Harmonised projections of future forest resources in Europe

Data PaperAbstract • Key message A dataset of forest resource projections in 23 European countries to 2040 has been prepared for fores trelated policy analysis and decision-making. Due to applying harmonised definitions, while maintaining country-specific forestry practices, the projections should be usable from national to international levels. The dataset can be accessed at https://doi.org/10.5061/dryad.4t880qh. The associated metadata are available at https://metadata-afs.nancy.inra.fr/ geonetwork/srv/eng/catalog.search#/metadata/8f93e0d6-b524-43bd-bdb8-621ad5ae6fa9info:eu-repo/semantics/publishedVersio

Assessment of Growing Stock Components for Data Harmonization in International Reporting. Lithuanian Case Study

Vienas iš pagrindinių miškų inventorizacijos tikslų yra medienos tūrio įvertinimas. Daugelis Šalių šiam tikslui pasiekti naudoja tuos pačius pagrindinius medžių stiebų rodiklius - stiebų skersmenį, išmatuotą 1,3 m aukštyje nuo šaknies kaklelio ir medžio stiebo aukštį arba ilgį, t.y. atstumą tarp šaknies kaklelio ir viršūninįo pumpuro. Tačiau medienos tūris skirtingų šalių apskaitose apskaičiuojamas gana skirtingai. Pateikiami apskaitoms skirtingų šalių medienos tūriai dažnai skiriasi pagal kelmų, viršūnių, smulkių medžių ar net šakų tūrius. Tinkamiausias būdas suderinti medienos tūrius būtų miškų inventorizacijos metu nustatytą medžio stiebo, kaip pagrindinio inventorizacijos objekto, tūrį priimti už etaloną. Atsižvelgiant į miškų inventorizacijų nacionalinius ypatumus yra siūloma atskirai įvertinti kelmų, viršūnių, smulkių medžių arba šakų tūrius ir atitinkamai koreguoti nacionalinius duomenis. Šiame darbe pasiūlytas metodas, kaip naudojant nacionalinius apskaitos duomenis ir nacionalinius medžių stiebo ir atskirų jo dalių tūrio įvertinimo metodus, pakoreguoti nacionalinius duomenis ir taip suderinti juos su Europos ir globalinės miškų apskaitos duomenimis. Darbe pateiktas atskirų medžio dalių ir smulkių medžių medienos tūrio įvertinimas gali būti panaudotas kaip etalonas medienos tūrio apskaitai panašaus klimato ir dirvožemio šalyse. Lietuvos miškų medienos tūris, nustatytas naudojant nacionalinius standartus. 8% viršija turį, nustatytą pagal globalinės miškų apskaitos reikalavimus (FAO 2001) ir 2% - pagal COST E-43 (Vidal et al 2008) reikalavimusOne of the main goals of forest inventories is estimation of the growing stock volume. Practically all countries for this purpose use the same main parameters of trees – measured stem diameters at breast height (DBH) and the height or length of tree stems, i.e. the distance between root collar and terminal bud. At the same time growing stock volume estimates differ between countries and assessments. Sometimes they do not include stumps, tops, small size stems, while sometimes they include large branches. To unify the estimates of the growing stock volume, the most reasonable way is to follow the practice of forest inventory and to use the main inventory object, i.e. tree stem as the reference object during forest assessments. Assuming the traditions of various countries to use different national reference objects, it is suggested to estimate the volume of stumps, tops, small sized trees or large branches and to make adequate corrections in the national data. This study suggests a method of how using the data of national forest inventory and estimation models of stem volume and its separate parts to adjust national data in compliance with all European or global forest resources assessment data. Presented in the study are estimates of separate parts of stems or small sized stems that can be used as the default values for the harmonization of growing stock volume estimates in countries with similar climatic and soil conditions. The growing stock volume of Lithuanian forests, assessed using the national definition, overestimates volumes assessed using global forest resources definition by 8%, while using COST Action E43 definition – by 2%Vytauto Didžiojo universitetasŽemės ūkio akademij

Dubravos girios medynų augimas ir naudojimas gamtinių veiksnių įtakoje

Valstybinė miškų tarnybaVytauto Didžiojo universitetasŽemės ūkio akademij

Dubravos girios medynų augimas ir naudojimas gamtinių veiksnių įtakoje

Valstybinė miškų tarnybaVytauto Didžiojo universitetasŽemės ūkio akademij

Coarse Woody Debris in the Forest of Lithuania

Vytauto Didžiojo universitetasŽemės ūkio akademij

Combining sampling-based forest inventory data and remote sensing to improve volume estimates of mature forest stands

In Lithuania, sampling-based surveys of mature forests started in 2008–2009. These surveys focused on statistically sound and NFI-compatible estimates at the forest enterprise level. They are based on measurements of large number of sample plots, thus making forest inventory labor-intensive and costly. The results of such inventories are hardly applicable at local level. This study tested several methodological approaches to improve forest enterprise and local level stand volume estimates for mature stands utilizing the Landsat 5 Thematic Mapper (TM) images and non-parametric k-nearest neighbor estimation technique. As the study object we used information available from the surveys of mature forest stands conducted in 4 state forest enterprises in Northern part of Lithuania (total area around 6000 sq. km), with over 4500 precisely geo-referenced circular field plots and major forest characteristics measured in the field. Information on National Forest Inventory (NFI) plots for the area of the satellite image scenes as well as the stand-wise forest inventory data was available for the study at the State Forest Survey, too. Different approaches to reduce the number of field plots to be measured during the surveys of mature stands were tested considering the estimate achieved with the full set of sample plots as a true value: using just the NFI plots, using subsets of sample plots from the survey of mature stands, using stratified subsets of sample plots utilizing the stand-wise forest inventory data. Simultaneously, the potential of providing local level stand volume estimates utilizing the no cost satellite images, surveyed sample plots and information borrowing technique was discussed, tooVytauto Didžiojo universitetasŽemės ūkio akademij

Ar gali tarptautiniai klimato kaitos susitarimai apriboti miško naudojimą Lietuvoje?

Vytauto Didžiojo universitetasŽemės ūkio akademij

Lithuania

eISBN 9783319440156Forest inventory in Lithuania consists of two national inventories: a stand level forest inventory (SFI) and a national forest inventory (NFI) using statistical sampling methodsLietuvos Valstybinė miškų tarnybaVytauto Didžiojo universitetasŽemės ūkio akademij

Validation of Generalized Height-Diameter Model Based on Lithuanian NFI Data

The height estimation of every tree included in NFI sample plots is based on height-diameter ratio measurements of small amount of subsample trees. Height is measured for systematically selected every seventh tree on the sample plot (Kuliešis et al. 2003a, 2009b). On an average, height and diameter of 1–7 trees of prevailing and 1–3 trees of admixture tree species are measured per one plot. Heights of the remaining trees are estimated using generalized height-diameter model (Kuliešis 1993) based on measured diameters of all trees as well as height-diameter ratio of subsample trees. The goal of this study is to estimate the accuracy of tree height prediction using generalized height-diameter model based on measurement of height-diameter relation of small amount of subsample trees. This study makes use of the data of height-diameter ratio measurements on 1998–2010 NFI plots. This data derives from 47.5 thousand subsample trees of prevailing eight tree species as follows: pine, spruce, birch, aspen, black alder, grey alder, oak, and ash, and 24.6 thousand subsample trees of the same tree species as admixture in stands. Deviations of modeled heights from measured ones and their significance were estimated in respect of tree species, tree position – prevailing or admixture, mean diameter, and mean height. Spruce and oak stands have the most, and black alder and aspen stands have the least tree height variation per group with the range of mean diameter ± 2 cm and the range of mean height ± 1 m. Accuracy of mean tree height estimation per plot shifts from 3–5% in stands with mean diameter equal to 40 cm and more up to 5–15% in stands with mean diameter equal to 4–20 cm. Mean height deviations of predicted values from those obtained by measuring all tree populations on stand is negligible for all species, -0.6 cm per prevailing tree, -2.5 cm per admixture tree and -1.3 cm per any treeVytauto Didžiojo universitetasŽemės ūkio akademij