Complete Enclosure of Stunted Trees to Study Greenhouse Gas Fluxes in Birch-Invaded Peatland

2021 ◽  
Author(s):  
William Barrop ◽  
Russell Anderson ◽  
Roxane Andersen ◽  
Sylvia Toet
Keyword(s):  
Management Practice ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Average Height ◽  
Flux Chamber ◽  
Wooded Area ◽  
Flux Measurements ◽  
Peat Surface ◽  
Growing Conditions ◽  
A Site

<p>Ombrotrophic, naturally open peatlands are increasingly susceptible to invasion by scrub and trees due to human disturbance, N deposition and climate change. There is limited research on the effect these trees have on ecosystem functions and their removal can be costly, making decisions over best management practice challenging. The adverse growing conditions associated with many of these peatlands can result in stunted tree growth meaning that complete enclosure of a tree remains a practical possibility. In this study we aim to quantify the CH<sub>4</sub> and CO<sub>2</sub> fluxes from whole trees growing on a disturbed peatland and assess their significance relative to the fluxes between the vegetated peat surface and atmosphere. We also aim to identify if the establishment of trees impacts CH<sub>4</sub> and CO<sub>2</sub> fluxes from the vegetated peat surface, as compared to adjacent uninvaded peatland.</p><p>We have developed a removable chamber capable of enclosing whole trees of up to 3 metres high, making it suitable for use on juvenile or stunted trees. Being able to enclose an entire tree removes potential errors caused by estimating whole tree fluxes by upscaling measurements from a subsample of tree surfaces. The chamber is constructed with a transparent membrane and removable cover so that light and dark measurements can be taken. We use the chamber to take CH<sub>4</sub> and CO<sub>2</sub> flux measurements on a site with approximately 20-year-old silver birch trees (Betula pendula) of an average height of 2-3 metres. Flux measurements have been taken from the trees and ground collars at different times of year. We have also studied diurnal variation.</p><p>Our initial results have shown that the trees on our site are emitters of CH<sub>4</sub>, although this emission is small in comparison to that produced by the rest of the habitat. The vegetated peat surface in the wooded area had lower CH<sub>4</sub> emission but reduced CO<sub>2</sub> uptake as compared to the open area. The diurnal study on one tree indicates that methane emissions increase at night. A further diurnal study is planned to explore this further. This study extends the limit on the size of vegetation that can be sampled by a manually operated flux chamber.</p>

Methodological errors in radioisotope flux measurements

1988 ◽  
Vol 255 (5) ◽  
pp. G696-G699
Author(s):  
R. W. Egnor ◽  
S. G. Vaccarezza ◽  
A. N. Charney
Keyword(s):  
Specific Activity ◽  
Flux Measurement ◽  
Sampling Interval ◽  
Flux Chamber ◽  
Sources Of Error ◽  
Counting Time ◽  
Flux Measurements ◽  
The Absolute ◽  
The Difference ◽  
Serial Samples

We examined several sources of error in isotopic flux measurements in a commonly used experimental model: the study of 22Na and 36Cl fluxes across rat ileal tissue mounted in the Ussing flux chamber. The experiment revealed three important sources of error: the absolute counts per minute, the difference in counts per minute between serial samples, and averaging of serial samples. By computer manipulation, we then applied hypothetical changes in the experimental protocol to generalize these findings and assess the effect and interaction of the absolute counts per minute, the sampling interval, and the counting time on the magnitude of the error. We found that the error of a flux measurement will vary inversely with the counting time and the difference between the consecutive sample counts per minute used in the flux calculations and will vary directly with the absolute counts per minute of each sample. Alteration of the "hot" side specific activity, the surface area of the tissue across which flux is measured and the sample volume have a smaller impact on measurement error. Experimental protocols should be designed with these methodological considerations in mind to minimize the error inherent in measuring isotope flux.

AN EVALUATION OF SEVERAL METHODS OF ESTIMATING SITE INDEX OF IMMATURE STANDS

1952 ◽  
Vol 28 (3) ◽  
pp. 63-74 ◽  
Author(s):  
John W. Ker
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Site Quality ◽  
Average Height ◽  
Office Procedure ◽  
Minimum Sample ◽  
A Site ◽  
The University ◽  
Site Classes

The use of dominant heights for the estimation of site index is compared with the use of the average of dominant and codominant heights. Data collected on the University Research Forest are presented to illustrate the variability in tree heights and diameters within the two upper crown classes in well-stocked stands of immature Douglas fir.HeightIt is shown that the use of dominant heights reduces considerably the number of measurements required for a site index determination of given accuracy. Minimum sample sizes are given for three limits of accuracy for use in different site qualities. A general field and office procedure is outlined for the determination of minimum sample size in stands other than those described.DiameterThe use of diameter in site determination is discussed. Site indices based on the height of the tree of mean diameter, the height of the tree of mean basal area, and mean height are compared.ConclusionsQuick estimates of site quality can best be obtained by the measurement of total height of sample dominant trees, selected at random. For this purpose, tables are presented which list the average height of dominant trees by age and site classes for use in stands of Douglas fir, and western hemlock, respectively.

Measuring and tracking nighttime inversions within a forest canopy

2020 ◽  
Author(s):  
Bart Schilperoort ◽  
Miriam Coenders-Gerrits ◽  
Hubert Savenije
Keyword(s):  
Forest Canopy ◽  
Fiber Optic ◽  
Forest Understory ◽  
Forest Site ◽  
Distributed Temperature Sensing ◽  
Fiber Optic Cable ◽  
Vertical Temperature Profile ◽  
Flux Measurements ◽  
Response To Temperature ◽  
A Site

<p>One of the challenges of flux measurements above tall canopies, is that parts of the canopy can be decoupled from the atmosphere above. This decoupling can, for example, occur when the forest understory is colder than the air above, limiting exchange through convection. While concurrent above and below canopy eddy covariance (EC) measurements help with addressing the decoupling issue, these are still disconnected point measurements and do not show what is happening along the entire vertical profile. For this, Distributed Temperature Sensing (DTS) can give additional insights, as it can perform continuous temperature measurements along a vertically deployed fiber optic cable.</p><p>Measurements were performed at the ‘Speulderbos’ forest site in the Netherlands, where a 48 m tall measurement tower is located in a stand of 34 m tall Douglas Fir trees.  We measured a vertical temperature profile through the canopy using DTS (from the surface up to 32 m). The measurement frequency was ~0.5 Hz, with a vertical resolution 0.30 cm, and data was collected for two months. The fiber optic cable used had a diameter of 0.8 mm, allowing a sufficiently quick response to temperature changes. With this data we were able to detect the presence, height, and strength of inversions. The inversions appeared to occur mostly at night. The height of the inversion showed a bistable behavior, either staying around 1 m above the ground, or at approximately 16 m, which is just below the dense branches of the canopy.</p><p>By locating and tracking inversions within the canopy, decoupling events can be studied and explained in more detail. If vertical DTS profiles are available at a site, these can be used for filtering EC measurements as well. While more research will be needed before a wide application at flux sites is possible, this study can serve as a ‘proof-of-concept’ and demonstrates how vertical DTS profiles can help understand problematic flux sites.</p>

scholarly journals Indicator of tension in the living space of protective forest stands

2020 ◽  
Vol 11 (4) ◽  
Author(s):  
V. M. Maliuha ◽  
V. V. Minder
Keyword(s):  
Self Regulation ◽  
Significant Loss ◽  
Average Height ◽  
Forest Stands ◽  
Scotch Pine ◽  
Cross Sectional ◽  
High Productivity ◽  
Living Space ◽  
Growing Conditions ◽  
The Stability

The density of stands remains a controversial issue to this day, requiring a practical solution in terms of the optimal liquefaction of plantings without a significant loss of the quantitative productivity of the trunk stock of wood and the stability of forest stands. Only as a result of focused efforts can the patterns of natural liquefaction or the process of self-regulation of complex biological systems, to which the forest belong, be achieved. Natural liquefaction of forest stands is an extremely complex process due to its multifactorial nature, to the manifestation of which climatic, soil, biological conditions and many other mutual influences are involved. In forest biogeocenoses, the edifacatory role belongs to the main stand. This tier represents a group of tree species in a phytocenosis, which determines its structure and, to a certain extent, composition. In this study, it is proposed to evaluate the functional load by an indicator of the tension of the living space of the plantation. Since Scotch pine is one of the most common edificators, widely used in the creation of anti-erosion plantations on soils of varying degrees of washout, substantiation of the indicator of tension is carried out on its example. The formula for calculating the tension indicator of the living space, characterizing the growing conditions of the plantation, is given. The indicator of the tension of living space is the ratio of the average height of plantings to their absolute completeness. The verification of the proposed indicator was carried out using tables of the course of growth, highlighting the patterns of the structure of tree stands. A graphic interpretation of the static research of forest stands is carried out. If the values of the tension indicators coincide with the distribution curve obtained from the standard tables of the sum of the cross-sectional areas of tree trunks with a completeness of 1.0, this indicates the optimal use of living space by plantations. The values of the indicators placed above the curve indicate the intensive use of living space. If the values of the indicators are located under the curve - it is incomplete use of living space. Since there is continuous forest management in Ukraine, and for timely forestry measures, it is necessary to constantly monitor the state of plantations. For successful cultivation of anti-erosion plantings of sufficiently high productivity and convenience of monitoring their condition, the proposed indicator can be used.

scholarly journals Assessment of the impact of the urbanized territory of Yekaterinburg city on the formation of undergrowth in the forest park zone

2021 ◽  
Vol 38 ◽  
pp. 00130
Author(s):  
Olga Tolkach ◽  
Olga Dobrotvorskaya
Keyword(s):  
Natural Forest ◽  
Forest Types ◽  
Floristic Similarity ◽  
Adventive Species ◽  
Forest Park ◽  
Urbanized Territory ◽  
Growing Conditions ◽  
Forest Parks ◽  
A Site ◽  
The Impact

The parameters of the undergrowth in the forbs and berry groups of pine forest types in 9 parks in Yekaterinburg and areas of natural forest have been investigated. Data on the species composition, density, and distribution by groups of heights of plants that make up the undergrowth collected. It has been established that the transformation of the undergrowth by an urbanized environment neutralizes the influence of the growing conditions of the considered forest types on it. In the forest-park zone, an increase in the density of the undergrowth is observed in comparison with the natural forest. The specificity of the forest park undergrowth is the floristic contamination with adventive species, the number of which is close to 50% of the total number of undergrowth species. The coefficient of floristic similarity of the undergrowth, according to the Sorensen coefficient between forest parks and a site of natural forest, was 0.26-0.46. In quantitative terms, the self-seeding of adventive species in the undergrowth is less than that of native plants. The invasive activity of ash-leaved maple in city parks and its dynamics over a 10-year period are considered, using the example of one of the parks.

scholarly journals Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It

2021 ◽  
Author(s):  
Yinliu Wang ◽  
Signe Lett ◽  
Kathrin Rousk
Keyword(s):  
Boreal Forests ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Organic N ◽  
Inorganic N ◽  
Atmospheric N Deposition ◽  
Moss Species ◽  
The Impact ◽  
N Additions

Abstract Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha−1 yr−1) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha−1 yr−1) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

scholarly journals Assessing soil compaction and micro-topography impacts of alternative heather cutting as compared to burning as part of grouse moor management on blanket bog

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7298
Author(s):  
Andreas Heinemeyer ◽  
Rebecca Berry ◽  
Thomas J. Sloan
Keyword(s):  
Bulk Density ◽  
Habitat Degradation ◽  
Management Practice ◽  
Water Storage ◽  
Calluna Vulgaris ◽  
Suitable Alternative ◽  
Water Storage Capacity ◽  
Blanket Bog ◽  
Peat Surface ◽  
Micro Topography

Background Over 25% of the UK land area is covered by uplands, the bulk of which are comprised of blanket bog. This not only contains most of the UK’s terrestrial carbon stocks, but also represents 15% of this globally rare habitat. About 30% of UK blanket bog is managed for red grouse by encouraging ling heather (Calluna vulgaris) with rotational burning, which has been linked to habitat degradation, with reduced carbon storage and negative impacts on water storage and quality. Alternative cutting is currently being pursued as a potential restoration management. However, the often used heavy cutting machinery could cause considerable compaction and damage to the peat surface. Two particular issues are (i) a potential increase in bulk density reducing water storage capacity (i.e., less pore volume and peat depth), and (ii) a possible reduction of the micro-topography due to cutting off the tops of hummocks (i.e., protruding clumps or tussocks of sedges). Methods We set up a fully replicated field experiment assessing cutting versus burn management impacts on peat physical and surface properties. Both managements reflected commonly used grouse moor management practice with cutting using heavy tractors fitted with load distributing double wheel and tracks (lowering ground pressure), whilst burning was done manually (setting heather areas alight with flame torches). We assessed management impacts on peat depth, bulk density and peat surface micro-topography which either included pre-management measurements or plot-level data for uncut plots. Total peat depth and bulk density in four 5 cm sections within the top 50 cm was assessed. Micro-topography was determined as the standard deviation of the height offsets measured over several plot transects in relation to the plot peat surface level at the start and end points of each transect. Results Despite an anticipated compaction from the heavy machinery used for cutting, the peat showed resilience and there was no lasting plot-level impact on either peat depth or bulk density. Notably, bulk density showed differences prior to, and thus unrelated to, management, and an overall increasing bulk density, even in uncut plots. However, cutting did reduce the plot micro-topography by about 2 cm, mostly due to removing the tops of hummocks, whereas burnt plots did not differ from uncut plots. Discussion Cutting is suggested as a suitable alternative to burning on grouse moors, although compaction issues might be site specific, depending on the nature of the peat, the machinery used and impacts at resting and turning points (which were not assessed). However, any observed bulk density differences could reflect natural changes in relation to changes in peat moisture, requiring adequate experimental comparisons. Moreover, where micro-topography is a priority, cutting equipment might need to consider the specific ground conditions, which could involve adjusting cutting height and the type of cutting machinery used.

scholarly journals Effect of a New Manure Amendment on Ammonia Emissions from Poultry Litter

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 257
Author(s):  
Kelsey Anderson ◽  
Philip A. Moore ◽  
Jerry Martin ◽  
Amanda J. Ashworth
Keyword(s):  
Aluminum Sulfate ◽  
Management Practice ◽  
Block Design ◽  
Poultry Litter ◽  
Poultry Production ◽  
Ammonia Emissions ◽  
Best Management ◽  
Randomized Block Design ◽  
Flux Measurements ◽  
Ammonia Flux

Treating manure with aluminum sulfate (alum) is a best management practice (BMP) which reduces ammonia (NH3) emissions and phosphorus (P) runoff from poultry litter. However, the price of alum has increased markedly in recent years, creating a need for less expensive products to control NH3 volatilization. The objective of this study was to evaluate the effects of a new litter amendment made from alum mud, bauxite, and sulfuric acid (alum mud litter amendment or AMLA) on NH3 emissions, litter chemistry, and poultry production in a pen trial. Three separate flocks of 1000 broilers were used for this study. The first flock of birds was used to produce the poultry litter needed for the experiment. The second and third flocks of birds were allocated to 20 pens in a randomized block design with four replicates of five treatments: (1) control, (2) 49 kg AMLA/100 m2 incorporated, (3) 98 kg AMLA/100 m2 incorporated, (4) 98 kg AMLA/100 m2 surface applied, and (5) 98 kg alum/100 m2 incorporated. Ammonia flux measurements and litter samples were collected from each pen at day 0, 7, 14, 21, 28, 35, and 42. The average litter pH for both flocks was higher in untreated litter (7.92) compared to incorporating alum (7.32) or AMLA (7.18). The two flocks’ average NH4-N concentrations at day 42 were 38% and 30% higher for the high rates of incorporated alum and AMLA compared to the untreated litter. Compared with untreated litter, AMLA reduced overall NH3 emissions by 27% to 52% which was not significantly different from reductions in emissions by alum (35%). Alum mud litter amendment reduced cumulative NH3 losses from litter as much as, and in some cases more than, alum applied at the same rate. These data indicate that AMLA, which can be manufactured for lower price than alum, is an effective alternative litter amendment for reducing NH3 emissions from poultry litter.

Growth of 20-Year-Old Virginia Pine Planted at Three Spacings in Tennessee

1985 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Glendon W. Smalley
Keyword(s):  
Basal Area ◽  
Site Index ◽  
The Other ◽  
Average Height ◽  
Cumberland Plateau ◽  
Plantation Age ◽  
A Site ◽  
Pinus Virginiana Mill

Abstract Average height of dominant and codominant Virginia pines (Pinus virginiana Mill). on a Mid-Cumberland Plateau site was 46 feet at plantation age 20, equivalent to a site index (base age 50) of 75. Trees planted at a spacing of 8 x 8 feet had a merchantable yield (outside bark to a 4.0 inch top for all trees with a dbh of 4.6 inches and larger) of 1,987 ft³ per acre with a basal area of 114 ft² per acre. Comparative statistics on the other spacings tested were: 6 x 6 feet—2,067 ft³ and 123 ft² and 4 x 4 feet—2,155 ft³ and 141 ft². Survival on the plots was: 4 x 4 feet—38%; 6 x 6 feet—58%; and 8 x 8 feet—75%. Height to base of live crown averaged 25 feet, and dead branches remained nearly to the ground on most trees at all spacings.

Improved Chamber Systems for Rapid, Real-Time Nitrous Oxide Emissions from Manure and Soil

2017 ◽  
Vol 60 (4) ◽  
pp. 1235-1258 ◽  
Author(s):  
David B. Parker ◽  
Kenneth D. Casey ◽  
Richard W. Todd ◽  
Heidi M. Waldrip ◽  
Gary M. Marek ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Greenhouse Gas ◽  
Real Time ◽  
Nitrous Oxide Emissions ◽  
Chamber System ◽  
Flux Chamber ◽  
Total N ◽  
Recirculating Flow ◽  
Flux Measurements ◽  
Flow Through

Abstract. Nitrous oxide (N2O) emission rates have traditionally been measured using non-flow-through (NFT), non-steady-state (NSS) chambers, which rely on measuring the increase in N2O concentration in the sealed chamber headspace over time. These flux measurements are very labor- and time-intensive, requiring three to four gas samples collected over a 30 to 60 min period, followed by laboratory N2O measurement with a gas chromatograph (GC) and subsequent flux rate calculation. The objective of this research was to develop and evaluate improved, real-time flux chamber designs that rapidly quantify N2O emissions from manure and soil. The first chamber system consisted of six square 0.95 m2 chamber pans. The chamber pans were mounted on a rail system to facilitate controlled indoor/outdoor laboratory research at a pilot scale. An aluminum lid was moved among the chamber pans. A second portable chamber system with a circular footprint (0.49 m internal dia.) was designed for use in field measurements. With both systems, N2O concentrations were measured each second with 0.1 ppb resolution by recirculating sample air through a real-time continuous N2O analyzer with return flow into the recirculating-flow-through (RFT-NSS) chamber. Performance and observational data are presented for different chamber vent designs, sealing mechanisms between the chamber pan and lid, recirculation pumps, and presence/absence of an internal fan that mixes headspace air within the sealed chamber. As examples of the repeatability and precision of the methodology, ten consecutive flux measurements were obtained using moist manure (32.6% wet basis water content, WCWB) within a 15 min period in which chamber pans were fitted with lids for 60 s and removed for 30 s. The mean calculated N2O flux was 43.08 ±0.89 mg N2O m-2 h-1. Using dry manure (WCWB = 10.8%), five consecutive flux measurements showed a very low, but consistent, flux that averaged 0.025 ±0.0016 mg N2O m-2 h-1. Five case study experiments demonstrate the usefulness of these chamber systems and highlight discoveries and lessons learned to enhance future research efforts. Major discoveries and observations include: (1) installation of a small internal fan within the chamber lids decreased N2O fluctuation over small time periods, allowing precise measurement of manure N2O fluxes as low as 0.0073 mg N2O m-2 h-1 during a 60 s measurement period; (2) two distinct N2O peaks were observed at 1 and 21 d following the addition of water to manure (initial WCWB = 32.6%), with the second peak accounting for 83% of the total N2O emitted over 45 d; and (3) there was notable diurnal variation in N2O fluxes due to temperature variation, even when the manure was dry (WCWB = 10.8%). These flux chamber systems proved to be more rapid, precise, and repeatable than traditional flux chamber methods and offer promise for future greenhouse gas emissions research on manure and soil. Keywords: Cattle, Chamber, Diurnal, Fan, Feedlot, Greenhouse gas, Manure, Precision.

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