Patch‐Size Effects on Early Succession in Southern Appalachian Forests

Abstract

Four sizes of forest opening (0.016, 0.08, 0.4, 0.4, and 2.0 ha; two replicates each) were established in a Southern Appalachian forest to examine the effects of disturbance size on earl successional community structure and function. Solar radiation, soil temperature, and air temperature were all higher in large openings than small openings and increased from edge to center of disturbance patches. Aboveground net primary productivity (NPP) was 3—4 times as highe in larger (2.0 ha) as small (0.016 ha) openings, presumably in response to greater light availability in large patches. Stump and root sprouts of tree species accounted for the largest fraction of NPP in all patch sizes. Herbs, vines, shrubs, advance regeneration trees, and tree seedlings had progressively smaller NPP, respectively. Vegetation biomass reached 0.7—2.6% of undistributed forest levels and aboveground NPP reached 17—58% of forest levels by the 2nd yr after cutting. Plant species richness was generally higher in large than small patches. Tree species composition shifted considerably followed disturbance. Liriodendron tulipifera was important before and after logging. Large canopy dominants such as oaks and hickories were relatively unimportant sources of sprouts during early revegetation. Instead, minor canopy and understory species such as Robinia pseudoacacia, Halesia carolina, Acer rubrum, Cornus florida, and Magnolia fraseri were the major sprouters in all patch sizes. The N—fixing black locust (Robinia) was much more important in large than small openings. Disturbance size within the Southern Appalachians thus affects microenvironment, species composition, and NPP during early revegetation.

Gaps promote plant diversity in beech forests (Luzulo-Fagetum), North Vosges, France

“…The gaps have thus a positive effect on the diversity of shade tolerant species and light-requiring species, at least some years after disturbance. The lack of change for the other resource requirements of the plant community was unexpected as many studies have shown a change of resources within the gaps when directly measured [10,45,56]. In our case (a forest without water deficit or water surplus), the lack of variation for water needs suggested that the different species may find their water requirements in the gaps.…”

“…The effect of canopy gaps on the environmental factors is also quite well known [10,45,56]. Forest gaps are characterized by a strong change of many factors such as air and soil temperatures, air and soil moistures, irradiance, wind speed and soil properties (e.g., humus mineralization and humification) [10,45,56]. The resource availability (light, water and nutrients) increases with disturbances [7,11].…”

Group and single-tree selection cutting in mixed tolerant hardwood–white pine stands: Early establishment dynamics of white pine and associated species

“…Regeneration gaps created by this method can emulate the northern hardwood disturbance regime, which is characterized by small fires, windthrow and natural senescence (Borman and Likens 1979, Runkle 1981, Canham and Loucks 1984, Whitney 1986, Frelich and Lorimer 1991. The effects of group selection on regeneration have been documented in Eastern Canada (Hatcher 1966), northeastern (Marquis 1965, Leak and Filip 1977, McClure and Lee 1993, Smith and Ashton 1993 and central United States (Phillips and Shure 1990, Dale et al 1995, Weigel and Parker 1997. Among these studies, only Smith and Ashton (1993) mentioned the effects of regeneration gaps (45 m) on white pine regeneration.…”

Herbivorous Insect Response to Group Selection Cutting in a Southeastern Bottomland Hardwood Forest

“…The increased availability of light, water, and nutrients in gaps increases plant diversity and net primary productivity and encourages the growth and regeneration of less shade tolerant species (Bormann and Likens 1979, Boring et al 1981, Brokaw 1982, Phillips and Shure 1990, Wilder et al 1999. Predicting the response of herbivorous insects to such complicated and dynamic environments is difÞcult and quickly confounded by factors such as gap size and age.…”

“…In many forests, canopy gaps created by treefalls, wind damage, and other minor events serve as important centers of plant growth and succession (Runkle 1981, White et al 1985, Phillips and Shure 1990, Clinton et al 1993. The increased availability of light, water, and nutrients in gaps increases plant diversity and net primary productivity and encourages the growth and regeneration of less shade tolerant species (Bormann and Likens 1979, Boring et al 1981, Brokaw 1982, Phillips and Shure 1990, Wilder et al 1999.…”