Next Article in Journal
Comparing the Quantity and Structure of Deadwood in Selection Managed and Old-Growth Forests in South-East Europe
Next Article in Special Issue
Resistance of a Local Ecotype of Castanea sativa to Dryocosmus kuriphilus (Hymenoptera: Cynipidae) in Southern Italy
Previous Article in Journal
Night Light-Adaptation Strategies for Photosynthetic Apparatus in Yellow-Poplar (Liriodendron tulipifera L.) Exposed to Artificial Night Lighting
Open AccessArticle

Encroachment Dynamics of Juniperus virginiana L. and Mesic Hardwood Species into Cross Timbers Forests of North-Central Oklahoma, USA

1
Department of Natural Resource Ecology and Management, Oklahoma State University, 008 Agricultural Hall, Stillwater, OK 74078, USA
2
Bureau of Indian Affairs, Southern Plains Region, P.O. Box 368, Anadarko, OK 73005, USA
*
Author to whom correspondence should be addressed.
Forests 2018, 9(2), 75; https://doi.org/10.3390/f9020075
Received: 8 January 2018 / Revised: 29 January 2018 / Accepted: 1 February 2018 / Published: 3 February 2018
(This article belongs to the Special Issue Ecology and Management of Invasive Species in Forest Ecosystems)
Cross Timbers forests, typically dominated by Quercus stellata Wangenh. and Q. marilandica Muenchh., are the transition zone between eastern deciduous forest and prairie in the southern Great Plains. Fire exclusion beginning in the mid-1900s has led to increasing stand density and encroachment of fire-intolerant Juniperus virginiana L. and mesic hardwood. We measured current forest structure and tree ages of 25 stands (130 plots) in north-central Oklahoma to characterize the extent and dynamics of encroachment. The respective basal area and stand density of the overstory (diameter at breast height; dbh > 10 cm) were 19.0 m2 ha−1 and 407 trees ha−1 with Q. stellata comprising 43% of basal area and 42% of stand density. Quercus marilandica represented only 3% of basal area and 4% of overstory density. Juniperus virginiana represented 7% of basal area and 14% of stand density while mesic hardwoods, e.g., Celtis spp., Ulmus spp., Carya spp., 33% of basal area and stand density. The sapling layer was dominated by mesic hardwoods (68%) and J. virginiana (25%) while the seedling layer was dominated by mesic hardwoods (74%). The majority of Quercus recruited into the overstory between 1910–1970, while recruitment of J. virginiana and mesic hardwoods began more recently (post 1950s). Growth rate, based on the relationship between age and dbh, was faster for mesic hardwoods than for J. virginiana and Q. stellata. These results indicate that removal of recurrent surface fire as a disturbance agent has significantly altered forest composition in the Cross Timbers region by allowing encroachment of J. virginiana and fire-intolerant, mesic hardwoods. This increases wildfire risk because J. virginiana is very flammable and will alter how these forests respond to future drought and other disturbance events. View Full-Text
Keywords: Quercus stellata; Quercus marilandica; Juniperus virginiana; densification; fire exclusion; Cross Timbers Quercus stellata; Quercus marilandica; Juniperus virginiana; densification; fire exclusion; Cross Timbers
Show Figures

Figure 1

MDPI and ACS Style

Hoff, D.L.; Will, R.E.; Zou, C.B.; Lillie, N.D. Encroachment Dynamics of Juniperus virginiana L. and Mesic Hardwood Species into Cross Timbers Forests of North-Central Oklahoma, USA. Forests 2018, 9, 75.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop