Middle Canopy Research Articles

Sabina chinensis and Liriodendron chinense improve air quality in Beijing, China.

Urban forests have been shown to be efficient for reducing air pollutants especially for particulate matters (PMs). This study aims to reveal the PM blocking capacity of two common artificial landscape species, Sabina chinensis and Liriodendron chinense and to investigate spatial-temporal heterogeneities by estimating the vegetation collection velocity of coarse (PM10) and fine particles (PM2.5) during different seasons and heights. PM concentration and meteorological data were collected on both leeward and windward sides of trees during the daytime in both summers and winters from 2013 to 2015. Concentration and meteorological monitors were installed at three heights, bottom (1.5 m), middle (3.5 m), and top (5.5 m) of the canopy. The results showed: During daytime, the collection velocity changed and PM2.5 collection velocity was much higher than that of PM10. Furthermore, the maximum collection velocities of L. chinense and S. chinensis occurred at 14:00–16:00 both in summer and winter. Moreover, the collection velocity had a positive correlation with wind speed and temperature. The blocking capacities of L. chinense and S. chinensis varied from season to season, and the concentrations of particulate matter indicate the middle canopy of both species as the most effective part for TSP blocking. Furthermore, these two species are more effective blocking in PM2.5 than PM10. The blocking capacity of S. chinensis is generally better. The vegetation collection is the major process of PM removal near the ground and sedimentation was not taken into consideration near the ground.

Karakteristik Pemanfaatan Pohon oleh Jalak Bali (Leucopsar Rothschildi) di Taman Nasional Bali Barat Wilayah SPTN III, Buleleng, Bali

Leucopsar rothschildi (Jalak Bali) is an endemic bird species that only be found in the forests of the western of Bali Island. Wild catching and declining forest are the main factors of the declining population. The National Park of West Bali is the last bastion. The habit of living for activity and nesting in the trees make the importance of tree stand to be preserved. Therefore, this study was conducted to analyze the utilization's characteristics of trees by the birds in their original habitat in SPTN III West Bali National Park. The method used was concentration count to observe the characteristics utilization of trees and canopy. Behavior in their natural habitat was observed using Ad Libitum method. Data analysis was conducted by calculating percentage in each part of the usage of canopy and behavior type. The use of the canopy of trees in SPTN III of Labuhan Lalang TNBB by the birds for Tanjung Gelap was more frequent in the upper canopy (TA) section, in Labuhan Lalang more often in the middle canopy (TT) and the middle side canopy (TTt). Frequently activity in the canopy of SPTN III Labuhan Lalang by the birds was social activity.

Vertical stratification of bird community in Cikepuh Wildlife Reserve, West Java, Indonesia

Dinanti RV, Winarni NL, Supriatna J. 2018. Vertical stratification of bird community in Cikepuh Wildlife Reserve, West Java, Indonesia. Biodiversitas 19: 134-139. The complexity of heterogeneous strata can be used to determine the distribution of resources in bird communities. However, deforestation causes damage and may disturb the bird community in the forest. Cikepuh Wildlife Reserve in West Java, Indonesia is an example of degraded forest due to deforestation. Illegal logging in the area leads to approximately 7000 hectares of forest conversion into a plantation area. This study was conducted to test the hypothesis of the differences in the diversity of birds in each stratum of vegetation and the differences in the diversity of birds in forest and plantation. The study was conducted in March 2016. Point count method was used for bird surveys. The calculation of Shannon-Wiener diversity index showed that forest had a higher diversity of birds (Hʹ = 3.09) than plantation (Hʹ = 2.78). Based on the rank abundance graph, each vegetation stratum had a different type of curve. The middle canopy layer had the highest bird abundance while the emergent and understory layers had the lowest abundance.

Monitoring thrips species with yellow sticky traps in astringent persimmon orchards in Korea

Thrips are one of the insect pests of persimmon (Diospyros kaki Thunb.) in the major production areas of astringent persimmon in Korea. We surveyed astringent persimmon orchards in the Damyang, Sangju and Cheongdo regions of Korea to determine thrips species composition and abundance. Orchards sprayed with either organic or conventional pesticides were sampled over the course of one flowering season, using yellow sticky traps to determine if this is a suitable method for monitoring thrips populations, and to determine thrips species composition and abundance. Eight thrips species were captured on yellow sticky traps in both the tree canopy and ground cover: Ponticulothrips diospyrosi Haga et Okajima, Scirtothrips dorsalis (Hood), Frankliniella occidentalis (Pergande), F. intonsa (Trybom), Thrips tabaci (Lindeman), T. hawaiiensis (Morgan), T. coloratus (Schmutz) and T. palmi (Karny). In all regions, F. occidentalis and F. intonsa dominated in both organic and conventional orchards. S. dorsalis, F. occidentalis, F. intonsa and T. hawaiiensis were found in persimmon flowers, with S. dorsalis the dominant thrips. Significantly more S. dorsalis were captured from flowers in the lower and middle canopy than in flowers from the upper canopy. Fruit damage was also significantly higher in fruit from the lower canopy than in fruit from the middle and upper canopy.

Herbicide Spray Penetration into Corn and Soybean Canopies Using Air-Induction Nozzles and a Drift Control Adjuvant

AbstractDrift reduction technologies aim to eliminate the smaller droplets that occur with some sprays because these small droplets can move off-target in the wind. Commonly used drift reduction technologies such as air-induction nozzles and spray additives impact on reducing off-target movement is well documented, however, the impact on herbicide penetration into an established crop canopy is not well known. This experiment evaluated the canopy penetration and efficacy of glyphosate treatments applied using four nozzle types (XR11005, AIXR11005, AITTJ11005, and TTI11005), two carrier volume rates (94 and 187 L ha-1), and glyphosate applications with and without a commercial drift reducing adjuvant. Applications were made to corn and soybean fields using glyphosate applied at 1.26 kg ae ha-1with liquid ammonium sulfate at 5% v/v. A rhodamine dye was added (0.025% v/v) to the spray tank of each mixture as a tracer. MylarTMcards were placed in the field above the canopy, in the middle canopy, and on the ground for corn and above and below canopy for soybean. Five cards were at each position in the canopy arranged across the crop row. The addition of a drift reducing adjuvant did not impact canopy penetration. Doubling the carrier volume increased the amount of penetration proportionally and as such the percent reduction was not different. The TTI11005 nozzle had the greatest amount of spray penetration (28%) in the soybean canopies and the XR nozzle had the greatest amount (50%) in the corn canopies. Deposition across the row, beginning in-between the row crop and ending in the row of the crop was 44, 18, and 8% for soybean and 59, 50, and 36% for corn. For both crops, more than half of the herbicide application was captured in the crop canopy. Proper nozzle selection for canopy type can increase herbicide penetration and increasing the carrier volume will increase penetration proportionally.

Chemical Utilization of Albizia lebbeck Leaves for Developing Protein Concentrates as a Dietary Supplement

ABSTRACTIn search of nonconventional sources of protein to combat widespread malnutrition, the possibility of developing a protein concentrate as an alternative dietary supplement from abundantly available yet poorly valorized leaves of Albizia lebbeck (siris) was examined. A process for recovery of leaf protein concentrate (LPC) from these leaves was optimized and applied for isolation of LPCs from lower, middle, and upper canopies of the tree. The optimized conditions (leaves to water 1:9, coagulation at pH 4.0 using 1 N citric acid at 90°C for 11 minutes) afforded LPCs containing protein 37.15%, 37.57%, and 37.76% in 5.99%, 5.97%, and 6.07% yield, respectively. The proximate nutritional composition, pigments, minerals, in vitro digestibility, and antinutritional factors of these LPCs were determined. Analysis of variance of these data revealed no significant difference with respect to canopy. Use of Albizia lebbeck leaves for development of LPC as a food/feed supplement was revealed.

Foliar water use efficiency of Platycladus orientalis of different canopy heights in Beijing western mountains area, China

In this study, we focused on Platycladus orientalis, a widely distributed tree species in Beijing western mountains area, and precisely determined its foliar water use efficiency (including instantaneous water use efficiency derived from gas exchange and short-term water use efficiency obtained on carbon isotope model) by carefully considering the discrepancies of meteorological factors and atmosphere CO2 concentration and δ13C among different canopy heights, hoping to provide theoretical basis for carbon sequestration and water loss in regional forest ecosystem, and offer technical support for regional forest management and maintenance. The results showed that the foliar instan-taneous water use efficiency tended to increase with the increasing canopy height, following the order of the upper canopy > the middle canopy > the lower canopy. A variety of meteorological factors synergistically influenced stomatal movement, and stomatal conductance would in turn have an effect on foliar instantaneous water use efficiency. Foliar short-term water use efficiency also increased with increasing canopy height, following the order of the upper canopy > the middle canopy > the lower canopy. The differences of foliar short-term water use efficiency among different heights could be explained by discrepancies of environmental drivers and atmosphere CO2 concentration and δ13C. Platycladus orientalis leaves in upper canopy adapted to ambient condition by improving water use efficiency.

Analysis of changes in anatomical characteristics and physiologic features of heteromorphic leaves in a desert tree, Populus euphratica

Populus euphratica Oliv. is well-adapted to extreme desert environments and possess the characteristic of heterophylly. On the same tree, the lanceolate, broad-ovate, and dentate broad-ovate leaves distribute in the different tiers of the canopy. The lanceolate leaves distribute on the lower canopy, broad-ovate leaves on the middle canopy, and dentate broad-ovate leaves on the upper canopy. The leaf structure was found to be xeromorphic. The stomatal densities of the three typical leaves were different and decreased in value from dentate broad-ovate, to broad-ovate, and to lanceolate leaves. The osmotic potentials at full and zero turgor were lowest in dentate broad-ovate leaves. In an appropriate growth environment, the chlorophyll fluorescence parameters of the three leaf types were almost the same and significantly changed upon exposure to short-term water stress. These results showed that dentate broad-ovate leaves can maintain their normal size and shape under arid and hot conditions because of their relatively thick cell wall and high mechanical strength. Moreover, dentate broad-ovate leaves had more developed vascular bundles in the main vein than the other types and thus more efficiently transported water and salts. These results suggested that dentate broad-ovate leaves can efficiently adapt to changing conditions, with more obvious xeromorphic characteristics and a relatively higher photosynthesis rate under drought conditions, compared with the others leaf types.

Response of greenhouse tomato to different vertical spectra of LED lighting under overhead high pressure sodium and plasma lighting

Different light spectra trigger different plant growth processes. Therefore, the optimum light spectrum for various plant growth processes such as leaf and fruit growth may be different. Greenhouse mini-cucumber (Cucumis sativus L.) is a tall crop, with most leaf growth occurring in the top and middle canopy while fruit growth occurs in the middle and bottom canopy. Therefore, optimized vertical light spectral distribution profiles could be developed for improving both vegetative and fruit growth. In this study, we investigated the effects of different vertical spectra of light-emitting diodes (LED) lighting under high-pressure sodium (HPS) and plasma overhead lighting on plant growth and fruit yield of mini-cucumber. The study was conducted from October 2014 to April 2015 in a large greenhouse divided into 4 sections (50 m2 growing area in each section). Two sections were installed with plasma overhead light and the other two sections with HPS light, with both of them providing the same amount of overhead light (165 μmol m-2 s-1). Four vertical LED regimes (the top far red with bottom blue; the top blue with bottom far red; the top far red with bottom red; the top red with bottom far red) were applied to 4 plots inside each of the 4 sections. The blue or red LED each provided 10 µmol m-2 s-1, while the far red LED provided 8 µmol m-2 s-1 of light. The vertical LED treatments resulted in more than a 10% difference in fruit yield despite the small amount of light, indicating that the vertical light distribution had a large influence on plant growth. Top blue LED reduced leaf size and plant height in the early growth period which reduced total fruit yield for the plants grown under plasma light but not under HPS. Far red LED placed at the top of the canopy increased fruit yield, in comparison to bottom canopy placement, for plants grown under plasma light. This study has demonstrated that vertical light spectral distribution can have a large influence on plant growth and development, and optimized light distribution should and can be developed for year-round greenhouse vegetable production with supplemental lighting.

Within-Plant Distribution and Dynamics of Thrips Species (Thysanoptera: Thripidae) in Cotton.

A 2-yr study in cotton (Gossypium hirsutum L.) was conducted to determine the abundance and species composition of thrips (Thysanoptera: Thripidae) on different plant parts throughout the season in Alabama, Georgia, North Carolina, South Carolina, and Virginia. Plant parts sampled included seedlings, terminals with two expanded leaves, leaves from the upper, middle, and lower sections of the canopy, white flowers, and medium-sized bolls. Adult thrips were significantly more abundant on seedlings and flowers in 2014, and on flowers followed by seedlings and leaves from the middle canopy in 2015. Immature thrips were significantly more abundant on seedlings, followed by flowers in 2014, and on seedlings followed by leaves from the lower canopy and flowers in 2015. Across locations and plant parts, thrips consisted of Frankliniella tritici (Fitch) (46.8%), Frankliniella fusca Hinds (23.5%), Frankliniella occidentalis (Pergande) (17.1%), Neohydatothrips variabilis (Beach) (7.4%), Thrips tabaci (Lindeman) (1.8%), and other species (3.4%). Frankliniella fusca represented 86.7% of all thrips on seedlings, while F. tritici was more abundant on terminals (51.6%), squares (57.5%), and flowers (75.1%). Across all leaf positions, F.fusca was the most abundant species (28.8%), followed by F. tritici (19.2%), N. variabilis (18.8%), F. occidentalis (12.9%), and T.tabaci (5.2%), as well as other species (15.0%). As neonicotinoid insecticides remain a primary tool to manage seedling infestations of F. fusca, our data indicate that mid- to late-season applications of neonicotinoid insecticides targeting other insect pests will intensify selection pressure for resistance on F. fusca, the primary pest of seedling cotton.

Use of a Canopy Opener in Fungicide Applications to Improve Asian Soybean Rust Control

Abstract. In soybeans, the leaves of the upper canopy often act as a shield against fungicide penetration, preventing pesticide deposition on target. Fungicide applications to control Asian soybean rust (ASR) are especially difficult because the infection usually starts on the lower canopy. In this study, soybean plants of an early indeterminate cultivar and a determinate cultivar were sprayed with the fungicide azoxystrobin + benzovindiflupyr at six different times of the day with or without the addition of a curtain of chains on the spray boom, which acted as a canopy opener. The number of uredia of cm-2 and grain yield were measured to evaluate application efficacy. We found that the use of the curtain of chains reduced ASR control on the upper canopy for the indeterminate cultivar; however, less of a negative effect was observed for the determinate cultivar. The curtain of chains improved ASR control on the lower and middle canopies at more hours of the day for the determinate cultivar. For both cultivars, the curtain of chains increased ASR control at 6:00, 9:00, and 18:00 h on the lower canopy. Grain yield was also higher with the curtain of chains at 6:00 and 9:00 h for the determinate cultivar. Our results showed that using the curtain of chains could improve fungicide droplet deposition on the lower canopy, leading to greater ASR control and possibly increasing yield. However, it is important to consider the plant architecture and hour of application to maximize the benefit of the curtain of chains. Keywords: Canopy opener, Fungicide penetration, Phakopsora pachyrhizi, Plant architecture, Spray deposition.

Spray Tip Effect on Glufosinate Canopy Deposits in Palmer Amaranth (Amaranthus palmeri) for Pulse-Width Modulation versus Air-Induction Technologies

<abstract> Five nozzle tip treatments included nozzle tip designs and selected use of blended pulse-width modulation (bPWM), with tip selections based on a maxim of reduced spray drift potential, either through droplet size classification or spray entrainment of dual sprays. Spray nozzle technologies prioritized for this study included bPWM of pre-orifice tips in various configurations of single and dual tips, and air-induction tips operated in constant (non-bPWM) mode. A self-propelled sprayer equipped with a 30.5 m boom and bPWM applied glufosinate-ammonium herbicide simultaneously through the five different spray nozzle tip treatments. Ambient wind veleocities ranged from 3.1 to 4.1 m s^-1during application. Herbicide deposits on leaves and water-sensitive paper (WSP) coverage, spot density, and droplet size characteristics at top and middle canopy locations in Palmer amaranth were used to compare nozzle tip treatments. Treatment 1 (pre-orifice tips, bPWM and non-bPWM) produced significantly greater herbicide deposits than all tips except Treatment 2 (pre-orifice tip, bPWM). The latter was not significantly different from all other tips. The numerically lowest deposit level, based on the overall means, was produced by Treatment 5 (air-induction deflector tip, non-bPWM), although the leaf deposit was not significantly different from most tips. Deposits of glufosinate-ammonium for top canopy locations were greater than middle canopy location deposits for a given nozzle tip treatment. Summation of deposits across locations sometimes exceeded the application rate of 4.5 μg cm^-2, attributed to spray cloud momentum due to the application speed of 24 km h^-1. The addition of more weed plants or crop plants could possibly alter spray cloud momentum or serve as interceptors of droplets at the expense of deposit levels on Palmer amaranth. Glufosinate-ammonium leaf deposits were inversely proportional to and significantly correlated with canopy coverage of the ground, which supported this hypothesis. The highest mean WSP coverage occurring at top location for Treatment 1 was significantly greater than the mean WSP coverage at top locations for Treatment 4 (air-induction extended-range tip, non-bPWM) and Treatment 5, and greater than mean WSP coverages for all tip treatments at middle locations based on p-level observations. The highest mean WSP spot deposit for the top location of Treatment 1 (57.9 cm^-2) was significantly greater than the mean WSP spot deposits for all other tip treatments and canopy locations. A wide range of droplet sizes resulting from the entrainment of a Fine spray into an Extremely Coarse spray may have contributed to high values of coverage and spot deposit for Treatment 1. In conclusion, use of a pre-orifice nozzle tip with bPWM plus a pre-orifice nozzle tip in constant (non-bPWM) mode that produced contrasting droplet sizes for spray entrainment between the two tips provided a means to increase glufosinate-ammonium deposits on leaves and increase coverage and spot density on WSP. On the other hand, Y-adapter mounted pre-orifice tips with bPWM and separate air-induction nozzle tips (extended-range and deflector designs) operated as non-bPWM applications did not result in high levels of glufosinate-ammonium deposits on leaves and did not result in high levels of coverage and spot density on WSP.

Influence of plant architecture on maize physiology and yield in the Heilonggang River valley

The size and distribution of leaf area determine light interception in a crop canopy and influence overall photosynthesis and yield. Optimized plant architecture renders modern maize hybrids (Zea mays L.) more productive, owing to their tolerance of high plant densities. To determine physiological and yield response to maize plant architecture, a field experiment was conducted in 2010 and 2011. With the modern maize hybrid ZD958, three plant architectures, namely triangle, diamond and original plants, were included at two plant densities, 60,000 and 90,000plantsha−1. Triangle and diamond plants were derived from the original plant by spraying the chemical regulator Jindele (active ingredients, ethephon, and cycocel) at different vegetative stages. To assess the effects of plant architecture, a light interception model was developed. Plant height, ear height, leaf size, and leaf orientation of the two regulated plant architectures were significantly reduced or altered compared with those of the original plants. On average across both plant densities and years, the original plants showed higher yield than the triangle and diamond plants, probably because of larger leaf area. The two-year mean grain yield of the original and diamond plants were almost the same at 90,000plantsha−1 (8714 vs. 8798kgha−1). The yield increase (up to 5%) of the diamonds plant at high plant densities was a result of increased kernel number per ear, which was likely a consequence of improved plant architecture in the top and middle canopy layers. The optimized light distribution within the canopy can delay leaf senescence, especially for triangle plants. The fraction of incident radiation simulated by the interception model successfully reflected plant architecture traits. Integration of canopy openness is expected to increase the simulation accuracy of the present model. Maize plant architecture with increased tolerance of high densities is probably dependent on the smaller but flatter leaves around the ear.

Golden-cheeked Warbler Behavior in Relation to Vegetation Characteristics across their Breeding Range

Abstract We examined golden-cheeked warbler (Setophaga chrysoparia; hereafter warbler) behavior by age, sex, and habitat characteristics across their breeding range in central Texas (1995–1997). This federally endangered songbird foraged more on oak (Quercus spp.) substrates early in the breeding season and more on Ashe juniper (Juniperus ashei) late in the breeding season. We observed no overall difference in tree species use by warbler sex and age; however, we detected female and juvenile warblers in the low and middle canopy more often for all behaviors than males. Also, female warblers rested less and foraged twice as much as male warblers, who instead vocalized more than females and juveniles. In the southernmost study location, male warblers foraged more and vocalized less. More specifically, they foraged more on oaks when compared to other tree species, suggesting vegetation may influence warbler behavior in some locations. As the breeding season progressed, warblers increased their use of lower tr...

Investigating the European beech (Fagus sylvatica L.) leaf characteristics along the vertical canopy profile: leaf structure, photosynthetic capacity, light energy dissipation and photoprotection mechanisms.

Forest functionality and productivity are directly related to canopy light interception and can be affected by potential damage from high irradiance. However, the mechanisms by which leaves adapt to the variable light environments along the multilayer canopy profile are still poorly known. We explored the leaf morphophysiological and metabolic responses to the natural light gradient in a pure European beech (Fagus sylvatica L.) forest at three different canopy heights (top, middle and bottom). Structural adjustment through light-dependent modifications in leaf mass per area was the reason for most of the variations in photosynthetic capacity. The different leaf morphology along the canopy influenced nitrogen (N) partitioning, water- and photosynthetic N-use efficiency, chlorophyll (Chl) fluorescence and quali-quantitative contents of photosynthetic pigments. The Chl a to Chl b ratio and the pool of xanthophyll-cycle pigments (VAZ) increased at the highest irradiance, as well as lutein and β-carotene. The total pool of ascorbate and phenols was higher in leaves of the top and middle canopy layers when compared with the bottom layer, where the ascorbate peroxidase was relatively more activated. The non-photochemical quenching was strongly and positively related to the VAZ/(Chl a + b) ratio, while Chl a/Chl b was related to the photochemical efficiency of photosystem II. Along the multilayer canopy profile, the high energy dissipation capacity of leaves was correlated to an elevated redox potential of antioxidants. The middle layer gave the most relevant contribution to leaf area index and carboxylation capacity of the canopy. In conclusion, a complex interplay among structural, physiological and biochemical traits drives the dynamic leaf acclimation to the natural gradients of variable light environments along the tree canopy profile. The relevant differences observed in leaf traits within the canopy positions of the beech forest should be considered for improving estimation of carbon fluxes in multilayer canopy models of temperate forests.

Efficacy of unmanned helicopter in rainwater removal from cherry canopies

Rain-induced fruit cracking causes significant economic loss for fresh market sweet cherry growers annually. To prevent cherry cracking, timely removal of rainwater from fruit is the key. This study evaluated the efficacy of an unmanned middle-size helicopter to remove rainwater from Y-trellised cherry canopies. Helicopter downwash in hover at four altitudes, with and without a payload, was quantified with six anemometers deployed in tree canopies. Results showed that payload and altitude significantly affected hover downwash, which was greater at higher altitude of 7.6m above ground level (AGL) than lower altitude of 4.9m AGL with payload. In the absence of payload, hover downwash peaked at the altitude of 6.1m AGL. In the efficacy study, 5.0-mm rainwater was applied to cherry canopies by a rainfall simulation system, followed by the helicopter flying over canopies at three altitudes (4.9, 5.5 and 6.1m AGL), two travel speeds (1.3 and 2.7ms−1) and with or without payload. Rainwater removal at bottom (1.1m), middle (1.9m) and top (2.7m) of the canopies was calculated based on the change of leaf wetness of target canopies in 10min after rain. Overall, helicopter with payload flying 2.7ms−1 at 6.1m AGL removed significantly more rainwater (96.3%) from top section of canopies than groups without treatment (71.2%) and compared to other payload and travel speed conditions. Results also confirmed that the unmanned helicopter could provide sufficient downwash to remove rainwater effectively from bottom and middle canopy sections.

Feeding Postures of Cao Vit Gibbons (Nomascus nasutus) Living in a Low-Canopy Karst Forest

Food acquisition is an important factor in the evolution of primate postural behavior. Gibbons are well known for their ability to exploit terminal branches by means of below branch suspensory feeding, but few studies of gibbon positional behavior have been conducted since the seminal work of the 1970s and 1980s. We studied the feeding posture of three cao vit gibbon groups living in degraded karst forest in Bangliang Gibbon Nature Reserve between August 2008 and December 2009 to determine if body mass, age, and food type affect feeding posture. We found that cao vit gibbons spent most of their time feeding from branches (59.4 %) and twigs (33.2 %) in the middle canopy of the forest (5–10 m). They used suspensory hanging and sitting as their main feeding postures. Large-bodied gibbons spent more time on larger supports than smaller juveniles when feeding on nonfig fruit and leaves. In addition, gibbons of all age–sex classes adopted a suspensory posture more often when using smaller (twigs) or more flexible (lianas) supports. We found little evidence of age–sex differences in the frequency of suspensory feeding. The subtle differences we did detect suggest that intragroup feeding competition or ontogeny may confound the body size effects on feeding posture. Overall our findings conform to the view that within species positional behavior is largely constrained by musculoskeletal anatomy and not by habitat quality because cao vit gibbons showed a similar pattern of canopy and substrate use to gibbons occupying less disturbed forests.

Reliability and limitations of a novel terrestrial laser scanner for daily monitoring of forest canopy dynamics

Leaf area index (LAI) or plant area index (PAI) are commonly used to represent canopy structure and dynamics, but daily estimation of these variables using traditional ground-based methods is impractical and prone to multiple errors during data acquisition and processing. Existing terrestrial laser scanners can provide accurate representation of forest canopy structure, but the sensors are expensive, data processing is complex, and measurements are typically confined to a single event, which severely limits their utility in the interpretation of canopy trends indicated by remotely sensed data. We tested a novel, low-cost terrestrial laser scanner for its capacity to provide reliable and successive assessments of canopy PAI in an evergreen eucalypt forest. Daily scans comprised of 920 range measurements were made by three scanners at one forest site over a two-year period, providing mostly consecutive estimates of PAI, and of vertical structure profiles (as Plant Area Volume Density, PAVD). Data filtering, involving objective statistical methods to identify outliers, indicated that scan quality was adversely affected by moist weather and moderate wind speeds (>4ms−1), suggesting limited utility in some forest environments. Data cleaning (associated with sensor malfunctions) plus filtering removed 32 to 49% of scans, leaving on average 57% of data over the two-year period. Nonetheless, we found strong agreement between lidar-derived PAI estimates, and those from monthly hemispherical images (±0.1 PAI); with both methods indicating mostly stable PAI over multiple seasons. The PAVD profiles from the laser scanner indicated that leaf flush in the upper canopy concomitantly balanced leaf loss from the middle canopy in summer, which was consistent with measured summer peaks in litter fall. This clearly illustrated the advantages of three-dimensional lidar data over traditional two-dimensional PAI estimates in monitoring tree phenology, and in interpreting changes in canopy reflectance as detected by air- and space-borne remotely sensed data.

Structure of the epiphyte community in a tropical montane forest in SW China.

Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height), while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest.

Impacts of fertilization on photosynthesis, growth and yield of two soybean cultivars (Glycine maxL. Merr) in Northeast China

Soybean ( Glycine max L. Merr) is an important source of protein and oil in human and animal diets in many countries, but information about the interactive effects of fertilization and cultivar on its growth and yield was inadequate. A field experiment was conducted to investigate the effects of three fertilization regimes (CK, NPK, and NPK+manure) and two soybean cultivars, Liaodou14 and Liaodou21, on photosynthesis, growth and yield. NPK and NPK+manure increased leaf area index (LAI) and shoot biomass but did not affect time-course for two cultivars. P N (net photosynthetic rate) of the same treatment in different canopy showed the order of upper canopy > middle canopy > lower canopy. Cultivar, fertilization and the interaction had significant effects on yield of soybean. NPK and NPK+manure increased soybean yield compared with CK, but significant difference among fertilizer treatments was found at Liaodou21 not at Liaodou14 according to Duncan's test. Liaodou14 had significant higher yield than that of Liaodou21 regardless of fertilization application. Liaodou14 also showed consistently lower plant height, more main stem nodes, shorter internode length than that of Liaodou21 regardless of fertilization, which may be contributed to reasonable plant type with high yield in soybean.