Mariko Yamasaki

Songbird response to group selection harvests and clearcuts in a New Hampshire northern hardwood forest

Clearcutting creates habitat for many species of early successional songbirds; however, little information is available on bird use of small forest openings created by group selection harvests. Group selection harvests are increasing on the White Mountain National Forest due to negative public response to clearcutting. The objective of this study was to determine if avian species richness and composition differ between clearcut and group selection openings, and between mature stands and the uncut portions of group selection stands. Point count surveys were conducted during the 1992 and 1993 breeding seasons within six study blocks in the White Mountain National Forest, NH. Each block consisted of a clearcut stand, a group selection stand and a mature stand. Species richness per stand was significantly higher in clearcut openings (p = 0.010) than in group selection openings. Forested areas surrounding group selection openings were similar to mature stands in species richness (p = 0.848) and composition. Our data suggest that, relative to avian use, the group selection system does not provide habitat similar to that created by clearcutting in extensive northern hardwood stands. The group selection system appears to retain much of the mature forest bird community while providing for a limited number of early successional bird species. Gradual replacement of clearcutting with group selection harvests could result in reduced avian diversity across large forested tracts.

Bat habitat use in White Mountain National Forest

In 1992 and 1993, we surveyed the foraging and feeding activity of bat species with broadband bat detectors at 2 foliage heights in 4 age classes of northern hardwood and spruce/fir forest stands in White Mountain National Forest, New Hampshire and Maine. The association of bat activity with trails and water bodies and the effect of elevation were measured. Mist nets, a harp trap, and ultrasonic detectors were used to establish species presence. Bat activity was concentrated at trail and water body edges and was uniform within a forest stand at the same sampling height. Within the forest, bat activity was highest in overmature (>119 yr, 35% of mean bat activity/night) hardwood stands and in regenerating (0-9 yr) stands of both forest types (26% of mean bat activity/night). The majority of bats trapped (56%) were adult male little brown bat (Myotis lucifugus). Our data indicate that a matrix of forest types and age classes including areas of regeneration (clearcuts and group cuts) and overmature hardwood, in combination with trails and water bodies, help fulfill the summer habitat requirements of bats in White Mountain National Forest.

Associations between breeding bird abundance and stand structure in the White Mountains, New Hampshire and Maine, USA

Assessment of faunal distribution in relation to landscape features is becoming increasingly popular. Technological advances in remote sensing have encouraged regional analyses of the distributions of terrestrial vertebrates. Comparisons of the strength of association of habitat characteristics at various scales of measurement of habitat structure are rare. We compared the associations of forest cover-type, stand size-class, and stand structure to abundance of breeding bird species in managed forest in northern New England. We surveyed breeding birds and measured stand structure in 20 stands to test the hypothesis that forest cover-type, stand size-class, and structure variables were equally associated with numbers of forest birds. We fit regression models to data from each data source to predict the log number of individuals for each species. We restricted our analyses to cover-types with > 1 size-class and to size-classes representing > 1 cover-type, and restricted our comparisons to bird species with at least 10 observations/yr for 2 yr. Of 31 bird species that met our criteria for analysis, a significant (P < 0.05) association was detected between bird abundance and structure data for 30 species, cover-type data for 19 species, and size-class data for 10 species. Stand structure was the best predictor of bird abundance for 25 species, cover-type for 5 species, and size-class for none. Of the 14 structure variables used in the analyses, total foliage volume of large and mid-size deciduous trees, density of mid-size trees, total woody stem density, total deciduous understory volume and total volume of large conifers were most frequently important in explaining variation in species abundances. Although each species had a unique set of structural affinities, multi-layered stands are apparently more important to long-distance migrants, in general, than to resident/short distance migrants. Large-scale efforts to identify important habitats, assess degree of protection, or monitor species/habitat trends are important to conservation. For forest birds, such efforts must include estimates of the factors to which the species of concern respond. At the stand scale in New England, it seems that bird abundance is more strongly associated with forest structure than with forest cover-type or stand size-class.

Silvicultural guide for northern hardwoods in the northeast

This revision of the 1987 silvicultural guide includes updated and expanded silvicultural information on northern hardwoods as well as additional information on wildlife habitat and the management of mixed-wood and northern hardwood-oak stands. The prescription methodology is simpler and more field-oriented. This guide also includes an appendix of familiar tables and charts useful to practicing field foresters. Northern hardwood forest types can be managed as even- or unevenaged stands using a variety of silvicultural practices. In planning these practices, there are many factors to consider including access, species composition, desired regeneration, wildlife habitat needs and environmental concerns. The aim of this document is to provide guidelines to assist the manager in choosing the right methods to meet the landowner objectives consistent with stand conditions.

Early‐successional forest ecosystems: far from “forgotten”

Figure 1. Annual increase in number of references (416 altogether) resulting from a Web of Science search, conducted on 16 Mar 2011, for “(early AND succession AND conservation) OR Topic = (early AND seral AND conservation) OR Topic = (early AND succession AND ecosystem)”. world. We suggested planning for “off world” colonization as a last resort and as a precautionary response to an unstoppable redesign of the Earth. Holl and Loik argue that the large monetary sums needed for such colonization could be better spent directly on solving environmental problems here on Earth. It’s hard to argue with that sentiment in the short term. A major increase in resources directed toward goals such as K–12 education and empowering women globally would be of great value, both environmentally and economically. Yet, when we proposed the drastic step of considering space colonization, we were musing about the long term – because we believe that the deployment and extent of novel technologies will happen so fast, and may arrive with such intensity, that people may not have time to respond adequately. The increase in technological “progress” in the 21st century has been estimated to be of the same order of magnitude as that of the last 20 000 years (at today’s rate of technological change; Kurzweil 2003). Under this scenario of technological transformation, our suggestion of a “couple of centuries” for deployment of humans to space might be too long. The bulk of our editorial focused on the world today and in the near future. That’s where we’d like the focus to remain, because no one has the remotest idea of what the continued emergence of the neoenvironment will mean for us, for societies, and for the rest of life on Earth. However, it’s time we also started thinking about the distant future, which really may not be so far away. Peter Haff and Rob Jackson Duke University, Durham, NC (jackson@duke.edu)

Seventy-year record of changes in the composition of overstory species by elevation on the Bartlett Experimental Forest

Remeasurements over a 70-year period (1931-1932 to 2002-2003) on 404 cruise plots on the Bartlett Experimental Forest in New Hampshire provided a record of landscape-level changes in the composition of overstory species over time by elevation and d.b.h. (diameter at breast height) classes. Typically, early to midsuccessional species declined while late successional species, especially hemlock, increased. The exception was at upper elevations (2,000 feet and higher), where natural wind disturbance maintained a variable component of paper and yellow birch. There is no evidence of species decline or migration that is inconsistent with natural succession or natural disturbance.

Synchrony in small mammal community dynamics across a forested landscape

Long-term studies at local scales indicate that fluctuations in abundance among trophically similar species are often temporally synchronized. Complementary studies on synchrony across larger spatial extents are less common, as are studies that investigate the subsequent impacts on community dynamics across the landscape. We investigate the impact of species population fluctuations on concordance in community dynamics for the small mammal fauna of the White Mountain National Forest, USA. Hierarchical open population models, which account for imperfect detection, were used to model abundance of the most common species at 108 sites over a three year period. Most species displayed individualistic responses of abundance to forest type and physiographic characteristics. However, among species, we found marked synchrony in population fluctuations across years, regardless of landscape affinities or trophic level. Across the region, this population synchrony led to high within-year concordance of community composition and aggregate properties (e.g., richness and diversity) independent of forest type and low among-year similarity in communities, even for years with similar species richness. Results suggest that extrinsic factors primarily drive abundance fluctuations and subsequently community dynamics, although local community assembly may be modified by species dispersal abilities and biotic interactions. Concordant community dynamics across space and over time may impact the stability of regional food webs and ecosystem functions. This article is protected by copyright. All rights reserved.

Regeneration of upper-elevation red oak in the White Mountains of New Hampshire

Northern red oak occurs in limited amounts with a mixture of softwoods on the shallow soils at upper elevations in northern New England. These stands are important for wildlife habitat and forest diversity as well as a modest amount of timber harvesting. Little experience or research is available on how to regenerate upper-elevation oak. However, an examination of a 35-year-old clearcut on an upper slope of the Bartlett Experimental Forest reveals successful oak regeneration. We describe the species mix and tree sizes in the clearcut stand, the species composition and advanced oak regeneration in the adjacent uncut portion of the stand, and suggest methods for regenerating upper-elevation oak.

Tree species migration studies in the White Mountains of New Hampshire

The movement of tree species in either latitude or elevation has attracted increased recent attention due to growing national/international concerns over climate change. However, studies on tree species movements began in the early 1970s in the White Mountains of New Hampshire, mostly due to ecological interests in the episodic behavior of upper-elevation tree species on some of the most scenic mountains. Observations taken while making elevational transects appeared to indicate that regeneration of some species was advancing or retreating in relation to the main stand of mature trees. This process was formalized into a graphical model that would predict rates of movement which was then tested on the Bartlett Experimental Forest located in the White Mountain National Forest. This paper describes the several types of migrational models that were developed as well as long-term remeasured plot evidence against significant recent changes in the species distributions.

80 Years of thinning research on northern hardwoods in the Bartlett Experimental Forest, New Hampshire

Commercial and noncommercial thinning studies in northern hardwoods on the Bartlett Experimental Forest, New Hampshire, began in 1932. One of the studies, still maintained today, consisted of several precommercial treatments at age 25 (1959) and a commercial treatment in 2003. Although economic returns from precommercial work appear somewhat marginal and require additional research, commercial thinning in northern hardwoods is clearly advisable--almost necessary because evenaged northern hardwoods offer a unique thinning opportunity: a component of shade-intolerant aspen and paper birch maturing in 50 to 70 years coupled with a component of long-lived species that will mature at age 100 to 120 years.