Seth W. Bigelow

Tall Timbers Research Station and Land Conservancy · Research

The Red Hills Region of southern Alabama, northern Florida, and southwestern Georgia is one of the most prominent areas in the United States for conducting prescribed fire research and is the birthplace of fire ecology. The culture of prescribed burning in the Red Hills has been influenced by multiple ethnic groups, including the Seminole and Creek...

Abstract Longleaf pine woodlands of the North American Coastal Plain are proposed to be resilient to climate change impacts, but little is known about changes in limiting factors to longleaf pine growth as climate has changed in late 20th century and early 21st century. Moreover, the role that neighborhood trees play in the context of climate chang...

Longleaf pine forests and woodlands are an ecologically important ecosystem that once dominated much of the southeastern U.S. Frequent fire is well-known to be a driver of forest dynamics in these systems, but far less is known about how wind disturbance may reorganize plant communities. To gain a better understanding of how hurricane impacts may a...

Modeling forest attributes using lidar data has been a useful tool for forest management but the need to correlate lidar to ground-based measurements creates challenges to modeling in diverse forest landscapes. Many lidar models have been based on metrics derived from summarizations of individual lidar returns over sample plot areas, but more recen...

Planting native groundcover is often recommended to restore the understory of longleaf pine stands in the southeastern United States, but the effectiveness of such restoration activities remains poorly evaluated. We conducted a study in 25-year-old longleaf pine plantation stands in Georgia, USA, to examine the effects of seeding native groundcover...

Natural disturbance-based silviculture emphasizes harvest methods that emulate the timing and structural changes of natural disturbances. Longleaf pine woodlands are ecologically important ecosystems of the southeastern U.S. that support high biodiversity. Options for multi-aged silviculture include individual tree and group selection methods to pr...

Tropical cyclones can physically alter ecosystems, causing immediate and potentially long‐lasting effects on carbon dynamics. In 2018, Hurricane Michael hit the southeastern United States with category 5 winds at landfall and category 2 winds reaching over 100 miles inland, resulting in extensive damage. Longleaf pine woodlands in the path of the h...

Litter from pine trees in open woodlands is an important fuel for surface fires, but litter from hardwood species may quell fire behavior. Lower intensity fires favor hardwood over longleaf pine regeneration, and while overstory hardwoods are important sources of food and shelter for many wildlife species, too many could result in canopy closure an...

The Adaptive Silviculture for Climate Change (ASCC) network tests silvicultural treatments to promote ‘resistance’ or ‘resilience’ to climate change or speed ‘transition’ to new forest types. Based on projected increases in air temperatures and within-season dry periods in southeastern USA, we installed resistance, resilience and transition treatme...

We established a five-century long tree-ring chronology partitioned between earlywood and latewood growth to examine intra-annual climate response and attempt to establish linkages to agricultural production. Longleaf pine earlywood and latewood width chronologies spanned the period 1491 to 2017 (527 years) and constitute one of the longest records...

Research Highlights: We applied neighborhood and dendro-ecological methods in a stand with a 33-year record of forest dynamics, finding that growth will decrease for several species under predicted climate trends. Background and Objectives: Conventional tree-ring analysis removes the influence of competition and size on growth, precluding assessmen...

Regulation of the dominance of resprouting understory hardwoods is a common objective for prescribed fire in open-canopy longleaf pine (Pinus palustris Mill.) woodland of the southeastern USA. Nevertheless, little is known about the influence of individual pines on fire and hardwood mortality. We studied growing-season fires in stem-mapped stands i...

Seasonal timing of prescribed fire and alterations to the structure and composition of fuels in savannas and woodlands can release understory hardwoods, potentially resulting in a global increase of closed-canopy forest and a loss of biodiversity. We hypothesized that growing-season fire, high overstory density, and wiregrass presence in longleaf p...

Silvicultural selection systems present trade-offs between concentrating soil impacts in small areas and dispersing them across a stand. We applied three selection methods in longleaf pine forest on coarse-textured soils: single-tree, group (ca. 0.2 ha opening size), and group with reserved trees. Area disturbed was determined from GPS units on ski...

Trees affect soil chemistry and nutrient availability via a broad range of processes. Effects can vary dramatically among species, whose distinctive spatial “footprints” can vary for different nutrients. Potentially overlapping effects of neighboring trees in mixed-species stands make footprint shape and interspecific interactions important: If int...

Climate and local stand density (i.e., neighborhood) are major factors determining growth of individual trees, yet disentangling their relative importance is challenging because most dendroclimatological approaches use ring-width indices that remove growth variation resulting from stand dynamics. We sought to estimate the relative influence of targ...

Northern hardwood forests can exhibit considerable temporal stability in their species composition, which litterfall may help to maintain by modifying the soil environment to create an ecological inheritance. We evaluated the evidence for this niche-construction perspective by carrying out a spatially explicit analysis of redistribution of calcium...

A principal challenge of federal forest management has been maintaining and improving habitat for sensitive species in forests adapted to frequent, low- to moderate-intensity fire regimes that have become increasingly vulnerable to uncharacteristically severe wildfires. To enhance forest resilience, a coordinated landscape fuel network was installe...

Large trees (>76 cm breast-height diameter) are vital components of Sierra Nevada/Cascades mixed-conifer ecosystems because of their fire resistance, ability to sequester large amounts of carbon, and role as preferred habitat for sensitive species such as the California spotted owl. To investigate the likely performance of large trees in a rapidly...

Forests in the Sierra Nevada, similar to those across the continent, have been substantially altered by logging, fire exclusion, and other human activities. Current forest management emphasizes maintenance or restoration of resiliency in the face of contemporary disturbance factors that include wildfire, climate change, continued urbanization, and...

The Herger-Feinstein Quincy Library Group Forest Recovery Act of 1999was in the vanguard of large national forest management projects in the Sierra Nevada aimed at protecting forests from wildfire. Detailed monitoring was done because of the newness and large spatial extent of the management treatments which included thinning small- and medium-diam...

This conservation assessment is an unpublished report to Region 5 of the USDA Forest Service. It is a synthesis of information on the abundance, distribution, ecology, and management of Northern Goshawks (Accipiter gentilis) in California.

Fire suppression and other past management practices in the western USA have led to dense conifer forests with high canopy cover and thick layers of surface fuels, changes likely to alter understory microclimate relative to historical conditions. Silvicultural treatments are used to restore forest resilience, but little is known about their microcl...

Many semi-arid coniferous forests in western North America have reached historically unprecedented densities over the past 150 years and are dominated by shade-tolerant trees. Silvicultural treatments generally open the canopy but may not restore shade-intolerant species. We determined crossover-point irradiance (CPI) (light at which the height gro...

An ecosystem containing a mixture of species that differ in phenology, morphology, and physiology might be expected to resist leaching of soil nutrients to a greater extent than one composed of a single species. We tested the effects of species identity and plant-life-form richness on nutrient leaching at a lowland tropical site where deep infiltra...

Background/Question/Methods Mixed-conifer forests of the Sierra Nevada underwent a marked shift to dominance by shade-tolerant trees during the 20th century, but the concomitant emergence of a disturbance regime of large high-intensity fires may now provide opportunities for establishment of shade-intolerant pine species. We assessed conifer seedli...

Tree species composition of hardwood forests of the northeastern United States corresponds with soil chemistry, and differential performance along soil calcium (Ca) gradients has been proposed as a mechanism for enforcing this fidelity of species to site. We conducted studies in a southern New England forest to test if surface-soil Ca is more impor...

Fuels treatments are the primary response to the urgent priority of dealing with wildfire in mixed-conifer forests of the Lake Tahoe Basin. Compared to mid-19th century, these forests are characterized by dense concentrations of small shade-tolerant trees, a dominant even-age cohort of overstory trees, shaded and floristically depauperate understor...

Thinning to reduce wildfire hazard is a common management practice in frequent-fire forests of the American west, but it is uncertain whether projects will help regenerate fire-resistant, shade-intolerant pines. We studied naturally established saplings of six conifer species in mixed-conifer forest in northern California, USA to determine how thre...

Group selection silviculture creates canopy openings that can alter connectivity in patchy forests, thereby affecting wildlife movement and fire behavior. We examined effects of group selection silviculture on percolation (presence of continuously forested routes across a landscape) in Sierra Nevada East-side pine forest in northern California, USA...

To document the relationship between a plant's position in the canopy and its leaf nutrient content, leaf nitrogen and phosphorus were determined for 30 species growing in mature evergreen lowland rain forest at La Selva Biological Station, Costa Rica. Species that grow either in the understory, midstory, or the canopy were selected. Species were f...

Since the 19th century, 41% of the land on Chiloé Island (41°50′S, 73°40′W) in Chile was cleared. Following clearing and burning, much of the converted land remains in sparse shrub cover. We hypothesized that the arrested conversion back to forests may reflect a nearly permanent condition associated with a rise in the water table. To evaluate this...

Nitrogen (N) has historically been considered the most important mineral nutrient affecting performance of saplings in transitional northern hardwood forest of eastern North America, but recent attention has focused on the role of exchangeable soil calcium. Relative limitation by these factors may be changing because of enrichment of soil N from at...

Effective management strategies require an understanding of the spatial scale at which fauna use their habitat. Toward this end, we sampled small mammals in the northern Sierra Nevada, California, over 2 years at 18 livetrapping grids among 5 forest types. Forest types were defined by overstory tree composition, and 19 microhabitat variables were m...

In the humid tropics large quantities of nutrients can be rapidly leached when the soil is unprotected by actively growing vegetation. We established experimental plan-tations of three indigenous tree species on a fertile Andisol in Costa Rica and managed them under 1-or 4-year cutting cycles with uncut stands as controls. Our goals were to test wh...

Spatial and temporal heterogeneity can make ecological systems hard to understand and model. We propose a simple classification of the types of spatial and temporal complexity contained in ecological systems, and describe the kinds of data and models needed to account for each. We classify ecological systems by the presence of heterogeneity at the...

A study was carried out in oak‐northern hardwood forest in NW Connecticut USA involving measurements of growth, light and soil environment of saplings of six canopy trees that are strongly associated with particular soil types as adults. The objectives were to determine patterns of growth response along soil factor gradients, and to discriminate am...

To examine the impact of tree species on the water cycle in a wet tropical region, annual evapotranspiration (ET) was estimated in Costa Rican plantations of three native, broad-leaved tree species that contrasted strongly in leaf size, leaf area and phenology. Evapotranspiration was estimated using the Penman–Monteith equation for transpiration fr...