Although boreal forest management typically results in an increased frequency of even-aged forest stands in managed landscapes, fire history research suggests that much of the natural forest mosaic is composed of stands characterised by multiple cohorts of trees. To aid in the development of multicohort management, I investigated stand structural characteristics and small mammal communities as a function of their tree cohort structures. I also tested key alternatives: stand age, productivity, and tree species composition, as correlates of structural variation and small mammal communities. Results reveal that in mixedwood and black spruce forests, three-dimensional structure of boreal forests is strongly correlated with small mammal community structure, and indicate that tree diameter distribution is a succinct descriptor of such structural variation, performing better than alternative stand characteristics. This represents a new approach to characterising habitat supply as a function of within-stand heterogeneity, contrasting with existing approaches that focus on among-stand characteristics.

Although boreal forest management typically results in an increased frequency of even-aged forest stands in managed landscapes, fire history research suggests that much of the natural forest mosaic is composed of stands characterised by multiple cohorts of trees. To aid in the development of multicohort management, I investigated stand structural characteristics and small mammal communities as a function of their tree cohort structures. I also tested key alternatives: stand age, productivity, and tree species composition, as correlates of structural variation and small mammal communities. Results reveal that in mixedwood and black spruce forests, three-dimensional structure of boreal forests is strongly correlated with small mammal community structure, and indicate that tree diameter distribution is a succinct descriptor of such structural variation, performing better than alternative stand characteristics. This represents a new approach to characterising habitat supply as a function of within-stand heterogeneity, contrasting with existing approaches that focus on among-stand characteristics.

La relation diversité-productivité est au cœur des enjeux actuels dans de nombreux écosystèmes. Dans l’étude de cette relation en peuplements forestiers, un aspect de la diversité a été longtemps négligé : l’hétérogénéité des tailles. Nous nous intéressons à l’effet de l’hétérogénéité des tailles sur la production en peuplements purs et mélangés et à ses interactions avec les traits fonctionnels des espèces. L’utilisation de données de l’inventaire forestier national nous a permis de démontrer un effet globalement négatif de l’hétérogénéité des tailles en peuplements purs de différentes espèces ainsi qu'en peuplements mélangés. Dans ce dernier cas, nous avons mis en évidence un effet positif sur la production de la richesse spécifique et un effet positif d’une diminution de la tolérance à l’ombre avec la taille des arbres c’est à dire lorsque les espèces les moins tolérantes dominent la canopée. Nous discutons les intérêts et limites de de ces résultats et leurs conséquences à plus ou moins long terme pour la stabilité et la résilience des peuplements forestiers. / Understanding the link between diversity ecosystem functioning has been a major topic of ecology for the last decades. When studying the relationship between diversity and productivity in tree populations and communities, size heterogeneity has often been disregarded. Our study focuses on the effect of size heterogeneity on the production of pure and mixed forest stands as wells its interactions with species’ functional traits. By using national forest inventory data, we were able to demonstrate a negative effect of size heterogeneity in both pure and mixed stands. In the latter case, we showed a positive effect of species richness as well as a positive effect of a decrease of shade tolerance with tree size, i.e. when the less tolerant species are dominant in the overstorey. We propose potential mechanisms to explain our results and discuss the consequences of such findings at larger time scale for the stability and resilience of forest stands.

The southeastern United States is one of the most productive forestry regions in the world, encompassing approximately 100 million ha of forest land, about 87% of which is privately owned. Any alteration in this region's duration or rate of forest recovery has consequential economic and ecological ramifications. Despite the need for forest recovery monitoring in this region, a spatially comprehensive evaluation of forest spectral recovery through time has not yet been conducted. Remote sensing analysis via cloud-computing platforms allows for evaluating southeastern forest recovery at spatiotemporal scales not attainable with traditional methods. Forest productivity is assessed in this study using spectral metrics of southern yellow pine recovery following stand-replacing disturbance. An annual cloudfree (1984-2021) Landsat time series intersecting ten southeastern states was constructed using the Google Earth Engine API. Southern yellow pine stands were detected using the National Land Cover Database (NLCD) evergreen class, and pixels with a rapidly changing spectrotemporal profile, suggesting stand-replacing disturbance, were found using the Landscape Change Monitoring System (LCMS) Fast Loss product. Spectral recovery metrics for 3,654 randomly selected stands in 14 Level 3 EPA Ecoregions were derived from their 38-year time series of Normalized Burn Ratio (NBR) values using the Detecting Breakpoints and Estimating Segments in Trend (DBEST) change detection algorithm. Recovery metrics characterizing the rate (NBRregrowth), duration (Y2R), and magnitude (K-shift) of recovery from stand-replacing disturbances occurring between 1989 and 2011 were evaluated to identify long-term and wide-scale changes in forest recovery using linear regression and spatial statistics respectively. Sampled stands typically recover 35% higher in NBR than pre-disturbance and, on average, spectrally recover within seven years of disturbance. Recovery rate is shown to be increasing over time; temporal slope estimates for NBRregrowth suggest a 33% increase in early recovery rate between 1984 and 2011. Similarly, recovery duration measured with Y2R decreased by 43% during the study period with significant spatial variation. Results suggest that the magnitude of change in stand condition between rotations has decreased by 21% during the study period, has substantial regional divisions in high and low magnitude recovery between coastal and inland stands, and low NBR value sites have the most potential to increase their NBR value. Observed spatiotemporal patterns of spectral recovery suggest that changes in management interventions, atmospheric CO2, and climate over time have changed regional productivity. Results from this study will aid the understanding of changing productivity in southern yellow pine and will inform the management, monitoring, and modeling of this ecologically and economically important forest ecosystem. / Master of Science / The Southeast United States contains approximately 100 million hectares of forest land and is one of the world's most productive regions for commercial forestry. Forest managers and those who model the effects of different types of forest land on the changing climate need up-to-date information about how productive these forests are at removing carbon and producing wood and how that productivity differs across space and time. In this study, we evaluate the productivity of southern yellow pine stands by measuring stand recovery attributes from a disturbance that removes the majority or all of the trees in the stand. This is accomplished by locating 3,654 of randomly selected disturbed pine stands through ten southeastern states using freely available national data products derived from Landsat satellite imagery, namely a combination of the National Land Cover Database (NLCD) and the Landscape Change Monitoring System (LCMS), which provide information about the type of forest, and the year and severity of disturbance respectively. Annual Landsat satellite imagery from 1984 to 2021 is used to create a series of values over time for each stand representing the stand condition each year using an index called the Normalized Burn Ratio (NBR). A change detection algorithm called DBEST is applied to each stands NBR values to find the timing of disturbance and recovery, which is used to create three metrics characterizing the rate (NBRregrowth), duration (Y2R), and magnitude (K-shift) of recovery. We evaluated how these metrics change through time using linear regression and how they differ across space using regression residuals and spatial statistics. Across the region, stands typically increase in recovery rate, decrease in recovery duration, and decrease in recovery magnitude. On average, stands recover within seven years of disturbance and to a higher NBR value than pre-disturbance. However, there is significant spatial variation in this metric throughout the Southeast. The results indicate that stands with a lower vegetation condition, measured with NBR, before the disturbance had the most significant gain in stand condition after recovery, and stands with initially higher vegetation condition did not increase as much after recovery.

The purpose of this study is to explore haw thinning planning standards agree with standards of estimation. Study was carried out in Kretinga forest enterprise Grūšlaukė forestry. Study of ratio of stands medial diameter and medial high was carried out in 11 – 60 years old pure spruce. The main purpose of thinning is to increase total productivity of forest stands and to form desirable structure and closeness of stands. It is important that all kinds of forest thinning concern biodiversity, increase resistance to wind and snow damage of forest stands, improve the quality of growing timber. Forests thinning use that timber part which rots in forests and gives no profit. To reach all these purpose forests thinning must be planned. Planning standard must be definite as it possible. It is important that these standards be suit with forests thinning normative. It was estimated that both standards has different rates and they are not matched. Thinning is planning by thickness of stands, but they are estimating by the number of trees in one hectare of stands. It was estimated that the ratio of forest stands medial diameter and medial high can be used in thinning planning. In pure spruce stands thinning must planned until ratio of medial diameter and medial high reach value: 0,8 in 11 – 20 years old stands; 0,9 in 21 – 40 years old stands; 1,0 in 41 – 60 years old stands.

Baigiamajame darbe tiriama bebrų įtaka VĮ Vilniaus miškų urėdijos medynams. Darbo objektas – Vilniaus miškų urėdijos girininkijų miškuose esanti bebrų populiacija ir jų įtaka aplinkai. Darbo tikslas – išanalizuoti ir įvertinti bebrų įtaką medynams VĮ Vilniaus miškų urėdijos miškuose. Tikslui įgyvendinti buvo iškelti tokie uždaviniai: 1. Nustatyti bebrų gausą ir tankį Vilniaus urėdijos miškuose. 2. Nustatyti bebraviečių pasiskirstymą urėdijos girininkijų miškuose. 3. Įvertinti bebrų poveikį medynams. Darbo metodai – literatūros analizė, bebraviečių įvertinimas, bebrų veiklos žymių analizė – fotofiksacija. Naudojama kartografinė medžiaga, miškotvarkos duomenys, atliekama bebrų apskaita, vertinamas poveikis medynams. Išsamesni bebrų populiacijos būklės ir veiklos tyrimai atlikti VĮ Vilniaus miškų urėdijos dvylikos girininkijų teritorijose 2012 – 2014 metų rudenį, žiemą ir pavasarį. Pirminiai duomenys apie bebraviečių išsidėstymą, klasifikaciją, įtaką aplinkai buvo renkami iš miškininkų bei miškotvarkos pateiktos informacijos. Tai buvo tikslinama natūroje, ieškomos naujos bebravietės. Darbo rezultatai. Atlikus tyrimą nustatyta, kad Vilniaus urėdijos miškuose yra 67 bebravietės. Apie du trečdalius bebrų šeimų įkuria naikintinas bebravietes melioracijos kanaluose, pelkėse – ketvirtadalis toleruotinų bebraviečių, o likusios – upelių ir upės šlaituose. Dėl bebrų veiklos urėdijos urėdijos miškuose medienos nuostoliai per penkerius metus sudarė 121,1 tūkst. litų. Vienos... [toliau žr. visą tekstą] / In the research the influence of beaver activity on forest stands in Vilnius State Forest Enterprise is analyzed. The subjekt of research – beaver population living in the forests of Vilnius State Forest Enterprise and its influence on the environment. The aim of the research – to analyze and evaluate the influence of beaver activity on forest stands in the forests of Vilnius State Forest Enterprise. The achieve the aim, the following tasks were raised: 1. To determine the abundance and density of beaver population in the forests of Vilnius State Forest Enterprise. 2. To ascertain the distribution of beaver lodges in the forests og the enterprise. 3. To assess the influence of beaver activity on forest stands. Methodology – analyzis of literature, assessment of beaver lodges, analysis of beaver activity signs, photofixation. Cartographic material is used along with forest inventory data, account of beaver population is conducted and its influence on the environment is evaluated. A more dateiled research of beaver population and its activity on the territory of twelve forest districts in Vilnius State Forest Enterprise were carried out in autumn, winter and spring of the years 2012 – 2014. Primary data on the location of beaver lodges, classification, influence on the environment were collected based on information provided by foresters and forest inventory. It was specified in nature, looking also for new lodges. Results. The research has shown that in the Vilnius State... [to full text]

The aim with this study was to investigate factors that affect the occurrence of mycorrhizal fungi species of nature conservation concern in sand pine forests in Norrbotten County in Sweden. In 2019, the occurrence of fruit-bodies of the species in focus was inventoried in 21 forest stands in three different areas located in three municipalities on land that SCA Skog owns and manages in Norrbotten County. The fungi included in study had been noted in the studied areas in previous inventories between the years 2013–2016, which makes it possible to compare variation in fruit body production between years. Specifically, the study tested whether mean age and diameter of trees, and base area and size of forest stands affect the occurrence of fruit bodies of the studied mycorrhiza species in the forest stands. A multiple regression analysis found a positive significant relationship between the number of species that occurred and the size and base area in the forest stands, while there was no effect of mean age and mean diameter of the trees. This indicates that it is important to consider the size and base area of forest stands to maintain mycorrhizal fungi when planning management in dry sandy pine forests. However, because fruit body production is highly variable among years further research is required to get a better understanding of how tree structure affect mycorrhizal fungi.

Forest stand delineation is an essential task of forest management planning which can be time consuming and exposed to subjectivity. The increasing availability of LiDAR data and multispectral imagery offers an opportunity to improve stand delineation by means of remotely-sensed data. Under these premises, ASTER imagery and low-density LiDAR data have been used to automatically delineate forest stands in several forests of Navarra (Spain) through Object-Based Image Analysis (OBIA). Canopy cover, mean height and the canopy model have been extracted from LiDAR data and, along with VNIR ASTER bands, introduced in OBIA for forest segmentation. The outcome of segmentation has been contrasted, on the one hand, assessing segments’ inner heterogeneity. On the other, OBIA’s segments and existing stand delineations have been compared with a new method of geometrical fitting which has been ad hoc designed for this study. Results suggest that low-density LiDAR and multispectral data, along with OBIA, are a powerful tool for stand delineation. Multispectral images have a limited predicting utility for species differentiation and, in practical terms, they help to discriminate between broad-leaved, conifer and mixed stands. The performance of ASTER data, though, could be improved with higher spatial resolution VNIR imagery, specifically sub-metric VNIR orthophotos. LiDAR data, in contrast, offers a great potential for forest structure depiction. This perspective is connected with the increasingly higher resolution datasets which are to be provided by public institutions and the rapid development of drone technology. Complexity of OBIA may limit the use of this technique for small consulting firms but it is an advisable instrument for companies and institutions involved in major forestry projects. / No

O Ipê Felpudo (Zehyera tuberculosa (Vell) Bur) é uma espécie nativa, pioneira que possui um alto potencial silvicultural. Essa está ameaçada de extinção devido ao caráter extrativista e predatório da exploração florestal brasileira. A eliminação de complexos ecossistemas florestais por atividades agrícolas, agropecuárias, madeireiras e industriais tem levado a drásticas reduções da base genética dessa essência. O espaçamento é de grande importância para o desenvolvimento das árvores sob aspectos tecnológicos, silviculturais e econômicos. Esse influencia na morfologia e crescimento das árvores. O espaçamento ótimo é aquele que concorrerá para o maior volume do produto e a qualidade almejada. A modelagem florestal inicia-se no inventário de parcelas permanentes que sofrem remedições, pois as florestas são um sistema biológico que está sempre em mudanças e, necessita-se da projeção destas mudanças para que se possa tomar decisões necessárias a fim de ser executado um manejo adequado nesse ecossistema. As decisões de manejo são baseadas em informações sobre as situações atuais e futuras dos povoamentos.Os objetivos desse trabalho são: analisar um experimento com 6 diferentes espaçamentos; definir um modelo de crescimento para a espécie, em função de variáveis do povoamento e climáticas coletadas na Estação Experimental de Linhares, Espírito Santo. / The Ipê Felpudo (Zeyhera tuberculosa (Vell) Bur) is a native and pioneer species, which possesses a high silvicultural potencial. It has been threatened of extinguishing due the intense predatory exraction of the Brazilian forestry exploitation. The elimination of the complex forestry ecosystem for agricultural, farming, lumber and industrial activities has induced to the drastic redutions of it’s genetic base. Plantation density is one of the most important factor or is the most important factor has a great importance for the development of the trees under technological, sivicultural and economic aspects. It influences in the morphological and trees growth. The excellent plantation density is the one that will concur for the biggest volume of the product and it’s quality. Forest modeling initiates through the inventory of permanent plots that suffer remeasures, therefore, forests are biological systems that are always changing and requires a projection of theese changes, in order to permit executinge management adjustments in this ecosystem. This decisions are based on information of the current and future situations of the stand. The purposes of this work are: to analyze an experiment with 6 different plantation densities; to define a growth model for this species, with stand and climatic variables, collected in the Experimental Station of Linhares, Espírito Santo.

Magistro darbe yra nagrinėjamos neparametrinio knn (k-nearest neighbor) metodo taikymo galimybės Lietuvos sąlygomis vertinant tradicinius miško taksacinius rodiklius bet kokiame šalies teritorijos taške. Darbo objektas – Dubravos miškų urėdijos Dubravos miškas. Darbo tikslas – įvertinti neparametrinio knn (k-nearest neighbor) metodo taikymo Lietuvos miškų inventorizacijose galimybes. Darbo rezultatai. Nustatyta, kad taksacinių rodiklių įvertinimo knn metodu tikslumas kyla didinant apskaitos vienetų, išmatuotų vietovėje, skaičių. Pagrindiniai knn metodo parametrai, kuriais gauti geriausi rezultatai, buvo: 10 artimiausių kaimynų (k reikšmė), atvirkščiai proporcingo atstumo schema, nusakant kiekvieno iš artimiausių kaimynų svertus. Papildomos pagalbinės informacijos – tradicinės sklypinės miškų inventorizacijos metu nustatytų medynų taksacinių rodiklių – panaudojimas kartu su kosminiais Spot Xi vaizdais padidina taksacinių rodiklių įvertinimo tikslumą. Pritaikius optimalų knn metodo taikymo taktikos variantą, mažiausios pasiektos taksacinių rodiklių nustatymo vidutinės kvadratinės paklaidos sudarė 27% medyno vidutinio skersmens, 20% vidutinio aukščio, 40% skerspločių sumos, 35% vidutinio amžiaus, 43% tūrio viename ha, 33% spygliuočių procento rodiklio. Pasitelkus 1999 metų Spot Xi kosminius vaizdus, 1986 apskaitos bareliuose išmatuotas pagrindines medynų taksacines charakteristikas bei 1988 metų sklypinės miškotvarkos duomenis, knn metodu nustatyti pagrindinių taksacinių... [toliau žr. visą tekstą] / The research is dealing with investigations of non-parametric knn (k-nearest neighbor) method for estimation of standard forest characteristics at any point of an area under Lithuanian conditions. Study object: Dubrava forest, managed by Dubrava experimental forest enterprise. Objectives: to assess the usability of non-parametric knn (k-nearest neighbor) method in Lithuanian forests inventory. Results. The increase in number of sample plots with known field information was found to improve the estimation accuracy. The most important parameters for use of knn methods were the following: 10 nearest neighbors (value of k), inverse distance weighted scheme for defining the weights of selected neighbors. Integrating of additional auxiliary information – characteristics of forest compartments, estimated during the conventional stand-wise inventory – to be used together with Spot Xi images improved the overall accuracy of estimations. The lowest achieved root mean square errors were 27% of the average value of all plots within the study area for mean diameter, 20% for mean height, 40% for basal area, 35% for mean age, 43% for volume per 1ha and 33% for the percent of coniferous species in stand tree species composition, when the optimal knn tactics were applied. Spot Xi images from the year 1999, main forest characteristics from 1986 field measured sample plots and data of conventional stand-wise forest inventory from the year 1988 were utilized to estimate using knn method the... [to full text]