Updates from May, 2016 Toggle Comment Threads | Keyboard Shortcuts

  • Eric Kramer, ASLA 2:56 pm on May 19, 2016 Permalink | Reply
    Tags: Eric Kramer   

    Let’s Dig: crowd-sourcing data on urban soil performance 

    A soil core of sand-based structural soil Photo credit:

    A soil core of sand-based structural soil

    Data, data, data.

    We know that all good science is based on adequate data. And if you’re reading this page, you probably also already know there is a lack of adequate data when it comes to the real-world performance of urban tree planting soils. This post is your chance to change that and add your own information to a shared database of soil performance data.

    A bit of background: In 2014 we (Eric Kramer, ASLA, and Stephanie Hsia of ReedHilderbrand; Robert Uhlig, ASLA, of Halvorson Design; Bryant Scharenbroch, PhD of University of Wisconsin – Stevens Point; and Kelby Fite, PhD of Bartlett Research Labs) undertook a micro-study of seven sites in Boston — constructed urban landscape projects anywhere from 5 to 45 years old. Each project took a pro-active approach to designed soil systems, using suspended pavements, Cornell University structural soils, or sand-based soils. We took soil cores, recorded soils horizons, took lab samples and compared findings to what we knew about what had been installed. We also assessed the performance of the trees over time.

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  • James Urban FASLA 2:56 pm on May 19, 2016 Permalink | Reply
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    Nursery Standards – Rootstock Problems and Specification 

    Roots properly pruned with no roots above the root collar Photo credit: James Urban

    Roots properly pruned with no roots above the root collar
    Photo credit: James Urban

    Stem girdling roots, kinked roots, J roots, T roots, and root collars buried deeply in the root package are one of the principle reasons whey trees and large shrubs fail to recover from transplanting or decline and even die at a young age after planting. These problems are typically created in the nursery by practices that do not produce plants with radial root architecture and place the root collar close to the surface of the soil. As a plant moves thru the production process from propagation to delivery at the site, there are many opportunities for root problems to develop in the plant.

    Most plants are started in small containers and then gradually moved into larger containers. If the plant is sold in a container there may be three or four different container sizes. Each of these containers may result in a series of roots circling around the edges of the pot forming circling roots. Any of the circling roots above the root color can eventually choke the tree. Other roots may be deflected from the bottom of the container and grow upward to the surface forming a sharp kink in a root that may eventually become an important structural root. If these misshapen roots are not pruned at each shift in pot size they form an imprint of constricting roots in the next container. As trees are repotted they are also often placed too deeply in the next pot. Trees lined in the field may also be buried in the soil. This places the roots too deep in the soil where oxygen is less available at a critical point in the trees development.

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    • Aris W. Stalis 10:17 pm on July 6, 2016 Permalink | Reply

      One thing about this, is I am trying to upload image associated with discussion, and not working to well, or I just am missing something. Instead of new post, I wish to add to the discussion.

      Like

    • Aris W. Stalis 10:21 pm on July 6, 2016 Permalink | Reply

      Further trying of this tool – we find we cannot be on site for plantings. The result is a need to dig up the plants. Messy, since we disturb the “perfect mulch circle” hiding problems, but that is what we have to do to see if it was installed properly.

      Like

    • James Urban FASLA 1:12 pm on July 21, 2016 Permalink | Reply

      Bringing these ideas into the work of LA’s is going to be difficult but is not impossible. Using the referenced specifications and details will give you the basis to reject plants and get plants modified. But getting the time and fees to actually do the field inspections is the tough part. In the end it will fall to how committed is the designer to delivering sustainable quality products to their clients. But atlas the above is a start in the process and an new tool to use.

      Like

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