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Plant Sciences

2012

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Articles 1 - 30 of 40

Full-Text Articles in Forest Sciences

The Effect Of Temperature On Seed Quality And Quantity In Crosses Between European (Populus Tremula) And Hybrid Aspens (P. Tremula X P. Tremuloides), L. Koviuranta, T. Latva-Karjanmaa, P. Pulkkinen Dec 2012

The Effect Of Temperature On Seed Quality And Quantity In Crosses Between European (Populus Tremula) And Hybrid Aspens (P. Tremula X P. Tremuloides), L. Koviuranta, T. Latva-Karjanmaa, P. Pulkkinen

Aspen Bibliography

Hybrid aspen (Populus tremula L. Populus tremuloides Michx.) plantations are expanding in Fennoscandia and the Baltic countries; however, the possible effects of plantations on the native European aspen (P. tremula) and the level of gene flow between European and hybrid aspen have not been investigated. We studied seed quantity and quality in intraspecific and interspecific crosses of the European and hybrid aspens over a two year period. In order to study whether elevated temperatures due to climate change would benefit the species differently, we performed the crosses in different temperatures. In both years, interspecific crosses produced more seeds with higher …


Effects Of Felled Shortleaf Pine (Pinus Echinata Mill.) Moisture Loss On Oviposition Preferences And Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Jessica Hartshorn Dec 2012

Effects Of Felled Shortleaf Pine (Pinus Echinata Mill.) Moisture Loss On Oviposition Preferences And Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Jessica Hartshorn

Graduate Theses and Dissertations

The European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae) utilizes pine as its host during larval development. Females drill through pine bark to deposit eggs, a symbiotic fungus, Amylostereum, and phytotoxic mucus into the tree. In their native range, these insects are not viewed as primary pests because they attack dead or dying trees. Over the last century, this woodwasp has been accidentally introduced into several countries in the southern hemisphere. Some regions have incurred millions of dollars in damage to large plantations of the widely planted pine species, radiata pine (Pinus radiata D. Don). Sirex noctilio was discovered …


Effects Of Slash Pile Burning After Restoring Conifer- Encroached Aspen, Christa M. Dagley, John-Pascal Berrill, Stephanie Coppeto, Kyle Jacobson Dec 2012

Effects Of Slash Pile Burning After Restoring Conifer- Encroached Aspen, Christa M. Dagley, John-Pascal Berrill, Stephanie Coppeto, Kyle Jacobson

Aspen Bibliography

Removal of conifers encroaching aspen stands has been advocated and is being practiced in the Lake Tahoe Basin (EIP Project #10080: Aspen Community Restoration Projects). In remote and roadless areas, thinning of conifers is generating large volumes of wood and pile burning is currently being implemented to handle this biomass on site. However, the effects of pile burning on aspen are unknown, and there is an urgent need for guidelines to support design of thinning treatment prescriptions; specifically burn pile size and safe distances from live aspen trees of any size to prevent injury.


Mortality Assessment Of Redwood And Mixed Conifer Forest Types In Santa Cruz County Following Wildfire, Steve R. Auten Dec 2012

Mortality Assessment Of Redwood And Mixed Conifer Forest Types In Santa Cruz County Following Wildfire, Steve R. Auten

Master's Theses

On August 12, 2009, the Lockheed Fire ignited the west slope of the Santa Cruz Mountains burning approximately 7,819 acres. Foresters and other land managers were left with challenging decisions on how to evaluate tree mortality. Big Creek Lumber Company, California Polytechnic State University, San Luis Obispo (Cal Poly)’s Swanton Pacific Ranch (SPR), and other resource professionals familiar with this region teamed up to develop a method for evaluating damage and thereby mortality for redwood, California nutmeg, live oak, tanoak, California bay, Pacific madrone, big leaf maple, Douglas-fir, Monterey pine, and knobcone pine. Quantitative damage criteria were used to design …


Economic Contribution Of The Agricultural Sector To The Arkansas Economy In 2010, Katherine Mcgraw, Jennie Popp, Wayne Miller Nov 2012

Economic Contribution Of The Agricultural Sector To The Arkansas Economy In 2010, Katherine Mcgraw, Jennie Popp, Wayne Miller

Research Reports and Research Bulletins

This report is the seventh in a series of reports examining agriculture’s economic contribution on the Arkansas economy. Utilizing data from the United States Bureau of Economic Analysis (BEA), USDA Economic Research Service (ERS), USDA National Agricultural Statistics Service (NASS), and Minnesota IMPLAN Group, Inc. (MIG), the economic contribution of agriculture on the Arkansas economy was estimated for the most recent year available, 2010. Gross Domestic Product (GDP) by State information for Arkansas in 2010 was compared with those of other states in the Southeast U.S. to give a measure of the relative importance of agriculture in Arkansas.2 The total …


Naturalization Of Sequoiadendron Giganteum (Cupressaceae) In Montane Southern California, Rudolf Schmid, Mena Schmid Sep 2012

Naturalization Of Sequoiadendron Giganteum (Cupressaceae) In Montane Southern California, Rudolf Schmid, Mena Schmid

Aliso: A Journal of Systematic and Floristic Botany

After the August 1974 fire in the upper Hall Canyon area on the southwestern flank of Black Mountain in the northwestern San Jacinto Mountains, Riverside County, California, the United States Forest Service revegetated the burn in the mixed-conifer forest with the Sierra Nevada endemic Sequoiadendron giganteum (Cupressaceae). On 1 May 2009 a GPS census starting at the head of Hall Canyon revealed both in the canyon and upslope beyond it at least 157 individuals in the vicinity of the Black Mountain Trail, plus an outlier 450 m distant near the summit. This species alien to southern California is regenerating prolifically …


Effects Of Nitrogen On Temporal And Spatial Patterns Of Nitrate In Streams And Soil Solution Of A Central Hardwood Forest, Frank S. Gilliam, Mary Beth Adams Sep 2012

Effects Of Nitrogen On Temporal And Spatial Patterns Of Nitrate In Streams And Soil Solution Of A Central Hardwood Forest, Frank S. Gilliam, Mary Beth Adams

Frank S. Gilliam

This study examined changes in stream and soil water NO3−and their relationship to temporal and spatial patterns of NO3−in soil solution of watersheds at the Fernow Experimental Forest, West Virginia. Following tenfold increases in stream NO3−concentrations over a 13-year period (1969–1981) on untreated WS4, concentrations have declined through 2006. Followingfourfold increases in stream NO3−on treatment WS3 from pretreatment levels to a 1998 maximum, concentrations have declinedthrough 2006, despite additions of N. Concentrations of soil water NO3−were consistently lower for WS4 compared to WS3.Data for soil water NO3−on WS3 versus WS4 followed patterns of net mineralization and nitrification for these watersheds.Nitrogen …


Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang Sep 2012

Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang

Frank S. Gilliam

Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (withharvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha1yr1, and 100kg N ha1yr1. Nitrogen additions did not significantly affect understory plant richness, density,and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in thisforest. In the rehabilitated forest, species richness and density showed no significant response to Nadditions; however, understory cover …


Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries Sep 2012

Global Assessment Of Nitrogen Deposition Effects On Terrestrial Plant Diversity : A Synthesis, R. Bobbink, K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, E. Davidson, F. Dentener, B. Emmett, J. W. Erisman, M. Fenn, Frank S. Gilliam, A. Nordin, L. Pardo, W. Devries

Frank S. Gilliam

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now …


Effects Of Experimental Nitrogen Additions On Plant Diversity In An Old-Growth Tropical Forest, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guoyi Zhou, Yunting Fang Sep 2012

Effects Of Experimental Nitrogen Additions On Plant Diversity In An Old-Growth Tropical Forest, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guoyi Zhou, Yunting Fang

Frank S. Gilliam

Response of plant biodiversity to increased availability of nitrogen (N) has been investigated in temperate and boreal forests, which are typically N-limited, but little is known in tropical forests. We examined the effects of artificial N additions on plant diversity (species richness, density and cover) of the understory layer in an N saturated old-growth tropical forest in southern China to test the following hypothesis: N additions decrease plant diversity in N saturated tropical forests primarily from N-mediated changes in soil properties. Experimental additions of N were administered at the following levels from July 2003 to July 2008: no addition (Control); …


Geographical Distribution And Survival Of Iris Yellow Spot Virus In Spiny Sowthistle, Sonchus Asper, In Georgia, Claudia Nischwitz Aug 2012

Geographical Distribution And Survival Of Iris Yellow Spot Virus In Spiny Sowthistle, Sonchus Asper, In Georgia, Claudia Nischwitz

All Current Publications

No abstract provided.


Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair Jun 2012

Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair

Aspen Bibliography

While it is well established that facilitation and competition are important structuring forces in plant communities, a clear understanding of the interactions between them and how they change through the life stages of plants and affect long-term plant community development is lacking. We have observed that conifer seedlings are rarely found growing in meadows but readily establish under adjacent aspen stands, particularly at the base of aspen trees, creating the potential for antagonistic interactions in later life stages. To examine these relationships and their potential consequences on forest community development, we characterized patterns of establishment, regeneration, and overstory mortality of …


Herbaceous 2012 (June 3), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan Jun 2012

Herbaceous 2012 (June 3), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


Herbaceous 2012 (May 19), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan May 2012

Herbaceous 2012 (May 19), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


Herbaceous 2012 (May 5), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan May 2012

Herbaceous 2012 (May 5), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


An Investigation Of Fraxinus Americana Branch Sway Using A 3 Dimensional Motion Capture System, Anna T. Campiformio May 2012

An Investigation Of Fraxinus Americana Branch Sway Using A 3 Dimensional Motion Capture System, Anna T. Campiformio

Master's Theses

Abstract

Wind is a dominant abiotic factor that a tree experiences throughout its lifetime and can cause severe tree damage, resulting in risk of injury to humans, and economic and ecological losses. It is thought that trees develop structural properties and architectures that help withstand loading conditions by dissipating wind energy through damping mechanisms. The role of branch motion in reducing potential dangerous wind loads has been the focus of relatively few studies. Even fewer studies have examined tree sway response to natural wind loaded conditions. In this investigation, branch frequencies were calculated for three Fraxinus americana using a three-dimensional …


Chemical Responses Of Two Deciduous Trees After 10-Years Of Exposure To Free Air Co2 Enrichment, Keonhee Kim May 2012

Chemical Responses Of Two Deciduous Trees After 10-Years Of Exposure To Free Air Co2 Enrichment, Keonhee Kim

Masters Theses

Globally, the mean atmospheric carbon dioxide level has risen steadily since pre-industrial times, which is largely attributable to human activities such as increased emissions from fossil fuel burning, and clearing of forests. Numerous research efforts have been made to understand responses of trees in higher atmospheric carbon dioxide levels in short term, small-scale experiments. To overcome the limitations of these experiments and understand the response of trees in a natural environment, the Free Air Carbon dioxide Enrichment (FACE) project was proposed. FACE is a global project that involves experimentally enriching carbon dioxide in the atmosphere of terrestrial ecosystems. The FACE …


Interacting Effects Of Fire Activity, Climate, And Habitat Diversity On Forest Dynamics, El Malpais National Monument, New Mexico, Usa, Alex John Pilote May 2012

Interacting Effects Of Fire Activity, Climate, And Habitat Diversity On Forest Dynamics, El Malpais National Monument, New Mexico, Usa, Alex John Pilote

Masters Theses

The historic effects of fire and climate on stand dynamics in the ponderosa pine-dominated forests of the American Southwest are of increasing concern to land management agencies. Using present forest stand structure, the mixed-conifer forests of the volcanic features in El Malpais National Monument were analyzed at three separate sites: a cinder cone, an ancient basalt flow, and an isolated “island” (kipuka) completely surrounded by basalt flows. Increment cores were collected from 632 trees in 19 plots within the monument to obtain dates of establishment. These dates were compared with historic fire histories and precipitation records to analyze the effects …


Herbaceous 2012 (April 21), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan Apr 2012

Herbaceous 2012 (April 21), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


Maple Syrup: St. John’S Sweetest Springtime Tradition, Stephen G. Saupe Apr 2012

Maple Syrup: St. John’S Sweetest Springtime Tradition, Stephen G. Saupe

Biology Faculty Publications

St. John’s is the home of one of Minnesota’s oldest maple syrup operations. The monks began making syrup in 1942 and have continued roughly every other spring until the present. Currently, the operation is jointly run by the Abbey and St. John’s Arboretum and it is one of the few maple syrup operations associated with a Minnesota college or university. The process by which maple syrup is made at St. John’s differs little from the procedures begun more than 60 years ago. In spring, sugar maple trees are tapped, sap is collected, and then it is boiled in the sugar …


Herbaceous 2012 (April 9), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan Apr 2012

Herbaceous 2012 (April 9), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


Adaptation Of Annual Forage Legumes In The Southern Great Plains, John A. Guretzky, Twain J. Butler, Jim P. Muir Apr 2012

Adaptation Of Annual Forage Legumes In The Southern Great Plains, John A. Guretzky, Twain J. Butler, Jim P. Muir

Great Plains Research: A Journal of Natural and Social Sciences

Our objective was to evaluate adaptation and compatibility of cool-season annual legumes overseeded into perennial grasses in the southern Great Plains. Freeze damage, vigor, and standing crop of 14 annual legume species were evaluated during spring at three locations in Oklahoma and Texas from 2006 to 2008. Across locations and years, standing crop of hairy vetch (Vicia villosa Roth) and Austrian winter pea (Pisum sativum L. ssp. arvense (L.) Poir.] averaged 3,513 and 3,210 kg dry matter (DM) ha-1, respectively. Standing crop of crimson clover (Trifolium incarnatum L.) and arrowleaf clover (T. vesiculosum Savi) averaged …


Phylogenetics Of Morus (Moraceae) Inferred From Its And Trnl-Trnf Sequence Data., Madhav Nepal Mar 2012

Phylogenetics Of Morus (Moraceae) Inferred From Its And Trnl-Trnf Sequence Data., Madhav Nepal

Madhav Nepal

Morus (Tribe Moreae, Moraceae) consists of ca. 13 species of trees distributed in Asia, Africa, Europe, and North, Central, and South America. The broad geographical distribution of the genus, overlapping ranges of many taxa, and documented hybridization between some species present interesting questions of taxonomy, phylogeny, and biogeography. Phylogenetic data for Morus also contribute to higher level taxonomic work in the family. We used sequence data from ITS of the nrDNA and the chloroplast trnL-trnF intergenic spacer to study phylogenetic relationships of Morus. Phylogenies based on separate data sets were not statistically incongruent, and the combined tree …


Herbaceous 2012 (March 25), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan Mar 2012

Herbaceous 2012 (March 25), Amy L. Myers, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2012 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.


Super Efficient Irrigation With Buried Clay Pots, David A. Bainbridge Jan 2012

Super Efficient Irrigation With Buried Clay Pots, David A. Bainbridge

David A Bainbridge

Buried clay pot irrigation was first described in an agricultural extension bulletin in China more than 2000 years ago. The clay pot provides demand responsive irrigation at very high efficiency. Clay pot irrigation can be 5-10 times more efficient than conventional irrigation. It is being used more widely in Asia, Africa, Latin American and the US.


The Philadelphia Award For 1960: Allston Jenkins, James Gross Jan 2012

The Philadelphia Award For 1960: Allston Jenkins, James Gross

James Gross

This biography of Allson Jenkins is part of a collective work for recipients of the Philadelphia Award. Allston Jenkins won the award in 1960 for his efforts in environmental conservation and preservation. He helped preserve the Tinicum Marsh, renamed the John Heinz National Wildlife Refuge, located in Philadelphia, PA and Delaware County.


Suitability Of Low Cost Commercial Off-The-Shelf Aerial Platforms And Consumer Grade Digital Cameras For Small Format Aerial Photography, Anthony Allen Turley Jan 2012

Suitability Of Low Cost Commercial Off-The-Shelf Aerial Platforms And Consumer Grade Digital Cameras For Small Format Aerial Photography, Anthony Allen Turley

Theses, Dissertations and Capstones

Many research projects require the use of aerial images. Wetlands evaluation, crop monitoring, wildfire management, environmental change detection, and forest inventory are but a few of the applications of aerial imagery. Low altitude Small Format Aerial Photography (SFAP) is a bridge between satellite and man-carrying aircraft image acquisition and ground-based photography. The author’s project evaluates digital images acquired using low cost commercial digital cameras and standard model airplanes to determine their suitability for remote sensing applications. Images from two different sites were obtained. Several photo missions were flown over each site, acquiring images in the visible and near infrared electromagnetic …


Effect Of Nitrogen Fertilization On Net Nitrogen Mineralization In Grassland Soil Of Northern China: Implications For Grassland Management, X. Zhang, Q. Wang, Frank S. Gilliam, W. Bai, X. Han, L. Li Jan 2012

Effect Of Nitrogen Fertilization On Net Nitrogen Mineralization In Grassland Soil Of Northern China: Implications For Grassland Management, X. Zhang, Q. Wang, Frank S. Gilliam, W. Bai, X. Han, L. Li

Biological Sciences Faculty Research

Nitrogen (N) applications can have a significant effect on soil N availability. The effect of 3 years of N fertilization on soil net N mineralization during the growing season (May–September) was studied in 2005 and 2006 in grassland of northern China. The experimental design was a randomized complete block with four replications of five rates of N addition as urea (0, 2, 4, 8 and 16 g N m−2 year−1). Results indicated that net N mineralization rate varied seasonally and between years, ranging from −0.04 to 0.52 μg g−1 d−1 in 2005 and from −0.09 …


Fish And Other Aquatic Resource Trends In The United States A Technical Document Supporting The Forest Service 2010 Rpa Assessment, Andrew J. Loftus, Curtis H. Flather Jan 2012

Fish And Other Aquatic Resource Trends In The United States A Technical Document Supporting The Forest Service 2010 Rpa Assessment, Andrew J. Loftus, Curtis H. Flather

USDA Forest Service / UNL Faculty Publications

The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires periodic assessments of the status and trends in the Nation’s renewable natural resources including fish and other aquatic species and their habitats. Data from a number of sources are used to document trends in habitat quality, populations, resource use, and patterns of imperilment among aquatic fauna. Freshwater habitat quality varied widely across the United States. Nationwide, more than half of monitored lakes were ranked in good condition, but the percentage ranged from a high of 91 percent in the upper Midwest to a low of 1 percent in …


Terrestrial Biosphere Models Need Better Representation Of Vegetation Phenology: Results From The North American Carbon Program Site Synthesis, Andrew D. Richardson, Ryan S. Anderson, M. Altaf Arain, Alan G. Barr, G. Bohrer, Guangsheng Chen, Jing M. Chen, Philippe Ciais, Kenneth J. Davis, Ankur R. Desai, Michael C. Dietze, Danilo Dragoni, Steven R. Garrity, Christopher M. Gough, Robert Grant, David Y. Hollinger, Hank A. Margolis, Harry Mccaughey, Mirco Migliavacca, Russell K. Monson, J. William Munger, Benjamin Poulter, Brett M. Raczka, Daniel M. Ricciuto, Alok K. Sahoo, Kevin Schaefer, Hanqin Tian, Rodrigo Vargas, Hans Verbeeck, Jingfeng Xiao, Yongkang Xue Jan 2012

Terrestrial Biosphere Models Need Better Representation Of Vegetation Phenology: Results From The North American Carbon Program Site Synthesis, Andrew D. Richardson, Ryan S. Anderson, M. Altaf Arain, Alan G. Barr, G. Bohrer, Guangsheng Chen, Jing M. Chen, Philippe Ciais, Kenneth J. Davis, Ankur R. Desai, Michael C. Dietze, Danilo Dragoni, Steven R. Garrity, Christopher M. Gough, Robert Grant, David Y. Hollinger, Hank A. Margolis, Harry Mccaughey, Mirco Migliavacca, Russell K. Monson, J. William Munger, Benjamin Poulter, Brett M. Raczka, Daniel M. Ricciuto, Alok K. Sahoo, Kevin Schaefer, Hanqin Tian, Rodrigo Vargas, Hans Verbeeck, Jingfeng Xiao, Yongkang Xue

USDA Forest Service / UNL Faculty Publications

Phenology, by controlling the seasonal activity of vegetation on the land surface, plays a fundamental role in regulating photosynthesis and other ecosystem processes, as well as competitive interactions and feedbacks to the climate system. We conducted an analysis to evaluate the representation of phenology, and the associated seasonality of ecosystem- scale CO2 exchange, in 14 models participating in the North American Carbon Program Site Synthesis. Model predictions were evaluated using long-term measurements (emphasizing the period 2000–2006) from 10 forested sites within the AmeriFlux and Fluxnet-Canada networks. In deciduous forests, almost all models consistently predicted that the growing season started …