Development of Latvian land use and land use change matrix using geospatial data of National forest inventory

ArticleLand use and land use change calculation matrix is one of the most important parts of the national greenhouse gas (GHG) inventory in land use, land use change and forestry (LULUCF) sector providing information of an overall summary and changes in land use at a national level over a specified period of time. Information on land use and land use changes are further used to calculate other parameters important for determination of GHG emissions and carbon stock changes in living and dead biomass, soil and litter, as well as basic information on the impact of applied climate change mitigation measures. Calculations of land use change can be carried out in a partly automated process using GIS tools, which makes calculations easier to perform, reduces time consumption for this task and occasional mistakes due to manual operations. The aim of this study is to improve the methodology for development of land use and land use change matrix in the national GHG inventory system using geospatial data of National forest inventory (NFI) and auxiliary data sources. The developed system uses geospatial NFI data and auxiliary information provided by the land parcel information system (LPIS) and stand-wise forest inventory, and it improves accuracy and consistency of the land use and land use change matrix, providing the ability to apply the same land use accounting method for the whole reporting period since 1990 without a significant increase of uncertainty. The developed method determines land use changes in a 5-year period by comparing three successive NFI cycles. To determine the actual land use category in a particular year, we adjusted weights for different land use categories. Interpolation is used to determine year-by-year transitions

Stochastic Stokes' drift of a flexible dumbbell

We consider the stochastic Stokes drift of a flexible dumbbell. The dumbbell consists of two isotropic Brownian particles connected by a linear spring with zero natural length, and is advected by a sinusoidal wave. We find an asymptotic approximation for the Stokes drift in the limit of a weak wave, and find good agreement with the results of a Monte Carlo simulation. We show that it is possible to use this effect to sort particles by their flexibility even when all the particles have the same diffusivity.Comment: 12 pages, 1 figur

Intra-annual height growth dynamics of Scots and lodgepole pines and its relationship with meteorological parameters in central Latvia

The Scots pine (Pinus sylvestris L.) is the second-most widely used tree species in forestry in Latvia and is the only species used for afforestation on nutrient poor soils that cover considerable forest land in Latvia. Several studies have shown that, in such conditions, the lodgepole pine (Pinus contorta var. latifolia) may be more productive in terms of biomass and yield. It is important to consider climate change studies to assess the potential for a larger-scale use of the lodgepole pine in forestry. The aim was to assess the intra-annual height growth patterns of both species, the differences between them, and the influence of meteorological parameters on their height growth. Their height growth was monitored on a weekly basis in two sampling sites in central Latvia, and the height increment curves were described by Gompertz’s model. The height growth dynamics of individual trees and species differed notably, indicating the potential for the selection of the best-adapted genotypes. Our results indicate that the early onset of the active growth phase might be the most important factor determining the total height increment for both species. Temperature-related meteorological parameters were the only ones with a statistically significant influence on pines height growth and only when at least one of the variables were standardised prior to the analysis. A temperature increase had a slightly stronger positive effect on the growth of the lodgepole pine, indicating that it might be suitable for more intensive use in forestry under the climate change scenarios for Latvia

Evaluation of greenhouse gas emissions and area of organic soils in cropland and grassland in Latvia – integrated National forest inventory data and soil maps approach

ArticleThe aim of the research was to assess distribution of organic soils in farmlands for the time period between 1990 and 2015, as well as to carry out a recalculation of GHG emissions from organic soils in grassland and cropland. We evaluated the area of typical organic soils using digitized soil maps created between 1960s and 1980s there were 183,000 ha of cropland and grassland on organic soils. A selected number of areas on organic soils intersecting with the National forest inventory (NFI) plots were surveyed. We found that 66 ± 10% of surveyed plots still conforms to criteria for organic soils according to Intergovernmental Panel on Climate Change (IPCC) guidelines; in the rest of plots soil organic matter has been mineralized and these areas do not conform to IPCC criteria of organic soils. The following distributionof organic soils was estimated in cropland – 6.3 ± 3.3% in 1990 and 4.1 ± 3.4% in 2015, but in grassland – 11.6 ± 3.6% in 1990 and 7.7 ± 3.9% in 2015. The annual reduction of GHG emissions due to reduction of area of organic soils in cropland in 2015 corresponds to 1,400,000 tonnes CO2 eq. in comparison to 1990 and in grassland – to 1,100,000 tonnes CO2 eq. The estimated reduction of the GHG emissions due to conversion of organic soils into mineral soils, comparing the average value in 2005–2009 with the projection for 2021–2030 on average will correspond to 313,000 tonnes CO2 eq. annually, however LULUCF sector still won’t become a net CO2 sink according to the GHG inventory data on other land use categories and carbon pools

Feasibility and acceptability of a remotely delivered, home-based, pragmatic resistance ‘exercise snacking’ intervention in community-dwelling older adults: A pilot randomised controlled trial

Background: Very few older adults meet current muscle strengthening exercise guidelines, and several barriers exist to supervised, community-based resistance exercise programs. Older adults therefore require access to feasible resistance exercise modalities that may be performed remotely. This pilot study assessed the feasibility and acceptability of undertaking a four-week home-based resistance ‘exercise snacking’ intervention (performed either once, twice, or thrice daily) when delivered and monitored remotely in older adults. Methods: Thirty-eight community-dwelling older adults [mean ± SD age 69.8 ± 3.8 y, 63% female] were randomised to complete resistance ‘exercise snacks’ (9-minute sessions) either once (n = 9), twice (n = 10), or thrice (n = 9) daily, or allocated to usual-activity control (n = 10). Exercise adherence and adverse events were assessed using an exercise diary, and acceptability of the intervention was explored using an online questionnaire. Physical function [balance, 5-times sit-to-stand (STS), and 30-second STS tests] was assessed remotely at baseline and follow-up using videoconferencing. Results: The intervention was feasible and safe, with 100% participant retention, high adherence (97, 82, and 81% for once, twice, and thrice daily, respectively), and only two adverse events from a total of 1317 ‘exercise snacking’ sessions. The exercise intervention was rated as enjoyable (75% reported their enjoyment as ≥ 4 on a 5-point Likert scale), easy to perform, and most (82%) planned to continue similar exercise at home. We also found it was feasible to assess measures of physical function via videoconferencing, although effect sizes for 4-week changes in both 5-STS (d range, 0.4–1.4) and 30-STS (d range, 0.7–0.9) following the exercise intervention were similar to controls (d = 1.1 and 1.0 for 5-STS and 30-STS, respectively). Conclusions: Resistance ‘exercise snacking’ may be a feasible strategy for engaging older adults in home-based resistance exercise when delivered and monitored remotely. The findings of this pilot feasibility trial support the need for longer-term studies in larger cohorts to determine the effectiveness of resistance ‘exercise snacking’ approaches for improving physical function in older adults. Trial registration: The trial was retrospectively registered on 10/11/2021 with the Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN12621001538831)

Production and profitability of low density Norway spruce (Picea abies (L.) Karst.) plantation at 50 years of age: case study from eastern Latvia

ArticleNorway spruce (Picea abies (L.) Karst.) is one of the most important commercial tree species, for which wider spacing are being advocated to reduce management costs and improve radial growth. Nevertheless, little is known about tree and stand parameters at the larger age in stands of extremely low density. The aim of our study was to assess growth and economic profitability of 50 years old low density Norway spruce plantation in Latvia. Allometric parameters for all trees of Norway spruce clonal plantation planted in 1964 with two spacings (1×3 m and 5×5 m) were measured and profitability were estimated. Norway spruce plantation with wider (5×5 m) spacing ensured significantly larger tree diameter and height (35 cm and 25 m, respectively) than trees from higher density trial. However, mean net present value (3% interest rates) was non–significantly (P = 0.12) different between 5×5 m and 1×3 m spacings, 2,571.9 ± 355.6 and 3,085.8 ± 452.9 € ha-1 , respectively. Values observed in low density (5×5 m) plantation fitted well in the observation of impact of density and stand parameters drawn based on National inventory data, showing a considerable potential to use plantations with low density in practice

Barriers and enablers associated with participation in a home-based pragmatic exercise snacking program in older adults delivered and monitored by Amazon Alexa: A qualitative study

Background: ‘Exercise snacking’, which is characterised by shorter and more frequent exercise bouts compared with traditional exercise guidelines, may be an acceptable strategy for increasing physical activity and reducing sedentary behaviour in older adults. Aim: The aim of this study was to evaluate the enablers and barriers for older adults associated with participation in a home-based exercise snacking program delivered and monitored using an Amazon Echo Show 5 device (Alexa). Methods: This study used an interpretive description qualitative design to conduct semi-structured interviews following a 12-week pilot study in 15 adults aged 60–89 years with at least one chronic condition. All participants were prescribed a home based, individualised, lower limb focussed ‘exercise snacking’ program (involving ≤ 10 min of bodyweight exercises 2–4 times per day) delivered and monitored by an Alexa. Qualitative interview data were analysed using thematic analysis. Results: All 15 participants (mean age 70.3 years) attended the semi-structured interview. Themes including time efficiency, flexibility, perceived health benefits, and motivation were enablers for participation in the ‘exercise snacking’ program. A lack of upper body exercises and omission of exercise equipment in the program, as well as a lack of time and motivation for performing exercise snacks three or more times per day, were barriers to participation. Conclusion: While ‘exercise snacking’ is acceptable for older adults, future trials should provide equipment (e.g. adjustable dumbbells, exercise bands), prescribe whole-body exercise programs, and establish strategies to support participation in more than three exercise snacks per day

Conformal Mapping on Rough Boundaries II: Applications to bi-harmonic problems

We use a conformal mapping method introduced in a companion paper to study the properties of bi-harmonic fields in the vicinity of rough boundaries. We focus our analysis on two different situations where such bi-harmonic problems are encountered: a Stokes flow near a rough wall and the stress distribution on the rough interface of a material in uni-axial tension. We perform a complete numerical solution of these two-dimensional problems for any univalued rough surfaces. We present results for sinusoidal and self-affine surface whose slope can locally reach 2.5. Beyond the numerical solution we present perturbative solutions of these problems. We show in particular that at first order in roughness amplitude, the surface stress of a material in uni-axial tension can be directly obtained from the Hilbert transform of the local slope. In case of self-affine surfaces, we show that the stress distribution presents, for large stresses, a power law tail whose exponent continuously depends on the roughness amplitude

Regional variations in diffuse nitrogen losses from agriculture in the Nordic and Baltic regions

International audienceThis paper describes nitrogen losses from, and the characteristics of, 35 selected catchments (12 to 2000 ha) in the Nordic and Baltic countries. Average annual losses of N in 1994?1997 ranged from 5 to 75 kg ha-1, generally highest and characterised by significant within-country and interannual variations, in Norway and the lowest losses were observed in the Baltic countries. An important finding of the study is that the average nutrient losses varied greatly among the studied catchments. The main explanations for this variability were water runoff, fertiliser use (especially the amount of manure), soil type and erosion (including stream bank erosion). However, there were several exceptions, and it was difficult to find general relationships between the individual factors. For example, there was poor correlation between nitrogen losses and surpluses. Therefore, the results suggest that the observed variability in N losses cannot have been due solely to differences in farm management practices, although the studied catchments do include a wide range of nutrient application levels, animal densities and other relevant elements. There is considerable spatial variation in the physical properties (soil, climate, hydrology, and topography) and the agricultural management of the basins, and the interaction between and relative effects of these factors has an important impact on erosion and nutrient losses. In particular, hydrological processes may have a marked effect on N losses measured in the catchment stream water. The results indicate that significant differences in hydrological pathways (e.g. the relationship between fast- and slow-flow processes) lead to major regional differences in N inputs to surface waters and therefore also in the response to changes in field management practices. Agricultural practices such as crop rotation systems, nutrient inputs and soil conservation measures obviously play a significant role in the site-specific effects, although they cannot explain the large regional differences observed in this study. The interactions between agricultural practices and basic catchment characteristics, including hydrological processes, determine the final losses of nitrogen to surface waters, hence it is necessary to understand these interactions to manage diffuse losses of agricultural nutrients efficiently. Keywords: agriculture, catchments, diffuse sources, nitrogen, losses, Baltic, Nordi