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ECOLOGY AND CONTROL OF EASTERN REDCEDAR (JUNIPERUS VIRGINIANA L.)
Abstract
Eastern redcedar (Juniperus virginiana L.) is the most widespread tree east of the Rocky Mountains. In the past several decades, the species has spread across many areas of the midwest that were formerly pure grassland. Attention has been focused on this spread, since the tree's presence reduces forage production. The purpose of this dissertation was to investigate the control of eastern redcedar with herbicides, and to study several ecological relationships between the tree species and it associated understory herbaceous vegetation. Six studies were conducted: (1) Compare the ability of three herbicides (hexazinone, picloram, and tebuthiuron) to control eastern redcedar. (2) Determine the allelopathic influence of eastern redcedar foliage and duff extracts on native grass germination and growth. (3) Quantify the reduction in forage production caused by the tree's presence. (4) Quantify the tree's influence on soil water content and on understory light levels. (5) Compare the impact of two previous grass clipping heights (5 cm and 25 cm) on subsequent eastern redcedar establishment. (6) Observe the successional patterns following the mechanical removal of eastern redcedar. Results indicated that all three herbicides provided at least 80% kill. Germination was inhibited by both foliage and duff extracts, while few cases occurred where either height or weight growth was depressed by either extract. Overall forage production was 83% less under eastern redcedar canopy outlines than in adjacent open areas. Soil water content and understory light levels were also less under the canopy on all dates when a difference between canopy zone and adjacent open areas was detected. Depauperate areas underneath eastern redcedar canopies were found to have revegetated after two growing seasons following tree removal. New species were identified as primarily annual forbs, indicating initial secondary successional patterns common to Midwest prairies. Overall establishment of eastern redcedar seedlings under the two clipping regimes was less following the 5 cm clipping treatment. No differences between treatments was found at a second study site.
Subject Area
Range management
Recommended Citation
SMITH, STUART DOUGLAS, "ECOLOGY AND CONTROL OF EASTERN REDCEDAR (JUNIPERUS VIRGINIANA L.)" (1986). ETD collection for University of Nebraska-Lincoln. AAI8706249.
https://digitalcommons.unl.edu/dissertations/AAI8706249