Institute of

Forest Ecosystems

National Forest Inventory (NFI)

The diameter at breast height measured by a special measuring tape is an important parameter.
The diameter at breast height measured by a special measuring tape is an important parameter. (© Christina Waitkus)

The National Forest Inventory provides sample-based data on status and development of Germany`s forests. Every ten years field crews measure trees on permanent plots and take many more parameters. From this data we caculate statistics on forest area, tree species diversity, the age structure of forests, growing stock and timber harvesting. Since 1995, we coordinate the scientific part of the NFI. In collaboration with experts of the Federal States we develop the inventory method, organise the data management and analyse the inventory.

As a central monitoring instrument the NFI provides the information needed to assess Germany's forests. This is the basis for decision-making in politics and economy. Concerning for example the challenges of climate change and the related question: What kind of forests do we need in the future? Another question is: How much wood can be used according to the principles of a sustainable forestry. Furthermore the data is an integral part of international reports such as the Kyoto Protocol and the United Nations Framework Convention on Climate Change (UNFCCC).

Results of the Third National Forest Inventory are available on and on our web portal In particular specialists can find a variety of results and visualise them in tables, graphs and maps.

How to collect the data?

Stichprobennetz in Deutschland
Stichprobennetz in Deutschland (© BMEL)

Before field crews collect data in the forest, scientists of the Thünen Institute for Forest Ecosystems and experts of the Federal States analyse the previous inventory method and adapt it to the new requirements. The scientists determine what data will be measured, to answer as many questions as possible representative and unbiased.

Also technological progress, new scientific findings and questions need to be considered. Thus for example the survey threshold of deadwood was lowered and the survey of forest habitat types was established. Therefore it was necessary to estimate the cost and time required in a preliminary study. Every minute more at the plot adds a man-year to the inventory.  

The field crews of the Federal States collected data at randomly selected samples. The samples are reticulated at a distance of 4 km x 4 km. In some Federal States, the network is compressed to 2.83 km x 2.83 km or 2 km x 2 km. At each grid point a square tract is created of 150 m side length. On the corners located in forests the surveys were carried out. The field crews collect data of about 150 parameters in total. They take measurements of tree diameters and heights of selected sample trees, determine the tree species and collect data of deadwood.  

Data collection for the Third National Forest Inventory

Data collection for the Third National Forest Inventory 

Focus: The Third National Forest Inventory data have been well-structured and stored in high data quality during the data collection phase (2010-2012). An important principle for ensuring data quality is to review the information immediately at data collection. The databases are pre-initialized, so that well-known objects (areas, specimen trees recovered etc.) can be clearly identified and examined. The data collection software includes input masks, validation routines, and many service functions to make the work during the data collection as efficiently as possible.



  • Centralized data storage in a MS-SQL database
  • Online Client for inventory manager (federal states)
  • Offline client for field crews on mobile field computers
  • Data synchronization technology between central database and field computers

The databases and software are developed in cooperation with the company Nüssler IT Consulting GmbH. The project is technically supported by the central IT department of the Thünen Institute in Braunschweig. The two servers used for this project (database and application servers) are supervised in Braunschweig as well as the network and safety infrastructure.  



 Software development for the third NFI and data management

Provision of conclusions:

  • Forest conditions in 2012
  • Changes (balance, increment, loss)

    • from BWI 2002
    • from Inventory Study 2008


  • Calculation of characteristics which were not directly collected during BWI 2002, e.g. growing  area of trees and trees volume.
  • Extrapolation

    • data transfer to extrapolation program
    • extrapolate / aggregate data
    • file results in databases

  • Results selection and presentation from databases at


  • Centralized data management in MS SQL-database
  • Procedures, functions in SQL-server, DLLs
  • .NET-applications
  • Web-presentation
  • Webservices  

Inventory dates

  • 1986-1991  First National Forest Inventory (year of reference 1987)
  • 2000-2002  Second National Forest Inventory (year of reference 2002)
  • 2011-2012  Third National Forest Inventory (year of reference 2012)
  • Furthermore, data were collected in a subsample in the year 2008


The National Forest Inventory is a joint project of the Federal Government and the Federal States. The Federal Ministry of Food and Agriculture has assigned the national inventory administration to the Thünen Institute for Forest Ecosystems. The Federal States are responsible for the data collection.  


Further informations and results of National Forest Inventory:

Survey of forest