Field inventories of deciduous forests and grasslands
Last changed: 05 October 2023
The inventory comprises two stages of inventory: first, an aerial image inventory; and second, a field inventory. All sample plots are classified through an aerial image inventory. These classes are combined into selection classes that are used to randomly select field plots to be inventoried in the field. Since a large proportion of Sweden's landscape contains both deciduous forests and grasslands, there are significant synergies in inventorying both simultaneously.
The aim of conducting field inventory
The aim of conducting a field inventory is to gather data that cannot be acquired through remote sensing, such as the definitive classification of natural types, quality of the habitat, and species occurrences.
Which plots are inventoried in the field?
Each tract consists of 196 circular plots. Only those sample plots that contain focal grasslands or deciduous forests can be selected for a inventory in the field. If there are many sample plots within the area that potentially contain the sought-after natural types, a random selection is made.
Plots and variables
Each area consists of 196 circular sample plots with a radius of 10 meters. Within each sample plot, there are three subplots and one 0.1-hectare assessment polygon. Within the plots on variables such as, natural types (including Annex I natural types included in the Habitat Directive), ground cover, land use, quality variables, vegetation, and species. An overview of the variables can be found here.
Training and support
We conduct a large-scale training session every year, one for each inventory. Whenever possible, new personnel work in pairs with more experienced colleagues. We provide support from the office throughout the inventory to answer queries, review submitted data, and assist in solving any problems that may arise.
Data is collected in three Apps
We use a variant of ESRIs Survey system for our three Apps. One is used to save field photos, one to manage sharing of sample plots, and one to register classes and variables.
We utilize a modified version of ESRIs Survey system for our three applications. One is employed to store field photographs, another to manage sharing of sample plots, and the third to register classes and variables.
Status Portal
This is the central hub for all information, which can be accessed from both the field and the office. Personnel receive their assigned tracts, plan their fieldwork and report their location. All collected data is available in portal and can be reviewed and corrected by both field staff and office personnel.
There are error controls built into the system. An example is that species observations are checked against the species portal's occurrences, which will indicate if the observation of a species is far from previous observations and therefore requires additional scrutiny.
A unique archive of landscape images
Up to 15 photos are recorded per sample plot. The directions are shown in the figure. In addition, photos are also taken directly downward on the subplots and directly upward from the center point.
Habitat types, land use, and species
We collect several types of vegetation data, including habitat types, land use, and quality variables of interest for grasslands and deciduous forests. An overview of the variables can be found here.
Data flow in the field
In the field, data is collected using three apps. The data is sent via ESRIs cloud and continuously uploaded to a server at SLU. The data can then be checked in the status portal.