EFI : European Forest Institute
Le réseau pour la gestion durable des forêts cultivées.

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FORSEE : Indicateur évalué

Indicator 1.4.4: Carbon stock in the litter stock
Forest area covered (1995):
4956,1 ha

Percentage of the total forest
area in Sousa Valley: 14,3 %

No of plots: 35


TOTAL COST: 1707,3 €

Costs/ha: 0,34 €

Costs/plot: 48,8 €

The total cost includes:

1- Data collection

959 €

2- Data analysis

748,3 €


Dry matter in the litter stock


Sources : UTAD estimates


Litter stock was evaluated in subplots of 25 x 25 cm (one per plot) implemented inside the IFN plot.

Dry matter in the litter stock was measured only in eucalyptus stands.

Dry matter was not converted in carbon because the litter stock was in decomposition and is not adequate to use values of carbon of non decomposed material.

Problems and improvements

According to the Portuguese field manual (adapted from the guideterrain.V16.en.v2 from 12/07/2005), litter depth should be taken in 16 points (in 4 corners per 4 squared subplots). North Portugal team decided to reduce the number of the sample to 4 points. Comparative studies should be accomplished in order to assess the ratio precision versus the time spent (and associated costs) of having a different number of samples.

A “hidden” problem that could affect the estimates is the moment of data collection. In order to get reliable values, samples should be taken immediately after the delimitation of the subplot. The collection of litter before the collection other inventory parameters (e.g. trees measurements and soil sampling) does not seem a reliable method because the litter becomes compacted during the movements of the collectors across the plot.

Comments and conclusions

This criterion is easy to evaluate. In order to reduce laboratorial work, litter dry mass could be evaluated with litter models using the height of the layers as explanatory variable. UTAD researchers in forest fires have studies and results on this subject.

Carbon stock is one of the indicators of Criterion 1 considered by NP 4406 2003. NP 4406 2003 considers that one of the main functions in the forest ecosystems is the capacity of being a carbon sink. The increase of volume of the forest stands has positive consequences in the behaviour of this indicator though the effectiveness of this function is strongly limited by the use given to the products extracted from the forest.

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