Rangeland Ecology & Management

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ESTIMATION OF AVAILABLE FORAGE IN ASHE JUNIPER
Author
Tolleson, Douglas R.
Malambo, Lonesome
Angerer, Jay
Rhodes, Edward
Garza, Nick
Pecilunas, Emily
Golpin, Jesse
Moen, Robert
Redden, Reid
Russell, Morgan
Publisher
Society for Range Management
Publication Year
2018
Body

Ashe juniper (Juniperus ashei) occupies approximately 8 million acres of Texas rangeland and is one of three native junipers in the state. Considered an invasive, countless resources have been expended in efforts to manage and control its expansion. One biological method available is goat browsing. There is a need to better quantify available forage in junipers in order to inform goat stocking rate decisions. Our objective was to compare two methods of determining forage content in Ashe juniper: 1) allometric measurements (height, width, basal diameter) and 2) terrestrial Light Detection and Ranging (LiDar) scans. Nine Ashe juniper trees were selected at the Texas A&M Sonora Research Station; three < 0.9 m (small), three 0.9 to 1.8 m (medium) and three > 1.8 m (large). LiDar point clouds were collected prior to harvesting. Trees were hand cut and sorted into standard timelag fuel categories. Available forage was considered to be plant material (needles and stems) within the 1-hour category and that were less than 1.8 m from ground level. All harvested plant material was dried to a constant weight at 60o C. Subsets of the 1-hour category material was separated by hand into needle (~70%) and stem (~30%). Relationships between allometric measurements and area, volume, or weight were determined by linear regression. Available dry matter forage was 0.27� 0.14, 2.40 � 1.17, and 13.02 � 3.36 kgs for the small, medium, and large trees respectively. Basal diameter was the most effective single predictor of available forage (y = 0.8009x � 2.2757; R2 = 0.99; SE = 0.76; P < 0.01). LiDar prediction of available forage was also effective (y = 0.0026x+ 0.385; R2 = 0.95; SE = 1.57; P < 0.01). Data obtained by either method can be used to help inform stocking rate decisions for goats in pastures with Ashe juniper.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Reno, NV