Robert T. Brooks

Abundance, distribution, trends, and ownership patterns of early-successional forests in the northeastern United States

Abstract Early-successional forests are ephemeral and distinct forest communities, maintained by disturbance and dominated by small-sized trees and shrubs. These structural and compositional conditions form a unique habitat that is preferred by many wildlife species. Various sources have indicated that there have been declines in early-successional forest area and in the populations of many wildlife species associated with these habitats across the northeast. Results of the Forest Inventory and Analysis (FIA) Program from four survey occasions were summarized for 11 states in the northeastern United States to identify recent trends in the area of early-successional forests. Early-successional forests were defined as sapling/seedling-size and non-stocked-size timberland. The area of total forest land has remained relatively constant in the northeast; however, the area of early-successional forests has declined since the first forest surveys (ca. 1950). Losses were greater in the coastal states than among interior states. The area of early-successional forest among coastal areas is approaching or below conditions that are estimated to have existed under disturbance regimes occurring prior to European settlement of the northeast; for interior areas, the current area of early-successional forest still exceeds estimated historic conditions. The majority of forest land in the northeastern United States have been privately owned by individuals since European settlement; this ownership pattern has affected forest change more than natural disturbances. Population increases in the northeast over the last 50 years have not resulted in the loss of forest land to residential and associated developments. However, the fragmentation of forest ownerships (i.e. parcelization) into ever smaller ownerships has imposed social and logistic restrictions on forest management options. The creation and maintenance of sufficient early-successional forests to sustain wildlife populations dependent on this habitat will require active intervention and management.

Effects of thinning and deer browsing on breeding birds in New England oak woodlands

Over a 3-year period we compared the effects of forest thinning and white-tailed deer (Odocoileus virginianus) browsing intensity on breeding birds in central Massachusetts oak (Quercus spp.) forests across 12 stands with dominant trees having a diameter at breast height greater than 27.9 cm. Unthinned stands with few deer had moderately dense woody understories and moderate ground cover; unthinned stands with many deer had sparse woody understories and little ground cover. Thinned stands with few deer had dense, tall woody understories and moderate ground cover; thinned stands with many deer had sparse woody understories and lush ground cover. Understory changes associated with high deer densities were apparently offset by effects of thinning so that thinned stands supported more breeding bird species. We recorded 65 species of birds; 28 occurred in all treatment classes. Thinned stands contained significantly (P < 0.05) more bird species than did unthinned stands. Of species that occurred more than once, nine occurred only in thinned stands, one occurred only in uncut stands, and another only in stands with 13–23 deer km−2. Occurrences of six species differed significantly (P < 0.05) by deer browsing intensity or thinning. Numbers of omnivores and ground gleaners (both species and individuals) were greater in thinned stands. Numbers of canopy gleaners were greater in stands with 1–3 deer km−2.

Effects of the removal of overstory hemlock from hemlock-dominated forests on eastern redback salamanders

Eastern hemlock (Tsuga canadensis) is a common conifer throughout northeastern North America. The species is threatened by the exotic hemlock woolly adelgid (HWA), Adelges tsugae; infestation by this forest pest can result in high levels of mortality of overstory trees with a resultant change in understory vegetation composition and structure. Pre-salvage harvesting of overstory hemlock results in a residual stand compositionally and structurally similar to that resulting from mortality due to adelgid infestation, except for the occurrence of standing or fallen dead trees in adelgid infested stands. The vertebrate fauna of hemlock-dominated forests is poorly studied and the effects of the mortality or removal of overstory hemlock on forest fauna in these stands is unknown. This study reports the findings of a 3-year study of the effects of pre- or green-tree salvage of overstory hemlock from hemlock-hardwood stands on terrestrial salamanders. The residual hemlock stocking was reduced an average of 60% following harvesting and the understory vegetation responded vigorously. The relative abundance of eastern redback salamanders was reduced in harvested stands but the effect was ephemeral and salamander numbers appear to be increasing within a few years of the logging. It appears that hemlock defoliation and mortality due to HWA infestation or pre-salvage harvesting of live hemlock will result in only a brief reduction in the principal terrestrial salamander of hemlock-dominated forests.

A review of basin morphology and pool hydrology of isolated ponded wetlands: implications for seasonal forest pools of the northeastern United States

Seasonal forest pools (SFPs) are geographically- and hydrologically-isolated ponded wetlands, in that they are topographically isolated from other surface waters. SFPs occur commonly throughout the temperate forests of the eastern United States and adjacent Canada. SFPs are ephemeral in occurrence, typically drying annually. The regular drying of SFPs excludes fish from these habitats, and as a result, they are the preferred breeding habitat of some amphibians, notably ambystomid (‘mole’) salamanders and wood frogs (Rana sylvatica Le Conte). The pools also support a rich and diverse invertebrate fauna. The duration of the wet phase, or hydroperiod of SFPs, has been repeatedly shown to be the dominant influence on the composition and fitness of the faunal community of the pools. Despite the importance of SFP hydrology, it is a poorly studied subject. This paper reviews the limited state-of-knowledge of seasonal forest pool hydrology and associated basin morphology. The review discusses findings from studies of other isolated ponded wetlands that could be applicable to our understanding of the hydrology of SFPs.

Habitat-associated and temporal patterns of bat activity in a diverse forest landscape of southern New England, USA

The development and use of acoustic recording technology, surveys have revealed the composition, relative levels of activity, and preliminary habitat use of bat communities of various forest locations. However, detailed examinations of acoustic surveys results to investigate temporal patterns of bat activity are rare. Initial active acoustic surveys of bat activity on the Quabbin Reservoir watershed in central Massachusetts recorded high numbers of call sequences by five bat species. The results showed the importance of aquatic and open habitats for bats in this diverse forest landscape. Because the preliminary surveys were restricted in extent (habitats), number (replicates), and duration (active surveys only, limited number of repeated surveys), the authors strongly recommended more comprehensive and extensive surveys of bat activity on the area. This paper reports the results of active (manual) and passive (automated) acoustic bat activity surveys in three replicates of ten habitats, conducted three to four times per year over the course of the study between 2004 and 2006. Over the full study, 2,800 actively-recorded 37,632 passively-recorded call sequences were examined and identified to species when possible. General patterns in activity did not differ by habitat between the two survey methods. Call sequences were recorded more often in open, especially aquatic habitats than in cluttered habitats. The use of passive surveys allowed for the assessment of temporal patterns of activity and an analysis of the relationship between ambient temperature and activity.

Bat Activity in a Forest Landscape of central Massachusetts

Abstract Nine species of bat are known to occur across the six New England states, but most aspects of their natural history, such as foraging habitat use, are poorly understood. Recent published research has documented the importance of still-water habitats as foci of bat flight activity. To better understand and document habitat use in southern New England, we used the AnaBat II acoustical monitoring system to assess species composition and relative levels of summer flight activity. Active acoustic surveys were conducted in six habitat types on the Quabbin Reservation in central Massachusetts in 2003 and 2004. Bat flight activity, as measured by numbers of echolocation call sequences, was high, with an average of 24 search-phase and 4 feeding-buzz calls per 20-minute survey period. Myotis lucifugus (little brown bat) was the most commonly recorded species. Bat flight activity was high over all still-water habitats, but greatest over large ponds. Large-bodied bats, such as Eptesicus fuscus (big brown bat), were recorded more often in open, structurally uncluttered habitats. Of the small-bodied bats, little brown bats were ubiquitous, whereas Myotis septentrionalis (northern myotis) was most common in structurally cluttered habitats of seasonal forest (vernal) pools and along forest streams. Generalized habitat associations among the bat species we recorded are similar to those reported for other New England forest sites. The Quabbin Reservation is an excellent site to continue examining bat-habitat relationships because of the abundance and diversity of aquatic habitats, in both cluttered closed-canopy and uncluttered open-canopy settings.

Residual effects of thinning and high white-tailed deer densities on northern redback salamanders in southern New England Oak Forests

Research has demonstrated that even-aged regeneration harvests, especially clearcutting, can have a major and long-lasting detrimental effect on forest amphibians, but the effects of less intensive silvicultural treatments have not been well documented. Additionally, the chronic overabundance of white-tailed deer (Odocoileus virginianus) has become a problem in many parts of North America, with associated effects on vegetation composition and structure and on other wildlife. I assessed the effects of crown thinning and deer overabundance on the relative abundance of forest-floor salamanders in a southern New England mixed oakhardwood forest. I surveyed salamanders by using cover boards in 16 forest stands with thinned or unthinned treatments and with histories of low (3-6 deer/km2) or high (10-17 deer/km2) deer densities. Surveys were conducted 5 times a year for 3 years. Northern redback salamanders (Plethodon cinereus) were the dominate species in all surveys and in all treatment classes. Redbacks were most abundant in spring and fall surveys and in the second and third year of the study. Neither thinning nor white-tailed deer density had a significant effect on the number of redback observations: stands with high numbers of redbacks occurred in all treatment classes.

The impact of urbanization on water and sediment chemistry of ephemeral forest pools

ABSTRACT We compared the water and sediment composition of two ephemeral pools located in forested settings in a developed suburban area with two similar pools located in extensive forest in Massachusetts. We also compared the macroinvertebrate communities. The sediments of the forest pools were 100% organic material, while those of the urban pools were predominantly silt. The sediments of the urban pools were contaminated with elevated levels of barium, chromium, and lead. The water of the urban pools had higher pH, conductivity, and alkalinity and less dissolved oxygen than did the forest pools. Both urban and forest pool macroinvertebrate communities were dominated by Oligochaeta and Chironomidae, and while we expected to find differences in the macroinvertebrate communities, no commonly used metric or index clearly indicated differences. More extensive surveys of urban and reference pools may lead to the development of invertebrate biomonitoring protocols for ephemeral forest pools.

Introduction to the Special Section — Bat Habitat Use in Eastern North American Temperate Forests: Site, Stand, and Landscape Effects

Abstract Forest bats of eastern North America select habitats for roosting, foraging, and winter hibernation/migration over a myriad of scales. An understanding of forest-bat habitat use over scales of time and space is important for their conservation and management. The papers in this Special Section report studies of bat habitat use across multiple scales from locations across the eastern forests of North America. The consensus of the studies in the Special Section is that the larger portion of the variability in bat habitat use occurs at the smaller scales of sites (roost trees) and stands (foraging areas). Nevertheless, it was also recognized that these features occur discontinuously across larger-scale watersheds and landscapes.

Forest area characteristics for metropolitan and nonmetropolitan counties of three northeastern states of the United States

Abstract Analysis of county-level forest area statistics for 208 counties in New York, Pennsylvania, and Ohio, shows: (a) All counties have substantial forest acreage regardless of the degree of urbanization; even counties with urban centers are more than 30% forested; and (b) Forest area distribution by stand-size class shows no clear association with the degree of urbanization in the county.