Forest structure and individual tree inventories of northeastern Siberia along climatic gradients

We compile a data set of forest surveys from expeditions to the northeast of the Russian Federation, in Krasnoyarsk Krai, the Republic of Sakha (Yakutia), and the Chukotka Autonomous Okrug (59–73∘ N, 97–169∘ E), performed between the years 2011 and 2021. The region is characterized by permafrost soils and forests dominated by larch (Larix gmelinii Rupr. and Larix cajanderi Mayr). Our data set consists of a plot database describing 226 georeferenced vegetation survey plots and a tree database with information about all the trees on these plots. The tree database, consisting of two tables with the same column names, contains information on the height, species, and vitality of 40 289 trees. A subset of the trees was subject to a more detailed inventory, which recorded the stem diameter at base and at breast height, crown diameter, and height of the beginning of the crown. We recorded heights up to 28.5 m (median 2.5 m) and stand densities up to 120 000 trees per hectare (median 1197 ha−1), with both values tending to be higher in the more southerly areas. Observed taxa include Larix Mill., Pinus L., Picea A. Dietr., Abies Mill., Salix L., Betula L., Populus L., Alnus Mill., and Ulmus L. In this study, we present the forest inventory data aggregated per plot. Additionally, we connect the data with different remote sensing data products to find out how accurately forest structure can be predicted from such products. Allometries were calculated to obtain the diameter from height measurements for every species group. For Larix, the most frequent of 10 species groups, allometries depended also on the stand density, as denser stands are characterized by thinner trees, relative to height. The remote sensing products used to compare against the inventory data include climate, forest biomass, canopy height, and forest loss or disturbance. We find that the forest metrics measured in the field can only be reconstructed from the remote sensing data to a limited extent, as they depend on local properties. This illustrates the need for ground inventories like those data we present here. The data can be used for studying the forest structure of northeastern Siberia and for the calibration and validation of remotely sensed data. They are available at https://doi.org/10.1594/PANGAEA.943547 (Miesner et al., 2022).</p

Ground vegetation cover at 47 lake sites in Central and Eastern Yakutia, Siberia, in summer 2021 (RU-Land_2021_Yakutia)

The vegetation surveys were carried out in four different study areas in the Sakha Republic, Russia: in the mountainous region of the Verkhoyansk Range within the Oymyakonsky and Tomponsky District (Event EN21402 - EN21415), and in three lowland regions of Central Yakutia within the Churapchinsky, Tattinsky and the Megino-Kangalassky District (Event EN21416 - EN21464). The study area is located within the boreal forest biome that is underlain by permafrost soils. The aim was to record the projective ground vegetation in the shore area of the lakes studied during the RU-Land_2021_Yakutia summer field campaign in August and September 2022. Baisheva et al. (2022) gives an overview of the lakes studied and the corresponding hydrochemistry. The ground vegetation was estimated as a percentage within 2 x 2 m plots. The location of the plots was selected on site at the lake to represent the typical ground cover. Some of the vegetation plots were located directly on the shore in the transition to the water, others were chosen nearby the lakeshore. The elevation corresponds to the lake level, as the plots were in the immediate vicinity. The number of plots per lake depended on the different land cover classes, with more plots selected if the vegetation cover was more heterogeneous. The vegetation cover was estimated for each taxon within the plot. If only a few specimens of a species were represented within the plot (less than 1%), they are marked with ' 1.70 m) and trees (> 3-5 m). In total, 92 plots at 47 lakes were investigated. All data were collected by scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) Germany, the University of Potsdam Germany, and the North-Eastern Federal University of Yakutsk (NEFU) Russia

Tree data set from forest inventories in north-eastern Siberia

The data set presents about 40,000 trees which where surveyed during several Russian-German expeditions by North-Eastern Federal University Yakutsk and Alfred-Wegener-Institute Potsdam to the North-East of the Russian Federation between the years 2011 and 2021. The purpose was to gather information on trees and forests in this region, which was then used to understand tree line migration, stand infilling and natural disturbance and succession processes and to initialize and validate a forest model. Trees are located on more than 160 vegetation plots, each of which has a size of several hundred square meters. For every tree, height was estimated, and the species recorded. Some individuals were subject to more detailed inventory, including diameters at base and at breast height, crown diameters, and other information

Tree data set from forest inventories in north-eastern Siberia - Tree measurements

The data set presents more than 12,000 of about 40,000 trees, which were surveyed during several Russian-German expeditions by the North-Eastern Federal University Yakutsk and the Alfred-Wegener-Institute Potsdam in the North-East of the Russian Federation between the years 2011 and 2021. The purpose was to gather information on trees and forests in this region, which was then used to understand tree line migration, stand infilling and natural disturbance and succession processes and to initialize and validate a forest model. Trees are located on more than 160 vegetation plots, each of which has a size of several hundred square meters. For every tree, height was estimated, and the species recorded. Some individuals were subject to more detailed inventory, including diameters at base and at breast height, crown diameters, and other information. This table partially overlaps with the data set: “Tree data set from forest inventories in north-eastern Siberia - Tree heights.” (doi: 10.1594/PANGAEA.949863), but includes all tree measurements as well as all inventoried trees, which were not included in the Tree heights dataset due to small or lying deadwood

Tree data set from forest inventories in north-eastern Siberia - Tree heights

The data set presents more than 32,000 of about 40,000 trees, which were surveyed during several Russian-German expeditions by the North-Eastern Federal University Yakutsk and the Alfred-Wegener-Institute Potsdam in the North-East of the Russian Federation between the years 2011 and 2021. The purpose was to gather information on trees and forests in this region, which was then used to understand tree line migration, stand infilling and natural disturbance and succession processes and to initialize and validate a forest model. Trees are located on more than 160 vegetation plots, each of which has a size of several hundred square meters. For every tree, height was estimated, and the species recorded, while a few individuals were subject to more detailed inventory. This table contains every standing tree of at least 40 cm height that was encountered on the vegetation plots described in the Plot Data Base. It partially overlaps with the dataset “Tree data set from forest inventories in north-eastern Siberia - Tree measurements.” (doi: 10.1594/PANGAEA.949861), which additionally contains details on small or lying deadwood