The Vario Treebox provides a load bearing and pressure spreading system for use in Urban Tree Planting Solutions. A sandwich construction is a system of which the Vario Treebox is a part. A sandwich construction consists of a load-bearing rootable volume, with the sandwich box on top wrapped in geotextiles. Above is the road construction. Bricks, tiles, asphalt or semi-hardened surfaces can be applied on top of the Vario Treebox. And it is precisely the application of permeable pavements that is extremely suitable on top of the Vario Treebox. The water is quickly drained into the open structure of the sandwich construction. After which it spreads over the entire growing area
and becomes available to the tree.

Application on top of sand based-  or gravel based structural soils   

There is not much difference between the two applications. The reinforcement fabric beneath the crates is to prevent any mutual settling of the crates. Assuming that the Gravel based structural soil cannot settle, because unlike sand based structural soil (Amsterdam Tree soil) it is already fully compacted during application, it is not required to apply a reinforcement fabric underneath. One can then completely enclose the crates with a separation fabric.

Vario Treebox is available in various heights

Most commonly used height is the 10 cm high Vario Treebox. In case more organic matter / nutrient-rich nutrient soil needs to be applied in the system, the 15 cm high system is preferred. For existing trees in paving where damage to the paving has already been caused by root growth, the lower Vario Treeboxes are applied, usually the 6.5 cm high ones. In humid climate conditions, such as in northern Europe, experience shows that roots still manage to root upwards through the 5 cm moist air layer. With the 6.5 cm, this phenomenon has not yet been observed.

Suitable for heavy/intensive traffic.

For every situation, the Vario Treebox has not only the right height but also the right load-bearing capacity available.  With a unique load-bearing capacity of over 2400 kN/m2, the Vario Treebox is even suitable for heavier traffic or intensively used roads. Especially in locations with turning and braking traffic, the system must withstand these very high point loads.

Vario Treebox to prevent pavement lifting.

Compaction of the subsoil is prevented because the boxes and additional geotextiles form a complete grid. But the coupled system not only reduces subsoil settlement, it also reduces visual damage to the pavement as the tree roots grow bigger. The roots will lift the system as a whole, eliminating the dangerous bumps people might trip over.

Application close to the trunk of the tree

Shortly around the tree you have to deal with the zone of rapid taper (stability zone). It is recommended to install the tree pit edging beyond this zone. If this is not possible or desirable, we recommend installing a root guiding. This will prevent the stability roots from causing problems once the tree grows bigger. See our RootGuideRoll for more information on this.

Aeration of the Sandwich construction.

If no permeable pavement is being used on top of the sandwich construction, it is recommended to use aeration inlets. Aeration inlets can be fixed on top of the system. For each tree at least 1 inlet.

The Vario treebox Sandwich construction offers a load and pressure distribution system for use in Urban Tree Planting Solutions. Both for parking spaces/bicycle lanes but also for more heavily used roads. Vario Treebox has the right load class for each application.

The system provides a pressure spreading system that spreads the load from vehicle movements around the root area of the tree and eliminates/reduces soil compaction within the pit. This also depends on the subsoil.  The Vario Treebox is available from 50 mm height up to 150 mm. Lower heights increase the available root growth volume under the system. The higher heights are suitable for adding extra nutrition in the form of organic material while maintaining a sufficiently thick air layer. This open air layer under the pavement prevents root damage to the pavement. Sandwich structures are designed for situations where compaction of the root space can be expected due to traffic loads.

The VarioTreebox is a modularly designed product. Available in different heights. To meet the required load capacity, the VarioTreebox system is a combination of specially matched materials and has been tested as a system for its applicability under pavement.

The VarioTreebox system prevents damage to the root structure through vertical pressure by absorbing all of the imposed loads. As a result, the roots of new and existing trees grow in a healthier environment. The air layer in the system, can be filled with nutrient-rich soil to improve and or supplement any lack of soil biology in the structural soil under the system, thereby slowly releasing nutrients to the tree. The VarioTreebox also acts as a drainage layer for your permeable or porous paving, continuously watering the root structure but also providing it with additional oxygen. This will all benefits the tree’s growth.