Bruce Larson

Germination and seedling growth of Quercus (section Erythrobalanus) across openings in a mixed-deciduous forest of southern New England, USA

Abstract In this study three species of the genus Quercus section Erythrobalanus (Quercus coccinea, Quercus rubra, Quercus velutina) were investigated. All occur together as canopy trees in forests of southern New England. Acorns of each Quercus species were planted in plots located in five zones that represent a range of forest gap/canopy conditions that can occur within a southern New England forest. These five zones were demarcated adjacent to and across large openings of two physiographic sites—valley and ridgetop. Experiments were designed to monitor germination and initial growth of seedlings for the first three growing seasons. During the start of the first growing season germination was monitored. At the end of the first growing season measurements of height and number of flushes were taken and destructive samples of seedlings made for dry mass of root, stem and leaves. At the end of the third growing season height was recorded for surviving seedlings. Comparisons were made of germination and growth of seedlings located in the different gap/canopy conditions. Results demonstrated clear differences in patterns of germination and early growth among species and among gap/canopy conditions of the sites. All species showed an increased lag in germination with reduced amounts of light. Highest growth and flushing rate were in the center conditions of the openings for all species during the first growing season. Quercus rubra had the greatest height growth the first growing season but a lower number of flushes than Q. velutina and Q. coccinea. In comparison with the other species, Q. rubra had the greatest total dry mass in most gap/canopy conditions after the first growing season. However, Q. velutina had the greatest total dry mass in the center of the ridgetop opening. In almost all gap/canopy conditions Q. velutina had greater proportions of dry mass allocated to roots compared with the other species. After 3 years, greatest height growth in any of the gap/canopy conditions was recorded for all three species in the center of the valley site. Under this condition Q. rubra had significantly greater growth than Q. velutina and Q. coccinea. Quercus rubra also had significantly greater height growth and survival beneath the canopy conditions of the valley site than the other species. On the ridgetop site regeneration failed to establish beneath canopy conditions that provided low amounts of light. Quercus velutina showed greatest height growth after three years in the center and edge conditions of the ridgetop opening compared with the other species. Environmental influences that determine species germination and growth performance are suggested.

A fuzzy set approach to the problem of sustainability

Evaluating sustainability in forest management requires decision makers to consider multiple, conflicting definitions in an environment of risk, uncertainty, and incomplete or non-quantitative information. Zadehs fuzzy set theory provides a rigorous, flexible approach to the problem of defining and evaluating sustainability and comparing alternative scenarios. We discuss how fuzzy set concepts can be used to better manage for goals such as sustainability, equity, and ecosystem health. We then show how a simple tabular technique using fuzzy sets can be used to compare management alternatives, incorporate multiple objectives, and identify knowledge gaps and areas of disagreement. The simplicity and flexibility of this technique provides needed support for more explicit, objective decisions.

Forest Certification: Roots, Issues, Challenges, and Benefits

ISSUES IN FOREST CERTIFICATION Improvements Crucial to Successful Implementation of Forest Certification Why Certification is Relevant ROOTS OF FOREST CERTIFICATION: ITS DEVELOPMENTAL HISTORY, TYPES OF APPROACHES, AND STATISTICS Origins of the Concept of Forest Certification Other Relevant Initiatives in Forest Certification The Certification of Environmental Claims in Industrialized Countries Analysis of Forest Certification Approaches Current Statistics and Characterization of Certified Forests by Ownership Type and Land Area DEFINITIONS AND CURRENT VALUES INTEGRATED INTO CERTIFICATION PROTOCOLS Defining Terminology Value-Laden Issues of Certification CASE STUDY AND EVALUATION OF THE DOMINANT CERTIFICATION PROTOCOLS Relevance of Toumey Forest to Assess Certification Protocols Analysis of the Elements Comprising the Dominant Certification Protocols as structured in January 1998 Case Study: Student Evaluation of Protocols at Yales Toumey Forest INDICATORS RELEVANT FOR INCLUSION IN ASSESSMENTS: TYPES, MINIMUM NUMBER, AND THOSE DERIVED FROM NON-HUMAN VALUES Indicators Selection Criteria Non-Value-Based Parameters Relevant for Incorporation into Certification Social Legacies Constraining Natural Resource Uses DIRECT AND INDIRECT IMPACTS OF NATURAL RESOURCE MANAGEMENT PRACTICES ON THE ECOSYSTEM Introduction Forest Management Activities Leading to Regeneration Forest Management Activities Not Associated with Regeneration Infrastructure Related to Forest Management Activities Summary SYNTHESIS DISCUSSION OF ISSUES RELEVANT TO CERTIFICATION Necessity of Assessing the Landscapes Matrix Within Which a Management Unit is Embedded Social and Natural Science Links Public Participation in Certification Importance and Participation of Non-Industrial Private Forests Certification: Constraints and Opportunities for Non-Industrial Private Forest Landowners Estimating Price Premiums Necessary to Pay for Forest Certification Chain of Custody as an Impediment to Certification Challenges and Opportunities for Tropical Timber Certification: Mexicos Experience CHALLENGES AND BENEFITS OF CERTIFICATION Summary Discussion of the Advantages and Challenges of Certification Reason for Forestland Owners Not To Become Certified The Past and Future Goals of Certification

Integrating Landscape Ecology into Natural Resource Management: Linking ecological and social scales for natural resource management

Natural resource management has moved from a single disciplinary and one resource management approach to an interdisciplinary and ecosystem-based approach. Many conceptual models are being developed to understand and implement ecosystem management and forest certification initiatives that require an integration of data from both the social and natural systems (Vogt et al, 1997, 1999a,b). These changed approaches to natural resource management arose from a perception that variables critical in controlling the health and functioning of an ecosystem could only be determined by integrating information from both the social and the natural sciences (Vogt et al., 1997). However, it has been difficult to take many of the theoretical discussions and the frameworks or conceptual models that they have produced and to operationalize or put them into practice on the ground.

Optimising seedling management: Pouteria sapota, Diospyros digyna, and Cedrela odorata in a Mexican rainforest

Seedlings of three commercial native tree species were planted under heterogeneous light and nutrient conditions in primary rainforest, secondary forest, and open pasture in Los Tuxtlas (Veracruz, Mexico). Management consisted of weeding around seedlings, and watering during the dry period. The objective was to find those natural growth conditions that maximize height growth in the first 2 years after transplantation from a nursery. Using stepwise multiple linear regression, the combined effect of varying canopy openness, leaf nutrients, initial seedling height, and seed mass on the plant height at the end of the study were analysed. The effect of the light environment differed clearly between species: the fruit species Pouteria sapota (Jacquin) H.E. Moore & Stearn (Mamey) and Diospyros digyna Jacquin (Black Sapote) revealed an optimal canopy openness of 60 and 55%, respectively, while the timber species Cedrela odorata Linnaeus (Spanish Cedar) grew best under maximum openness. Consequently, P. sapota and D. digyna are recommendable for an enrichment or shelterwood system in the forest, while C. odorata is recommendable as a reforestation species in the open. For P. sapota and D. digyna, plant height variation at the end of the study was also explained by the leaf zinc concentration, initial plant height, and in P. sapota by the seed mass and leaf calcium/magnesium ratio (for C. odorata, seed mass and nutrients had not been measured). The regression model indicated that considerable height increases are possible by optimizing these growth parameters within the encountered ranges. For P. sapota, average height growth after 24 months in the field could be increased 2.5-fold, from 111 cm with average values to 280 cm with optimal values. For D. digyna, average height growth after 17 months could be increased 1.8-fold, from 78 to 138 cm. For C. odorata, the possible increase after 16 months was 2.7-fold, from 55 to 147 cm. # 2000 Elsevier Science B.V. All rights reserved.

A protocol for measuring abundance and size of a neotropical liana,Desmoncus polyacanthos (Palmae), in relation to forest structure

This study investigated the relationship between the abundance and size ofD. polyacanthos and measures of forest canopy structure. Várzea and terra firme forest were selected for study at the mouth of the Amazon estuary, Pará, Brazil. The forest canopy characteristics investigated included individual tree height and height to base of the live portion of the crown, forest canopy depth (the distance from the lowest foliage in the understory to the top of the canopy including all free space between top and bottom), forest canopy thickness (the portion of the forest canopy depth occupied only by foliage) and forest canopy density (the sum of lengths of each of the individual crowns that make up forest canopy depth) (see Fig. 2b). The attributes ofD. polyacanthos measured included leaf number, stem height and percent coverage within the stands. Results from this study suggest thatD. polyacanthos can be encouraged to grow through selective cutting of canopy trees and promotion of regenerating forest stands on terra firme fallow. The protocol used to relateD. polyacanthos abundance and size to kind of forest canopy structure can be used for evaluation of other climbing palms.ResumenBotânica Econômica. Esses estudo investigou a relação entre a abundância e tamanho deD. polyacanthos e medidas da estrutura do dossel da floresta. Florestas de várzea e terra firme foram selecionadas para o estudo no estuario Amazônico, Pará, Brasil. As características do dossel florestal investigadas incluíram a altura das árvores e a medida da altura entre o topo da copa e a base da copa viva profundidade do dossel florestal (a distância entre a folhagem mais baixa no sub-bosque e o topo do dossel incluindo todo espaço livre entre o topo e a base da folhagem), espessura do dossel (a porção da profundidade do dossel da floresta ocupado somente por folhagem) e densidade do dossel da floresta (a soma do comprimento de todas as copas que compõe a profundidade do dossel) (veja Fig. 2b). Os atributos deD. polyacanthos meridos incluíram número de folhas, altura do tronco e percentual de cobertura dentro do povoamento. Os resultados desse estudo sugerem queD. polyacantos pode ser estimulado a crescer através do corte seletivo de árvores que ocupam o dossel da floresta e da promoção da regeneração florestal em áreas de pousio (resultante de uso agrícola) na terra firme. O protocolo usado para relacionar a abundância e tamanho deD. polyacanthos ao tipo de dossel florestal pode ser usado para avalição de outras palmeiras trepadoras.