Development of stand structural stage indices to characterize forest condition in Upstate New York     

Lisa Goodell  Don Faber-Langendoen 《Forest Ecology and Management》2007

Stand development stages are often used to describe temperate forest dynamics, but defining them using stand history or age can be difficult, especially for extensive surveys. The purpose of this study was to define stand development stage indices for forest stands on state forest land in Upstate New York using stand structure alone. A total of 508 stands were sampled, including 442 in Upstate New York. Two structural stage indices were defined for each of the 442 stands. The first index, based on SILVAH, was calculated using weighted mean diameter of trees in different size classes. The second index, based on work from Frelich and Lorimer, was calculated using the ratio of basal area of large trees to mature trees and either (1) exposed crown area (ECA) of trees in different size classes, or (2) basal area of trees in different size classes. Both indices were tested on stands with known stand histories. The second index was preferred for its superior ability to distinguish old-growth stands and was used to characterize structural stages of major forest types in Upstate New York: hemlock–hardwood (9% of state forest land), red spruce-fir (16%), and northern hardwood (51%). Results showed that the vast majority of stands in Upstate New York are in the mid-developmental stages. Structural characteristics of old-growth stands from this study were found to be in agreement with other old-growth stands in the northeastern United States.  相似文献   

Pristiphora abietina (Hym., Tenthredinidae)— ein Bioindikator für Luftverschmutzung? Besonderheiten unreifer Fichtennadeln als Larvenfutter     

Christa Schafellner  R. Berger  E. Führer 《European Journal of Forest Research》1993,112(1):116-128

  相似文献   

Immunological detection of decay in wood     

J. Jellison  B. Goodell 《Wood Science and Technology》1988,22(4):293-297

Summary An enzyme-linked immunosorbent assay (ELISA) was used to detect and quantify Postia placenta (Fr.) M. Lars. et Lomb. in decaying wood. The fungus was detected as early as ten days after inoculation suggesting that ELISA may be effective in detecting early incipient decay. Decay-induced weight loss in P. placenta decayed spruce blocks was correlated with the absorbance values obtained in the ELISA reaction.  相似文献   

Quality Criteria for Re-Use of Organotin-Containing Sediments on Land (7 pp)     

Christa Cornelis  Johan Bierkens  Ingeborg Joris  Peter Nielsen  Stany Pensaert 《Journal of Soils and Sediments》2006,6(3):156-162

Background, Aim and Scope   The use of organotin compounds as antifouling agents on ships is prohibited at EU level since 1 July 2003. Because of its persistence, the presence of organotin compounds in harbour sediment will however remain a problem for years. Dumping of dredged sediment in sea is subject to very strict quality criteria, stimulating the exploration of re-use alternatives, such as re-use on land. Within the TBT Clean project (EU LIFE Project 02/ENV/B/341) an assessment framework for re-use of organotin containing treated sediment on land as secondary granular building material was developed. Three scenarios were considered: free re-use on land, re-use above groundwater level with cover layer, and re-use under groundwater level (the latter two scenarios are referred to as restricted re-use). Receptors considered were humans, ecosystem and groundwater. Generic upper concentration limits and sediment leaching limits were calculated. Materials and Methods: Upper concentration limits were calculated with the Vlier-Humaan model. This model allows to calculate soil remediation values according to the Flemish legal framework. The focus of the methodology is the protection of human health, although a check for ecotoxicity was included in the project. The soil remediation value for residential land-use was selected within the scenario for free re-use; for restricted re-use (no direct contact possible), the soil remediation value for industrial land-use was selected. Leaching values were calculated with an analytical soil and groundwater transport model. The reference scenario behind the leaching criteria of the European Landfill Directive was modified to fit the project objectives. Default values for application height and length were used. The point-of-compliance was situated at 20 m distance in the groundwater. Physicochemical properties were taken from literature; sorption characteristics were taken from literature and were measured on 6 treated sediment samples during the project. Plant-uptake values were taken from the literature. Toxicological criteria were taken from EFSA. Results: The assessment framework provided an upper limit (SedUL) and an leaching value (SedLV) for each scenario, expressed as mg/kg dm in the sediment. Criteria were calculated for tributyltin (TBT) and dibutyltin (DBT); too few data were available for monobutyltin (MBT). The SedUL equalled 0.51 mg TBT/kg dm and 0.07 mg DBT/kg dm for free re-use and 195 mg TBT/kg dm and 205 mg DBT/kg dm for restricted re-use (two scenarios). For free re-use the SedLV was only limiting for TBT at Kd of < 2000 l/kg in the sediment. Under re-use above groundwater level with coverage SedLV values ranged from 6.9 – 29 mg TBT/kg dm and from 12 – 33.3 mg DBT/kg dm (Kd ranging from 100 – 10000 l/kg); under re-use below groundwater level SedLV values ranged from 0.007 – 0.77 mg TBT or DBT/kg dm (Kd ranging from 100 – 10000 l/kg). Discussion: Results are subject to large uncertainties because of variation in input data; the model output is sensitive to variation in plant uptake (SedUL for free re-use), Koc or Kd (SedUL for restricted re-use, SedLV for re-use with coverage), Henry's law coefficient (SedUL for restricted re-use); all these parameters show orders of magnitude variation. Conclusions: A feasible and consistent framework for evaluation of the re-use of treated organotin containing sediment was developed. However, the resulting quality criteria are still subject to large uncertainties, due to uncertainties in input data. Recommendations and Perspectives: High-quality data on plant uptake and soil sorption of organotin compounds, the influence of soil properties on these processes, and long-term terrestrial toxicity data are needed to refine the calculations. The quality criteria should be reviewed when these data become available.  相似文献   

Microbial biomass and N mineralization in relation to N supply of sugar beet under reduced tillage     

Christa Hoffmann  Heidrun Platte  Thomas Lickfett  Heinz-Josef Koch 《植物养料与土壤学杂志》1997,160(2):187-193

Reduced tillage may affect N supply of plants by influencing soil microbial biomass and thereby N release. The aim of this study was to evaluate changes in microbial biomass due to tillage in relation to N mineralization and to assess the contribution to the N supply of sugar beet. For this purpose, in a field trial near Göttingen in 1995 microbial biomass and net N mineralization were determined in an in situ incubation of ploughed and reduced tilled soil in plots which were not given application of mineral N fertilizer. In reduced tilled soil the increase in mineral N concentration in the upper 10 cm of soil was mainly attributed to an increase in microbial biomass. The organic matter was more easily decomposable, indicated by the increase in C_mic/C_org and N_mic/N_t ratios; this was further supported by the enhanced turnover of microbial biomass in reduced tillage plots. A regression function was used to relate seasonal fluctuations of microbial biomass, soil moisture and soil temperature to N mineralization rate. There was a good agreement between measured and calculated N mineralization rate. Reduced tillage affected N mineralization by affecting the quantity and quality of microbial biomass. In 0–30 cm soil depth 169 kg N/ha were mineralized, 30 kg more N than in ploughed soil. However, despite improved N availability, the N uptake of sugar beet was decreased in reduced tilled soil. Because the N concentration in plants did not differ, it was concluded that sugar beet growth in reduced tilled soil was impaired due to other factors than N supply.  相似文献   

Parameters causing variation between soil screening values and the effect of harmonization   总被引：3，自引：2，他引：3  

Jeroen Provoost  Lucas Reijnders  Frank Swartjes  Jan Bronders  Claudio Carlon  Marco D’Alessandro  Christa Cornelis 《Journal of Soils and Sediments》2008,8(5):298-311

Background, aim, and scope

This paper discusses the variation between generic soil screening values (SSV) from 17 countries for 11 volatile organic contaminants (VOC). The variation between SSV was one to four orders-of-magnitude (OOM) depending on the SSV and landuse type. What would be the variation if parameter values are harmonized between member states?

Main Features

The effect of harmonization was visualized by firstly reviewing the technical derivation procedure for SSV for 7 SSV from five countries and collecting all parameter values that are involved in the deviation. The parameters were subdivided in scientific (e.g. algorithm plus its parameter values), political (e.g. toxicological reference) or geographical (e.g. building and soil properties) elements. Secondly, new SSV were calculated with progressively harmonized sets of scientific and/or political parameter values, while the geographical parameters varied. Thirdly, the variation between SSV was compared before and after harmonization.

Results

Results show that harmonizing algorithms plus other scientific and political parameters are suited for harmonization. The variation decreases to 1 OOM, after scientific and political parameters were harmonized. Geographical parameters seem to have less impact on the differences between SSV.

Discussion

So, should we harmonize the procedures for deriving SSV between EU member states? The need for discussing harmonization is also raised by the upcoming EU Soil Framework Directive.

Conclusions

Clearly common generic SSV across all of Europe are not appropriate, since countries are allowed to include member state specific geographical and cultural elements and also political decision making. By harmonizing scientific and/or political parameters differences between SSV can be made more transparent between member states and it will encourage convergence in procedures among member states to ensure neutral conditions of competition and a coherent soil protection regime throughout Europe.

Recommendations and perspectives

To promote uniformity it is recommended to construct a toolbox for the calculation of human health risk exposure, carried by a European consensus, that includes different model algorithms for which fixed and flexible input parameters are made available. Fixed algorithm parameters are standardized and applied uniformly by all member states, e.g. physico-chemical parameters, while flexible input parameters permits member states to include region or country specific parameter values and policy decisions.  相似文献   

Inoculum Densities of Fusarium oxysporum f. sp. vasinfectum and Meloidogyne incognita in Relation to the Development of Fusarium Wilt and the Phenology of Cotton Plants (Gossypium hirsutum)     

Devay JE  Gutierrez AP  Pullman GS  Wakeman RJ  Garber RH  Jeffers DP  Smith SN  Goodell PB  Roberts PA 《Phytopathology》1997,87(3):341-346

ABSTRACT Development of Fusarium wilt in upland cotton (Gossypium hirsutum) usually requires infections of plants by both Meloidogyne incognita and Fusarium oxysporum f. sp. vasinfectum. In this study, the soil densities of M. incognita and F. oxysporum f. sp. vasinfectum and the incidence of Fusarium wilt in three field sites were determined in 1982-1984. Multiple regression analysis of percent incidence of Fusarium wilt symptoms on population densities of M. incognita and F. oxysporum f. sp. vasinfectum yielded a significant fit (R (2) = 0.64) only on F. oxysporum f. sp. vasinfectum. Significant t-values for slope were also obtained for the interaction of M. incognita and F. oxysporum f. sp. vasinfectum, but densities of M. incognita and F. oxysporum f. sp. vasinfectum were also related on a log(10) scale. The physiological time of appearance of first foliar symptoms of Fusarium wilt, based on a degree-days threshold of 11.9 degrees C (53.5 degrees F), was used as a basis for determining disease progress curves and the phenology of cotton plant growth and development. Effects of Fusarium wilt on plant height and boll set were determined in three successive years. Increases in both of these plant characteristics decreased or stopped before foliar symptoms were apparent. Seed cotton yields of plant cohorts that developed foliar wilt symptoms early in the season (before 2,000 F degree-days) were variable but not much different in these years. This contrasted with cohorts of plants that first showed foliar symptoms late in the season (after 2,400 F degree-days) and cohorts of plants that showed no foliar symptoms of wilt. Regression analyses for 1982-1984 indicated moderate to weak correlations (r = 0.16-0.74) of the time of appearance of the first foliar symptoms and seed cotton yields.  相似文献   

Feldstudie zum Nachweis und zur Regulation von Weizenschädlingen und natürlichen Antagonisten     

Nawal Gaafar  Nabil El-Wakeil  Abdellah S.H. Abdel-Moniem  Christa Volkmar 《Gesunde Pflanzen》2014,66(3):121-128

Wheat insect pests and the beneficial arthropod populations were assessed using sweep net across a large scale winter wheat field in Bad Lausick (Free State of Saxony, Germany) before and after insecticide applications. The insecticides used were Karate (pyrethroid), Biscaya (neonicotinoid) and NeemAzal T/S (botanical insecticide). The tested compounds were sprayed twice during the early season growth stage (Elongation- GS 32) and at the heading stage (GS 55), and their effects were evaluated on wheat insect pests. The side effects of these insecticides on associated natural enemies were also studied. Monitoring was conducted for 4 weeks after each treatment. Cereal aphids, thrips, leafhoppers, cereal leaf beetles, cereal bugs and also many natural enemies such as predators (lady beetles, lacewings, syrphids, dance flies and spiders) and parasitoids (parasitic wasps) were surveyed. The dose of these insecticides resulted in reductions of wheat insect and natural enemy populations and this reduction was corrected based on Abbott equation. The results showed that Karate is correlated with the highest percentage reduction (79.5 %) to wheat insect pests. Karate use also resulted in a percentage reduction to natural enemies (30–60 %). Biscaya and NeemAzal T/S is correlated with an equivalent mortality percents (50–65 %) to wheat insect pests and resulted in a smaller percentage reduction of natural enemies (10–40 %) compared to Karate. Thrips and cereal bugs were more affected than leafhoppers. Lacewings and dance flies were more susceptible; while spider, syrphids and parasitoid wasps were more tolerant. Compatibility between natural insecticides and natural enemies is highly required to keep the environment clean.  相似文献   

Impact of sensor‐controlled variable‐rate fungicide application on yield,senescence and disease occurrence in winter wheat fields          下载免费PDF全文

Maria Tackenberg  Christa Volkmar  Michael Schirrmann  Antje Giebel  Karl‐Heinz Dammer 《Pest management science》2018,74(6):1251-1258

  相似文献   

Are beech (Fagus sylvatica) roots territorial?     

Christa Lang  Alexandra Dolynska  Reiner Finkeldey  Andrea Polle 《Forest Ecology and Management》2010

Root competition between conspecific neighbours has been notoriously difficult to determine in intact ecosystems. Here we applied microsatellite markers to genotype beech trees (Fagus sylvatica, L.) and roots in subplots in an undisturbed, old-growth monospecific forest (Hainich, Germany). Roots were quantified and assigned to individuals. As a measure for territoriality, we determined root segregation. The hypothesis was tested that intraspecific root diversity was higher in the geometric centre of a triangle formed by beech trees than at positions closer to the stem of a tree. Space exploration measured as presence of an individual was correlated with stem diameter but not soil occupation. Fine root biomass, intraspecific Shannon diversity, effective numbers of genotypes and Evenness were stable and unrelated to the distance of the target tree. We conclude that beech shows no indication for territoriality or asymmetric competition in the presence of conspecific neighbours.  相似文献