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Spatial Distribution of Hemlock Woolly Adelgid Induced Hemlock Mortality in the Southern Appalachians

Open Journal of Forestry 2014年第5期4卷 492-506页

作者： Tuula Kantola Paivi Lyytikainen-Saarenmaa Robert N.Coulson Sheryl Strauch Maria D.Tchakerian markus holopainen Hannu Saarenmaa Douglas A.Streett Knowledge Engineering Laboratory Department of EntomologyTexas A&M UniversityCollege StationTXUSA Department of Forest Sciences University of HelsinkiHelsinkiFinland SIB Labs School of ComputingUniversity of Eastern FinlandJoensuuFinland Alexandria Forestry Center USDA Forest ServiceSouthern Research StationPinevilleLAUSA

Hemlock woolly adelgid (Adelges Tsugae Annand, HWA) outbreaks are posing a major threat to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.) forest landscapes in the eastern USA. As foundation species, hemlocks play a variety of functional roles in forest landscapes. These species usually occur as isolated canopies and mixed species in landscapes where variation in topography is extreme. Spatially explicit inventory information on HWA induced hemlock mortality at landscape scale does not exist. High resolution aerial imageries enable landscape scale assessment even at the individual tree level. Accordingly, our goal was to investigate spatial pattern and distribution of HWA induced hemlock mortality using a high resolution aerial image mosaic in the Linville River Gorge, Southern Appalachians, western North Carolina. Our study objectives were: 1) to detect dead trees within the Lower Linville River watershed;2) to estimate the area occupied by dead trees in the forest canopy surface;3) to investigate the relationship of dead hemlocks and topography;and 4) to define the spatial pattern of the dead trees. We found ca. 10,000 dead trees within the study area, occupying over 7 ha of the canopy surface with an average area of 36 m2 per dead tree. The density of the dead trees was higher in proximity to the Linville River, at higher elevations, and on northern and northwestern aspects. Spatial pattern of the dead trees was generally clustered at all spatial scales. We suggest that although the reduction in plant biomass resulting from herbivory within the landscapes is modest, impact of the clustered distribution of hemlock mortality, especially in the riparian zones, is noteworthy. Our analysis of the pattern of hemlock decline provides new means for projecting future impacts of HWA on the range of hemlock distribution in eastern North America.

关键词： Adelges Tsugae Eastern Hemlock Southern Appalachians Spatial pattern Topography Tree Mortality Tsuga

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Language of plants: Where is the word?

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Journal of Integrative Plant Biology 2016年第4期58卷 343-349页

作者： Maja impraga Junji Takabayashi Jarmo K.holopainen Botanical Garden Faculty of Science Ghent University Department of Environmental Science University of Eastern Finland Center for Ecological Research Kyoto University

Plants emit biogenic volatile organic compounds（BVOCs） causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called ＂plant language＂. Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants＂hear＂ volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plantinsect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles,reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds.

关键词： Green leaf volatiles plant-insect communication plant language semiochemicals volatiles

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Quantifying temporal changes in Tornionjoki river ice breakup dates and spring temperatures in Lapland since 1802

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Journal of Geographical Sciences 2013年第6期23卷 1069-1079页

作者： Samuli HELAMA Jianmin JIANG Johanna KORHONEN Jari holopainen Mauri TIMONEN Finnish Forest Research Institute Rovaniemi Northern Unit 96300 Finland Training Centre of China Meteorological Administration Beijing 100081 China Finnish Environment Institute Helsinki P.O. Box 140 00251 Finland Department of Geosciences and Geography University of Helsinki Helsinki P.O. Box 64 00014 Finland

Cryophenological records （i.e. observational series of freeze and breakup dates of ice） are of great importance when assessing the environmental variations in cold regions. Here we employed the extraordinarily long observational records of river ice breakup dates and air temperatures in northern Fennoscandia to examine their interrelations since 1802. Historical observations, along with modern data, comprise the informational setting for this analysis carried out using t-test. Temperature history of April-May season was used as cli- matic counterpart for the breakup timings. Both records （temperature and breakup） showed seven sub-periods during which their local means were distinctly different relative to preced- ing and subsequent sub-periods. The starting and ending years of these sub-periods oc- curred in temporal agreement. The main findings of this study are summarized as follows：（1） the synchrony between the temperature and river ice breakup records ruled out the possibility that the changes would have occurred due to quality of the historical series （i.e. inhomoge- neity problems often linked to historical time-series）; （2） the studied records agreed to show lower spring temperatures and later river ice breakups during the 19th century, in comparison to the 20th century conditions, evidencing the prevalence of cooler spring temperatures in the study region, in agreement with the concept of the Little Ice Age （1570-1900） climate in North-West Europe; （3） the most recent sub-period demonstrate the highest spring tem- peratures with concomitantly earliest river ice breakups, showing the relative warmth of the current springtime climate in the study region in the context of the past two centuries; （4） the effects of anthropogenic changes in the river environment （e.g. construction and demolition of dams） during the 20th century should be considered for non-climatic variations in the breakup records; （5） this study emphasizes the importance of multi-centurial （i.

关键词： climatic change historical climatology Lapland Little Ice Age phenology

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Effects of Rising Temperature on Secondary Compounds of Yeheb (<i>Cordeauxia edulis</i>Hemsley)

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American Journal of Plant Sciences 2014年第5期5卷 517-527页

作者： Meseret C. Egigu Mohamed A. Ibrahim Johanna Riikonen Asha Yahya Toini holopainen Riitta Julkunen-Tiitto Jarmo K. holopainen Department of Biology Haramaya University Dire Dawa Ethiopia Department of Biology University of Eastern Finland Joen-suu Finland Department of Crop Production Ecology Swedish University of Agricultural Sciences (SLU) Uppsala Sweden Department of Environmental Science University of Eastern Finland Kuopio Campus Kuopio Finland The Finnish Forest Research Institute Suonenjoki Finland

The effects of temperature on net photosynthesis and stomatal conductance, emission of foliar volatile organic compounds (VOCs), and phenolics were investigated after exposing Cordeauxia edulis seedlings to control (27/19°C) and three levels of elevated (32/23, 37/27, or 42/31°C) day/night temperature regimes in controlled growth chambers. Emissions of foliar VOC were measured on 7th and 14th day (d) of exposures, whereas net photosynthesis and stomatal conductance were measured on the 8th and 15th d. Net photosynthesis and stomatal conductance were not significantly affected by elevated temperatures. Emission rate of isoprene increased by 4-fold with 10°C rise from the control on 7th d of exposure. Emission rates of monoterpenes, sesquiterpenes and total isoprenoids increased to 2-5-fold higher than that of control plants with 5°C rise. Foliar isoprene emission peaked at daytime maximum of 37°C and the mono- and sesquiterpenes at 32°C. Few individual foliar phenolics, and total foliar phenolics showed significant concentration differences between treatments. Although high VOC emissions under warming appeared to help plants to sustain abiotic stresses, arid/semi-arid species might substantially release highly reactive compounds that affect atmospheric chemistry. Hence, more studies are required on plant species of arid/semi-arid ecosystems of Africa to estimate the emission patterns and their role in atmospheric chemistry under the predicted future atmospheric warming.

关键词： Cordeauxia edulis Climatic Warming Elevated Temperature Gas Exchange Isoprenoids Phenolics

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