scholarly journals Living Particulate Fluxes in Throughfall and Stemflow During a Pollen Event

Author(s):  
Michele Guidone ◽  
D. Alex R. Gordan ◽  
John Toland Van Stan

Abstract Pollen shedding can produce rapid, abundant exchanges of nutrient-rich biomass 9 from plant canopies to the surface. When pollen deposits onto understory plants, it can be 10 washed off during storms via throughfall (a drip flux) and stemflow (a flux down plant stems). 11 Pollen deposition may also alter the organismal community on plant surfaces, changing other 12 biological particulates transported by throughfall and stemflow. We report concentrations and 13 fluxes of pollen and other biological particulates (flagellate cells, nematodes, rotifers, mites and 14 hexapodans) in throughfall and stemflow from an understory forb, Eupatorium capillifolium 15 (Lam. dogfennel), during a Pinus palustris (Mill. longleaf pine) pollen shedding event, then 16 compare these results to observations collected when pollen was absent. Pollen flux was 95.6 x 17 106 grains ha-1 season-1 from dogfennel canopies (63% and 37% transported by throughfall and 18 stemflow, respectively), representing 0.1-3.2 g ha-1. Median concentrations in flagellates, 19 nematodes and rotifers for throughfall and stemflow were higher during pollen shedding; 20 however, mites and hexapodan concentrations were similar regardless of pollen presence. This 21 is the first report of flagellate and hexapodan concentrations in canopy drainage waters. 22 Flagellate concentrations were higher than for other organisms—being similar to those 23 reported for streams, 105-107 cells L-1—and hexapodan fluxes were ~50 individuals m-2 per 1 cm 24 of rainfall. These results indicate that throughfall and stemflow can (i) transport ecologically 25 relevant amounts of pollen and organisms from the phyllosphere to the surface, and (ii) that 26 the composition and flux of biological particulates can change markedly during pollen shedding.

2021 ◽  
Author(s):  
John P McGuire ◽  
John S Kush ◽  
J Morgan Varner ◽  
Dwight K Lauer ◽  
J Ryan Mitchell

Abstract Efforts to restore longleaf pine (Pinus palustris Mill.) in the southeastern US require substantial artificial regeneration. Once established, important questions remain about when to introduce fire. We investigated the impact of initial planting density on tree branching and how prescribed fire might interact with tree architecture and survival. A particular focus was on how prescribed fires could “prune” lower branches. Lower density plantings (897 trees ha−1) had more and larger live lower branches than higher density plantings (2,243 trees ha−1). Fire was effective in pruning lower branches regardless of season burned, but fire in the growing season was more effective at pruning. Branches up to a height of 1.5 to 2 m were killed by fire. Fire applied in August caused greater damage with more needles scorched and/or consumed and more stem char. Prescribed fire did not impact longleaf pine tree survival. In general, fire applied to longleaf pine facilitated pruning lower branches that affect long-term wood quality, an additional argument for its utility in restoration and management of these ecosystems.


2011 ◽  
Vol 20 (2) ◽  
pp. 268-276 ◽  
Author(s):  
Benjamin J. Shepherd ◽  
Deborah L. Miller ◽  
Mack Thetford

2021 ◽  
Vol 39 (3) ◽  
pp. 115-122
Author(s):  
Zachary Singh ◽  
Adam Maggard ◽  
Rebecca Barlow ◽  
John Kush

Abstract Longleaf pine (Pinus palustris Mill.), and slash pine (Pinus elliottii Engelm.) are two southern pine species that are popular for producing pine straw for landscaping. The objective of this research was to determine the response of soil properties and weed growth to the application of pine straw. Longleaf pine, slash pine, and two non-mulched controls (with and without chemical weed control) were tested. Volumetric soil water content, soil nutrients, soil temperature, weed biomass, and seedling growth were measured. Compared to non-mulched controls, both longleaf and slash pine plots had a greater soil moisture during extended periods without rainfall in the full sun environment. When soil temperatures increased, mulched plots had lower soil temperature relative to non-mulched plots. Soil pH and soil nutrients were generally similar between pine straw types with few significant differences in measured variables. Both pine straw treatments reduced weed growth and longleaf pine maintained a greater straw depth over the study period compared to slash pine, but no differences were observed for decomposition. These results indicate that longleaf pine straw and slash pine straw perform equally as well in terms of increasing soil moisture, moderating soil temperature, and reducing weed growth compared to not using mulch. Index words: Pinus elliottii, Pinus palustris, organic mulch, soil properties, landscaping. Species used in this study: Shumard oak, Quercus shumardii Buckl., Eastern redbud, Cercis canadensis L.


2020 ◽  
Vol 14 (2) ◽  
pp. 413-433
Author(s):  
William J. McFarland, ◽  
Danielle Cotton, ◽  
Mac H. Alford ◽  
Micheal A. Davis

Longleaf pine (Pinus palustris Mill.) ecosystems exhibit high species diversity and are major contributors to the extraordinary levels of regional biodiversity and endemism found in the North American Coastal Plain Province. These forests require frequent fire return intervals (every 2–3 years) to maintain this rich diversity. In 2009, a floristic inventory was conducted at the Lake Thoreau Environmental Center owned by the University of Southern Mississippi in Hattiesburg, Mississippi. The Center is located on 106 ha with approximately half covered by a 100+ year old longleaf pine forest. When the 2009 survey was conducted, fire had been excluded for over 20 years resulting in a dense understory dominated by woody species throughout most of the forest. The 2009 survey recorded 282 vascular plant species. Prescribed fire was reintroduced in 2009 and reapplied again in 2010, 2012, 2014, 2016, and 2018. A new survey was conducted in 2019 to assess the effects of prescribed fire on floristic diversity. The new survey found an additional 268 species bringing the total number of plants species to 550. This study highlights the changes in species diversity that occurs when fire is reintroduced into a previously fire-suppressed system and the need to monitor sensitive areas for changes in species composition.


Author(s):  
Scott Pokswinski ◽  
Michael R. Gallagher ◽  
Nicholas S. Skowronski ◽  
E. Louise Loudermilk ◽  
Joseph J. O'Brien ◽  
...  

Firebrands are an important agent of wildfire spread and structure fire ignitions at the wildland urban interface. Bark flake morphology has been highlighted as an important, yet poorly characterized factor in firebrand generation, transport, deposition, and ignition of unburned material. Using pine species where bark flakes are the documented source of embers, we conducted experiments to investigate how bark structure changes in response to diurnal drying. Over a 3-day period in a longleaf pine (Pinus palustris Mill.) stand in Florida, we recorded changes in temperature, moisture content and structure of bark across different facing aspects of mature pine trees to examine the effects of varying solar exposure on bark moisture. We further compared results to bark drying in a pitch pine (Pinus rigida Mill.) plantation in New Jersey. Under all conditions, bark peeled and lifted away from the tree trunk over the study periods. Tree bole aspect and the time of day interacted to significantly affect bark peeling. General temperature increases and moisture content decreases were significantly different between east and west aspects in pitch pine, and with time of day and aspect in longleaf pine. These results illustrate that bark moisture and flakiness is highly dynamic on short time scales, driven largely by solar exposure. These diurnal changes likely influence the probability of firebrand production during fire events via controls on moisture (ignition) and peeling (lofting).


2002 ◽  
Vol 32 (11) ◽  
pp. 1984-1991 ◽  
Author(s):  
Michael A Battaglia ◽  
Pu Mou ◽  
Brian Palik ◽  
Robert J Mitchell

Spatial aggregation of forest structure strongly regulates understory light and its spatial variation in longleaf pine (Pinus palustris Mill.) forest ecosystems. Previous studies have demonstrated that light availability strongly influences longleaf pine seedling growth. In this study, the relationship between spatial structure of a longleaf pine forest and spatial pattern of understory light availability were investigated by comparing three retention harvest treatments: single-tree, small-group, large-group, and an uncut control. The harvests retained similar residual basal area but the spatial patterns of the residual trees differed. Hemispherical photographs were taken at 300 stations to calculate gap light index (GLI), an estimate of understory light availability. Stand-level mean, variation, and spatial distribution of GLI were determined for each treatment. By aggregating residual trees, stand mean GLI increased by 20%, as well as its spatial variation. Spatial autocorrelation of GLI increased as the size of the canopy gaps increased and the gaps were better defined; thus, the predictability of GLI was enhanced. The ranges of detrended semivariograms were increased from the control to the large-group harvest indicating the spatial patterns of understory GLI became coarser textured. Our results demonstrated that aggregated canopy structure of longleaf pine forest will facilitate longleaf pine seedling regeneration.


1980 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Robert C. Sparks ◽  
Norwin E. Linnartz ◽  
Harold E. Harris

Abstract Pruning and thinning a young natural stand of longleaf pine (Pinus palustris Mill.) in southwest Louisiana had little influence on height. However, diameter growth was reduced substantially as pruning intensity or stocking rate increased up to 25-percent live crown and 200 stems per acre, respectively. Improved diameter growth at lower stocking rates was not sufficient to equal the total basal area increment of 200 trees per acre.


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