Indicator: Mixed forest

A graph shows the proportion of the forested area made up of mixed stands (2, 3 or 4 species of trees) and that of pure stands (semi-natural and non semi-natural). The proportion of mixed stands rose from almost 55 percent to almost 58 percent.Click to enlarge
Proportion of mixed forest area in total forest area
Source: German Environment Agency Figure as PDF

Table of Contents

 

At a glance

  • Between 2002 and 2012 the proportion of mixed stands in the total forest area increased from 55 to 58 %.
  • The Federal Government has set itself the aim of increasing the proportion of mixed forest.
  • It will require many decades until the forest conversion is completed.
 

Environmental importance

Woodlands cover around a third of the surface of Germany. Besides providing timber, they fulfil various functions, such as purifying the air, providing a habitat for many species of plants and animals, protecting the soil, etc. The forest therefore needs to be as vigorous and robust as possible.

However, in recent years, it has become increasingly obvious that monocultures are particularly susceptible. This relates in particular to changing site conditions, such as those caused by climate change. These woodlands are therefore at increased risk of losing their protective and compensatory functions. Mixed cultures with a larger number of tree species with differing characteristics and requirements increase structural and genetic diversity. Semi-natural mixed stands also provide a habitat for typical species of woodland plants and animals.

However, mixtures are not automatically valuable in terms of nature and environmental conservation. Mixed stands can also be made up of tree species which do not correspond to the natural forest community or are not adapted to the site.

 

Assessing the development

The proportion of mixed forest in the total forested area has grown between 2002 and 2012. It rose from 54.9 % to 57.8 %. It is particularly encouraging that the percentage of stands with four or more tree species has increased from 24.4 % to 26.1 %

This development shows that forestry is increasingly moving away from monocultures (pure stands). The percentage of the latter has fallen from 40.3 % to 37.3 % since 2002. The percentage of semi-natural pure stands has remained constant.

In the German Strategy for Adaptation to Climate Change and the Forest Strategy 2020 the Federal Government has set itself the target of increasing the tree species diversity of the forests (Federal Government 2008 and BMELV 2011). No specific target has been set. The percentage of mixed forests with many tree species should therefore increase further. However, this forest conversion will last for many more decades.

 

Methodology

The indicator values are based on the results of the second and third National Forest Inventories. Here ‘forest’ is essentially defined as ‘[...] every piece of ground stocked with forest plants irrespective of the information in the land register or similar registers.’ This definition and detailed descriptions of the methods are given in a working report by the Thünen Institute (Schmitz et al. 2008) and the ‘Aufnahmeanweisung für die dritte Bundeswaldinventur’ (BMELV and vTI 2011, in German only).

More detailed information: 'Strukturvielfalt der Wälder' (in German only).