproduce canopy resistances within a certain range of intervals. In general, the SVM model performs better, and the analytical solution systematically underestimates the canopy resistances and leads to an overestimation of evapotranspiration. It is found that the analytical solution is only suitable for low canopy resistance (less than 100 s/m) conditions.

Response of soil organic carbon to forested wetlands in East China

Afforestation has been suggested as an ecosystem restoration approach for mitigating carbon loss after land-use changes. Understanding soil organic carbon (SOC) by conversion from abandoned aquaculture ponds to afforestation is crucial. We investigated soil organic carbon from a poplar (Populus spp., 19 years after planting, PS) plantation site with ditches and a pond cypress (Taxodium spp., 4 years after planting, TS) forest with non-ditches on abandoned aquaculture ponds in East China. Soils with three layers (0–10, 10–20, and 20–30 cm) were sampled. The results showed that there were no significant differences in SOC between soil layers for PS with 5.09 ± 2.27, 2.60 ± 0.59, and 6.94 ± 3.56 g kg−1, respectively; compared to TS with 4.16 ± 1.48, 3.31 ± 0.88, and 4.32 ± 1.41 g kg−1, respectively. However, significant differences of soil water contents (SWC) and bulk density (BD) were found between two sampling sites, and both BD and pH had significant negative relationships with SOC. It is suggested that low SWC resulting from the ditch could lead to a potential risk of SOC decomposition and offset the soil carbon sink by afforestation. Additionally, pond cypress might be a preferred species selection for ecosystem restoration in both soil carbon sink and landscape aesthetics.

PHOSPHORUS FRACTIONS AND ARBUSCULAR MYCORRHIZAL FUNGI AS INFLUENCED BY FOREST CONVERSION IN CENTRAL HIGHLANDS OF KENYA

<p><strong>Background:</strong> Forest conversion to other land use types lead to changes in soil physico-chemical properties and a reduction in soil fertility. Although forest conversion is extensively recognized to alter soil properties, the influence on distribution of soil phosphorus (P) fractions and abundance and diversity of soil biota is not well explored. <strong>Objective:</strong> To assess the effects of converting undisturbed natural forest to plantation forest (cypress), grazed pastures and potato fields on soil phosphorus (P) fractions and abundance and diversity of arbuscular mycorrhizal fungi (AMF) in Nyandarua County, Kenya. <strong>Methodology:</strong> Transects laid out in triplicate were established in each land use type. In potato fields and grazed pastures, transects measured 50 m with three sampling points established 15 m apart along each transect, each point measuring 1 m² divided into 25 grids with each grid being 400 cm². Transect length was increased to 150 m in forest sites due to relatively larger size of the area studied and sampling points were placed at 50 m apart, each point measuring 25 m² and divided into 1² m grids. Soil and plant samples were randomly collected from sampling points and were used to determine chemical properties, soil P fractions and AMF spore examination. Data were analyzed by analysis of variance (ANOVA). <strong>Results:</strong> Soil chemical properties were significantly (<em>p</em><0.001) higher in natural forest compared to potato fields, grazed pasture and cypress forest. On the contrary, readily labile and moderately labile P was higher in fields cultivated with potato (125.3 mg and 258.2 mg P kg<sup>-1</sup>, respectively) than in natural forest (51.1 mg and 95.3 mg P kg<sup>-1</sup>) and cypress forest (36.4 mg and 82.7 mg P kg<sup>-1</sup>, respectively). However, non-labile P was higher in natural forest (599.1 mg P kg<sup>-1</sup>) and lower in cypress forest (251.3 mg kg<sup>-1</sup>). Of the ten AMF genera identified, only <em>Glomus</em> and <em>Acaulospora</em> were significantly (<em>p</em><0.01) affected by land use change, where they were more abundant in fields cultivated with potato than the other three land use types. Land use type did not significantly influence diversity and richness in AMF. However, AMF composition varied across the land use types. <strong>Implication:</strong> Land use change may negatively affect soil chemical properties, enhance redistribution of soil P, and change AMF community composition, and this could have long-term implications on soil fertility. <strong>Conclusion:</strong> Land use change from natural ecosystems to croplands, grazed pastures and tree plantations alter soil chemical properties, AMF composition and spore abundance, and redistribute soil P fractions by increasing labile P and reducing non-labile P fractions showing that the type of land use chosen significantly influence soil physical and chemical properties and soil biodiversity.</p>

Effects of land use types on soil erodibility in a small karst watershed in western Hubei.

Soil erosion is a severe problem in the karst watershed, and analysis of soil erosion at the watershed scale is urgently needed. This study tried to estimate the soil erodibility factor (K-factor) using the Erosion Productivity Impact Calculator (EPIC) nomograph and evaluate the spatial distribution of the predicted K-factor in a karst watershed. Soil properties and K-factors of five land use types (NF: natural mixed forest, CF: cypress forest, EF: economic forest, ST: stone dike terrace, VF: vegetable land) in the Xialaoxi small watershed were compared and key factors affecting erodibility were analyzed. Results showed that (1) The erodibility K-factor was unevenly distributed within different site types and strongly influenced by anthropogenic activities. The soil K-factors of sample sites subjected to frequent human disturbance (ST, VF) were high, ranging from 0.0480-0.0520 thm2h/(MJmmhm2), while the soil K-factors of natural site types (NF, CF, and EF) were low, ranging from 0.0436-0.0448 thm2h/(MJmmhm2). (2) The soil texture in the Xialaoxi watershed was mostly loamy, and that of the agricultural areas frequently disturbed by agricultural practices (ST, VF) was silty loam. (3) Soil carbon fractions were affected by land use types. Soil organic carbon storage of NF and CF had strong spatial heterogeneity. The soil organic carbon (SOC) and labile organic carbon (LOC) of the two were significantly higher than those of the disturbed EF and cultivated land soil. (4) There was a synergistic effect between the soil properties and the K-factor. K was significantly negatively related to sand fractions (2-0.05 mm) and non-capillary porosity, while positively related to silt content (0.05-0.002 mm). Overall, changes in bulk density (BD), total porosity (TP), non-capillary porosity (NCP), texture, and organic matter content caused by natural restoration or anthropogenic disturbance were the main reasons for soil erodibility. Natural care (sealing) and construction of stone dike planting practices were effective ways to reduce soil erosion in small karst watershed areas of western Hubei.

Does interception evaporation occur from both sides of leaves at the wet Japanese cypress canopy during and after rainfall?

AbstractThe interception by the lower (abaxial) side of needle leaves not only contributes to the forest evapotranspiration but will also cause a diffusion barrier of CO2 over the stomata and depresses the plant gas exchange. This study combined the eddy covariance (EC) technique and leaf wetness measurement with a soil–vegetation–atmosphere transfer (SVAT) multilayer model to examine the occurrence of interception evaporation from both sides of leaves at a Japanese cypress forest canopy relating to rainfall intensity and different wetting periods. We compared the measured latent heat flux (λE) with the simulated wet canopy λE with two models that interception evaporation only happens from the upper (adaxial) side of leaves and both sides of leaves. Both models showed a low λE during the rainfall as the EC data did. The simulated λE at the wet period after rainfall indicates that the interception evaporation from both sides of leaves is more likely to happen after heavy rainfall (>15 mm/12 h). However, for the most frequent small rainfall events (0–5 mm/12 h) at this site, interception evaporation is more likely to occur only from the adaxial side than both sides, which helps the wet leaves to maintain stomata opening and process CO2 uptake after rainfall.

Batı Anadolu’da Silisleşmiş Ağaç Türlerinin Bazı Mineralojik ve Gemolojik Özellikleri

The silicified wood samples identified in Western Anatolia are located in the Late Miocene-Pliocene aged Çokköy Formation in Tavşanlı (Kütahya) and its surroundings, in Osmancalı (Manisa) and its vicinity in the Early (?)-Middle Miocene aged Foça Tuff and in Banaz (Uşak) around in the Middle-Late Miocene aged Yeniköy Formation within the terrestrial sediments. The formation of woods petrified by the silicification mechanism is associated with the sedimentation of clastic sediments formed simultaneously with the Neogene period volcanic activities in the region. In the mineralogical-petrographic examinations on three oriented thin sections, including transverse, radial and tangential, chalcedony polymorphs of silica and less quartz and opal were detected in silicified wood samples. Mineralogical interpretations were also supported by X-Ray Diffractometry (XRD) analysis. As a result of paleobotanical definitions made with thin sections in the botanical microscope; Taxodioxylon Hartig 1848 (Swamp cypress), Pinuxylon Gothan 1906 (Pine), Pterocaroxylon Müll.-Stoll et Mädel 1960 (Walnut), Quercoxylon (Kräusel 1939) Gros 1988 (evergreen oak), Glyptostroboxylon Conwentz 1884 (Swamp cypress) fossil wood species were identified. According to these findings, a warmer and more humid climate prevails than today, cypress forests on the edges of swamps and streams, and pine and evergreen oak forests on the slopes were determined. Within the scope of gemological examinations of silicified wood samples, samples which are rich in color/pattern were selected, polished by giving cabochon forms, then mounted with silver. A small amount of facet cutting studies were carried out from unpatterned and monochromatic samples. Silicified wood samples, which have high values in terms of hardness, exhibit an unstable character due to the weak zones they contain and do not show the desired performance in terms of pattern/color.

Effects of Forest Gaps on the Structure and Diversity of Soil Bacterial Communities in Weeping Cypress Forest Plantations.

The decline in forest ecological function caused by pure forest plantations planted in the Yangtze River basin is becoming increasingly serious. To investigate this problem, we selected the local low-efficiency weeping cypress plantations for forest gap transformation. Three forest gap sizes, specifically large, medium, and small gaps, were established, and the effects of gap sizes on soil bacterial community structure and diversity in winter and summer were studied compared to no gaps (CK; control). Compared to CK, forest gaps had a significant effect on soil organic carbon (SOC) and soil total nitrogen (TN), and the highest values of SOC and soil TN under two seasons occurred in large forest gaps. The interactions of forest gap sizes and seasons had significant effects on pH, SOC, TN, and alpha diversity indices, including Simpson, Chao1, and ACE indices. Compared to winter, forest gaps significantly increased the soil bacterial community diversity indices in summer. Forest gap sizes significantly affected the composition of the bacterial community, but the composition of the dominant bacteria at the phyla and genera levels was similar. Linear discriminant effect size (LEfSe) analysis showed that there were 32 indicator bacterial species in two seasons. Co-occurrence network analysis revealed that the relationship of the soil bacterial community at the phyla level was complex, and there was a significant positive correlation among bacterial species. Soil bulk density (BD) and soil moisture (SM) significantly affected the soil bacterial alpha diversity indices. The composition of the dominant bacteria at the phyla level was significantly affected by soil microbial carbon (MBC), whereas the composition of dominant bacteria at the genera level was affected by soil hydrolysable nitrogen (AN) and the carbon/nitrogen (C/N) ratio. In this study, compared to the other forest gaps, large forest gaps were more conducive to the accumulation of soil nutrients, thus improving the structure of the soil bacterial community. Importantly, changes in the soil bacterial community structure due to gap formation may have profound effects on soil biogeochemical processes in weeping cypress forest plantations.

Habitat characteristics of <i>Shortia uniflora</i> as a local resource plant with the flower landscape in Tomiyama-funato district, Nakagawa Town, Tochigi Prefecture.

This study examined the habitat characteristics of Shortia uniflora, which is one of the main attractors of flower tourism in hilly and mountainous areas. Due to the distribution and vegetation surveys around the open flowering site, nine colonies with areas of 300–700 m2 and some above 1000 m2 were found in addition to seven colonies with an areas of 50–200 m2. The results revealed that S. uniflora prefers steep, upper parts of the north-facing slope and avoids the cedar forest with many litters. The communities were also commonly distributed within evergreen cypress forests, which were deciduous broadleaf forests 70 years ago, in 1950. Regardless of the type of forest canopy (cypress forest, including the open flowering site, and deciduous broad-leaved forest), the floristic composition was dominated by common species. This species is shade-tolerant and has continued to grow in the forest even after the conversion to cypress forest. The area of the community in the open flowering site was 8,000 m2, and the community size was much larger than other surrounding communities. The extremely large size of the community is a result of the continuous appropriate forest floor management according to the habitat characteristics, and the flowering landscape was evaluated as a local resource based on the ecological and sociological area-context.

Vertical profiles of methane concentration above and within the canopy of a temperate Japanese cypress forest

Methane (CH 4 ) is one of the major greenhouse gases, and therefore its source identification and quantification are quite important. So far water-unsaturated soils of upland forests are usually recognized as sinks, but recent increasing evidence supports tree stems in certain environments can be a source of CH 4 , and thereby research on the dynamics of CH 4 in forest ecosystems has entered a new phase. In this study, we measured vertical distributions of CH 4 concentrations within and above a forest canopy to examine how they are influenced by local ecological processes and synoptic-to local-scale atmospheric processes. Profile measurements were conducted using a meteorological tower in a temperate Japanese cypress forest with a 30-min time resolution. Time series data of CH 4 concentrations above the canopy at our site showed occasional spikes relative to background levels, and these spikes corresponded with temporal variations in CO 2 concentrations. Backward trajectory analyses showed that most of the air masses associated with the spikes in CH 4 and CO 2 concentrations had continental origins. Seasonal-mean diurnal properties in CH 4 concentrations above and within the canopy were weaker than those for CO 2 concentrations. It was considered likely that nighttime accumulation of CH 4 in a stable surface layer and its convective diffusion into a mixed layer accounted for the diurnal properties in CH 4 , while ecological processes played a major role in the diurnal properties observed in CO 2 levels. Vertical distributions in CH 4 concentration within the canopy showed a monotonic decrease from the canopy to the forest floor, with variations depending on the season. The profiles agreed with soil-atmosphere CH 4 fluxes measured using a closed-chamber method at our site, indicating that the surface soil in upland areas plays a major role for determining the within-canopy distributions of CH 4 . Also, it was inferred that at least at our site, CH 4 emissions from stems and leaves, which has become a hot topic over the recent years, was not significant for cypress trees in upland area enough to influence the within-canopy distributions of CH 4 during the study period. • CH 4 concentrations above and within a cypress forest were measured for one year. • CH 4 and CO 2 concentrations are often affected by continental outflow. • Vertical CH 4 profiles are coherent with CH 4 uptake rates in upland soil. • Trunk and leaves of Japanese cypress do not emit or absorb CH 4 significantly.

주의회복이론의 타당성에 관한 탐색적 연구

This study examines the validity of the attention restoration theory by exploring the relationship between perception of recovery environment and psychological effect. It was also investigated whether the level of cognitive load in everyday life and the level of perception of congestion at the place of visit act as a moderating variable. Items to measure the variables were organized based on prior researches, and two preliminary surveys were conducted. The population of the study was tourists returning home after visiting Jangheung-gun Cypress Forest Woodland. The survey was conducted from September 25 to September 26, 2018, and a total of 250 samples were used for the final data analysis. Results show that the perception of the recovery environment had a positive effect on psychological recovery in the case of short-term psychological recovery. In addition, it was found that 'rest and universal attraction' among the components of the perception of recovery environment had the most significant effect on psychological recovery. Although the validity of the attention restoration theory hypothesis was not tested in this study, evidences of this study suggest that the hypothesis could be valid if the cognitive load of daily life was below an appropriate level. Also, findings of this study show that congestion perception in the natural environment has a significant effect on the causal relationship between recovery environment perception and short-term psychological recovery.

Maqui (Aristotelia chilensis [Mol.] Stuntz) morphological and phenolic traits associated with forests type and latitudinal gradient in natural populations of Patagonia Argentina

Maqui (Aristotelia chilensis [Mol.] Stuntz) is a native berry of the Patagonia Andean forests, which has one of the highest antioxidant levels currently known. This biochemical characteristic strongly depends on the phenolic profile and is highly influenced by the growing environment. The objective of this study was to characterize natural maqui populations in the immediate lee (Argentina) of the Northern Patagonian Andes, distributed in a latitudinal gradient and associated with coihue (Nothofagus dombeyi) and cypress (Austrocedrus chilensis) forests, humid and xeric environments, respectively. Twenty-five natural populations that spanned the geographical distribution of the species in Argentina, were identified. The sites were associated with two forests (coihue and cypress) and three latitudinal groups (north, center and south). Canopy cover and light interception were measured in the selected sites, as well as plant morphology, fruit yield components, phenolic profiles and oxygen radical absorbance capacity (ORAC) of mature berries. Maqui populations associated to cypress are exposed to greater incident total solar radiation and lesser rainfalls, and showed shorter plants with several main stems, multiple branching and smaller specific leaf area (SLA) as compared to those of coihue forest. Maqui populations associated to coihue presented an increase in the number of berries per bunch, and also in the accumulation of phenols and ORAC. The evaluation of the acclimation responses of the natural populations by different environments can contribute to the development of high-yield and quality maqui crops as source of bioactive compounds.

Canopy conductance and gas exchange of a Japanese cypress forest after rainfall‐induced wetness

AbstractIncreased stomatal conductance of the dry leaves right after wetness ended was reported before, while few studies paid attention to this phenomenon in canopy scale and its contribution to the forest carbon sink function. Therefore, we observed the continuous change of canopy wetness and ecosystem fluxes after wetness ended by using wetness sensors and eddy covariance method for a Japanese cypress forest (Chamaecyparis obtuse Sieb. Et Zucc.) in the Asian monsoon area. Larger gc (canopy conductance) were found in the relationships with both vapor pressure deficit and Rn (net radiation) during the first several hours after wetness ended. The results for λE (latent heat flux) were similar to that of gc in spring and summer. Net ecosystem exchange (NEE) in the relationships with Rn at different stages after wetness ended did not show clear difference except in spring. Nevertheless, annual summed‐up NEE showed that the average CO2 uptake at the first several hours after wetness ended was larger than the usual dry period. These results suggest that the improved stomatal opening at the first several hours after wetness ended plays a significant role in the canopy‐scale gas exchange processes.

Identifying forcing agents of environmental change and ecological response on the Mississippi River Delta, Southeastern Louisiana

Freshwater wetlands on the Mississippi River delta plain, containing extensive swamps and marshes, have experienced land loss of 5197 km2 since the 1930s as the ocean has transgressed landward, resulting in landward retreat of bottomland forest, and transition of fresh to intermediate marsh. The timing and rapidity of these ecotonal transitions, and the impacts of natural and anthropogenic forces on this deltaic environment are uncertain. This study details a 448 cm sediment core retrieved from the intermediate marsh on the northern edge of Lake Salvador in southeastern Louisiana. Multi-proxy data identify six ecological shifts since 3500 BP. The ecosystem has shifted from interdistributary environment with high concentrations of such terrestrial and marine elements as Ca, Zr (3.5–3.0 cal kyr BP), to a freshwater deltaic-plain with an increase in freshwater herbs and trees (3.0–2.6 cal kyr BP), to a lacustrine environment marked by high Mn, Fe concentrations (2.6–2.2 cal kyr BP), to a swamp ecosystem with high concentrations of Zn, Br (2.2–1.4 cal kyr BP), to freshwater marsh with an increase in marsh plants (1.4–0.3 cal kyr BP), and to an intermediate marsh marked by Typha and Baccharis with elevated marine elements (since 0.3 cal kyr BP).The study identified the external forcing agents driving each deltaic environmental transition using multivariable analyses. Ecosystem dynamics are highly associated with the St. Bernard deltaic cycles, with dominant fluvial processes introducing freshwater ecosystems while forming geomorphological features such as levees, oxbow lakes, and back swamp and marsh during delta progradation. Thereafter, reduced sediment supply and decreased freshwater flow during delta transgression caused land subsidence and uneven topography. As a result, the swamp converted to marsh. Eighteenth century logging and canal development by Activities from French and Spanish settlements reduced the cypress forests and enlarged the coastal lakes.