Target Tailored Forest Damage Inventory (TFDI) - Inventory of damage by spruce bark beetle in Götaland and Svealand 2022

Inventories of forest damage are carried out within the Swedish University of Agricultural Sciences (SLU) Forests programme. An annual monitoring of the most important sources of forest damage is carried out by the Swedish National Forest inventory (NFI). Although the Swedish NFI is an objective and uniform inventory of forest damage in Swedish forests at national and regional scales, less common or less widespread occurrences of forests pests and pathogens are difficult to survey solely through large-scale monitoring programmes. There is a need for complementary inventories to facilitate timely delivery of relevant information. Thus Target-tailored forest damage inventories (TFDI) aiming at providing data for operational decisions making at local level, and linked to specific damage events were introduced. TFDI’s are developed to give rapid response to requested information of specific damage outbreaks. The TFDIs are carried out in limited and concentrated samples, with flexible but robust methods and design. The data collected in the TFDI shall also be of such quality that it can be useful in research. During 2022 TFDI carried out a sample inventory of the volume Norway spruce (Picea abies) damage by European spruce bark beetle (Ips typographus) in older spruce forest in the region of Götaland excluding Gotland and Svealand excluding Dalarna. This as a follow-up to the extremely hot and dry summer in 2018, which resulted in many drought stressed spruce trees that favored the spruce bark beetle. The spruce bark beetle populations, which were already high before, increased rapidly and have in recent years caused extensive damage to spruce in Götaland och Svealand. This year´s inventory is a follow-up to the inventories carried out in 2020 and 2021. The inventory includes both standing infested trees as well as infested wind-felled trees and stumps from felled infested trees. The purpose of the inventory was to estimate the volume Norway spruce damage by the given bark beetles, but also to highlight geographical distribution and the appearance of the damage in different forest sites. The results from the inventory should be available for decisions making basis in forestry managements. The inventory was stratified by an objective sample of all the National Forest Inventory permanent sample plots in Götaland and Svealand. Included plots within the sample was all older thinning forest and final felling mature forest consisting of at least 7/10 proportion of spruce. For the selection of plots LPM (local pivotal method, Grafström et al) is used where the selection was spread based on the geographical position and the spruce volume of the sample plots. The radii of sample plots used for the damage inventory was 20 m, the area which was included for the described site. This means that the inventoried area was smaller than during the 2020 inventory, when the radius was 25 m. Other parts of the plot were not included in the inventory. The inventory in 2022 includes both trees with fresh infestations (season 0) and trees infested last year (season 1) by the spruce bark beetle. Diameter at breast height was measured on damage trees and wind-felled trees. Diameter on stump from cut trees with fresh damage was measured. In 2022, the sample was expanded in order to possibly provide reliable estimates at the county level. The dataset consist at plot level of 1310 rows with 28 column, at tree level (season 0) of 509 rows with 16 columns and at tree level (season 1) of 446 rows with 12 columns. Data on inventory date has been lost. The content and scope of the inventory has been developed in consultation with Swedish Forest Agency. References: Grafström, A., Lundström, N., & Schelin, L. Spatially Balanced Sampling through the Pivotal Method. Biometrics, 68(2), 514-520. https://doi.org/10.1111/j.1541-0420.2011.01699.xOpens in a new tab Some assessed and used variables: At sample plot level: Plot area measured The proportion of spruce at the sample plot Maturity class Number of infested trees Logging Sanitation At tree level season 0: Is the tree dead or alive? Position of tree – standing, wind-felled, stump Diameter at breast height Tree volume At tree level season 1: Diameter at breast height Tree volume See the document "Data_description" for more detailed information. As additional documentation, field instructions for the inventories are also provided, both for the specific inventory and for the National Forest Inventory (NFI). An English version of the National Forest Inventory field instruction is available for year 2021 only, which is why this is included here.