Red Maple Trees Research Articles

Operating a Process-based Simulation Model within a User-friendly Windows Environment to Predict the Transpiration and Photosynthesis of Red Maple Trees

Application of process-based models beyond the research community has been limited, in part because they do not operate in a user-friendly Windows environment. We describe the procedure of adapting a spatially explicit biological-process model, MAESTRA, to run in a standard graphical user interface (GUI). The methods used to adapt the MAESTRA model are generally applicable to other process-based models and therefore simplify other coupling attempts. We discuss recommendations based on our experiences for model input structure and interface design, two components that will allow various models to work with a generic interface. MAESTRA uses modified versions of the Ball-Berry stomatal conductance (gs) and Farquhar photosynthesis(Anet) models to estimate transpiration and photosynthesis on a leaf area basis and scale the sunlit and shaded fractions to the whole tree. We present MAESTRA estimates within a standardized graphical user interface for crop simulators (GUICS) windows environment and furthermore, we provide dialog boxes and graphical displays of the MAESTRA model input and whole tree output for red maple trees. In so doing, we present a technology transfer via the GUICS that prevents any watering down of the science behind the MAESTRA model, yet allows an accurate decision support tool to reach a wide audience.

TREESTRESS: A Within Canopy Spatial Distribution Model for Simulating the Carbon and Water Exchange Response to Atmospheric Thermal and Rhizospheric Water Stress

A model (TREESTRESS, a spatially explicit 3-D process-based model) for simulating the spatial distribution of intracanopy photosynthetic and transpirational responses to multiple stress factors is presented. The model includes intracrown validation on both deciduous and coniferous radiation transfer, incorporation of temperature response functions of Rubisco-, mesophyll-, and RuBP-limited photosynthesis to the widely used Farquhar et al. (1980) photosynthesis model, and a rhizospheric water stress submodel to constrain the Ball-Berry stomatal conductance submodel. The model also includes functions that account for acclimation and/or no acclimation to growth temperature. Taken together, the model aims at predicting spatially explicit intracrown response to multiple stresses (primarily temperature, water, and radiation stress). The model was parameterized for red maple trees under nursery conditions and validated by sap flow, photosynthesis, and radiation measurements. The integration of multiple stress response functions in a spatially explicit process-based model could provide a proficient method to simulate stress interactions and predict carbon uptake and water use in crowns, canopies, ecosystems, and landscapes.

Physiological and foliar symptom response in the crowns of Prunus serotina, Fraxinus americana and Acer rubrum canopy trees to ambient ozone under forest conditions

The crowns of five canopy dominant black cherry ( Prunus serotina Ehrh.), five white ash ( Fraxinus americana L.), and six red maple ( Acer rubrum L.) trees on naturally differing environmental conditions were accessed with scaffold towers within a mixed hardwood forest stand in central Pennsylvania. Ambient ozone concentrations, meteorological parameters, leaf gas exchange and leaf water potential were measured at the sites during the growing seasons of 1998 and 1999. Visible ozone-induced foliar injury was assessed on leaves within the upper and lower crown branches of each tree. Ambient ozone exposures were sufficient to induce typical symptoms on cherry (0–5% total affected leaf area, LAA), whereas foliar injury was not observed on ash or maple. There was a positive correlation between increasing cumulative ozone uptake ( U) and increasing percent of LAA for cherry grown under drier site conditions. The lower crown leaves of cherry showed more severe foliar injury than the upper crown leaves. No significant differences in predawn leaf water potential ( ψ L) were detected for all three species indicating no differing soil moisture conditions across the sites. Significant variation in stomatal conductance for water vapor ( g wv) was found among species, soil moisture, time of day and sample date. When comparing cumulative ozone uptake and decreased photosynthetic activity ( P n), red maple was the only species to show higher gas exchange under mesic vs. drier soil conditions ( P < 0.05). The inconsistent differences in gas exchange response within the same crowns of ash and the uncoupling relationship between g wv and P n demonstrate the strong influence of heterogeneous environmental conditions within forest canopies.

Ecosystem response to 15 years of chronic nitrogen additions at the Harvard Forest LTER, Massachusetts, USA

Humans have altered the global and regional cycles of nitrogen more than any other element. Alteration of N cycling patterns and processes in forests is one potentially negative outcome of accelerated N deposition worldwide. To assess potential impacts of N deposition on temperate forests, a series of chronic nitrogen additions in two contrasting forest types (red pine plantation and mixed hardwood stand) were designed as a core experiment of the Harvard Forest (HF) Long-term Ecological Research (LTER) program. This paper describes the chronic N experimental study site in detail and presents the long-term baseline measurements established at the beginning of treatments in 1988. Results reported here continue or accelerate trends presented in previous papers. Losses of inorganic N remain high in the high N plots (higher in pines than hardwoods) and low N plots in the pine stand also have measurable DIN losses. Foliar and fine root N concentrations are elevated significantly. Mortality of red pine reached 56% by 2002 in the pine high N plot, and biomass accumulation has stopped altogether. The high N hardwood stand shows increased ANPP, but excess N availability and a severe drought in 1995 contributed to mortality of 72% of red maple trees by 2002. Species importance and litterfall patterns were altered in several plots after 1995. Roots, foliage and wood have diminished as net sinks for added N, re-emphasizing the role of soils in N retention. Two mechanisms for large net retention of added N were suggested in a review paper in 1998. Of these, abiotic immobilization is supported by a growing set of papers, while assimilation and re-exudation by mycorrhizae is suggested by increased DON concentrations.

Spray Delivery to Nursery Trees by Air Curtain and Axial Fan Orchard Sprayers

Abstract Two types of air-assist sprayers were used to treat, from one side only, a single row of hedge-pruned, red maple (Acer rubrum L. ‘Red Sunset’) trees in a commercial Ohio nursery. A traditional orchard type sprayer and a prototype air curtain sprayer using crossflow fans and hydraulic nozzles were evaluated for differences in canopy deposits, spray coverage, and downwind ground deposits. The air curtain sprayer produced more uniform deposits vertically but not higher mean deposits than the traditional orchard type sprayer. The air curtain sprayer also produced somewhat higher ground deposits downwind of the treatment area. There were no differences in spray coverage between sprayers despite differences in the droplet spectrum produced by each sprayer. Evidence from the coverage and ground target samples indicate that slower fans on the air curtain sprayer might be needed to reduce air speed to retain more spray within the tree canopy. As operated, neither of the sprayers can be expected to produce uniform spray deposits around the nursery stock if treatments are made from one side of the row only. Canopy and ground target deposits indicate that alternate row spraying will not necessarily produce uniform deposits across two tree rows as planted at the test site.

Examining formulas that assess strength Loss due to decay in trees: woundwood toughness improvement in red maple (Acer rubrum)

Hazard trees are a concern for anyone who manages trees in a landscape setting, including arborists, urban foresters, and grounds managers. Through research, experience, observation, and common sense, arborists and urban foresters have identified many risk factors that predispose trees to failure. They have also developed thresholds to help determine the degree of hazard, whether a tree is in imminent danger of failing or needs annual (or more frequent) inspections. Two critical factors are involved in strength loss assessment in tree stems with defects. First, it is important to know how much tree strength is lost due to a defect such as a hollow or cavity. Second, the load required to cause failure needs to be considered since the wood of some trees can endure greater mechanical stress than others. Tests of woundwood and normal wood in red maple (Acer rubrum) trees from Massachusetts, U.S., showed woundwood to exhibit consistently greater toughness measures compared to normal wood. There was, however, no correlation between the degree of toughness improvement in woundwood and the severity of decay (calculated as the loss in moment of inertia of the stem). Woundwood toughness improvement appears to be an additional safety factor in red maple trees that reduces the risk of failure due to trunk decay.

The potential effects of sexual reproduction and seedling recruitment on the maintenance of red maple (Acer rubrum L.) populations at the northern limit of the species range

AimFor this study, we wanted to evaluate the reproductive potential of northern red maple (Acer rubrum L.) populations to identify the possible factors responsible for the scattered distribution pattern of these northern populations.LocationSamara production and long‐term establishment of seedlings were observed along a north–south transect crossing the transition zone between continuous and discontinuous stands of red maple (47°80′–49°27′ N) in western Quebec.MethodsEleven populations of red maple were selected along a latitudinal gradient extending to the northern limit of the species. Seed traps were placed in each stand and distributed under the canopy of mature red maple trees. Seed abundance was tracked for 6 years from 1988 to 1993. Phenological observations were made in 1992 and 1993 at Roquemaure (Roq), a site located at the centre of the latitudinal gradient. Red maple trees were randomly selected within the population; counts of flower buds, pollinated buds and samaras produced were made in 1992–93. Samaras were collected from each branch immediately before dispersal and counted. During the summer of 1987, seedlings (&lt; 1 cm d.b.h.) were collected and aged at each site in twenty 1 m2 quadrants and age of the seedlings (&lt; 1 cm d.b.h.) was determined by counting the annual scars left by terminal buds.ResultsSamaras were produced even at the northern limit but large yearly variations were observed. Over the 6‐year period we counted 3 years (1989, 1990, 1993) when samara production was high, and 3 years (1988, 1991, 1992) when production was low. Phenological observations indicate that the occurrence of spring frosts at the time of flower bud flushing could contribute to decreasing the abundance of seeds. The age structure of southern localities had a relatively constant production of seedlings, as indicated by an inverse J‐shaped distribution. However, the five northernmost localities show sporadic recruitment.Main conclusionsPopulations at the northern limit are maintained essentially through vegetative reproduction and infrequent sexual recruitment. Our results indicate that regeneration within established stands through sexual recruitment is possible in all of the populations we studied. This potential becomes very low at more northerly sites and sexual reproduction alone would be unlikely to ensure successful stand regeneration. Without major disturbances in those stands, shade tolerant conifer species such as balsam fir (Abies balsamea) or black spruce (Picea mariana) would readily dominate the canopy. The discontinuous distribution of red maple stands at the northern limit is the consequence of either a random colonization of few sites during a better climatic period or remnants of a much larger distribution that has been constrained because of climatic deterioration.

Photosynthetic characteristics in canopies of Quercus rubra, Quercus prinus and Acer rubrum differ in response to soil water availability.

Photosynthesis and related leaf characteristics were measured in canopies of co-occurring Quercus rubra L. (red oak), Quercus prinus L. (chestnut oak) and Acer rubrum L. (red maple) trees. Mature (20+m tall) trees were investigated at sites of differing soil water availability within a catchment (a drier upper site and a wetter lower site). Leaf photosynthetic characteristics differed significantly between species and in response to site and position in the canopy. Photosynthetic capacity (A max) was significantly greater at the wetter site in all canopy strata in A. rubrum but not in Q. rubra or Q. prinus. Our findings for A. rubrum are generally consistent with those predicting that species with higher specific leaf area (SLA) will have higher A max per unit leaf nitrogen (N) and that species with leaves with lower SLA (e.g. Q. rubra and Q. prinus) will have shallower slopes of the A max-N relationship. Importantly, the relationships between A max and N area (and by implication photosynthetic nitrogen-use efficiency, PNUE) differed in A. rubrum between the sites, with PNUE significantly lower at the drier site. The lower photosynthetic capacity and PNUE must substantially reduce carbon acquisition capacity in A. rubrum under these field conditions. Maximum stomatal conductance (g smax) differed significantly between species, with g smax greatest in Q. rubra and Q. prinus. In Q. rubra and Q. prinus, g smax was significantly lower at the upper site than the lower site. There was no significant response of g smax to site in A. rubrum. These stomatal responses were consistent with the C i/C a ratio, which was significantly lower in leaves of Q. rubra and Q. prinus at the upper site, but did not differ between sites in A. rubrum. Leaf δ13C was significantly lower in A. rubrum than in either Q. rubra or Q. prinus at both sites. These findings indicate differences in stomatal behaviour in A. rubrum which are likely to contribute to lower water use efficiency at both sites. Our results support the hypothesis that the two Quercus species, in contrast to A. rubrum, maintain photosynthetic capacity at the drier site whilst minimising transpirational water loss. They also suggest, based primarily on physiological evidence, that the ability of A. rubrum to compete with other species of these deciduous forests may be limited, particularly in sites of low moisture availability and during low rainfall years.

A COMPARISON OF FOUR EVAPOTRANSPIRATION MODELS IN A GREENHOUSE ENVIRONMENT

Advances in evapotranspiration modeling have led to a variety of formulas and terms used in irrigation controlresearch. Four models that represent the progression from outdoor, big leaf estimates to indoor, greenhousespecificformulations are compared in this article. Each of the models was algebraically reduced to common and consistent terms.The data from a lysimeter study were used to compare evapotranspiration combination models using evapotranspiration (ET)rates of a Red Sunset Red Maple tree (Acer rubrum Red Sunset) grown in a controlledenvironment greenhouse. Themeasured ET was compared with two empirical climatic factors (solar irradiance and vapor pressure deficit) and withcalculated ET based on four evapotranspiration models: (1) Penman, (2) PenmanMonteith, (3) Stanghellini, and (4) Fynn.A measure of the model performance is given by the NashSutcliffe R2, or model efficiency. The relationship between measuredand calculated ET for the Stanghellini model was calculated to have a model efficiency of R2 = 0.872, while the other modelsyielded correlations of R2 = 0.214, R2 = 0.481, R2 = 0.848 for Penman, PenmanMonteith, and Fynn, respectively. Thedifferences between the models are discussed, revealing the importance of the leaf area index factor and a submodel forirradiance in the plant canopy. Based on the coefficient of determination, vapor pressure deficit alone yielded a good linearcorrelation to measured ET (r2 = 0.884), while solar irradiance alone resulted in r2 = 0.652.

Environmental control of whole-plant transpiration, canopy conductance and estimates of the decoupling coefficient for large red maple trees

There is a strong need to extend whole-tree measurements of sap flow into broad-leaved forests where characteristics of stand structure, surface roughness, leaf dimension, and aerodynamic and canopy conductance may interact to partially decouple the canopy from the atmosphere. The implications of this partial decoupling to understanding the environmental control of canopy transpiration and to the modeling of forest water use are many. Therefore, thermal dissipation probes were used over a three-month period (June through August, 1997) to quantify day-to-day and tree-to-tree variation in whole-tree sap flow ( Q) for 12 red maple ( Acer rubrum L.) trees growing in an upland oak forest of eastern Tennessee. Whole-tree Q was calculated as the product of measured sap velocity, sapwood area and the fraction of sapwood functional in water transport. Daily canopy transpiration ( E c) was calculated from whole-tree Q and projected crown area, whereas average daily conductance ( g c) was derived by inverting the Penman–Monteith equation. Maximum Q averaged 73 kg per tree per day and varied between 45 and 160 kg per day for trees that ranged in stem diameter (DBH) from 17 to 35 cm, and from 19 to 26 m in height. Canopy transpiration peaked at 3.0 mm per day in early July and averaged 1.5 mm per day over the 3-month measurement period. Tree-to-tree variability for E c was high. Maximum rates of E c varied from 1.9 mm per day for the tree with the smallest projected crown area to 5.7 mm per day for one of the largest trees. Day-to-day variation in E c was a function of daily differences in net radiation ( R n) and atmospheric humidity deficit ( δ e). Increases in daily R n and δ e led to linear increases in canopy transpiration and there was no indication that a plateau-style relationship existed between E c and average daily δ e. Mean daily g c ranged from 1.4 to 6.7 mm s −1, and averaged 3.4 mm s −1 across the 12 study trees. Some of the tree-to-tree variation observed for E c and g c was related to the fact that not all trees occupied the same vertical position within the stand. Variation in estimates of the daily decoupling coefficient (0≤Ω≤1) was also considerable and for individual trees the seasonally-averaged Ω varied from 0.12 to 0.37, and averaged 0.23 for the 12 study trees. An Ω of this magnitude indicates that red maple canopies are partially decoupled from the atmosphere and suggests that significant vertical gradients of air temperature and δ e from the canopy surface to the bulk air several meters above the canopy are possible. Model analysis of hourly data indicated that simulated surface temperatures in mid-July were 3.6–5.8°C higher than above-canopy reference temperatures, and δ e at the canopy surface was 0.3 kPa higher than that of the bulk atmosphere. These calculations were partially supported by leaf-level measurements taken on one of the trees from a 20-m canopy-access tower. The implications of this partial decoupling to understanding and modeling the environmental control of canopy transpiration are discussed.

La Crosse encephalitis virus habitat associations in Nicholas County, West Virginia.

Aedes triseriatus (Say) population density patterns and La Crosse encephalitis virus infection rates were evaluated in relation to a variety of habitat parameters over a 14-wk period. Ovitraps and landing collections were used in a La Crosse virus-enzootic area in Nicholas County, WV. Study sites were divided into categories by habitat type and by proximity to the residences of known La Crosse encephalitis cases. Results demonstrated that Ae. triseriatus population densities were higher in sugar maple/red maple habitats than in hemlock/mixed hardwood habitats or in a site characterized by a large number of small red maple trees. Sites containing artificial containers had higher population densities than those without. La Crosse virus minimum infection rates in mosquitoes collected as eggs ranged from 0.4/1,000 to 7.5/1,000 in the 12 study sites, but did not differ significantly among sites regardless of habitat type or proximity to human case residences. La Crosse virus infection rates in landing Ae. triseriatus mosquitoes ranged from 0.0/1,000 to 27.0/1,000. La Crosse virus was also isolated from host-seeking Ae. canadensis (Theobald) in two study sites, at rates similar to those found in the Ae. triseriatus populations. The Ae. triseriatus oviposition patterns and La Crosse virus infection rates suggest that this mosquito species disperses readily in the large woodlands of central West Virginia. The La Crosse enzootic habitats in Nicholas County, WV, are contrasted with those studied in other geographic regions where La Crosse virus is found.

Dynamic changes in petiole specific conductivity in red maple (Acer rubrum L.), tulip tree (Liriodendron tulipifera L.) and northern fox grape (Vitis labrusca L.)

ABSTRACTDiurnal variation in petiole specific hydraulic conductivity and simultaneous measurements of leaf water potential were recorded in red maple, tulip tree and fox grape. Petiole specific conductivity was determined from in situ measurements of water flow into the distal (leaf‐bearing) end of an attached petiole as a function of applied hydrostatic pressure and petiole dimensions. The hydraulic properties of the petiole dominated the measurements, indicating that this technique can be used for rapid estimates of petiole hydraulic conductivity. There was a significant decrease in petiole specific conductivity associated with increasingly more negative leaf water potentials in maple and tulip tree, but not in grape. Petiole specific conductivity increased during the afternoon while the plant was actively transpiring and the xylem sap was under tension. The recovery of petiole conductivity during the afternoon suggests that hydraulic conductivity reflects a dynamic balance between a loss of hydraulic conductivity with increasing water stress, and its restoration as tension within the xylem decreases. Three experimental manipulations were applied to red maple and tulip tree to examine the sensitivity of diurnal changes in petiole conductivity to various physiological perturbations. Both phloem girdling and application of HgCl2 to the transpiration stream resulted in a marked decrease in the degree to which petiole specific conductivity recovered as xylem tension relaxed during the afternoon. Delivery of a surfactant to the xylem, however, did not significantly alter the relation between leaf water potential and petiole hydraulic conductivity.

High resolution Ka-band images of a small tree: measurements and models

Ka-band (27 GHz to 36 GHz) radar images of a 2.5-m red maple tree, measured in the Ohio State University ElectroScience Laboratory (ESL), Columbus, compact range, are presented. Radar images of the tree with and without leaves were obtained, as well as images of a 6 in diameter metal sphere obscured by the tree for investigation of attenuation effects. The large bandwidth (9 GHz) of these measurements provides a cm scale range resolution, so that backscatter from individual components of the tree canopy can be separated. In addition, measurements made as a function of azimuth angle in 0.1 degree steps allow inverse synthetic aperture radar (ISAR) images to be obtained with cm scale resolutions in down and cross range. A single scattering model, in which tree branches are represented as a deterministic collection of cylinders and leaves as a distributed collection of curved dielectric sheets, is combined with a detailed measurement of the tree geometry to provide theoretical ISAR images for comparison with the measured data. Although incomplete knowledge of tree geometry limits a direct quantitative comparison of the measured and modeled returns, a qualitative comparison of images shows that single scattering models may be sufficient for obtaining many features of foliage objects in Ka-band radar images.

Effect of Organic and Mineral Mulches on Soil Properties and Growth of Fairview Flame® Red Maple Trees

Five mineral mulches (crushed red brick, pea gravel, lava rock, carmel rock, and river rock) and 3 organic mulches (finely screened pine bark, pine wood chips, and shredded hardwood bark) were evaluated over 2 years to determine their influence on soil temperature, moisture, and pH, and to quantify their effect on growth of Fairview Flame® red maple (Acer rubrum L). Soil temperatures were highest and moisture percentages lowest under the mineral mulches and nonmulched control. Soil pH readings were highest under shredded bark and wood chips, and lowest in the nonmulched control. Trees growing in river rock, crushed brick, pea gravel, and carmel rock had larger stem calipers than those growing in shredded bark plots. Crushed brick, pea gravel, and carmel rock treatments also resulted in greater leaf dry mass than did shredded bark. These results, however, should not be interpreted as an indictment of organic mulches. Because stem caliper and leaf dry mass measurements of trees growing in wood chips and any of the mineral mulches were not statistically different, blanket statements and generalizations regarding the performance of woody plants mulched with organic or mineral (rock) materials are unwise.

Prediction of Spatial Cumulative Distribution Functions Using Subsampling

Abstract The spatial cumulative distribution function (SCDF) is a random function that provides a statistical summary of a random field over a spatial domain of interest. In this article we develop a spatial subsampling method for predicting an SCDF based on observations made on a hexagonal grid, similar to the one used in the Environmental Monitoring and Assessment Program of the U.S. Environmental Protection Agency. We show that under quite general conditions, the proposed subsampling method provides accurate data-based approximations to the sampling distributions of various functionals of the SCDF predictor. In particular, it produces estimators of different population characteristics, such as the quantiles and weighted mean integrated squared errors of the empirical predictor. As an illustration, we apply the subsampling method to construct large-sample prediction bands for the SCDF of an ecological index for foliage condition of red maple trees in the state of Maine.

Prediction of Spatial Cumulative Distribution Functions Using Subsampling

The spatial cumulative distribution function (SCDF) is a random function that provides a statistical summary of a random field over a spatial domain of interest. In this article we develop a spatial subsampling method for predicting an SCDF based on observations made on a hexagonal grid, similar to the one used in the Environmental Monitoring and Assessment Program of the U.S. Environmental Protection Agency. We show that under quite general conditions, the proposed subsampling method provides accurate data-based approximations to the sampling distributions of various functionals of the SCDF predictor. In particular, it produces estimators of different population characteristics, such as the quantiles and weighted mean integrated squared errors of the empirical predictor. As an illustration, we apply the subsampling method to construct large-sample prediction bands for the SCDF of an ecological index for foliage condition of red maple trees in the state of Maine.

TRANSPIRATION OF CONTAINER-GROWN ACER RUBRUM UNDER CONDITIONS OF HIGH EVAPORATIVE DEMAND

This study was preliminary to developing feed-forward computer control algorithms to irrigate Acer Rubrum(Red Maple) trees in proportion to predicted transpiration. Transpiration rates of Acer Rubrum and related climatevariables were measured continuously in a very high evaporative demand greenhouse environment and comparedindependently to solar radiation and vapor pressure deficit (VPD). Measured transpiration rates were further comparedto predicted transpiration based on the combination equation. Based on regression analyses and the coefficient ofdetermination (R 2 ), the single variable VPD predicted transpiration equally as well as the combination model with an Rsquared value for both equal to 0.861. Meanwhile, using the single variable solar radiation to predict transpirationresulted in an R squared value of 0.652.

Development of Solid Calibration Standards for Trace Elemental Analyses of Tree Rings by Laser Ablation Inductively Coupled Plasma-Mass Spectrometry

Laser ablation sampling (LAS) in conjunction with inductively coupled plasma-mass spectrometry (ICP-MS) was used for the quantitative multielemental analysis of red maple (Acer rubrum L.) tree rings. Slight differences in ablation were corrected using 13C as an internal standard. Calibration standards, consisting of individual tree rings from wood sections sampled from trees along a transect away from a metal smelter, were used to convert integrated signal intensities (cps) into concentrations (mg kg-1). The relative standard deviation (RSD) of element distribution within individual tree rings was <15% for 11 elements analyzed. Calibration curves were calculated for 43Ca, 55Mn, 63Cu, 64Zn, 114Cd, 202Hg, and 208Pb, as only these seven elements had different concentrations in the tree rings used as wood standards. Tree cores from red maple trees growing in contaminated soils adjacent to metal smelters and a discolored core from a tree growing in uncontaminated soil were analyzed by LAS ICP-MS. Differences in element concentration over time and between trees were found, but surprisingly, concentrations of Cu, Zn, Mn and Ca were up to five times greater in discolored regions of the tree core from the unpolluted site compared to cores from contaminated sites. Damaged or discolored tree cores should therefore be avoided in dendrochemical studies. LAS ICP-MS can be used for the quantitative analysis of Acer tree rings providing a rapid, nondestructive technique which involves minimal sample preparation and provides high spatial resolution with very low detection levels for many elements.

Humate-based Biostimulants Affect Early Post-transplant Root Growth and Sapflow of Balled and Burlapped Red Maple

Application of biostimulants, humate-based products marketed as aids to plant establishment, may increase early post-transplant root growth and water uptake of landscape trees. We tested three distinct types of biostimulants on root growth and sapflow of balled and burlapped red maple (Acer rubrum L. `Franksred') trees. Treatments included: humate, 1) as a wettable powder formulation, applied as a soil drench; 2) as a liquid formulation to which various purported root growth—promoting additives had been added, also applied as a soil drench; 3) as a dry granular formulation, applied as a topdress; and 4) a nontreated control. Root growth was monitored through single-tree rhizotrons, and sap flow was measured with a heat balance sapflow system. Roots were first observed in the rhizotron windows 38 days after planting. No biostimulant-treated trees had more root length than nontreated controls, and the two soil drench treatments had the lowest root length throughout the 20 weeks of post-transplant observation. All biostimulants increased sapflow.

Humate-based Biostimulants Affect Early Post-transplant Root Growth and Sapflow of Balled and Burlapped Red Maple

Application of biostimulants, humate-based products marketed as aids to plant establishment, may increase early post-transplant root growth and water uptake of landscape trees. We tested three distinct types of biostimulants on root growth and sapflow of balled and burlapped red maple (Acer rubrum L. `Franksred') trees. Treatments included: humate, 1) as a wettable powder formulation, applied as a soil drench; 2) as a liquid formulation to which various purported root growth—promoting additives had been added, also applied as a soil drench; 3) as a dry granular formulation, applied as a topdress; and 4) a nontreated control. Root growth was monitored through single-tree rhizotrons, and sap flow was measured with a heat balance sapflow system. Roots were first observed in the rhizotron windows 38 days after planting. No biostimulant-treated trees had more root length than nontreated controls, and the two soil drench treatments had the lowest root length throughout the 20 weeks of post-transplant observation. All biostimulants increased sapflow.