Diameter-Limit Cutting and Silviculture in Northeastern Forests: A Primer for Landowners, Practitioners and Policymakers

https://digitalcommons.library.umaine.edu/fac_monographs/1113/thumbnail.jp

MP753: The Role of Interfering Plants in Regenerating Hardwood Stands of Northeastern North America

An annotated bibliography for American beech (Fagus grandifolia Ehrh.), striped maple (Acer pensylvanicum L.), hobblebush (Viburnum alnifolium Marsh.), hayscented fern (Dennstaedtia punctilobula L.), New York fern (Thelypteris noveborecensis L.), bracken fern (Pteridium aquilinum (L.) Kuhn), raspberries (Rubus spp.), and pin cherry (Prunus pensylvanica L.f.). While accessible literature includes many references to these species, the information remains scattered. No one has previously consolidated the separate reports for easy reference, nor summarized the findings relative to interference with tree regeneration. This annotated bibliography serves that purpose.https://digitalcommons.library.umaine.edu/aes_miscpubs/1023/thumbnail.jp

Teaching Professional Codes of Ethics to Forestry and Wildlife Students: a Case Study Using Diameter-limit Harvesting in a Bottomland Hardwood Stand

Professional ethics involve statements by a professional organization to guide the behavior of its members, and to help them determine acceptable and unacceptable behavior in a given situation. Most, if not all, natural resource organizations have Code of Ethics. How to incorporate them across the curriculum and in individual courses of a natural resources program is a current challenge to faculty and administrators alike. We propose to capitalize on the role that professional ethics play in the daily activities of forestry and wildlife professionals engaged in hardwood resources management. Many hardwood stands today are subject to “selective harvesting” whereby trees of choice species and of the best quality are removed with little or no thought towards the future development of the stand or the benefits that landowners will derive from it (after Helms 1998). They are simply mined of the standing timber to the detriment of hardwood resource sustainability. A case study example relevant to the appropriateness of diameter-limit harvesting in a southern bottomland hardwood stand is presented as one way to integrate discussion of technical issues in forestry and wildlife management and professional ethics related to this practice. We propose its use in college and continuing education courses. Questions presented after the case study will help participants integrate knowledge of the ecology, silviculture, and management of bottomland hardwoods with the Code of Ethics of several professional organizations, including the Society of American Foresters and The Wildlife Society. Discussion of the issue will also help them to better appreciate the options for sustainable management of the bottomland hardwood resource

Silviculture : Concepts and applications

xxi, 682 hal; 24 c

Seedling density according to structure, dominance and understory cover in old-growth forest stands of the evergreen forest type in the coastal range of Chile Densidad de plántulas de acuerdo a la estructura, dominancia y cobertura del sotobosque en bosques siempreverdes adultos en la cordillera de la Costa de Chile

Securing timely regeneration is essential in maintaining the long-term ecological or silvicultural functions and values of forests. Its establishment, in turn, depends on many factors, including the structure and composition of the forest itself. Available information shows that seedling density varies greatly across the evergreen forest type in Chile. Yet stand variables that may affect the establishment of advance regeneration have not been studied. To that end, we evaluated seven stands of the coastal range, within the northern part of the evergreen forest type (39°14'-40°16' S). We documented understory cover, tree density and dominance, and stand structure, and used the information to assess their effects over seedling density. Findings indicate that Laurelia philippiana was the dominant canopy and regenerating species in these stands. Also, seedling density was significantly greater in stands at lower elevations where shade-tolerant Aextoxicon punctatum was important. Chusquea spp. and Lophosoria quadripinnata, both understory species, had a significant negative effect on seedling density. Basal area and canopy cover, per se, showed little relationship with seedling density. Vertical structure, evaluated through a crown index, had a significant relationship with seedling density, but the direction depended on the species (e.g., L. philippiana and A. punctatum) and the diameter structure within our plots. Fitted models that included these variables were highly significant, and in most cases their significance increased considerably (14 to 26 %) when we accounted for the diameter structures of the plotsLa regeneración es esencial para mantener en el largo plazo las funciones y valores ecológicos o silviculturales de los bosques. Su establecimiento depende de varios factores, incluyendo la estructura y composición del bosque. La información disponible indica que existe una gran variabilidad en la densidad de plántulas a través de la distribución del tipo forestal siempreverde en Chile. Sin embargo, las variables de rodal que puedan afectar el establecimiento de regeneración avanzada no se han estudiado. En este estudio se evaluaron siete rodales de la cordillera de la Costa, en la parte norte de la distribución del tipo forestal (39°14'-40°16' S). En ellos se midió la densidad de árboles, plántulas y brinzales, y se estimó la cobertura de copas de los árboles así como del sotobosque, con la finalidad de evaluar los efectos de la dominancia, la estructura y la cobertura del sotobosque sobre la densidad de plántulas de especies forestales. Laurelia philippiana fue la especie dominante a nivel arbóreo y de plántulas. El número de plántulas fue en general significativamente más abundante a altitudes menores donde Aextoxicon punctatum fue importante. Chusquea spp. y Lophosoria quadripinnata, ambas especies del sotobosque, tuvieron un efecto negativo significativo en la densidad de plántulas. El área basal y la cobertura de copas mostraron una pobre relación con la densidad de plántulas. La estructura vertical, evaluada a través del índice de copas, tuvo una relación significativa con la densidad de plántulas, pero su dirección dependió de la especie (i.e., L. philippiana y A. punctatum) y la estructura de diámetros de las parcelas. Los modelos ajustados con estas variables fueron altamente significativos, y en la mayoría de los casos su significancia aumentó considerablemente (14 a 26 %) cuando se ajustaron separadamente para parcelas con distintas estructuras diamétrica

Dynamics of the diameter distribution after selection cutting in uneven- and even-aged northern hardwood stands: a long-term evaluation

Selection cutting is defined as a tool for uneven-aged silviculture. Dependence on diameter distribution by forestry practitioners for identifying stand conditions has led to misuse of selection-like cuttings in even-aged northern hardwood stands. Our study used several long-term data sets to investigate the temporal stability in numbers of trees per diameter class in uneven-aged northern hardwood stands treated with single-tree selection, and in 45-year-old second-growth stands treated with selection-like cuttings. We analyzed data from New York, Michigan, and Wisconsin to determine changes through time in number of trees across 2.5-cm diameter classes, shifts in the shape and scale of the three-parameter Weibull function used to describe the diameter distributions, and dynamics of associated stand attributes. Findings showed that single-tree selection cutting created and sustained stable diameter distributions and uniformity of conditions through consecutive entries in uneven-aged stands. By contrast, these characteristics varied through time in the second-growth stands that had been treated with selection-like cuttings. Analysis also showed that the Weibull shape and scale parameters for stands under selection system migrated towards those of the recommended target diameter distribution in the uneven-aged stands. These parameters diverged from the target with repeated use of selection-like cuttings in the second-growth even-aged stands.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Initial Responses in Growth, Production, and Regeneration following Selection Cuttings in Hardwood-Dominated Temperate Rainforests in Chile

Hardwood-dominated forests in south-central Chile have shade-tolerant and mid-tolerant tree species capable of regenerating and growing well in partial shade. To test the potential for using an uneven-aged silviculture in these forests, we established single-tree selection treatments at two mid-elevation sites within the Evergreen forest type in the Coastal range (Llancahue and Los Riscos, 40–42° S Lat). They had an average initial basal area of 70–80 m2 ha−1. In each stand, we established four 2000 m2 plots with a residual basal area of ~40 m2 ha−1, and four with a residual basal area of ~60 m2 ha−1. We planned for a maximum residual diameter of 80 cm, but needed to leave 20%–25% of the residual basal area in larger trees due to their great abundance in these old-growth forests. We re-measured these plots 5–6 years after the cuttings. We used mixed-effects models to evaluate the periodic annual increment (pai) in diameter and the abundance of tree regeneration, and linear models to evaluate ingrowth and changes in the basal area and volume. At Llancahue, the diameter pai of individual trees was significantly greater in the treatment with lower residual densities, especially for mid-tolerant species in lower diameter classes (5–20 cm). At both sites, the pai in the stand basal area and volume was greater in the more heavily stocked treatment, but differences were significant only at Llancahue. Regeneration was dominated by shade-tolerant species at both sites but was more abundant and more diverse at Llancahue. Taller tree regeneration (50–<200 cm) significantly increased after the cuttings at both sites, while small regeneration (5–<50 cm) overall remained at pre-cut levels. This pattern was similar for mid- and shade-tolerant species. However, we found no differences in regeneration responses between the lower and higher levels of the residual basal area. Sapling densities did not differ at both sites for shade-tolerant species, but for mid-tolerant species these were more abundant at Los Riscos. While both sites had many similar trends after implementing selection cuts (a greater individual growth in the treatment with lower basal areas but a higher stand-level growth in the treatment with a high basal area, more abundant regeneration of shade-tolerant species, etc.), they illustrate a differential potential for implementing uneven-aged silviculture, especially due to site-species interactions. These results are a first step towards evaluating the prospects for selection cuttings in these experiments and elsewhere in Valdivian temperate rainforests