2022 CTRE: Improving transplant success in Abies fraseri Christmas tree plantations
From Bert Cregg
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From Bert Cregg
Improving transplant success in Abies fraseri Christmas tree plantations
Authors: Riley Rouse, Bert Cregg - Michigan State University, Department of Horticulture, 1066 Bogue St., East Lansing, MI 48824, USA
Occurred 9:00-9:30 am PDT, June 9, 2022
Abstract
In the Great Lakes region, of the United States Christmas tree plantations are established by planting seedlings or transplants. Limiting plant moisture stress after planting is crucial to successful establishment of these small conifers. A myriad of products have been marketed to Christmas tree producers with claims to improve transplant success by limiting transplant shock. The objective of this study was to determine the effect of various root dips and cultural treatments on survival and subsequent performance of Abies fraseri seedlings. In 2021, we initiated trials at four Christmas tree farms in Michigan. Root dip products applied at planting included 1) DieHardTM Root Dip (endo/ecto mycorrhizae + polymer), 2) MycoApply® Injector Ecto (ectomycorrhizae), 3) SoilMoistTM Fines (polymer), 4) Roots® Terra-Sorb® Fine Planting Gel (polymer), and 5) control. Cultural treatments applied following planting include 1) foliar anti- transpirant spray (Wilt-Pruf® [25% di-1-p-menthane]), 2) organic mulch (varied by location), 3) shade block (20.3 cm x 30.5 cm mesh screen), 4) mulch + shade block, or 5) control. First year survival was excellent (>97%) across all farms. Survival of untreated control trees was 100% at all farms, demonstrating that products and techniques used could not further improve survival. When examined across all farms, leader growth was unaffected by root dip treatments while the combination of mulch + shade blocks improved leader growth compared to the untreated control. The application of Wilt-Pruf reduced transpirational water loss but also reduced photosynthetic rate; otherwise, treatments did not affect gas exchange rates. While plots treated with mulch consistently maintained higher soil moisture, foliar nitrogen was lower for mulched seedlings at one farm compared to non-mulched trees. This result may suggest possible nutrient tie-up related to mulch use, or the lower foliar N values may be in response to growth dilution. Overall, first year survival and outplanting performance of A. fraseri seedlings was largely unaffected by root dip or cultural treatments.