The soil, the great forgotten after fires


When thinking about the devastation caused by a wildfire, we are very aware of the damage on vegetation, of trees burned or charred mountains. Less usual is to consider the damage to a vital element, the substrate on which the forests, crops and ultimately all living things settle: the ground. If there is soil, vegetation sprouting end sooner or later. But if this resource is not protected the damage is irreversible: what nature takes centuries to form (up to 1,000 years for every 2 or 3 centimeters of topsoil, FAO) erosion can destroy in a few weeks.

July 7 is celebrated worldwide Day of Soil Conservation, a good time to reflect on the importance of protecting this resource against desertification, ensuring food security and maintaining the health of ecosystems. This year has also been declared by the UN the “International Year of Soils”, a warning for us to be aware of the fundamental role played by the soil for the benefit of mankind.

In the forest restoration team of WWF we are convinced that it is vital to conserve soil and have always insisted that after the passage of fire is the primary resource to protect. Also often the most overlooked. After many of the largest and most devastating forest fires in Spain administrations promoted reforestation to restore forests affected, with the aim of recovering forests but often without sufficient urgency pose with emergency measures to prevent soil loss.

An example of the serious impacts that may occur if the ground is not protected we saw in Galicia in 2006 after the terrible wave of fires this summer -the 4% of the wooded area of ​​the region ended arrasada-, heavy rains That fall swept away tons of fertile soil into rivers and the sea. In villages like Cee were major flood damage, and the estuaries were covered with mud and sediment that prevented shellfish for weeks.

With one of our forest restoration projects in Galicia we are trying to recover an area affected by a large forest fire area in 2013, Mount Pindo. Analyze the state of the soil has been instrumental in this project: the disappearance of vegetation and loss of soil infiltration capacity caused that most of the lost ground. If you regularly to sample soil we make a hole one meter deep (soil pit), on the slopes of Monte Pindo only did 40 centimeters.

After bringing the samples to the laboratory, we can know the properties and characteristics of the soil, one of the keys to a successful restoration project. In the case of Mount Pindo, we discovered that the soil is sandy loam, an area in which water moves with relative ease and there is good ventilation (on average, 25% of any soil is water and 25% air) . That favors soil organisms live in adequate conditions and can benefit by helping plants absorb nutrients.

Another feature that we know is the acidity of the soil, pH, which affects the availability of nutrients for plants and the organic matter content. Pindo is overly acidic soil -pH of 5,26- but fortunately the organic matter content is very good, 6.81%, a very positive sign for the growth of seedlings.

We hope that this summer we will not regret that many fires in areas affected by flames timely emergency measures to protect the soil and stop the advance of desertification are taken. We need forests and society needs: for food, water, climate, biodiversity and life.


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