Kevin O’Hara

Professor

ohara-kevin

Research Interests

Stand dynamics silviculture forest management

Research Description

My research involves integrating stand dynamics into stand- and landscape-level decision-making. Stand dynamics generally refers to changes in stand structure and accompanying processes over time. With a good understanding of stand structure and stand development, silviculturists and other forest managers can anticipate changes in structure and make appropriate interventions to meet management objectives. These interventions can be in the form of treatments to enhance timber production, create wildlife habitat, or restore forest ecosystems.

One area of my research involves using leaf area to represent the occupied growing space of trees. Leaf area is useful for representing rates of energy and material exchange in tree canopies, and it is limited by site quality variables. By examining rates of tree increment per unit of leaf area, differences in the efficiency (or growing space efficiency) of trees based on crown class, age, or species can be measured. This work enables the identification of stand components that are making large contributions to stand increment and those that are not. For example, in even-aged stands, codominant trees appear to be most efficient. In multiaged ponderosa pine, the oldest age classes appear to be most efficient. This information is useful for silviculturists trying to maximize volume increment or examining the volume increment implications of changes in forest stand structure.

Other research has involved reconstruction of mixed-species stand development to compare growth rates of different species. Patterns of height growth development can vary between species enabling mixed-species stands to form multistrata canopies. Work is currently underway in the mixed-conifer forests of the Sierra Nevada. These multistrata canopies can meet some management objectives not met by single-species stands that under many management regimes lack structural variability. Pruning of forest trees to enhance wood quality is another area of interest.

Finally, a major portion of my research effort is focused on decision support tools that assist managers making silvicultural decisions. These decision support systems include models which predict stand growth, decision keys for prioritizing stands for precommercial thinning treatments, expert systems for prioritizing silvicultural treatments, and the development of stocking guidelines for single-species, mixed-species, and multiaged stands.

Current Projects

  • Reconstructing crown dynamics and development of multiaged stocking guidelines for mixed-species stands in the Sierra Nevada.
  • A long-term precommercial thinning study in coast redwood.
  • Development of multiaged stocking guidelines for coast redwood stands.
  • Pruning of sugar pine to reduce incidence of white pine blister rust.
  • Effects of pruning redwood on tree growth, heartwood formation, and epicormic sprouting.
  • Spatial patterns of trees in "sudden oak death" infected tanoak/redwood stands.
  • Stand structural development of tanoak/redwood stands and affects of "sudden oak death".
  • Effects of thinning and prescribed burning on "sudden oak death".

Selected Publications

Berrill, J.-P., and K.L. O’Hara. 2009.  Simulating multiaged coast redwood stand development: interactions between regeneration, structure, and productivity.  Western Journal of Applied Forestry 24(1): 24-32.

Waring, K.M., and K.L. O’Hara. 2009. Stand development and tree growth response to sugar pine mortality in Sierran mixed-conifer forests. Northwest Science 83(2): 89-100.

North, M., P. Stine, K. O'Hara, W. Zielinski, and S. Stephens. 2009. An ecosystem management strategy for Sierran mixed-conifer forests. USDA Forest Service General Technical report PSW-GTR-220.

O'Hara, K.L., and J.-P. Berrill. 2009. Epicormic sprout development in pruned coast redwood: pruning severity, genotype, and sprouting characteristics. Annals of Forest Science 66(4): artn 9, 9 pages. doi: 10.1051/forest/2009015

O’Hara, K.L. 2009. Multiaged silviculture in North America. Journal of Forest Science 55(9) 432-436.

Lorimer, C.G., D.J. Porter, M.A. Madej, J.D. Stuart, S.D. Viers, Jr., S.P. Norman, K.L. O’Hara, and W.J. Libby. 2009. Presettlement and modern disturbance regimes in coast redwood forests: implications for the conservation of old-growth stands. Forest Ecology and Management 258: 1038-1054. doi:10.1016/j.foreco.2009.07.008

O’Hara, K.L., and J.-P. Berrill. 2010. Dynamics of coast redwood sprout clump development in variable light environments. Journal of Forest Research 15:131-139. doi 10.1007/s10310-009-0166-0

O'Hara, K.L., L.A. Grand, and A.A. Whitcomb. 2010. Pruning reduces blister rust in sugar pine with minimal effects on tree growth. California Agriculture 64(1):31-36.

O’Hara, K.L., J.C.B. Nesmith, L. Leonard, and D.J. Porter. 2010. Restoration of old forest features in coast redwood forests using early-stage variable density thinning. Restoration Ecology 18(S1): 125.135. doi: 10.1111/j.1526-100X.2010.00655.x

Ramage, B.S., and K.L. O’Hara. 2010. Sudden oak death-induced tanoak mortality in coast redwood forests: Current and predicted impacts to stand structure. Forests 1(3): 114-130. doi:10.3390/f1030114

Ramage, B., and K. O’Hara. 2010.  Sudden oak death in redwood forests: vegetation dynamics in the wake of tanoak decline. Pp.213-216 in Proceedings of the Sudden Oak Death Fourth Science Symposium (edited by S.J. Frankel, J.T. Kliejunas, and K.M. Palmieri).  USDA For. Serv., Gen. Tech. Rep. PSW-GTR-229.

O’Hara, K.L., A. Youngblood, and K.M. Waring. 2010. Maturity selection versus improvement selection: lessons from a mid-20th century controversy in the silviculture of ponderosa pine.  Journal of Forestry 108(8):  397-407.

Nesmith, J.B., K.L. O’Hara, P.J. van Mantgem, and P. de Valpine.  2010.  The effects of raking on sugar pine mortality following prescribed fire in Sequoia and Kings Canyon National Parks, California, USA.  Fire Ecology 6(3): 97-116. doi: 0.4996/fireecology.0603097

Ramage, B.S., K.L. O’Hara, and B.T. Caldwell.  2010.  The role of fire in the competitive dynamics of coast redwood forests. Ecosphere 1:art20. doi:10.1890/ES10-00134.1

Ramage, B.S., K.L. O’Hara, and A.B. Forrestel.  2011.  Forest transformation resulting from an exotic pathogen: regeneration and tanoak mortality in coast redwood stands affected by sudden oak death.   Canadian Journal of Forest Research 41:763-772. doi:10.1139/X11-020

Ramage, B.S., A.B. Forrestel, M.A. Moritz, and K.L. O’Hara. 2012. Sudden oak death disease progression across two forest types and spatial scales. Journal of Vegetation Science 25:151-163.

Jones, D.A., and K.L. O’Hara.  2012. Carbon density in managed coast redwood stands: implications for forest carbon estimation  Forestry 85(1): 99-110.

O’Hara, K.L. and C.L. Redelshheimer. 2012. Divergent trends in accredited forestry programs in the United States: Implications for research and education. Journal of Forestry 110(4): 201-206.

O’Hara, K.L., L. Leonard and C.R. Keyes. 2012. Variable-density thinning and a marking paradox: Comparing prescription protocols to attain stand variability in coast redwood. Western Journal of Applied Forestry 27(3): 143-149.

Gspatl, M., H. Sterba and K.L. O’Hara. 2012. The relationship between available area efficiency amd area exploitation index in an even-aged coast redwood (Sequoia sempervirens) stand. Forestry 85(5): 567-577.

Chiono, L.A., K.L. O'Hara, M.J. De Lasaux, G.A. Nader, and S.L. Stephens. 2012. Development of vegetation and surface fuels following fire hazard reduction treatment. Forests 2012: 3, 700-722; doi:10.3390/f3030700

 York, R.A., K.L. O’Hara, and J.J. Battles. 2013. Density effects on giant sequoia (Sequoiadendron giganteum) growth through 22 years: Implications for restoration and plantation management. Western Journal of Applied Forestry 28: 30-36.

 

Honors and Awards

  • ESPM Award for Undergraduate Teaching Excellence - Department of Environmental Science, Policy and Management - 2007
  • Fulbright Scholar - Austria - 2005-06
  • Presidential Teaching Fellow - University of California - 2004
  • Registered Professional Forester License 2694 - State of California - 2000
  • Don Gasser Award - University of California Forestry Club - 2001, 2009
  • NorCal Society of American Foresters, Forestry Achievement Award - 2009
  • Society of American Foresters, Carl Alwin Schenck Award for Outstanding Achievement in Forestry Education - 2013

Recent Teaching

 

  • 105C - Silviculture and Utilization
  • 185 - Applied Forest Ecology
  • 264 - Silviculture Seminar
  • 276 - Advanced Silviculture
  • 298 - DIRECT GROUP STUDY
  • 299 - INDIVIDUAL RESEARCH

Contact Information

Email: kohara@berkeley.edu

Office: 207 Mulford Hall

Office Phone: 510-642-2127

Fax: 510-643-5438

Website(s)

Office Hours

MW 10-11 and by appointment

Research Group(s)

Mailing Address

Dept of Environmental Science, Policy, & Management
UC Berkeley
130 Mulford Hall #3114
Berkeley, CA 94720