Logging Trail Segmentation via a Novel U-Net Convolutional Neural Network and High-Density Laser Scanning Data

Logging trails are one of the main components of modern forestry. However, spotting the accurate locations of old logging trails through common approaches is challenging and time consuming. This study was established to develop an approach, using cutting-edge deep-learning convolutional neural networks and high-density laser scanning data, to detect logging trails in different stages of commercial thinning, in Southern Finland. We constructed a U-Net architecture, consisting of encoder and decoder paths with several convolutional layers, pooling and non-linear operations. The canopy height model (CHM), digital surface model (DSM), and digital elevation models (DEMs) were derived from the laser scanning data and were used as image datasets for training the model. The labeled dataset for the logging trails was generated from different references as well. Three forest areas were selected to test the efficiency of the algorithm that was developed for detecting logging trails. We designed 21 routes, including 390 samples of the logging trails and non-logging trails, covering all logging trails inside the stands. The results indicated that the trained U-Net using DSM (k = 0.846 and IoU = 0.867) shows superior performance over the trained model using CHM (k = 0.734 and IoU = 0.782), DEMavg (k = 0.542 and IoU = 0.667), and DEMmin (k = 0.136 and IoU = 0.155) in distinguishing logging trails from non-logging trails. Although the efficiency of the developed approach in young and mature stands that had undergone the commercial thinning is approximately perfect, it needs to be improved in old stands that have not received the second or third commercial thinning.

Structural peculiarities of forest litter in water protective pine stands in wet sites of Zhytomyr Polissia

The results of the study of the fractional composition, structure and formation of forest litter in water protection pine plantations, which grow in the predominant moist forest vegetation conditions of Zhytomyr Polissia, are presented. The age range of stands varies between 18 and 85 years. It is established that water-protected pine stands in wet hygrotopes accumulate significant reserves of forest litter, which ranges from 33.0 t/ha in young plantations 77.0 t/ha in mature stands. The distribution of forest litter throughout area in most stands is uniform, although in young plantations its greater share is accumulated between rows. In terms of composition, the forest litter of pure pines is characterized by a medium dense structure, and in pines with an admixture of deciduous species, the litter is usually loose, due to the presence of annual fallen leaves in its upper horizon. The thickness of forest litter between rows of young plantations varies within and 2.6-2.9 cm without its clear distribution on the horizons. In medieval plantations, the horizons of the litter are already clearly distinguished. The total thickness of the litter is 4.0–4.3 cm. In the pre mature and mature pine stands the thickness of the forest litter profile varies between 6.0–6.3 cm. In the stands of older age groups the forest litter has mainly a three-layer structure. The trend of intensive accumulation of forest litter in the conditions of wet boreal and sub boreal conditions with the age of maturity is revealed. In pre mature plantations, the accumulation of litter slows down and in mature plantations; the processes of accumulation and decomposition of litter are leveled. The tendency of predominance of the active part and, accordingly, reduction of the inactive fraction of litter in the pre mature and mature plantations of wet sub boreal site compared to boreal conditions is indicated, which indicates more active processes of mineralization of litter in wet subboreal conditions.

Polygon «Ural-carbon» (Severka)

На основе баз данных лесорастительных материалов проанализированы таксационные показатели насаждений, произрастающих на территории карбонового научно-исследовательского по- лигона, расположенного в Уральском учебно-опытном лесхозе (УУОл) Уральского государственного лесотехнического университета (УГлТУ). Отмечается, что основными лесными формациями на поли- гоне являются сосняки и березняки. Доля насаждений с доминированием в составе древостоев других пород-лесообразователей невелика. Помимо сосны обыкновенной (Pinus sylvestris L.) и березы повислой (Betula pendula Roth.), другие виды произрастают, как правило, в примеси с указанными. Среди дре- востоев преобладают среднеполнотные спелые и перестойные насаждения. большинство древостоев характеризуется относительно высокими классами бонитета. Насаждения, произрастающие на террито- рии полигона, относятся к 13 типам леса, что свидетельствует о разнообразии лесорастительных усло- вий. В целом можно отметить, что видовое разнообразие древесных пород и лесорастительных условий на карбоновом научно-исследовательском полигоне УУОл УГлТУ обеспечивает возможность изучения широкого спектра вопросов депонирования углерода лесными экосистемами в условиях подзоны южной тайги Урала. The taxation indicators of plantations growing on the territory of the carbonic research polygon located in the Ural educational experimental forest enterorize (UEEF) of the Ural State Forest Engineering University were analyzed on the base of the forestry materials database. It is noted that the main forest formations on the polygons are pine and birch forest stands. The share of stands with other species of forest formers dominating in composition of forest stands is small. In addition to scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.), other species usually grow in admixtures with the specified. Among the stands mature and over mature stands of average density prevails. Most of the stands are characterized by relatively high bonitet classes. Plantations growing on the territory of the polygon belong to 13 types of forest, which indicates a variety of forest growing conditions. In general, it can be noted that the species diversity of tree species and forest growing conditions at the carboniferous research sity (UEEF) provides an opportunity to study a wide range of problems of carbon deposing forest ecosystems in conditions of the Southern Taiga subzone in the Urals.

State forest register as basis of greenhouse gas inventory for land use, land use change and forestry sector

The data on the assessment of the dynamics of forested lands of the Republic of Belarus are presented. The characteristics of the forest fund for the period 1994–2019 are presented. Based on the materials of the provisions of international treaties, documents adopted within the framework of the implementation of the UN Framework Convention on Climate Change at the international and national levels, including the Paris Agreement, the provisions of regulatory legal acts of the Republic of Belarus, the results of scientific research, information from the Ministry of Forestry, according to the data of the State Forest Cadastre, an assessment of greenhouse gases in the forest fund of the Republic of Belarus was carried out. CO2 emissions and sinks from forestry have been calculated in accordance with the IPCC Guidelines for National Greenhouse Gas Inventories using the stock-difference method. It was found that as a result of purposeful work on reforestation and reforestation over a 26-year period, a positive dynamics of the forest fund was achieved in the Republic of Belarus: the forested area increased by 919,6 thousand ha from 7360,7 thousand ha to 8280,3 thousand ha; the forest cover of the territory of the republic increased by 4,3 % and reached 39,9 %; the total standing timber stock increased by 739,5 million m3 from 1092,3 to 1831,8 million m3 (including in mature and over-mature stands — by 300,3 million m3 and amounted to 348,8 million m3); the reserve per hectare of forested land increased by 72,8 m3 and amounted to 221,2 m3/ha; the stock of mature and over-mature stands increased by an average of 52,6 m3 and reached 273,9 m3/ha.

Assessing the Technical Efficiency of Timber Production during the Transition from a Production-Oriented Management Model to a Multifunctional One: A Case from Poland 1990–2019

The present work applied a data envelopment analysis (DEA) model to assess changes in the technical efficiency of timber production at a period of transition in forest management priorities. The study material consisted of data on timber sold by Polish State Forests (PSF) and on its forest management inputs in the years 1990–2019. During the period of economic transition in Poland (1990–2003) the technical efficiency of timber production on average amounted to 0.809 and was highly variable. In the free-market period, that efficiency was much higher (on average 0.939) and more stable. This improvement was achieved by substantial layoffs in the PSF, and steady rise in the share and standing volume of mature stands, which made it possible to increase timber production while adhering to sustainable management principles. Analysis of the various categories of inputs to timber production revealed that the greatest decline, in labor costs, was attributable to a fourfold reduction in the workforce, and was accompanied by a 2.4-fold increment in timber production. On the other hand, logging costs increased due to, among other causes, the pursuit of environmentally friendly but more expensive harvesting procedures and reductions in clearcutting, which entailed more dispersed harvesting operations.

Economic impacts of partial harvesting: Mitigating mid-term timber supply shortages as a result of pest outbreaks

Natural disturbances such as pest outbreaks have a significant impact on forest dynamics and services, including the loss of mature stands. From a wood production perspective, these disturbances can lead to long-lasting imbalances in the overall age-class structure of the forest, potentially resulting in a shortage of mature harvestable stands. Researchers from Natural Resources Canada’s (NRCan) Canadian Forest Service (CFS) have made a timber supply analysis of the Dunière forest located in the centre of the Gaspé Peninsula (Québec). This region suffers from an age-class structure imbalance caused by an eastern spruce budworm (ESB) outbreak that ended in 1984, and is consequently facing a reduced annual allowable cut, leading to long- term implications for the regional forest sector. The authors suggest that partial harvesting – the removal of a proportion of timber in a mature stand several years before a final cut is carried out – is a promising opportunity in the ESB-affected area for mitigating mid-term timber supply shortages by smoothing the fibre supply over time.

Retention of Matured Trees to Conserve Fungal Diversity and Edible Sporocarps from Short-Rotation Pinus radiata Plantations in Ethiopia

This study is conducted in the short-rotation plantations from the Afromontane Region of Ethiopia. Sporocarps were sampled weekly in a set of permanent plots (100 m2) in young, medium-aged, and mature Pinus radiata (Don) plantations. Fungal richness, diversity, and sporocarp yields were estimated. Composite soil samples were also collected from each plot to determine explanatory edaphic variables for taxa composition. We collected 92 fungal taxa, of which 8% were ectomycorrhizal (ECM). Taxa richness, the Shannon diversity index, and ECM species richness were higher in mature stands. Interestingly, 26% of taxa were classified as edible. Sporocarp yield showed increasing trends towards matured stands. OM and C/N ratio significantly affected fungal composition and sporocarp production. The deliberate retention of mature trees in a patch form rather than clear felling of the plantations could be useful to conserve and promote fungal diversity and production, including valuable taxa such as Morchella, Suillus, and Tylopilus in older stands. This approach has important implications for forest floor microhabitats, which are important for macrofungal occurrence and production. Thus, this strategy could improve the economic outputs of these plantations in the Afromontane Region, while the mature trees could serve as a bridge for providing fungal inocula to the new plantations.

Mature stand developmental stage has ceased to constitute the most suitable habitat for the capercaillie in the Augustów Forest, Poland

Background Forest management affects the habitat conditions for many forest-dwelling species. Among them, the capercaillie (Tetrao urogallus) is a rare forest grouse inhabiting old, mature forests. We compared the structure of forest habitat among 9 active and 9 abandoned leks in the Augustów Forest (North-Eastern Poland), within a radius of 1 km of the leks, defined as the Key Areas for the capercaillie in lowland temperate forest. Habitat measurements were conducted on 1779 circular plots. Assessments made on all plots related to 13 habitat variables measured or noted in the field, including stand structure, canopy closure, stand developmental stage, percentage of Scots pine (Pinus sylvestris), soil fertility and soil moisture, the share of undergrowth, the cover of shrubs, the cover of bilberry (Vaccinium sp.), and the presence of certain habitat elements important to the capercaillie. Results To compare the still-occupied and the abandoned KAs for the capercaillie, a logistic regression model was developed. The variables best explaining differences between these two categories were: the occurrence of undergrowth layers, canopy closure in the second canopy layer, and stand age. According to the model, with the increase of the shrub-layer cover as well as the density of trees, the probability of the presence of the capercaillie decreased. The capercaillie in the area of the Augustów Forest occupy mainly dry and poor, middle-aged, pine-dominated forests, with a moderate extent of stand canopy closure and only weakly-developed layers of undergrowth. Conclusions The filling-in of mature stands with sub-canopy trees and shrubs (the process which is stimulated by climate change and site eutrophication) causes structural changes, which are unfavourable to the capercaillie. This might explain why in the course of the recent decades the capercaillie has abandoned the oldest stands, distinguished by the presence of bigger shares of undergrowth. The capercaillie has shifted to younger stands, which reveal a lesser extent of canopy closure and a more limited development of understorey vegetation.

Natural formation stands composition in clearings of XIX century oak forests (Tellermanovskoe experimental forestry IFS RAS)

The article presents archival information about the composition of the stands in the Tellerman experimental forestry of ILAN RAS, which were formed naturally on the felling of mature stands of the late XIX century in the upland oak forest and forestry care carried out in them. On sample plots in such stands, the species and layered composition of stands were studied, volumetric and quantitative indicators of the composition of tree species and stands were calculated, and the priority of the presence of various species in the formation of the layered structure of stands was determined. In the stands, the state of all tree species is determined, the quantitative indicators of natural renewal, the characteristics of which determine the species structure of the stands that appear on the area of continuous felling of mature stands. The studies revealed that in the late nineteenth century clear-cutting of mature oak stands formed a mixed deciduous forest of ash, maple, linden, elm mainly complex vertical structure without (or with small presence) oak in the dense undergrowth of the same species and the complete absence of oak undergrowth. Records of the state of the main tree species showed the highest points of weakening in oak trees, the lowest in ash and Norway maple trees. The method of reproduction of oak forests from stumps left after continuous logging of mature stands has shown its complete failure and contributes to the reduction of the area of oak forests, the loss of the gene resource of valuable species and the indigenous biodiversity of natural forest ecosystems of the forest-steppe.