How to consider the effects of time of day, beam strength, and snow cover in ICESat-2 based estimation of boreal forest biomass?

Spaceborne lidar sensors have potential to improve the accuracy of forest above-ground biomass (AGB) estimates by providing direct measurements of 3D structure of forests over large spatial scales. The ICESat-2 (Ice, Cloud and land Elevation Satellite 2), launched in 2018, provides a good coverage of the boreal forest zone and has been previously shown to provide good estimates of forest canopy height and AGB. However, spaceborne lidar data are affected by various conditions, such as presence of snow, solar noise, and in the case of ICESat-2, the power difference between the so-called strong and weak beams. The aim of this study was to explore the effects of these conditions on the performance of AGB modeling using ICESat-2 photon data in a boreal forest area. The framework of the study is multiphase modeling, where AGB field data and wall-to-wall airborne laser scanning (ALS) data are used to produce proxy ALS plots on ICESat-2 track positions. Models between the ALS-predicted AGB and the ICESat-2 photon data are then formulated and evaluated by subsets, such as only strong beam data captured in snowy conditions.Our results indicate that, if possible, strong beam night data from snowless conditions should be used in AGB estimation, because our models showed clearly smallest RMSE (27.0%) for this data subset. If more data are needed, we recommend using only strong beam data and constructing separate models for the different data subsets. In the order of increasing RMSE\%, the next best options were snow/night/strong (30.5%), snow/day/strong (33.6%), and snowless/day/strong (34.2%). Weak beam data from snowy night conditions could also be used if necessary (31.1%).

Research on Tracking the Behavior of the Ciobanus Forest Road over a Season Time through Specific Tests and Analysis

Forest roads are of great economic importance as they ensure the transport of logs and forest biomass toward collection and processing centers, which is why they should be evaluated periodically, in order to establish the degree of degradation and periodicity and rehabilitation methodology and procedures. The main purpose of the paper is to follow the behavior of the Ciobanus forest road through specific tests over a difficult season of 5 months, in order to diagnose the degree of surface wear and structure degradation. Regarding the traffic on this forest road, an exhaustive study was made during the 2013–2017 period, and for in situ or in laboratory tests a more complex study during the year 2018, in the March-June period was also made. Out of the total of 20 tests that evaluated the Ciobanus forest road, 5 of them were classified as appropriate and 15 unsuitable for traffic, meaning the forest road had to be completely rehabilitated. Moreover, it has been shown that this forest road is part of the category of secondary forest roads and needs a total overhaul to cope with the increasing traffic or tonnage of trucks. Through the methodology and the obtained results, the paper supports the specialists in the field of forest roads to be able to diagnose or evaluate such a road, and to realize a program and its timing for maintenance.

Potential of Forest Biomass Resources for Renewable Energy Production in the Czech Republic

In the European Green Deal and the Climate Act, the European Union has committed itself to achieving climate neutrality by 2050. This goal is to be achieved by joint efforts of all economic sectors, including forestry and its downstream sectors. One way to attain this goal is the effective and sustainable use of forest biomass for energy production. This article aims to quantify the potential of forest biomass resources for the production of electrical and thermal energy based on official departmental statistics, the current legal framework for forestry and the environment, and research results in the context of an extreme change in the raw material base due to the ongoing calamity caused by the spread of insect pests in the Czech Republic. This extreme can classify as a significant risk to the security of the energy supply from renewable sources in the event of oversizing new installed energy production from renewable sources. Based on data and calculations, an overall annual volume of dendromass available for energy production in the Czech Republic for the period extending to 2036 was quantified at the value of 13.473 million tons per year. Consequently, it is clear that the overall dendromass resources for energy production in the Czech Republic are not sufficient to achieve the EU’s ambitious objective.

Height-diameter allometry for tropical forest in northern Amazonia

Height measurements are essential to manage and monitor forest biomass and carbon stocks. However, accurate estimation of this variable in tropical ecosystems is still difficult due to species heterogeneity and environmental variability. In this article, we compare and discuss six nonlinear allometric models parameterized at different scales (local, regional and pantropical). We also evaluate the height measurements obtained in the field by the hypsometer when compared with the true tree height. We used a dataset composed of 180 harvested trees in two distinct areas located in the Amapá State. The functional form of the Weibull model was the best local model, showing similar performance to the pantropical model. The inaccuracy detected in the hypsometer estimates reinforces the importance of incorporating new technologies in measuring individual tree heights. Establishing accurate allometric models requires knowledge of ecophysiological and environmental processes that govern vegetation dynamics and tree height growth. It is essential to investigate the influence of different species and ecological gradients on the diameter/height ratio.

Wood processing for energy use

Forest biomass has been used as an energy source since ancient times. Since then, several ways of using them have emerged, along with technologies to improve their energy quality. One can cite genetic improvement, thermal transformation through pyrolysis for charcoal and torrefied biomass production, and mechanical transformation through compaction, to produce pellets and briquettes and chipping for the production of chips. However, it is somehow difficult to find articles on these topics that are clearly and objectively presented, making it difficult to read them. The objective of this work was to search data on the ways of processing forest biomass and solutions for the better use of this biomass and its energy use. Therefore, Google Scholar was used as a database from which articles already recognized and others with less impact were obtained. The following search words were used: Eucalyptus, Pinus, wood chips, pellets, briquettes, charcoal, and torrefied wood. To filter the results obtained, the articles that appeared as the most relevant were selected first, then filtered for articles with less than five years from publication, and those at less than two years of publication. Next, the selected articles went through a verification of the data contained in them, and the necessary information was removed from each, which were the species, immediate analysis, extractives, HCV, etc. These data were organized in tables according to the type of processing, prioritizing the values of greatest interest in each analysis, along with the appropriate references. It was observed from the data obtained that the results are compatible among different researchers in their analyses. For samples processed without thermal treatment, the initial characteristics of the wood are maintained, and when going through pyrolysis or torrefaction, these characteristics are changed.