Growing-season stemflow production within a deciduous forest of southern Ontario

A multi-layer model (FORUG) was developed, to simulate the canopy photosynthesis of a mixed deciduous forest during the growing season. Measured photosynthesis parameters, for beech (Fagus sylvatica), oak (Quercus robur) and ash (Fraxinus excelsior), were used as input to the model. This information at the leaf level is then scaled up to the level of the canopy, taking into account the radiation profiles (diffuse and direct PAR) in the canopy, the vertical LAI distribution, the evolution of the LAI and the photosynthesis parameters during the growing season, and the temperature dependence of the latter parameters.

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Fire, land cover, and temperature drivers of bat activity in winter

Fire Ecology ◽

10.1186/s42408-021-00105-4 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Marcelo H. Jorge ◽

Sara E. Sweeten ◽

Michael C. True ◽

Samuel R. Freeze ◽

Michael J. Cherry ◽

...

Keyword(s):

Land Cover ◽

Habitat Management ◽

Deciduous Forest ◽

Pinus Palustris ◽

Growing Season ◽

Early Spring ◽

Bat Activity ◽

White Nose Syndrome ◽

Dormant Season ◽

Wind Energy Development

Abstract Background Understanding the effects of disturbance events, land cover, and weather on wildlife activity is fundamental to wildlife management. Currently, in North America, bats are of high conservation concern due to white-nose syndrome and wind-energy development impact, but the role of fire as a potential additional stressor has received less focus. Although limited, the vast majority of research on bats and fire in the southeastern United States has been conducted during the growing season, thereby creating data gaps for bats in the region relative to overwintering conditions, particularly for non-hibernating species. The longleaf pine (Pinus palustris Mill.) ecosystem is an archetypal fire-mediated ecosystem that has been the focus of landscape-level restoration in the Southeast. Although historically fires predominately occurred during the growing season in these systems, dormant-season fire is more widely utilized for easier application and control as a means of habitat management in the region. To assess the impacts of fire and environmental factors on bat activity on Camp Blanding Joint Training Center (CB) in northern Florida, USA, we deployed 34 acoustic detectors across CB and recorded data from 26 February to 3 April 2019, and from 10 December 2019 to 14 January 2020. Results We identified eight bat species native to the region as present at CB. Bat activity was related to the proximity of mesic habitats as well as the presence of pine or deciduous forest types, depending on species morphology (i.e., body size, wing-loading, and echolocation call frequency). Activity for all bat species was influenced positively by either time since fire or mean fire return interval. Conclusion Overall, our results suggested that fire use provides a diverse landscape pattern at CB that maintains mesic, deciduous habitat within the larger pine forest matrix, thereby supporting the diverse bat community at CB during the dormant season and early spring.

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Can vegetation index track the interannual variation in gross primary production of temperate deciduous forests?

Ecological Processes ◽

10.1186/s13717-021-00324-2 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Fan Liu ◽

Chuankuan Wang ◽

Xingchang Wang

Keyword(s):

Primary Production ◽

Vegetation Index ◽

Near Infrared ◽

Deciduous Forest ◽

Gross Primary Production ◽

Growing Season ◽

Temperate Deciduous Forest ◽

Near Infrared Reflectance ◽

Modis Ndvi ◽

Temperate Deciduous

Abstract Background Vegetation indices (VIs) by remote sensing are widely used as simple proxies of the gross primary production (GPP) of vegetation, but their performances in capturing the inter-annual variation (IAV) in GPP remain uncertain. Methods We evaluated the performances of various VIs in tracking the IAV in GPP estimated by eddy covariance in a temperate deciduous forest of Northeast China. The VIs assessed included the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), and the near-infrared reflectance of vegetation (NIRv) obtained from tower-radiometers (broadband) and the Moderate Resolution Imaging Spectroradiometer (MODIS), respectively. Results We found that 25%–35% amplitude of the broadband EVI tracked the start of growing season derived by GPP (R2: 0.56–0.60, bias < 4 d), while 45% (or 50%) amplitudes of broadband (or MODIS) NDVI represented the end of growing season estimated by GPP (R2: 0.58–0.67, bias < 3 d). However, all the VIs failed to characterize the summer peaks of GPP. The growing-season integrals but not averaged values of the broadband NDVI, MODIS NIRv and EVI were robust surrogates of the IAV in GPP (R2: 0.40–0.67). Conclusion These findings illustrate that specific VIs are effective only to capture the GPP phenology but not the GPP peak, while the integral VIs have the potential to mirror the IAV in GPP.

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Growing-Season Synoptic and Phenological Controls on Heat Fluxes over Forest and Cropland Sites in the Midwest U.S. Corn Belt

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-19-0019.1 ◽

2020 ◽

Vol 59 (3) ◽

pp. 381-400

Author(s):

Mikael P. Hiestand ◽

Andrew M. Carleton

Keyword(s):

Land Use ◽

Deciduous Forest ◽

Growing Season ◽

Heat Fluxes ◽

Corn Belt ◽

Sensible Heat ◽

Convective Rainfall ◽

Mesoscale Circulations ◽

Synoptic Weather ◽

South Central

AbstractSpatial variations in land use/land cover (LULC) in the Midwest U.S. Corn Belt—specifically, deciduous forest and croplands—have been suggested as influencing convective rainfall through mesoscale circulations generated in the atmosphere’s boundary layer. However, the contributing role of latent and sensible heat fluxes for these two LULC types, and their modulation by synoptic weather systems, have not been determined. This study compares afternoon averages of convective fluxes at two AmeriFlux towers in relation to manually determined synoptic pressure patterns covering the nine growing seasons (1 May–30 September) of 1999–2007. AmeriFlux tower U.S.-Bo1 in eastern Illinois represents agricultural land use—alternating between maize and soybean crops—and AmeriFlux tower U.S.-MMS in south-central Indiana represents deciduous forest cover. Phenologically, the latent and sensible heat fluxes vary inversely across the growing season, and the greatest flux differences between cropland and deciduous forest occur early in the season. Differences in the surface heat fluxes between crop and forest LULC types vary in magnitude according to synoptic type. Moreover, statistically significant differences in latent and sensible heat between the forest and cropland sites occur for the most frequently occurring synoptic pattern of a low pressure system to the west and high pressure to the east of the Corn Belt. The present study lays the groundwork for determining the physical mechanisms of enhanced convection in the Corn Belt, including how LULC-induced mesoscale circulations might interact with synoptic weather patterns to enhance convective rainfall.

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Identification of secondary fatty alcohols in atmospheric aerosols in temperate forests

Biogeosciences ◽

10.5194/bg-16-2181-2019 ◽

2019 ◽

Vol 16 (10) ◽

pp. 2181-2188

Author(s):

Yuzo Miyazaki ◽

Divyavani Gowda ◽

Eri Tachibana ◽

Yoshiyuki Takahashi ◽

Tsutom Hiura

Keyword(s):

Atmospheric Aerosols ◽

Deciduous Forest ◽

Growing Season ◽

Fatty Alcohols ◽

Forest Site ◽

Cloud Droplets ◽

Ice Nuclei ◽

Forest Sites ◽

Molecular Tracer ◽

First Time

Abstract. Fatty alcohols (FAs) are major components of surface lipids (waxes) and can act as surface-active organic aerosols in the atmosphere, influencing chemical reactions, particle lifetimes, and the formation of cloud droplets and ice nuclei. However, studies on the composition and source of the FAs in atmospheric aerosols are very limited. In this study, we identified five secondary FAs (SFAs) with C27 and C29 from aerosol samples collected throughout 1 year at two different deciduous forest sites in Japan. Fatty diols, such as n-heptacosan-5,10-diol, were identified in atmospheric aerosols for the first time. Among the identified SFAs, n-nonacosan-10-ol was the most abundant compound, followed by n-nonacosan-5-10-diol at both of the forest sites. Concentrations of the SFAs exhibited distinct seasonal variation, with pronounced peaks during the growing season at each forest site. The SFAs showed significant correlation with sucrose, which is used as a molecular tracer of pollen. A significant fraction of the SFAs was attributed to the submicrometer particles in the growing season. The results indicate that they originated mostly from plant waxes and could be used as useful tracers for primary biological aerosol particles.

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