Introduction:

The trees planted along the streets in our towns are subjec-ted to intensive vitality-sapping influences. Because of this, it is of major importance that the correct planting is used.

Mineral substrates lava stone and pumice are used in the new planting of trees and the renewal of tree substrates in areas with vihecular access.  Furthermore this structually stable granules whith high pore volume, high air and water permeability and high retension of water and nutrient is used in green roof and grassed areas .

Set of rules (Germany):

The requirement of quality control by producers and external institutes, maintenance of quality is based on:

FLL - Guidelines for planning, creation and mainte-nance of green roofs (2002)

FLL - letter of recommendation for tree planning  (2004) by Forschungsgesellschaft Landschaftsentwicklung und Landschaftsbau e.V. (FLL) 

Measuring principle:

The technique based on an isothermal gas expansion experiment according to BOYLE and MARIOTTE. 

Additionals:

The same samples can be used for determination of the defined parameters according FLL: 

• total pore volume 
• water permeability 
• maximum water retention capacity 
• air content 

total pore volume is not a specified parameter, but is to used to determine areation at maximum moisture content and pF 1,8 

Technical details:

The Air pycnometer is an innovative device for deter-mination of the pore volume of a cylindric sample (150mm inner diameter, 120mm high).

Prospects:

connection and standardization of laboratory methods in geotechnics and soil science