Canopy structure affects forest function by determining light availability and distribution. Many forests throughout the upper Great Lakes region are dominated by mature, even-aged, early successional aspen and birch, which comprise 35%–40% of canopy leaf area, and which are senescing at accelerating rates. In 2008 at the University of Michigan Biological Station, we initiated the Forest Accelerated Succession ExperimenT (FASET) by stem girdling all aspen and birch in replicated stands to induce mortality. Our objective was to understand type and rate of canopy structural changes imposed by rapid but diffuse disturbance consisting of mortality of a single age-species cohort. We characterized changes in canopy structural features in 2008–2011 using ground-based Portable Canopy Lidar (PCL) in paired treated and control stands. As aspen and birch in treated plots died, gap fraction of the upper canopy increased, average leaf height decreased, total canopy height declined, and openness of the whole-canopy increased. All of these trends became more pronounced with time. Our findings suggest that as forests throughout the region pass through the impending successional transition prompted by widespread mortality of canopy-dominant early successional aspen and birch species, the canopy will undergo significant structural reorganization with consequences for forest carbon assimilation.
References
[1]
Valverde, T.; Silvertown, J. Canopy closure rate and forest structure. Ecology 1997, 78, 1555–1562, doi:10.1890/0012-9658(1997)078[1555:CCRAFS]2.0.CO;2.
[2]
Parker, G.G.; Harding, D.J.; Berger, M.L. A portable LIDAR system for rapid determination of forest canopy structure. J. Appl. Ecol. 2004, 41, 755–767, doi:10.1111/j.0021-8901.2004.00925.x.
[3]
Brown, M.J.; Parker, G.G. Canopy light transmittance in a chronosequence of mixed-species deciduous forests. Can. J. For. Res. 1994, 24, 1694–1703, doi:10.1139/x94-219.
[4]
Vanderwel, M.C.; Coomes, D.A.; Purves, D.W. Quantifying variation in forest disturbance, and its effects on aboveground biomass dynamics, across the eastern United States. Glob. Change Biol. 2013, 19, 1504–1517, doi:10.1111/gcb.12152.
[5]
Canham, C.D. Growth and canopy architecture of shade-tolerant trees—Response to canopy gaps. Ecology 1988, 69, 786–795, doi:10.2307/1941027.
[6]
Duursma, R.A.; M？kel？, A. Summary models for light interception and light-use efficiency of non-homogeneous canopies. Tree Physiol. 2007, 27, 859–870, doi:10.1093/treephys/27.6.859.
[7]
North, M.; Chen, J.Q.; Oakley, B.; Song, B.; Rudnicki, M.; Gray, A.; Innes, J. Forest stand structure and pattern of old-growth western hemlock/douglas-fir and mixed-conifer forests. For. Sci. 2004, 50, 299–311.
[8]
Ishii, H.T.; Tanabe, S.; Hiura, T. Exploring the relationships among canopy structure, stand productivity, and biodiversity of temperature forest ecosystems. For. Sci. 2004, 50, 342–355.
[9]
Ishii, H.; Asano, S. The role of crown architecture, leaf phenology and photosynthetic activity in promoting complementary use of light among coexisting species in temperate forests. Ecol. Res. 2010, 25, 715–722, doi:10.1007/s11284-009-0668-4.
[10]
Bradshaw, G.A.; Spies, T.A. Characterizing canopy gap structure in forests using wavelet analysis. J. Ecol. 1992, 80, 205–215, doi:10.2307/2261007.
[11]
Parker, W.C.; Dey, D.C. Influence of overstory density on ecophysiology of red oak (Quercus rubra) and sugar maple (Acer saccharum) seedlings in central Ontario shelterwoods. Tree Physiol. 2008, 28, 797–804, doi:10.1093/treephys/28.5.797.
[12]
Chiang, J.-M.; Brown, K.J. The effects of thinning and burning treatments on within-canopy variation of leaf traits in hardwood forests of southern Ohio. For. Ecol. Manag. 2010, 260, 1065–1075, doi:10.1016/j.foreco.2010.06.033.
[13]
Goudiaby, V.; Brais, S.; Grenier, Y.; Berninger, F. Thinning effects on jack pine and black spruce photosynthesis in eastern boreal forests of Canada. Silva Fenn. 2011, 45, 595–609.
[14]
Moreno-Gutierrez, C.; Barbera, G.G.; Nicolas, E.; de Luis, M.; Castillo, V.M.; Martinez-Fernandez, F.; Querejeta, J.I. Leaf δ18O of remaining trees is affected by thinning intensity in a semiarid pine forest. Plant Cell Environ. 2011, 34, 1009–1019, doi:10.1111/j.1365-3040.2011.02300.x.
[15]
Forest Inventory and Analysis (FIA) Forest Inventory Data Online (FIDO). Available online: http://apps.fs.fed.us/fido/ (accessed on 3 July 2013).
[16]
Albert, D.A.; Minc, L.D. The Natural Ecology and Cultural History of the Colonial Point Red Oak Stands; University of Michigan Biological Station: Pellston, MI, USA, 1987.
[17]
Karamanski, T.J. Deep Wood Frontier—A History of Logging in Northern Michigan; Wayne State University Press: Detroit, MI, USA, 1989.
[18]
Gough, C.M.; Vogel, C.S.; Hardiman, B.; Curtis, P.S. Wood net primary production resilience in an unmanaged forest transitioning from early to middle succession. For. Ecol. Manag. 2010, 260, 36–41, doi:10.1016/j.foreco.2010.03.027.
[19]
Nave, L.E.; Gough, C.M.; Maurer, K.D.; Bohrer, G.; Hardiman, B.S.; Le Moine, J.; Munoz, A.B.; Nadelhoffer, K.J.; Sparks, J.P.; Strahm, B.D.; et al. Disturbance and the resilience of coupled carbon and nitrogen cycling in a north temperate forest. J. Geophys. Res. Biogeosci. 2011, 116, doi:10.1029/2011JG001758.
[20]
Frelich, L.E.; Reich, P.B. Spatial patterns and succession in a Minnesota southern-boreal forest. Ecol. Monogr. 1995, 65, 325–346, doi:10.2307/2937063.
[21]
Edenius, L.; Ericsson, G.; Kempe, G.; Bergstr？m, R.; Danell, K. The effects of changing land use and browsing on aspen abundance and regeneration: A 50-year perspective from Sweden. J. Appl. Ecol. 2011, 48, 301–309, doi:10.1111/j.1365-2664.2010.01923.x.
[22]
Korb, J.E.; Fule, P.Z.; Stoddard, M.T. Forest restoration in a surface fire-dependent ecosystem: An example from a mixed conifer forest, southwestern Colorado, USA. For. Ecol. Manag. 2012, 269, 10–18, doi:10.1016/j.foreco.2012.01.002.
[23]
Caspersen, J.P.; Pacala, S.W.; Jenkins, J.C.; Hurtt, G.C.; Moorcroft, P.R.; Birdsey, R.A. Contributions of land-use history to carbon accumulation in U.S. forests. Science 2000, 290, 1148–1151, doi:10.1126/science.290.5494.1148.
[24]
Pregitzer, K.S.; Euskirchen, E.S. Carbon cycling and storage in world forests: Biome patterns related to forest age. Glob. Change Biol. 2004, 10, 2052–2077, doi:10.1111/j.1365-2486.2004.00866.x.
[25]
Puettmann, K.J.; Coates, K.D.; Messier, C. A Critique of Silviculture: Managing for Complexity; Island Press: Washington, DC, USA, 2009.
[26]
Gough, C.M.; Hardiman, B.S.; Nave, L.E.; Bohrer, G.; Maurer, K.D.; Vogel, C.S.; Nadelhoffer, K.J.; Curtis, P.S. Sustained carbon uptake and storage following moderate disturbance in a great lakes forest. Ecol. Appl. 2013, 23. in press.
[27]
Gough, C.M.; Vogel, C.S.; Schmid, H.P.; Su, H.B.; Curtis, P.S. Multi-year convergence of biometric and meteorological estimates of forest carbon storage. Agric. For. Meteorol. 2008, 148, 158–170, doi:10.1016/j.agrformet.2007.08.004.
[28]
Pan, Y.; Chen, J.M.; Birdsey, R.; McCullough, K.; He, L.; Deng, F. Age structure and disturbance legacy of North American forests. Biogeosciences 2011, 8, 715–732, doi:10.5194/bg-8-715-2011.
[29]
Tardy, S.W. Soil Survey of Cheboygan County, Michigan; General Books: New York, NY, USA, 1991.
[30]
Nave, L.E.; Vogel, C.S.; Gough, C.M.; Curtis, P.S. The contribution of atmospheric nitrogen deposition to net primary productivity in a northern hardwood forest. Can. J. For. Res. 2009, 39, 1108–1118, doi:10.1139/X09-038.
[31]
Schmid, H.P.; Su, H.B.; Vogel, C.S.; Curtis, P.S. Ecosystem-atmosphere exchange of carbon dioxide over a mixed hardwood forest in northern lower Michigan. J. Geophys. Res. 2003, 108, doi:10.1029/2002JD003011.
[32]
Hardiman, B.S.; Bohrer, G.; Gough, C.M.; Vogel, C.S.; Curtis, P.S. The role of canopy structural complexity in wood net primary production of a maturing northern deciduous forest. Ecology 2011, 92, 1818–1827, doi:10.1890/10-2192.1.
[33]
Hardiman, B.S.; Gough, C.M.; Halperin, A.; Hofmeister, K.L.; Nave, L.E.; Bohrer, G.; Curtis, P.S. Maintaining high rates of carbon storage in old forests: A mechanism linking canopy structure to forest function. For. Ecol. Manag. 2013, 298, 111–119, doi:10.1016/j.foreco.2013.02.031.
[34]
Kucharik, C.J.; Norman, J.M.; Gower, S.T. Measurements of branch area and adjusting leaf area index indirect measurements. Agric. For. Meteorol. 1998, 91, 69–88, doi:10.1016/S0168-1923(98)00064-1.
[35]
Gonsamo, A.; Walter, J.-M.N.; Pellikka, P. Sampling gap fraction and size for estimating leaf area and clumping indices from hemispherical photographs. Can. J. For. Res. 2010, 40, 1588–1603, doi:10.1139/X10-085.
[36]
Kneeshaw, D.D.; Harvey, B.D.; Reyes, G.P.; Caron, M.N.; Barlow, S. Spruce budworm, windthrow and partial cutting: Do different partial disturbances produce different forest structures? For. Ecol. Manag. 2011, 262, 482–490, doi:10.1016/j.foreco.2011.04.014.
[37]
Ford, C.R.; Elliott, K.J.; Clinton, B.D.; Kloeppel, B.D.; Vose, J.M. Forest dynamics following eastern hemlock mortality in the southern Appalachians. Oikos 2012, 121, 523–536, doi:10.1111/j.1600-0706.2011.19622.x.
[38]
Parker, G.G. Structure and Microclimate of Forest Canopies. In Forest Canopies: A Review of Research on a Biological Frontier; Lowman, M., Nadkarni, N., Eds.; Academic Press: San Diego, CA, USA, 1995; pp. 73–106.
[39]
Kneeshaw, D.D.; Bergeron, Y. Canopy gap characteristics and tree replacement in the southeastern boreal forest. Ecology 1998, 79, 783–794, doi:10.1890/0012-9658(1998)079[0783:CGCATR]2.0.CO;2.
[40]
Parker, G.G.; Russ, M.E. The canopy surface and stand development: Assessing forest canopy structure and complexity with near-surface altimetry. For. Ecol. Manag. 2004, 189, 307–315, doi:10.1016/j.foreco.2003.09.001.
[41]
Walcroft, A.S.; Brown, K.J.; Schuster, W.S.F.; Tissue, D.T.; Turnbull, M.H.; Griffin, K.L.; Whitehead, D. Radiative transfer and carbon assimilation in relation to canopy architecture, foliage area distribution and clumping in a mature temperate rainforest canopy in New Zealand. Agric. For. Meteorol. 2005, 135, 326–339, doi:10.1016/j.agrformet.2005.12.010.
[42]
Niinemets, ü. Photosynthesis and resource distribution through plant canopies. Plant Cell Environ. 2007, 30, 1052–1071, doi:10.1111/j.1365-3040.2007.01683.x.
[43]
Mori, A.; Niinemets, ü. Plant responses to heterogeneous environments: Scaling from shoot modules and whole-plant functions to ecosystem processes. Ecol. Res. 2010, 25, 691–692.
[44]
Lemoine, D.; Jacquemin, S.; Granier, A. Beech (Fagus sylvatica L.) branches show acclimation of xylem anatomy and hydraulic properties to increased light after thinning. Ann. For. Sci. 2002, 59, 761–766.
[45]
Quentin, A.G.; Beadle, C.L.; O’Grady, A.P.; Pinkard, E.A. Effects of partial defoliation on closed canopy Eucalyptus globulus Labilladiere: Growth, biomass allocation and carbohydrates. For. Ecol. Manag. 2011, 261, 695–702, doi:10.1016/j.foreco.2010.11.028.
[46]
Ogunjemiyo, S.; Parker, G.; Roberts, D. Reflections in bumpy terrain: Implications of canopy surface variations for the radiation balance of vegetation. IEEE Geosci. Remote Sens. Lett. 2005, 2, 90–93, doi:10.1109/LGRS.2004.841418.
[47]
Luyssaert, S.; Schulze, E.D.; Boerner, A.; Knohl, A.; Hessenmoeller, D.; Law, B.E.; Ciais, P.; Grace, J. Old-growth forests as global carbon sinks. Nature 2008, 455, 213–215, doi:10.1038/nature07276.
