{"id":1450,"date":"2019-07-25T00:00:00","date_gmt":"2019-07-24T23:00:00","guid":{"rendered":"https:\/\/www.innovationnewsnetwork.com\/structural-soil-urban-horticulture\/1450\/"},"modified":"2020-02-16T11:30:34","modified_gmt":"2020-02-16T11:30:34","slug":"structural-soil-urban-horticulture","status":"publish","type":"post","link":"https:\/\/www.innovationnewsnetwork.com\/structural-soil-urban-horticulture\/1450\/","title":{"rendered":"Supporting trees in the inner city: the case for structural soil"},"content":{"rendered":"

The fact that trees have difficulties surviving in urban environments is not a surprise. Urban areas are rarely designed with trees in mind.<\/h2>\n

Trees are often treated as if they were afterthoughts in an environment<\/a> designed and built for cars, pedestrians, buildings, roadways, pavements and carparks. Urban trees face a range of environmental challenges, such as increased heat loads, de-icing salts, soil and air pollution; and interference from utilities, vehicles and buildings. Yet the most significant problem that urban trees face is the scarcity of soil suitable for root growth.<\/p>\n

While many of the problems faced by urban trees can be mitigated by planting species which are tolerant of a given challenge, there are no tree species which can tolerate the extreme soil compaction that is prevalent throughout urban and suburban landscapes.<\/p>\n

A large volume of uncompacted soil, with adequate drainage, aeration and reasonable fertility, is the key to the healthy growth of trees. The upfront investment in making the soil suitable for supporting a healthy tree is paid back in full when that tree fulfils the functions for which it was planted. These functions may include shade, beauty, noise reduction, wind abatement, pollution reduction, stormwater mitigation, wildlife habitat; and the creation of civic identity. An adequate soil volume is key, considering that soils are where levels of nutrients, water and air are sufficiently balanced to allow for root growth and the acquisition of water and nutrients. Simply put, when soils are inadequate, plant growth suffers and trees die prematurely.<\/p>\n

Human activities can severely damage soil structure. The process of construction in a city, or even the installation of a pavement in an otherwise rural area, necessarily dictates a high level of soil disturbance. Any construction effort requires soil excavation, cut and fill, re-grading and soil compaction. Often heavy machinery is brought on site to accomplish this work, increasing the potential for compaction of soils. There are two critical effects of soil compaction which directly impact plant growth and limit usable rooting space:<\/p>\n