FORSEE : Indicateur évalué

Indicator 5.3.2:Water Table Depth

Cost

Total Cost €2847

Shared Cost

€1886

Marginal Cost

€961

Cost/ha

€0.08

These costs include:

table1

Results

Figure 5.3.2 a: Mean water table depth in the FORSEE study sites.

graf1

Figure 5.3.2b: Water table depths in the FORSEE study sites.

graf2

Remarks

Figure 5.3.2a shows the mean water table depth for the different planting years in the FORSEE study sites. The water table depths range from 14cm to 35cm. A depth of 14cm would be considered very high for the water table and poor tree growth has been associated with high water tables (Adams et al, 1972). During forest establishment drainage channels are installed to a depth of 40cm to aid in lower the water table for successful tree establishment. From Figure 5.3.2b it can be seen that 59% of the study sites had a water table depth of 20cm or less.

It was not feasible to undertake the nutritive status component of this indicator.

Problems and Improvements

The water table depths were measured 2 weeks after installation and the sampling period was from September to March, when rainfall levels would usually be at their highest. It would be recommended that samples be taking during spring and summer during the growing season.

Remarks and Conclusions

This indicator shows that the water table depth is quite high is some of the study sites and could impact on tree productivity. The soils of the pilot zone are mainly peaty and high water tables would be associated with these soils. If adequate drainage was not carried out at establishment this will be reflected in this indicator. Forest drains should ideally remove surplus water to the depth of the drain, ideally to a depth of 50cm.

Logo IEFCimg2
Project co-financed by European Union
A community initiative ERDF
INTERREG the IIIB Atlantic Area