Tuesday 1 April 2014

Sensitive timber extraction from pingos

Over the past few months I've been learning about the use of horses for the extraction of timber. Last week I had a chance to actually witness it first hand and learn about the type of situations when horse powered timber extraction may be the most appropriate.



In Norfolk we're fortunate to have a relatively rare type of habitat known as a 'Pingo'. Essentially, a pingo is a large pond or lake that is fed by an aquifer located below the pingo, a spring at the base of the pingo feeds it with water from the aquifer.

Unlike regular ponds and lakes that are fed by rainfall either directly into the pond or from the surrounding rainfall catchment, the water level of pingos can be high even during periods of low rainfall. However, pingos can also periodically dry up at times when the water level within the aquifer is low.



This ephemeral persistence of a pingo creates some very interesting species assemblages within the ponds. For example, the young larval stage of great crested newts are often predated by fish (such as sticklebacks). The drying up of a pingo will kill off any species that are unable to disperse into surrounding water bodies, such as fish. Therefore, predation of great crested newts is reduced.

One of the sites in Norfolk where a number of these pingos are present is the Forestry Commision owned Frost's Common, near to Thetford Forest. A recent project was set up to clear a number of the trees surrounding the pingos present on Frosts Common, in the hope that this will allow more sunlight to reach the pingos which will in turn increase the pingos value for biodiversity.

A pingo that has become overgrown with vegetation. There is a danger that left in this state, the pingo will completely silt up with leaf litter and be lost. 

Because of the inherant sensitivity of this site, it was decided by the forestry commission that horses should be used to extract the majority of timber from Frosts Common. This is where Mark Tasker of Wildwood comes in, as his horses have been trained to pull logs through the woods for timber extraction.



His horses are a cross between a Suffolk punch mare and a Cob stallion. The brown and white horse is just 2.5 years old and is still learning from the all brown, 5 year old horse. Because Mark is using the slightly less experienced, younger horse he explained that he is unable work the horses for as long in a day as he would like to. Though he also explained that his younger horse has to learn how to do the job at some point!

Interestingly the majority of the trees being felled are located to the southern side of the pingos being opened up to the light. This is because the Forestry Commision have a limit to the number of trees that they are able to fell in one season; felling to the south of an area will allow the most light into an area, therefore making the most efficient use of the felling quota.

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