Forest Systems

Ratio estimators and simultaneous regression estimators for biomass in mixed plantation of Pinus elliottii Engelm. and Pinus taeda L.

2026-02-03T13:31:03+01:00

Aim of study: To evaluate the performance and biological consistency of ratio estimators for estimating the biomass of Pinus elliottii Engelm. and Pinus taeda L. and to compare the results obtained by this method with those generated by the nonlinear seemingly unrelated regression (NSUR) method in its weighted version (WNSUR), a procedure that was considered as a control.

Area of study: The study was carried out in the state of Paraná, in southern Brazil.

Material and methods: Data were collected on the following variables: diameter at 1.30 m height aboveground (D), total height (H), crown diameter (dc), crown height (hc), and the biomass of the following parts was quantified: roots, stem, bark, branches, needles, and total. The ratio model used for each part was obtained by the ratio between the biomass of the m^th part (dependent variable) and the estimated stem volume (independent variable). Nonlinear allometric models were fitted simultaneously by the NSUR and WNSUR methods.

Main results: The ratio estimators did not require additional procedures to achieve additivity and, in general, became more accurate for total aboveground biomass and its parts than regression estimators (WNSUR).

Research highlights: Due to its simplicity of application and because it meets the premise of additivity of the biomass parts in a natural way, the ratio estimators constitute an appropriate and promising procedure for compatible estimates of tree biomass.

Root volume dynamics reveal increasing stocks in Cerrado fragments in Southeastern Brazil

2025-12-10T16:37:24+01:00

Aim of study: We assessed root system volumes and their dynamics over intervals of up to 9 years in Cerrado (Brazilian savanna).

Area of study: Southeastern Brazil.

Material and methods: We used forest inventory data with repeated measurements over time from four Cerrado areas to estimate root volumes. Based on the estimated volumes, we calculated dynamic rates (gain, loss, turnover, and net change).

Main results: We found root volumes between 4.792 and 38.491 m³ ha^-1. The stocks observed are comparable to the aboveground wood volume reported by previous studies for Cerrado fragments. Our results indicate increasing carbon stocks in all areas, with faster dynamics observed in areas with denser tree cover.

Research highlights: Our findings underscore the role of the Cerrado as a carbon sink and reservoir, with significant below-ground biomass stocks. Conservation measures and management techniques should take this into account.

Productivity and nutrient accumulation of two native tree species in eastern Colombian tropical Andes

2026-02-03T13:37:19+01:00

Aim of study: To compare the productivity, nutrient content and carbon stock with the reforestation of native trees Cordia gerascanthus and Cariniana pyriformis in an agricultural area abandoned. In Colombia, these species are commonly known as móncoro and abarco, respectively.

Area of study: Pure forest of native species planted in the Andean region of Colombia with a typical tropical rainforest climate and naturally low-fertility soils.

Material and methods: After eight years of planting, the stem volume was evaluated in 27 trees per species using the Smalian formula. These data were used to develop allometric equations for stem volume. To estimate the nutrient and carbon content of the stem, a representative tree of each species was felled, and soil samples were collected up to 40 cm deep.

Main results: The two species showed similar survival, basal area and stem carbon stock, but for abarco the stem volume (62.0 m³ ha^-1) and stem biomass (35.2 Mg ha^-1) were two and 0.4 times higher (p < 0.05), respectively The zinc (41%), copper (128%), and Mg (+400) contents accumulated significantly more (p < 0.05) in the stem of móncoro. The nonlinear models of Spurr (R²= 0.94) and Schumacher-Hall (R²= 0.93) showed the highest accuracy for estimating volume. In the soil, the carbon content of both species averaged 69.3 Mg ha^-1 (p > 0.05).

Research highlights: The abarco shows higher commercial productivity than the móncoro. These results provide a baseline for understanding growth performance, but further studies involving reference sites or control plots are needed to evaluate the overall results of reforestation.

Optimization in the distribution and sequencing of machines in wood harvesting in planted forests

2026-02-03T13:31:46+01:00

Aim of study: The objective was to evaluate an optimized model for the distribution and sequencing of machines in tree felling and processing and extraction operations, aiming to reduce unproductive times and gains in production capacity.

Area of study: The study was conducted in a cellulose and paper company in the state of Parana, Brazil, in operational areas of the wood harvesting.

Material and methods: The times of tree felling, processing and extraction were obtained from a harvester (hv) and a forwarder (fw) to estimate the operational efficiency and productivity of the system. At the same time, vector features equivalent to the set of plots in the area, roads and a matrix feature of the digital terrain model were obtained from a geographic database for estimation of a matrix of distances between the plots. The Ward method of hierarchical grouping was used based on the matrix of distances between the fields to form two work groups (GI and GII). For each working group, the shortest walking sequence was estimated using the Kruskal algorithm.

Main results: An optimized distribution of 3 hw and 2 fw was necessary in GI to achieve the production target of 200 m³ PMH^-1, with the machines covering a distance of 2,335 m. The proportion of machines 3 hw and 3 fw was needed in GII with a distance covered of 2,878 m. The proposed model optimized the number of machines and provided a 26.7% reduction in the total displacement of machines.

Research highlights: The high cost of wood harvesting operations requires the use optimized of the forestry machines. The proposed model made it determine with efficiency the machines distribution and sequencing for a wood harvesting optimized. The model can be implemented in the operational planning in the forestry companies in more complex wood harvesting scenarios.

Short-term effects of management intensity on the spatial structure and biodiversity of Camptotheca acuminata-Liquidambar formosana mixed plantations

2026-02-03T13:27:59+01:00

Aim of study: We aimed to 1) analyze the initial responses of stand spatial structure and understory biodiversity in Camptotheca acuminata Decne and Liquidambar formosana Hance mixed plantations to crop tree release (CTR) under varying thinning intensities, and 2) further explore the structural mechanisms driving biodiversity changes, intended to provide a theoretical basis for formulating effective CTR strategies to adjust spatial structure and modify biodiversity in the plantation.

Area of study: Beishan Forest Farm, Tongshan County, Hubei Province, China.

Material and methods: Twenty-five permanent plots were subjected to five thinning treatments: CK (control), WT (low-intensity), MT (moderate-intensity), HT (high-intensity), and ST (very high-intensity). Six spatial structure indices —uniform angle index (W), size ratio (U), mingling (M), openness (O), competition index (CI), and stand layer index (S)— were evaluated before, immediately after, and three years following CTR. Herbaceous and shrub layer biodiversity changes were also analyzed using redundancy analysis (RDA) and path analysis to identify key structural drivers.

Main results: Three years following CTR, W increased from 0.462 to 0.472, M from 0.593 to 0.640, and S from 0.429 to 0.569, while CI decreased from 0.689 to 0.589 but slightly increased by the end of the third year. Structural score rankings shifted over time. WT and HT improved herb layer diversity, while WT also enhanced the shrub layer’s Shannon-Wiener index. Mingling promoted herb diversity, while competition intensity negatively affected it.

Research highlights: M and CI were key determinants of understory biodiversity. WT and HT treatments effectively improved diversity, offering practical guidance for sustainable mixed plantation management.

Silviculture alternatives evaluation for managing complex Quercus pyrenaica Willd. stands

2026-02-03T13:25:39+01:00

Aim of study: Despite its potential in the wood industry, Pyrenean oak (Quercus pyrenaica Willd.) has suffered from traditional use as firewood and the lack of profitable management guidelines, leading to the deterioration of its stands. This study explores the effects of different silvicultural scenarios on transforming regular coppice stands into irregular high forests and managing irregular stands sustainably.

Area of study: Castile and Leon (Spain), where Pyrenean oak stands are widespread and play a critical ecological and potential economic role.

Material and methods: Data were collected from pure coppice Pyrenean oak stands across the Castile and Leon region. Silvicultural scenarios were simulated using the SIMANFOR forest management simulator, incorporating various thinning intensities and periodicities to evaluate forest development and timber production. Main results: Intensive silviculture resulted in higher timber production. However, selective and continuous thinning based on Pro Silva guidelines effectively promoted the establishment and maintenance of high irregular forests, offering a sustainable alternative.

Research highlights: While numerical predictions may involve some bias, observed trends under different management guidelines allow them to be ranked according to management objectives. Skilled managers are essential to adapt thinning periodicity and intensity to the local conditions, considering the heterogeneity of the stands.

Estimation of the static modulus of elasticity of wood from the dynamic modulus of elasticity

2026-02-03T13:32:33+01:00

Aim of study: Analyze the behavior and predictive capacity of different non-destructive testing (NDT) methods—ultrasound, longitudinal and transverse vibrations, and static bending— for estimating the MOEGTO in two species of great forestry interest in Europe: Pinus sylvestris and Populus × euramericana. Additionally, this study focuses on developing global prediction models for MOEGTO using the NDT modulus of elasticity from both species, and on improving the reliability of prediction through the cross-validation process.

Area of study: Provenance Region 8 (Northern Iberian System, Spain) and Ribera del Carrión (Palencia, Spain).

Material and methods: A total 75 sawn lumber samples (45 of Pinus sylvestris and 30 of Populus x euramericana) with dimensions of 60 × 40 × 1200 mm were analyzed using ultrasonic testing, longitudinal and transverse vibration methods, and both destructive and non-destructive static bending tests performed with a universal testing machine. Regression models were developed to predict the static modulus of elasticity (MOEGTO).

Main results: The prediction model using the NDT method of longitudinal vibrations with Fast Fourier Transform (FFT) software for Pinus sylvestris showed the highest coefficient of determination with R²= 0.56, while for Populus × euramericana, the ultrasound method with the Sylvatest 4 device yielded R²= 0.67. For both species, the best-fit global prediction model was obtained with the ultrasound method using the Sylvatest Trio device, achieving R²= 0.60. Additionally, the application of cross-validation improved the predictive performance of the global models, particularly for the three ultrasound methods and the longitudinal vibration method, all of which attained R² values above 0.6.

Research highlights: This study confirms the reliability of ultrasound and longitudinal vibration techniques for estimating MOEGTO and contributes new insights by comparing multiple NDT methods across two species and developing robust cross-validated global prediction models.

Distance-dependent indices to assess deadwood diversity in forest ecosystems: an application in the Italian Alps

2025-12-15T17:04:36+01:00

Aim of study: To evaluate the effectiveness of distance-dependent indices in characterizing deadwood diversity at stand level.

Area of study: Four forest types in the Italian Alps (Trentino Alto Adige region): Norway spruce, mixed Silver fir–Norway spruce, European larch, and European beech forests.

Materials and methods: Distance-dependent indices from the literature, originally developed to assess stand structure, were applied to evaluate deadwood diversity in four forest stands (40 sample plots). The performance was assessed by comparing the “structural group of four” method, which considers the four deadwood elements closest to the plot center, with the fixed-area sampling method, which includes all deadwood elements in the plot (531 m²).

Main results: The results showed an average deadwood volume of 18.65 m³ ha^-1 and a higher deadwood diversity by species, decay class and size for European beech forests than the other three forest types. The non-parametric Wilcoxon signed rank test showed no statistically significant difference in the indices calculated using the three and five closest deadwood elements compared to all elements in the plots.

Research highlights: Distance-dependent spatial indices proved effective for characterizing deadwood diversity at the stand level. The “structural group of four” sampling method proved to be the most efficient, as including additional elements beyond four did not significantly improve accuracy. This approach represents a reliable and time-efficient tool for assessing deadwood diversity.

Perceptions of edible mushrooms among rural youth in northwestern Patagonia (Argentina): Who transmits knowledge?

2026-02-03T13:38:49+01:00

Aim of the Study: To analyze the role of experience and formal education in shaping the knowledge of Mapuche-Tehuelche and Criollo adolescents regarding edible fungi from the subantarctic forest.

Study Area: Northwest of Chubut Province, Patagonia, Argentina.

Materials and Methods: Free listings, collages, field walks, and workshops were carried out with 57 rural adolescents, differentiated by their sociocultural backgrounds (Mapuche-Tehuelche and Criollo) and the mycological content provided by their schools. Artistic productions and estimates of species richness and frequency of known fungi, were analyzed using a combination of quali-quantitative methods.

Main Results: Adolescents differed primarily in their theoretical knowledge, with Criollo adolescents who received mycology lessons at school citing a higher species richness (10 species) compared to Mapuche-Tehuelche adolescents who did not receive such instruction (3 species). Criollo participants included NUS (Neglected and Underutilized Species) and Pleurotus ostreatus (Jacq.) P. Kumm as part of the knowledge acquired through formal education. Experiential knowledge, on the other hand, was similar across both groups and aligned with that held by adults in the communities. This experiential knowledge includes three species of commercial importance (Morchella septimelata M. Kuo., Morchella tridentina Bres., Suillus luteus (L.) Roussel.) and Cyttaria hariotii E. Fisch. Only C. hariotii is widely consumed among the adolescents.

Research Highlights: School programs that teach mycology and encourage the sharing of traditional knowledge among students may contribute to the revaluation of local mycological knowledge, as well as reflection on the role of fungi in biocultural conservation and food sovereignty. We highlight the use of innovative inquiry methodologies as engaging tools to capture adolescents’ interest.

NIR spectroscopy for tree species identification based on different samples: a review

2026-02-03T13:58:33+01:00

Near-infrared spectroscopy is applied in a wide range of forestry studies. Among them is tree species identification based on leaf, wood, bark and seed samples. There are different mathematical pretreatments applied to spectra and a great range of processing or classification methods, as well as variation in the accuracy/precision of the results. This paper is a review of the main manuscripts found by searching the databases of Google and the Office to Coordinate Improvement of University Personnel (CAPES), using the species names along with identification/distinction/discrimination and NIR as keywords. It describes the state of the art regarding the use of near-infrared techniques for tree species identification, from 1969 to the first months of 2024, encompassing the use of different samples, devices and main analytic methods.

Mapping suitability for Tuber melanosporum growing in Patagonia, Argentina - an opportunity for agriculture diversification

2026-02-03T13:28:46+01:00

Aim of the study: The wide variety of climates, with significant gradients and abundance of microclimatic patches, and the vast diversity and availability of soils in Patagonia, suggests that there are extensive areas suitable for the cultivation of Périgord truffles (Tuber melanosporum Vittad.). The promotion of truffle cultivation as a profitable, off-season option for marginal and idle lands requires the identification and quantification of suitable areas on a regional scale. The objective of this study was to generate a regional map of areas suitable for the cultivation of T. melanosporum in Patagonia and a detailed map for the province of Chubut, using GIS data on physical and chemical soil characteristics, climatic variables and vegetation cover.

Area of study: The Argentinian Patagonia region (1,060,631 km²).

Material and methods: Two truffle suitability maps that include edaphic, climatic and vegetation cover requirements, together with irrigation availability, were developed: a Patagonia regional map (scale 1:10,000,000), and a Chubut province detailed map (scale 1:40,000). Both were built and analysed with Google Earth Engine (GEE) and validated with field ground truth points.

Main results: The suitable truffle growing area considering soil, climate and surface water availability is 2,680,000 ha for Patagonia region and 489,877 ha for Chubut province. The Chubut province map delimited suitability patches more accurately than the regional map, reducing the surface mapped as suitable while confirming the high potential for T. melanosporum cultivation of the valleys associated with the Mayo, Senguer and Chubut rivers.

Research highlights: The regional map indicates that T. melanosporum cultivation is feasible in 3% of Patagonia surface, considered together patches classified as suitable and suitable with surface-water irrigation. This regional model clearly identified major limiting factors in different parts of the region, such as temperatures in the northernmost and southernmost parts of Patagonia, the presence of ectomycorrhizal forests along the Andes Mountain range, and the critical role of water resource availability. The map of Chubut province showed that the model was useful not only for regional scale planning but also for more detailed purposes such as farmer’s decision making, while taking into account the significant small-scale variability of Patagonian topography and soils. These maps are pioneering for Argentina, constituting a powerful decision-making tool for territorial planning, aimed to diversify agricultural production in Patagonia by incorporating this novel and profitable crop in vast areas.

Towards the cultivation of the bay boletus, Imleria badia: Primordia formation, mycorrhizal synthesis and geographic distribution

2026-02-03T13:36:00+01:00

Aim of study: Here we take the first steps towards the cultivation of the gastronomically appreciated ectomycorrhizal fungus known as the bay boletus, Imleria badia (Fr.) Vizzini (2014). The cultivation of ectomycorrhizal species with their hosts presents a mycoforestry system in which food production and forestry can exist on the same parcel of land. We present results of attempts to synthesize I. badia mycorrhiza alongside an investigation into the distribution and climate tolerance of the species.

Area of study: The mycorrhizal-development component of the study takes place in laboratory and greenhouse facilities in Scotland, UK. The second component of biogeographic analysis covers the whole of Europe.

Material and methods: Strains of I. badia are sampled from forest sites in Scotland (UK), before being isolated in agar-based media within the laboratory. Mycorrhizal synthesis is attempted using the host tree species Pinus sylvestris L. in greenhouse conditions. Biogeographic analysis is then undertaken using global occurrence records from the Global Biodiversity Information Facility.

Main results: One isolated strain displayed the unusual characteristic of forming primordia in pure culture. Mycorrhizal synthesis occurred with the application of basidiospores, mycelia or a combination of both inoculation methods and identification was confirmed with PCR. Biogeographic analysis showed a broad distribution across Europe with some clear regional trends in seasonal fruiting patterns.

Research highlights: Successful mycorrhizal synthesis in greenhouse conditions of this gastronomically valued species presents the first step on the road to cultivation. A ready ability to produce primordia suggests high potential and biogeographic analysis allows informed selection of field-trial sites as the next step towards the goal of cultivation.

Ethnomycology of Yayo Coffee Forest Biosphere Reserve, southwest Ethiopia

2026-02-03T13:34:50+01:00

Aim of study: To gather ethnomycological knowledge from local communities inhabiting in the Yayo Coffee Forest Biosphere Reserve (Yayo CFBR).

Area of study: Yayo Coffee Forest Biosphere Reserve, located in Illuababora province, southwest Ethiopia. Material and methods: Semi-structured interviews involving 1,189 individuals, including group and key informant discussions performed in September and October 2023 were analyzed to assess the ethnomycological knowledge of six local communities. Weekly mushroom surveys were conducted during the main rainy season (July and August 2023) in the reserve’s buffer and transition zones.

Main results: Twenty-one of the 51 mushroom species found in the reserve were edible. Agaricus campestroides, Macrolepiota africana, Tremella mesenterica, Termitomyces sp., and Schizophyllum commune were the most popular. Although 51.6% of respondents were familiar with mushrooms and their use as a medicine and/or food, only 34% of respondents collected mushrooms for consumption. Women and children collect mushrooms during the main rainy season. Negative perceptions and cultural taboos contribute to mycophobia. Respondents identified five mushroom habitats and seven distinct substrates where mushrooms grow. The majority of respondents (61.2%) were aware that wild mushrooms can be toxic, and some were capable of distinguish mushrooms based on color, smell, and texture. Most respondents (84.3%) believed that the wild mushrooms abundance had decreased due to deforestation, overgrazing, fire, or settlements.

Research highlights: The baseline ethnomycological information obtained in this study could promote sustainable forest practices through training and awareness, which could help to preserve the biosphere reserve, boost coffee productivity, and aid regions dealing with similar challenges.

Sentinel-1 and Sentinel-2 data for predicting forest stand variables in GEE: A case study of timber plantations in northern Spain

2026-02-03T13:49:25+01:00

Aim of study: In this study we developed machine learning models for estimating five forest stand variables, including total over bark volume, number of trees per hectare, dominant height, basal area and aboveground biomass, from remote sensing data and ancillary variables in forest plantations of Eucalyptus globulus Labill, Pinus pinaster Aiton and Pinus radiata D. Don.

Area of study: The study was conducted in northern Spain (Autonomous Communities of Asturias, Cantabria, Basque Country and Galicia) where plantations of the species of interest are mainly concentrated due to the high productivity of forest stands in these areas.

Material and methods: We used ground-truth data from Spanish National Forest Inventory plots, two sources of remote sensing data and images from the Sentinel-1 constellation (radar) and from the Sentinel-2 constellation (optical) combined with terrain and climate data. We used the Google Earth Engine platform using Random Forest algorithm with 10-fold cross-validation to obtain forest stand variables, including density, size and yield variables.

Main results: Evaluation of the model accuracy and variable importance in estimating forest variables showed that the total volume models performed best, yielding R² values between 0.39 and 0.45 for the different tree species. Optical bands were very important in all cases, while radar bands were less important. Research highlights: The use of synthetic aperture radar, although promising, is limited in platforms like GEE, especially for complex terrains where shadowing and angles affect the image quality. The research contributions include the automation of preprocessing steps, and the findings highlight the need to develop more robust, adaptable models using AI and new radar sensors.

Refining current annual volume increment estimation for forest tree species in Spain

2026-02-03T13:36:34+01:00

Aim of study: The aim of this study is to improve the estimation of current annual volume increment of forest tree species in Spain.

Area of study: The volume increment of the main tree species was studied at national scale using the two most recent data sets of the Spanish National Forest Inventory (SNFI) available.

Material and methods: We developed both a tree diameter and height growth models considering the two most recent cycles of the SNFI and used the estimations obtained to calculate the annual volume growth. Diameter, height and volume estimates were validated using Second and Third SNFI cycles that were not been used for modelling.

Main results: The developed tree diameter and height growth models indicated a satisfactory model structure. In general, competition, expressed as basal area, negatively impacted tree growth. Although basal area of larger trees had a negative effect, it was modulated by site quality, where better site conditions positively affected growth. Furthermore, tree vitality was found to be an important factor modulating tree growth.

Research highlights: The proposed methodology to estimate tree growth considers tree size, competition, site quality and tree vitality and improves the estimates compared to previous methods based on current annual volume increment equations.

Stand competition and slope increase the probability of occurrence of Gremmeniella abietina in forest stands in Spain

2026-01-16T12:42:50+01:00

Aim of study: This study aimed to determine the distribution of the fungal pathogen Gremmeniella abietina in forest stands close to the first detection zone in Spain. Additionally, we aimed to identify stand characteristics associated with the presence of the pathogen and evaluate the use of remote sensing methods, such as the Normalized Difference Vegetation Index (NDVI), for early disease detection.

Area of study: Province of Palencia, northern Spain.

Material and methods: We surveyed 36 forest stands to assess the distribution of G. abietina. Stand inventories, NDVI values derived from Deimos-1 satellite imagery and DNA amplification techniques were used to characterize each stand and determine the presence or absence of the pathogen. Finally, a combination of a random forest algorithm and a permutational multivariate analysis of variance (PERMANOVA) was applied to identify the most significant predictors of the pathogen presence.

Main results: The presence of G. abietina was confirmed in 13 plots and was found to be correlated with lower NDVI values during the summer months and with greater competition (i.e., high basal area) on steeper slopes. The algorithm had limited predictive power but it was sufficiently reliable for descriptive purposes. Infected stands also showed higher levels of defoliation, distortion of terminal twigs and dry needles.

Research highlights: The results indicate that although the pathogen has spread beyond the initial detection zone, it currently causes only moderate damage. The absence of epidemic outbreaks in the region may be due to environmental conditions that are not conducive to disease development. Nevertheless, the presence of G. abietina could negatively affect forest productivity, particularly in stands located on steep slopes and characterized by a high level of competition. Use of the NDVI may be a useful tool for detecting trees affected by the pathogen at an early stage, but confirmation through field diagnosis surveys and molecular diagnostics remains essential.