Patterns Of Leaf Fall Research Articles

Urban Trees Are Sinks for Soot: Elemental Carbon Accumulation by Two Widespread Oak Species.

Urban trees could represent important short- and long-term landscape sinks for elemental carbon (EC). Therefore, we quantified foliar EC accumulation by two widespread oak tree species-Quercus stellata (post oak) and Quercus virginiana (live oak)-as well as leaf litterfall EC flux to soil from April 2017 to March 2018 in the City of Denton, Texas, within the Dallas-Fort Worth metropolitan area. Post oak trees accumulated 1.9-fold more EC (299 ± 45 mg EC m-2 canopy yr-1) compared to live oak trees (160 ± 31 mg EC m-2 canopy yr-1). However, in the fall, these oak species converged in their EC accumulation rates, with ∼70% of annual accumulation occurring during fall and on leaf surfaces. The flux of EC to the ground via leaf litterfall mirrored leaf-fall patterns, with post oaks and live oaks delivering ∼60% of annual leaf litterfall EC in fall and early spring, respectively. We estimate that post oak and live oak trees in this urban ecosystem potentially accumulate 3.5 t EC yr-1, equivalent to ∼32% of annual vehicular EC emissions from the city. Thus, city trees are significant sinks for EC and represent potential avenues for climate and air quality mitigation in urban areas.

Leafing patterns and leaf exchange strategies of a cerrado woody community

AbstractThe deciduousness of tropical trees and communities depend on ecosystems characteristics such as plant species diversity, and strength of the dry season. Based on seven years of phenological observations, we provide the first long‐term description of leafing patterns of a woody cerrado community, aiming to investigate (1) the leaf exchange strategies considering the interannual variation in the degree of deciduousness of individuals and species and quantify the community deciduousness; (2) the relationship between interannual patterns of leaf fall and leaf flush according to the species’ leaf exchange strategies and climate; (3) the onset of cerrado growing season and its relation to climate seasonality. To detect seasonality and leafing onset we applied circular statistics and to understand the relationships between environmental predictors and leaf exchange strategies, we used generalized additive models. From 106 species observed, we classified 69 as deciduous (26 species), semi‐deciduous (25) or evergreen (18) and defined the studied cerrado as a semi‐deciduous vegetation. Leaf phenology was markedly seasonal and similar among years. Leaf fall peaked in the dry season, and leaf flush in the dry‐to‐wet transition. Leaf fall patterns related to temperature and leaf flush to day length and rainfall. Semi‐deciduous and deciduous species were more constrained by climate than the evergreen ones. The cerrado growing season started in the dry‐to‐wet season transition. Interannual variations in rainfall and temperature affected the individuals’ and, consequently, species’ degree of deciduousness, highlighting individual and species variability, and suggesting that cerrado leafing patterns are likely susceptible to future climate change scenarios.

Do conspecific populations exhibit divergent phenological patterns? A study case of widespread savanna species

Widespread savanna tree species can grow and survive at sites that diverge in water availability and seasonality, thus these species may be able to adjust their phenology in response to site variations. Here we evaluated vegetative and reproductive phenology in five woody species whose populations grow at two savannas sites under divergent climatic regimes, inserted in a large transitional zone between the Amazon forest and the semi-arid region. Patterns of leaf fall, leaf flush and flowering were recorded monthly for five woody species growing under longer (LDS) and shorter (SDS) dry seasons. We evaluated the seasonality, the start and peak dates for phenological events and the associations between phenophases and climatic data. We found a close relationship between phenological events and site temperatures, with phenological peaks in the LDS occurring, in general, about one to three months later than at the SDS site. Leaf fall coincides with warmer and drier periods when the day length is shorter. Leaf production and flowering were associated with increased day length in some populations. Our results support the hypothesis that the conspecific populations have a high degree of association with climatic variables, especially temperature and day length, showing distinct phenological responses associated to the local climatic differences.

Nutrient Dynamics and Decomposition of Riparian Arundinaria gigantea (Walt.) Muhl. Leaves in Southern Illinois

<p class="1Body">Leaf litter quality and quantity can influence soil nutrient dynamics and stream productivity through decomposition and serving as allochthonous stream inputs. Leaf deposition, nitrogen (N)-resorption efficiency and proficiency, and decomposition rates were analyzed in riparian stands of <em>Arundinaria gigantea </em>(Walt.) Muhl.<em> </em>in southern Illinois for the first time to determine potential nutrient cycling from riparian canebrake restoration. Leaf litter was collected from five established canebrakes monthly over one year and a decomposition study was conducted over 72 weeks. Live leaves, freshly senesced leaves, and decomposed leaves were analyzed for carbon (C) and N content. Leaf litterfall biomass peaked in November at twice the monthly average for all but one site, indicating a resemblance to deciduous leaf fall patterns. Nitrogen and C concentrations decreased 48% and 30%, respectively, between live leaves and 72 weeks following decomposition. High soil moisture appeared to slow decomposition rates, perhaps due to the creation of anaerobic conditions. Cane leaves have low resorption proficiency and nutrient-use proficiency, suggesting that these riparian canebrakes are not N limited. Giant cane should be considered in multispecies riparian buffer creation since it has this potential to supply carbon and nitrogen to the soil and to macroinvertebrates in the streams for a longer period of time and year round.</p>

Uncertainties involved in leaf fall phenology detected by digital camera

We evaluated the uncertainty in the estimation of year-to-year variability in the timing of leaf fall detected by the analysis of red, green and blue (RGB) values extracted from daily phenological images in a deciduous broad-leaved forest in Japan. We examined (1) the spatial distribution of individual tree species within a 1-ha permanent plot and the spatio-temporal variability of leaf litter of various species for 8years; and (2) the relationship between the year-to-year variability of leaf fall detected by leaf litter and that detected by phenological images of various species. Uncertainties were caused by (1) the heterogeneous distribution of each species within the whole forest community; (2) the year-to-year variability of the timing of leaf fall among species; and (3) differences in leaf colouring and leaf fall patterns among species. Our results indicate the importance of integrating RGB analysis of each species and of the whole canopy on the basis of spatial locations of individuals and proportions of tree species within a forest to reduce uncertainty.

Relationship between spatio-temporal characteristics of leaf-fall phenology and seasonal variations in near surface- and satellite-observed vegetation indices in a cool-temperate deciduous broad-leaved forest in Japan

We examined the relationship between the spatio-temporal distribution of leaf litter for each species and the seasonal patterns of in situ and satellite-observed daily vegetation indices in a cool-temperate deciduous broad-leaved forest. The timing and distribution of leaf-fall revealed spatio-temporal relationships with species and topography. Values of the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and green–red vegetation index (GRVI), measured both in situ and by satellite, and those of the in situ-measured leaf area index (LAI), rapidly declined at the peak of leaf-fall. At the late stage of leaf-fall, in situ-measured values of NDVI, EVI, and LAI declined but those of GRVI changed from decreasing to increasing. The peak timing of leaf-fall, when 50–73% of the leaf litter had fallen, corresponds to LAI = 1.80–0.81, NDVI = 0.61–0.54, EVI = 0.29–0.25, and GRVI = 0.01 ∼ ‒0.07. Although the distribution of leaf litter among species displayed spatial characteristics at the peak of leaf-fall, spatial heterogeneity of amount of leaf litter at the peak timing of leaf-fall was less than that at the beginning and end. These facts suggest that the criterion for determining the timing of leaf-fall from vegetation indices should be a value corresponding to the peak of leaf-fall rather than its end. In a high-biodiversity forest, such as this study forest, the effect of spatial heterogeneity on the timing and patterns of leaf-fall on vegetation indices can be reduced by observing only the seasonal variation in colour on the canopy surface by using GRVI, which consists of visible reflectance bands, rather than that of both leaf area and colour of the canopy surface by using NDVI and EVI, which consist of visible and near-infrared reflectance bands.

利用不同方法测定红松人工林叶面积指数的季节动态

PDF HTML阅读 XML下载 导出引用 引用提醒 利用不同方法测定红松人工林叶面积指数的季节动态 DOI: 10.5846/stxb201306181727 作者: 作者单位: 东北林业大学生态研究中心,东北林业大学生态研究中心,东北林业大学林学院,东北林业大学生态研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项资助项目（201204320）；长江学者和创新团队发展计划资助（IRT1054） Seasonal dynamics of leaf area index using different methods in the Korean pine plantation Author: Affiliation: Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University,School of Forestry,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用2种异速生长方程法、凋落物法、综合法（对光学仪器法进行木质部分及集聚效应校正后结合凋落物法）和光学仪器法测定了小兴安岭红松（Pinus koraiensis）人工林的叶面积指数（LAI）。首先利用光学仪器法测定有效叶面积指数（Le）的季节动态；其次为获得相对准确LAI，基于生长季节（5-8月）的展叶调查，结合凋落物法、综合法和2种异速生长方程法分别测定LAI的季节动态。结果表明：生长季节红松叶片8月初停止生长，迟于其他树种约两周；不同方法测定红松人工林LAI的季节变化均呈单峰型，且在8月初达到峰值，分别为异速生长方法-B（10.58） > 凋落物法（7.90） > 异速生长方法-A（6.70） > 综合法（4.41） > 光学仪器法（1.81）；在整个调查期内（5月至11月），相对于异速生长方法-B、凋落物法、异速生长方法-A和综合法，光学仪器法分别平均低估81.69%、75.50%、70.18%和48.90%。本研究探讨了非破坏条件下测定红松人工林LAI季节动态的直接方法，并比较了不同方法之间的差异，研究结果可为有效测定常绿针叶林LAI提供参考。 Abstract:Leaf area index (LAI), defined as half the total leaf area per unit ground surface area, and is one of the most important characteristics of the plant canopy structure. LAI controls the flux of carbon, solar energy, and water in forest ecosystems. Thus, accurately estimating LAI is essential for simulating the forest process. Furthermore, the seasonality of LAI estimation is of particular interest. Methods directly estimating LAI mainly include destructive sampling, allometry, and litterfall. The results of these methods are assumed to provide values close to the true LAI. However, the first two methods destroy the samples, as well as labor intensive. By contrast, the litterfall method is the best choice in obtaining accurate LAI. At present, the optical method has been widely used to estimate LAI because of its convenience and speed. However, the accuracy of optically measured LAI needs to be verified. This verification is performed because the indirect method often underestimates LAI. In the present study, allometry method (including two different allometry equations, namely, A and B), litterfall method, combinational method (the LAI derived from optical method were calibrated by taking into consideration the woody-to-total ratio (α), as well as the clumping index, and combining the litterfall method), and optical method were used to estimate LAI in the Korean pine (Pinus koraiensis) plantation in Xiaoxing'an Mountains. First, we estimated the effective leaf area index (Le) and its seasonality in the Korean pine plantation using optical method (hemispherical photography). To obtain accurate LAI, we estimated the LAI seasonal dynamics by combining litterfall method, combinational method, and allometry methods in accordance with the leaf seasonality observation from May to August. Subsequently, we compared the results obtained from the different methods. The results showed that P. koraiensis leaf stopped growing in early August, which was approximately two weeks later than the other tree species. The major species had different leaf fall pattern in the Korean pine plantation. P. koraiensis had two rapidly decreasing flush. The first flush was in June. The second was in late September. However, other species had single rapidly decreasing flush in late September. The LAI seasonal dynamic derived from different methods all show a uni-modal pattern with a peak in early August, with the following order: Allometry-B method (10.58) > Litterfall method (7.90) > Allometry-A method (6.70) > Combinational method (4.41) > Optical method (1.81). In the entire study period (from May to November), the LAI derived from optical method underestimated LAI by an average of 81.69%, 75.50%, 70.18%, and 48.90%, respectively, which were in contrast with contrast Allometry-B method, Litterfall method, Allometry-A method, and Combinational method. In the present study, we investigated a practical method for estimating LAI in the Korean pine plantation using a non-destructive method. Furthermore, we compared the difference between the different methods. In addition, this study lays a foundation for the valid LAI estimation of evergreen conifer forest in subsequent studies. 参考文献 相似文献 引证文献

Early Leaf Abscission Has Little Effect on Larval Mortality of Ectoedemia cerviparadisicola (Lepidoptera, Nepticulidae) Associated with Quercus gilva

Abstract There has been an argument as to whether early leaf abscission substantially affects larval mortality of leafminers because of leaf senescence. Recently, a study reported that leaf abscission considerably increased the mortality of a leafminer (Ectoedemia cerviparadisicola Sato, sp. nov.) associated with Quercus gilva (Blume) in Nara Park, central Japan, where sika deer (Cervus nippon (Temminck)) have been protected for 1,200 yr, because deer consumed many abscised leaves containing living larvae. The study, however, did not investigate the life history of the leafminer or survey the leaf-fall pattern of Q. gilva through the season, so that it failed to quantify larval mortality because of deer predation. To test whether deer have a substantial effect on larval mortality of this leafminer, we regularly collected abscised and nonabscised leaves of Q. gilva through the season, examining mines and larvae in those leaves. Over 90% of mined leaves abscised in the period of peak leaf fall, when almost all larvae had already emerged from mines to pupate. Most dead larvae in abscised leaves were judged to have already died at the time of abscission from their instars and body features. The proportion of living larvae in abscised leaves was estimated to be <1.8%. Thus, even when deer preyed upon all living larvae in abscised leaves, they would hardly contribute to the increase in larval mortality. These results indicate that the effect of leaf abscission on leafminer mortality via deer predation and other causes is limited. The leafminer was described as new to science in the Appendix.

Using digital camera images to detect canopy condition of deciduous broad-leaved trees

Background: Recent studies have described a technique that incorporates a digital camera to observe aspects of tree phenology, such as leaf expansion and leaf fall. This technique has shown that seasonal patterns of red, green and blue digital numbers (RGB_DN) extracted from digital images differ between species. Aims: To identify the different characteristics of phenology between species by examining RGB_DN, the relationship between the seasonal patterns of RGB_DN and ecological characteristics for various species were evaluated throughout the year. Methods: The relationship between the normalised RGB_DN values extracted from digital images and in situ leaf area index (LAI) and leaf chlorophyll content (indicated by soil and plant analyser development, SPAD) was examined for three dominant species for multiple years in a cool-temperate, deciduous, broad-leaved forest in Japan. Results: The RGB_DN values in spring were not useful in detecting the different characteristics of leaf-flush patterns between species. In contrast, RGB_DN values in autumn showed differences in leaf-colouring as well as in leaf-fall patterns and timings between species. Conclusion: Differences in autumn phenology between tree species can be detected by using the normalised RGB_DN technique, while the technique cannot be applied in spring.

Leaffall Phenology in a Subtropical Wet Forest in Puerto Rico: From Species to Community Patterns

ABSTRACTLeaffall phenology is an important periodical event in forests, contributing to mobilization of organic matter from primary producers to soil. For seasonal forests, leaffall periodicity has been related to rainfall regime and dry season length. In weakly seasonal forests, where there is no marked dry season, other climatic factors could trigger leaf shed. In this study, we aimed to determine if other climatic variables (wind speed, solar radiation, photosynthetic photon flux density [PPFD], day length, temperature, and relative humidity) could be better correlated with patterns of litter and leaffall in a weakly seasonal subtropical wet forest in Puerto Rico. Leaffall patterns were correlated mainly with solar radiation, PPFD, day length, and temperature; and secondarily with rainfall. Two main peaks of leaffall were observed: April–June and August–September, coinciding with the periods of major solar radiation at this latitude. Community leaffall patterns were the result of overlapping peaks of individual species. Of the 32 species analyzed, 21 showed phenological patterns, either unimodal (16 species), bimodal (three species), or multimodal (two species). Lianas also presented leaffall seasonality, suggesting that they are subject to the same constraints and triggering factors affecting trees. In addition to solar radiation as a main determinant of leaffall timing in tropical forests, our findings highlight the importance of interannual variation and asynchrony, suggesting that leaffall is the result of a complex interaction between environmental and physiological factors.

Leaf-fall phenology along a topography-mediated environmental gradient in a cool—temperate deciduous broad-leaved forest in Japan

Leaf-fall phenology was studied in a cool—temperate deciduous broad-leaved forest in central Japan in relation to the topographic environmental gradients that occur along a short mountain slope. Leaf-fall phenology was described quantitatively using data from leaf litter collected along the slope. In autumn, leaf fall at the study site tended to occur slightly earlier on the upper slope than on the lower slope. This pattern was found at both the stand and the species levels. Our results suggest that leaf-fall phenology may be affected by difference in microclimatic conditions, because environmental conditions are thought to be more severe on the upper slope than on the lower slope. The less intensive methods used in this study, the litter trap method, and Dixon's model succeeded in quantifying the phenological patterns of leaf fall within stands and within species along the short mountain slope.

Tropical deciduous forests and the adivasi. Indigenous traditions as response to leaf fall in Bastar, India

Abstract This article draws attention to the crucial link between the tropical deciduous forest ecosystem and the lifestyle of the adivasi (indigenous) people. Taking the case of Bastar District in Chhattisgarh, Central India, an analysis is made of the various commonly used wild plants, their deciduous habit, and the adivasi calendar that regulates the peoples’ use of these plants. By examining the specific seasonal patterns of leaf fall of plants and the dates set for the commencement of their use, the article shows that there is an implicit relation between adivasi festivals and the deciduous character of Bastar's forests.

Ontogenetic changes in leaf phenology of a canopy species, Elateriospermum tapos (Euphorbiaceae), in a Malaysian rain forest

Leaf phenology was studied in individuals of a canopy species, Elateriospermum tapos (Euphorbiaceae), at various ontogenetic stages, in a Malaysian rain forest. The timing of leaf emergence was not synchronized among sapling individuals, and was not correlated with any meteorological factors of the preceding month. The timing of leaf fall in saplings was positively correlated with net radiation, and maximum and minimum temperature, but negatively correlated with relative humidity the preceding month, although these correlations were weak. The leaf production rate was larger under higher light, but the leaf fall rate was not related to the light regime of the saplings. Thus, leaf production was enhanced by the light availability for each individual, while leaf fall may have been enhanced by drought stress. Non-synchronous leaf production appears to be important for sapling growth, allowing saplings to occupy better-lit space quickly. On the other hand, tall trees showed a clear synchronous leaf-fall pattern, with an annual cycle, and no meteorological factors were correlated with the timing of leaf fall. Mature trees of this species produced flowers simultaneously with new leaves, after shedding their leaves. This suggests that the need to synchronize flowering might be the primary determinant of leaf production phenology in mature individuals.

Leaf dynamics and shoot phenology of eleven warm-temperate evergreen broad-leaved trees near their northern limit in central Japan

Dynamic features of shoot phenology including leaf emergence and leaf fall, and leaf life span for eleven evergreen broad-leaved tree species were investigated in a warm-temperate rain forest in Mount Kiyosumi, central Japan. All species had periodic leaf emergence or flushing pattern, and were classified into two types; single and multiple flush and only one species, Eurya japonica, represented the latter type and the rest had single flush in spring. The single flush type can further be subdivided into two groups according to their duration of shoot growth; short and long flush. Seasonal patterns of leaf fall were categorized into four; unimodal, bimodal, broad unimodal, and multimodal type though they were not fixed pattern. The leaf emergence and leaf fall patterns were correlated for the eleven species, and five phenological types were categorized. Four of them were the single flush types, i.e., short flush of leaf emergence with unimodal leaffall (SSU) type of Castanopsis sieboldii and Quercus salicina, short flush with bimodal leaf fall (SSB) type of Quercus acuta, Machilus thunbergii, Neolitsea sericea, and Cinnamomum japonicum, long flush with bimodal leaffall (SLB) type of Myrsine seguinii, and long flush with broad unimodal leaffall (SLR) type of Symplocos prunifolia, Cleyera japonica, and Illicium anisatum. The multiple flush type is only one species, Eurya japonica, and it had multimodal leaffall pattern (MM type). The phenological pattern varied in relation to leaf life span, leaf size, and tree habit. Leaf life span ranged from 1.1 to 5.8 yr. The short flush species or SSU and SSB types were all canopy or subcanopy trees, and the former had short and the latter had long leaf life spans. The long flush species were all microphyllous small trees, and SLB type had a relatively long leaf life span in understory, SLR type had a long leaf life span in understory or in open habitat and/or forest gap as a pioneer tree. MM type had a long leaf life span and colonizing species in open habitat but they can survive in understory as well. The phenological attributes of evergreen trees were well corresponded to the ecological guild of the tree in both forest structure and successional stage, and were also constrained by phylogenetic groups.

Litter production and its nutrient concentration in some fuelwood trees grown on sodic soil

Litter production was estimated in 8-year-old tree plantations of Acacia nilotica, Prosopis juliflora, Dalbergia sisso, and Terminalia arjuna planted in a monoculture tree cropping system on sodic soils of Lucknow Division, India. Mean annual litter fall of these trees amounted to 5.9, 7.4, 5.0 and 5.4 t ha −1, respectively. Irrespective of tree species, the leaf litter concentrations of N, K and Ca were greater than those of P and Mg. The concentration of nutrients in leaf tissues was negatively correlated for N and Ca, with the magnitude of leaf fall in D. sissoo, but was positively correlated for Ca and Mg in A. nilotica; no such correlations were found in P. juliflor and T. arjuna. The variations in the concentration of leaf litter nutrient did not appear to be species specific but depended on adverse edaphic properties including the fertility status of sodic soil. A. nilotica and P. juliflora with bimodal patterns of litter fall return greater amounts of nutrients to the soil surface than D. sissoo and T. arjuna which have unimodal patterns of litter fall. The study indicated the potential benefit of a mixed plantation system having variable leaf fall patterns among the planted trees so providing constant litter mulch to help in conserving soil moisture.

Phenology of the shrub strata of successional sub-tropical humid forests of north-eastern India

The phenology of 70 shrub species occurring in 5-, 25- and 60-yr old forest fallows, developed after slash and burn agriculture in north-eastern India, was studied. The early successional shrubs were largely deciduous with predominant leaf fall during the dry winter, while late successional shrubs were evergreen and with a less pronounced leaf fall pattern; the species in the 25-yr old fallow were largely of the leaf-exchanging-evergreen type. Peak leaf production, flowering and fruiting are delayed by one month in the 60-yr old fallow. The phenological separation of the growth types in the three fallows is discussed and related to possible micro-environmental differences.

Aspects of litter production in a New Zealand lowland podocarp/broadleaf forest

Abstract Litter-fall was collected monthly for 16 months in 69 funnels of 0.0625 m2 catching area on two 2.25 ha sites in lowland podocarp/broadleaf forest in the Orongorongo Valley, near Wellington. New Zealand. At both sites, litter fell throughout the year, with most leaves falling in summer, fruits in autumn, and twigs in spring. Seasonal patterns of leaf-fall were examined for seven species of trees. Five of the seven showed a summer peak of leaf-fall and two an autumn peak; all seven shed fewest leaves in winter. Leaf, fruit, and flower production differed markedly between sites. Total annualleafand flower fall at one site (area A) was estimated at 3026 kg/ha, with 260 kg/ha of fruit and seeds and 1234 kg/ha of twigs < 28 cm long. At a second site (area D). leaf and flower fall was 20% less, fruit and seed fall 60% less, and twig fall 22% less. Implications of the differences between these two areas are discussed in relation to the ecology of brush tail possums there.

Leaf mines: their effect on leaf longevity.

The effects of a number of factors, notably leaf mining insects, on the longevity of beech and holm oak leaves have been studied. The regular monitoring of individually labelled leaves was complemented by analysis of leaf fall data. Both methods confirm that these mining insects have only a slight impact on their host trees. The presence of first generation Phyllonorycter maestingella mines on beech leaves and winter generation P. messaniella mines on holm oak leaves accelerates leaf loss. Beech leaves mined by second generation P. maestingella and Rhynchaenus fagi did not show this accelerated loss. Their patterns of leaf fall can be explained by within-tree variation in both mine distribution and the timing of leaf fall. It is argued that this premature leaf fall is a damage response, and is not an attempt by the tree to regulate miner numbers.