Denmark's National Inventory Report 2005 - Submitted under the ...

As a first step, after the first full rotation (five years), the NFI is able to supply new activity data,
whereas remeasurements are necessary to assess carbon stock changes. Due to the continuous
monitoring every year of one fifth of the sample plots, the first estimates of carbon stock changes
may possibly following just one or two years of measurements in the second rotation of the NFI.
The NFI also supports reporting of more carbon pools than previously. Coarse woody debris and
understorey vegetation is monitored and carbon stock changes will be estimated. Unfortunately
soil sampling has not been included as part of the NFI so far. However, simple measurements of
forest floor thickness in each plot enable estimation of carbon stock changes in the litter pool. Existing
national data on forest floor depth/mass relationships can be used for this purpose.
For afforested cropland, the NFI will provide activity data for comparison with the other data
sources currently used (subsidized afforestation area). The NFI is possibly not able to better gauge
the relatively small afforestation area than the currently used data sources. However, the NFI will
provide a better estimate of the residual area of land afforested by private landowners without
subsidies than the current estimate based on the Forestry Census.
A weakness in the Danish biomass carbon estimates is the lack of national biomass expansion factors
or functions. However, national data on abovegroundbiomass expansion functions for Norway
spruce will be available within a couple of years. Data on belowground carbon is even more
scarce. So far it has only been possible to conduct a pilot study in Norway spruce in a thinning trial
at one site. However, root-top relationships from these stands will provide a better basis for selecting
root-top relationships for Norway spruce from the literature.
In addition work is currently being initiated on a reconstruction of the land use matrix by 1990 by
use of databases, satellite photos and aerial photos.
7.3 Cropland
As mentioned in the overview a detailed GIS analysis has been performed on the agricultural area
with data on land use in 1998. With data from EUs IACS (Integrated Administration and Control
System), the EUs LPIS (Land Parcel Information System) and detailed soil maps (1:25,000) a detailed
GIS analysis has been made. The total Danish agricultural area of approximately 2.7 mio.
hectares has been related to approximately 700,000 individual fields, which again is located at
220,000 land parcels. This gives an average field size of less than four hectares. The actual crop
grown in each field is known from 1998 and onwards. However, for simplicity the distribution
between mineral soils and organic soils is kept constant for all years from 1990 to 2003.
7.3.1 Source category description
The main sources/sinks on Cropland are land use, establishing of hedgerows and perennial horticulture.
Table 7.8 shows the development in the agricultural area from 1990 to 2003 (Statistics
Denmark). In Denmark a continuous decrease of 10-12,000 hectares per year in the agricultural
area is observed. A part of the area is used for reforestation, settlements, nature conservation etc.,
but no clear picture is available yet.
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