Spatial contagiousness of canopy dynamics-the tendency of canopy disturbances to occur nearby existing canopy openings due to an elevated risk of tree fall around gaps-has been demonstrated in many temperate-zone forests, but only inferentially for tropical forests. Hypothesized mechanisms increasing the risk of tree fall around tropical forest gaps are (1) increased tree exposure to wind aroun...

We installed a field experiment to support the development of protocols to restore longleaf pine (Pinus palustris Mill.) to existing mature loblolly pine (P. taeda L.) stands at Camp Lejeune, NC. Seven canopy treatments included four uniform and three gap treatments. The four uniform treatments were defined by target residual basal area (BA) [control (uncut), BA9, BA4.5, and BA0 (clearcut) m2/h...

Isolated canopy gaps involving one to several trees occur continuously and frequently in many moist and wet neotropical forests (sensu Holdridge et al. 1971), shaping tree community structure through a shifting mosaic of patches of high resource availability for small and young trees (Denslow 1980). Though there are few relevant data (Jans et al. 1993), forests with significant seasonal drought...

Surface roughness parameters, namely the roughness length and displacement height, are an integral input used to model surface fluxes. However, most models assume these parameters to be a fixed property of plant functional type and disregard the governing structural heterogeneity and dynamics. In this study, we use large-eddy simulations to explore, in silico, the effects of canopy-structure ch...

We present an application of 3D canopy modelling for assessing the structural accuracy of complex 3D structural models of Sitka spruce. Such models can be used to simulate canopy reflectance at the landscape-scale with a minimum number of assumptions. Typically, however, the underlying canopy structural models require a large number of parameters, many of which are hard to measure and so must b...

In this study three species of the genus Quercus section Erythrobulanus (Quercus coccinea, Quercus rubra, Quercus uelurina) were investigated. All occur together as canopy trees in forests of southern New England. Acorns of each Quercus species were planted in plots located in five zones that represent a range of forest gap/canopy conditions that can occur within a southern New England forest. ...

Forest pathogens and insects can accelerate tree mortality, increase stand structural heterogeneity, and alter tree community composition. In northern California, the canopy trees Abies concolor var. lowiana (Gord. & Glend.) Lemmon (white fir) and Pseudotsuga menziesii var. menziesii (Mirbel) Franco (Douglas-fir) co-occur but vary in shade tolerance and regenerative abilities following disturba...

In the coastal temperate rainforests of southeast Alaska, much progress has been made in describing landscape-level natural disturbances and formulating management systems that emulate those disturbances. Little is known, however, concerning canopy gaps, the dominant form of natural disturbance in the region. During June–August, 1991–1993, we characterized canopy gap patterns and dynamics at th...

Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ran...

1 We used isozyme variation to examine the genet structure of Uvularia perfoliata patches in gap and closed canopy habitats in a temperate deciduous forest in Maryland, USA. 2 A large patch in a gap habitat was composed of a small number of widely spread genets with many ramets, and a large number of genets with more restricted distribution and few ramets. Genets with many ramets were patchily ...