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Silvicultural Impacts

We can't know what silvicultural prescriptions to apply until we know how those activities will affect desired ecosystem services

Small-Scale Structural Complexity

What characteristics can be used to predict changes in small-scale structural complexity in managed stands? These projects used long-term monitoring data from southern Finland and Switzerland to explore which structures best explained the SCI in stands managed to create and sustain even- and uneven-size structures.

Publications:

  • Zenner, E.K.  2016.  Differential growth response to increasing growing stock and structural complexity in even- and uneven-sized mixed Picea abies stands in southern Finland. Canadian Journal of Forest Research 46:1195-1204.
  • Peck, J.E., E.K. Zenner, P. Brang, and A. Zingg.  2014.  Tree size distribution and abundance explain structural complexity differentially within stands of even- and uneven-aged structure types.  European Journal of Forest Research 133:335-346.
  • Zenner, E.K., J.E. Peck, E. Lähde, and O. Laiho.  2012.  Decomposing small-scale structural complexity in even- and uneven-sized Norway spruce dominated forests in southern Finland.  Forestry 85(1):41-49.

 

Compositional and Structural Resilience

Does the forest return to its pre-harvest condition sooner following some silvicultural treatments than others?  These studies compared the overstory species composition and structural features of stands that were subject to different harvesting techniques right after harvest and again ~15 years later using field and remote sensing techniques.

Publications:

  • Dickinson, Y.L., E.K. Zenner, and D. Miller.  2014.  Examining the effect of diverse management strategies on landscape scale patterns of forest structure in Pennsylvania using novel remote sensing techniques.  Canadian Journal of Forest Research 44:301-312.
  • Zenner, E.K., Y.L. Dickinson, and J.E. Peck.  2013.  Recovery of forest structure and composition to harvesting in different strata of mixed even-aged central Appalachian hardwoods. Annals of Forest Science 70:151-159.
  • Dickinson, Y.L. and E.K. Zenner.  2010.  Field Note: Allometric equations for the aboveground biomass of selected common eastern hardwood understory species.  Northern Journal of Applied Forestry 27(4):160-165.
  • Deal, R.L., T.D. Heithecker, and E.K. Zenner.  2010.  Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska.  Journal of Forest Research 15:31-37.

 

Riparian Silviculture

Riparian forests are often managed differently from upland forests to protect important hydrologic function and stream habitat, but what are the impacts of different management approaches on these ecological conditions? This project documented impacts of alternative management practices on subsurface flows (Kastendick), the composition, abundance, and diversity of understory vegetation (Martin), and understory light levels and the abundance of woody vegetation, including competition (Olszewski).

Publications:

  • Kastendick, D., B. Palik, E.K. Zenner, R. Kolka, C. Blinn, and J. Kragthorpe.  2014.  Regeneration responses in partially-harvested riparian management zones in northern Minnesota. Journal of Water Resource and Protection 6:556-564.
  • Zenner, E.K., M.A. Martin, B.J. Palik, J.E. Peck, and C.R. Blinn.  2013.  Response of herbaceous plant community diversity and composition to overstorey harvest within riparian management zones in northern hardwoods.  Forestry 86:111-117.
  • Kastendick, D.N., E.K. Zenner, B.J. Palik, R. Kolka, C.R. Blinn.  2012.  Effects of harvesting on nitrogen and phosphorus availability in riparian management zone soils in Minnesota, USA.  Canadian Journal of Forest Research 42:1784-1791.
  • Zenner, E.K., S.L. Olszewski, B.J. Palik, D.N. Kastendick, J.E. Peck, and C.R. Blinn.  2012.  Riparian vegetation response to gradients in residual basal area with harvesting treatment and distance to stream.  Forest Ecology and Management 283:66–76.
  • Palik, B.J., M.A. Martin, E.K. Zenner, C.R. Blinn, and R. Kolka.  2012.  Overstory and regeneration dynamics in riparian management zones of northern Minnesota forested watersheds.  Forest Ecology and Management 276:1-9.

 

Ground Flora, Regen, and Soil Properties

What are the immediate impacts of timber harvesting activities on the ground and its flora?  One project in the long-term Missouri Ozarks Forest Ecosystem Project (MOFEP) found short-term changes in the ground flora after the first wave of harvest entries.  How fast does heavy equipment compact the soil and does it matter?  Another project correlated re-vegetation following harvest with the number of times equipment was driven over a given spot (recorded using GPS).  Yet others have explored the effects of harvesting traffic in the Carpathian Mountains.  Sure enough, it doesn't take too many passes to compact the soil.  Suckering species like aspen don't seem to mind, but herbs sure do.

Publications:

  • Jourgholami M, Khoramizadeh A, Zenner EK.  2016.  Effects of soil compaction on seedling morphology, growth, and architecture of chestnut-leaved oak (Quercus castaneifolia C.A.M.) in greenhouse situations. iForest-Biogeosciences and Forestry 10(1):145-153.
  • Najafi, A., A. Solgi, and E.K. Zenner.  2015.  Soil disturbances caused by different skidding methods in northern mountainous forests of Iran.  International Journal of Forest Engineering, 26(3):212-224.
  • Jaafari, A., A. Najafi, and E.K. Zenner.  2014.  Ground-based skidder traffic changes chemical soil properties in a mountainous Oriental beech (Fagus orientalis Lipsky) forest in Iran.  Journal of Terramechanics 55:39-46.
  • Jourgholami, M., S. Soltanpour, A. Etehadi Abari, and E.K. Zenner.  2014.  Influence of slope on physical soil disturbance due to farm tractor forwarding in a Hyrcanian forest of northern Iran.  iForest – Biosciences and Forestry 7:342-348.
  • Sattar, E., A. Najafi, M.A. Rab, and E.K. Zenner.  2012.  Recovery of bulk density, porosity and rutting from ground skidding over a 20-year period after timber harvesting in Iran. Silva Fennica, 46(4):521-538.
  • Zenner, E.K. and A.L. Berger.  2008.  Influence of skidder traffic and canopy removal intensities on the ground flora in a clearcut-with-reserves northern hardwood stand in Minnesota, USA.  Forest Ecology and Management 256:1785-1794.
  • Zenner, E.K., J. T. Fauskee, A.L. Berger, and K.J. Puettmann.  2007.  Impacts of skidding traffic intensity on soil disturbance, soil recovery, and aspen regeneration in north-central Minnesota.  Northern Journal of Applied Forestry 24:177-183.
  • Zenner, E.K., J.M. Kabrick, R.G. Jensen, J.E. Peck, and J.K. Grabner.  2006.  Responses of ground flora to a gradient of harvest intensity in the Missouri Ozarks.  Forest Ecology and Management 222:326-334.

 

Seedling and Sapling Survival and Growth

What are the differences among stands that receive different silvicultural treatments from the point of view of a seedling or sapling?  One study evaluated the regeneration success of underplanted red pine, white pine, and jack pine seedlings under alternative silvicultural prescriptions.  Another study tested how light "early, light, and often" thinning should be in an aspen-paper birch stand.

Publications:

  • Peck, J.E., E.K. Zenner, and B.J. Palik.  2012.  Variation in microclimate and early growth of planted pines under dispersed and aggregated overstory retention in mature managed red pine in Minnesota.  Canadian Journal of Forest Research 42(2):279-290.
  • Zenner, E.K.  2008.  Short-term changes in Pinus strobus sapling height-to-diameter ratios following partial release:  testing the acclimative stem-form development hypothesis.  Canadian Journal of Forest Research 38:181-189.
  • Zenner, E.K. and K.J. Puettmann.  2008.  Contrasting release approaches for a mixed paper birch (Betula papyrifera) / quaking aspen (Populus tremuloides) stand.  Northern Journal of Applied Forestry 25:124-132.

 

Quality and Community Structure

How can silviculture be used to create old-growth structure in northern hardwoods forests?  Old-growth characteristics were evaluated along the north shore of Lake Superior to develop prescriptions for cutting nearby younger stands.  Natural disturbances create small gaps, which can be silviculturally recreated in younger forests to achieve management goals such as enhanced wildlife habitat and higher stem quality.

Publications:

  • Burton, J.I., E.K. Zenner, L.E. Frelich, and M.W. Cornett.  2009.  Patterns of plant community structure within and among primary and second-growth northern hardwood forest stands.  Forest Ecology and Management 258:2556-2568.
  • Burton, J.I., E.K. Zenner, and L.E. Frelich.  2008.  Frost crack incidence in primary and mature to old second-growth hardwood forests of the southern boreal – northern temperate transition zone.  Northern Journal of Applied Forestry 25:133-138.