During the past three years, six European SMEs and four RTD centres, coordinated by the Forest Sciences Centre of Catalonia (CTFC), have jointly developed together five innovative soil conditioninger and soil mulching products for more efficient and sustainable forest restoration in Europe and the Mediterranean. This project is also an important step towards bridging the knowledge-innovation divide.
- A new soil conditioner (TerraCottem Internacional), aiming at improving soil features at microsite level, especially, water retention capacity.
- Four new groundcovers, aiming at avoiding competing vegetation near the tree. Three of these groundcovers are biodegradable, based on either a new biopolymer (DTC) or woven jute fibres treated with bioresin (La Zeloise), while the other one is made on recycled rubber, with prolonged durability (EcoRub).
These techniques aim at minimizing the dependence of any type of tree planting (i.e. productive plantations, forest restoration, landscaping, gardening) on tending operations such as irrigation and weeding, which are recurrent, expensive and often unsustainable. The leading principle of these techniques is to concentrate the investment at the moment of planting but reducing dramatically the vulnerability of the newly established trees to drought and competing vegetation, and thus to minimize the need for maintenance.
The new techniques were evaluated compared to reference options (commercial soil conditioners, plastic groundcovers and herbicide application) with regard to tree performance and soil features. The testing was done in eight field trials in NE Spain in a range of four strongly contrasted conditions representative of Europe and the Mediterranean: Semiarid, Mediterranean continental sub-humid, Mediterranean humid and Montane/Continental, with a total of almost 4,000 experimental trees.
The new soil conditioner led to outstanding results in semiarid conditions, characterized by severe water deficit and a light poor soil. This technique increased significantly survival, aerial and root growth and tree water status. This technique also resulted in higher growth rates in Montane conditions, where the soil had a light texture and poor fertility. This new formulation, with a prescribed dose of 40 g/tree for seedlings up to 60 cm high, led to results similar to the best commercially available soil conditioner.
On the other hand, the new groundcovers brought major benefits to tree performance in the most productive sites (Mediterranean continental and humid). Compared to unweeded trees, those having a groundcover showed significantly higher growth rates. In limiting conditions (Semiarid and Montane), the new groundcovers had a slightly positive effect on tree growth. This performance was similar to plastic mulching and herbicide application, while bringing added technical and environmental benefits, as they are based on renewable or recycled raw materials.
These new techniques represent a new opportunity for more effective and sustainable implementation of multiple-purpose tree planting in Europe and the Mediterranean.