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  • Author or Editor: Susan D. Day x
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Four techniques for compaction amelioration were studied: 1) Vertical drainage panels; 2) vertical gravel-filled sump drains; 3) soil trenches filled with sandy loam; and 4) peat amended back fill. The control was backfilled with existing soil on the site. Vertical drainage mats and vertical gravel-filled sump drains were shown to increase O2% in surrounding soil; however, all O2 levels regardless of treatment were above what is considered limiting. Shoot and root growth of Pyrus calleryana `Redspire' was greatest for treatments that alleviated mechanical impedance (soil trenches and amended back fill) and least for treatments that did not (controls and vertical drains). Vertical drainage mats which alleviated mechanical impedance to a lesser degree showed intermediate growth.

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Root flares of landscape trees are increasingly found to be much deeper than their forest counterparts, indicating that their root systems have been situated deeper in the soil. Planting deeply in production containers contributes to this phenomenon, yet the consequences of deep planting in production containers or the consequences of any adjustments made to planting depth at the time of transplant on growth in the landscape have not been reported for many species. Container-grown (11.4 L) liners of Tilia cordata Mill. (littleleaf linden) and Quercus palustris Münchh. (pin oak) were planted in 50-L containers with the first main lateral roots (structural roots) at substrate-surface grade or 10 cm or 20 cm below grade (deep planting). Trees were grown in the 50-L containers for two growing seasons and in a simulated landscape for three additional seasons after transplanting with the top of the container substrate at soil level or with some roots and substrate removed such that the original structural roots were just below the soil surface (remediated). Deep planting pin oak, but not littleleaf linden, slowed growth during container production; however, the effect did not persist after transplanting. Remediation of the 20-cm-deep pin oaks slowed growth during all three post-transplant years. Littleleaf linden remediation slowed growth for the first season after transplanting to a simulated landscape for 10-cm-deep trees and for the first two seasons for 20-cm-deep trees. Evaluation of pin oak root systems 3 years after transplanting revealed vigorous growth of non-deflected adventitious roots that had formed on the trunks of deep trees, and these roots appeared to be developing into main structural roots. No adventitious roots were present on littleleaf linden; instead, deflected roots grew and produced deformed root systems. Deep planting of linden reduced suckering; however, we conclude that remediation of deep-planted littleleaf linden is warranted as a result of potential hazards from trunk-girdling roots. In some species such as pin oak, non-deflected, strong adventitious root systems may assume the role of structural roots and diminish the effect of deflected and circling roots systems formed during container production. Remediation of these trees is likely not as critical as for species without abundant adventitious roots.

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Landscape trees are frequently planted in heavily compacted soils, such as around newly constructed buildings or in urban areas. Under such conditions, trees frequently die, or decline prematurely. Techniques for ameliorating these conditions were studied: vertical drainage mat panels, gravel-filled sumps, soil trenching and peat-amended backfill. Acer saccharum Marsh. `Seneca Chief, ` a species sensitive to compaction stresses, and the less sensitive Pyrus calleryana Decne. `Red Spire' were planted in a compacted clay loam. Shoot growth, root distribution and soil oxygen levels were measured over two growing seasons. Oxygen levels varied with treatment, but were not limiting to root growth. Shoot growth of pears was greatest for soil trenches. Except for the gravel-filled sumps, all other treatments also showed increased shoot growth compared to controls. Maple mortality was generally high and inversely correlated with field drainage.

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Virginia Cooperative Extension's (VCE) Master Gardener!Tree Steward program (MGTS) provides advanced training in leadership development and arboriculture to Master Gardener (MG) volunteer educators so that they may expand the influence of extension through leadership in community forestry. According to a statewide survey, 70% of VCE MGs and agents with MG programs would like to be involved in community tree programming. Only 26% were currently involved. Typically, agents cite limited staff and volunteer resources as the primary factors in restricting program expansion. Furthermore, 90% of municipal foresters indicated they would like to work with trained volunteers. The MGTS program simultaneously answers the desire of MGs to expand their role in the community landscape and the need of VCE to expand its outreach with increasingly limited resources. MGTS training, guided by a 10-unit resource book, integrates technical and program management expertise to foster volunteer pride and self-sufficiency. This allows MGTSs to coordinate much of their own training and recruit and manage large numbers of non-MG volunteers to whom they can provide limited training for specific projects, thus, allowing program expansion without additional staff.

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