Mark J. Twery

Mark J. Twery
US Forest Service | FS · Northern Research Station

About

84
Publications
15,918
Reads
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2,006
Citations
Additional affiliations
March 1988 - present
US Forest Service
Position
  • Research Forester
Description
  • My primary personal research is decision-support tools for forest management for multiple benefits. Other research interests include biotic disturbances in forests, regeneration dynamics, stand development, and the roles of humans in the ecosystem.
September 1983 - December 1987
Yale University
Description
  • Ph.D. Dissertation on Changes in Vertical Distribution of Xylem Production in Hardwoods Defoliated by Gypsy Moth

Publications

Publications (84)
Article
Full-text available
Forests play a critical role sequestering atmospheric carbon dioxide, partially offsetting greenhouse gas emissions and thereby mitigating climate change. Forest management, natural disturbances and the fate of carbon in wood products strongly influence carbon sequestration and emissions in the forest sector. Government policies, carbon offset and...
Article
Full-text available
Abstract 1 Spatial pattern in the distribution and abundance of organisms is an emergent property of collective rates of reproduction, survival and movement of individuals in a heterogeneous environment. 2 The form, intensity and scale of spatial patterning can be used to test hypotheses regarding the relative importance of candidate processes to...
Chapter
Full-text available
This chapter is to explore various modelling approaches used for forest management and provides a brief description of some example models. It explores the ways that they have been used to aid the decision-making process, and makes suggestions for future improvements. The modelling approaches used in forest management are empirical models, mechanis...
Article
Full-text available
AbstrAct The Forest Ecosystem Research and Demonstration Area (FERDA) was established in 1998 adjacent to the Visitor Interpretive Center (VIC) for the Adirondack Park in Paul Smiths, NY, to provide visitors with first-hand exposure to forest management activities and to provide research opportunities for scientists and students at Paul Smith's Col...
Data
Full-text available
This report describes the background calibration, inputs, and outputs of ForGATE, a forest sector greenhouse gas (GHG) accounting tool designed primarily to communicate information relevant to the evaluation of projected net GHG exchange in the context of Maine's forests, the Northeast forest sector, and alternative national or regional carbon (C)...
Article
Full-text available
Despite the perceived value of DSS in informing environmental and natural resource management, DSS tools often fail to be adopted by intended end users. By drawing together the experience of a global group of EDSS developers, we have identified and assessed key challenges in EDSS development and offer recommendations to resolve them. Challenges rel...
Article
Full-text available
The abundance and distribution of rhizomorphs of Armillaria spp. in the soil were quantified in undisturbed stands and in stands defoliated 1 and 5 years previously by insects. Although the species of Armillaria was not determined, similar mixed oak forests in south central Pennsylvania contain North American biological species VII (Armillariabulbo...
Article
We described a general pattern of cohort development following two types of even-aged reproduction methods in northern hardwoods. Three clearcut sites initially had divergent numbers of stems, because of variable amounts of advance regeneration. By 10 years, total stem densities became quite similar across sites. Three sites treated by shelterwood...
Data
This is the user's guide for NED-2, which is the latest version of NED, a forest ecosystem management decision support system. This software is part of a family of software products intended to help resource managers develop goals, assess current and future conditions, and produce sustainable management plans for forest properties. Designed for sta...
Data
Full-text available
Conference Paper
Background/Question/Methods Land managers need specific information, strategies, and tools to address the unique challenges of managing forests given uncertainty about the future climate and ensuing ecosystem responses. Sustainable forest management will need to promote forest adaptation to changing climatic conditions in order to achieve desired...
Article
Full-text available
Scenarios are possible future states of the world that represent alternative plausible conditions under different assumptions. Often, scenarios are developed in a context relevant to stakeholders involved in their applications since the evaluation of scenario outcomes and implications can enhance decision-making activities. This paper reviews the s...
Article
Scenario analysis is a process of evaluating possible future events through the consideration of alternative plausible, though not equally likely, states (scenarios). The analysis is designed to enable improved decision making and assessment through a more rigorous evaluation of possible outcomes and their implications. For environmental impact and...
Article
We evaluated changes (hereafter, departures) in spatial patterns of various patch types of forested landscapes in two subwatersheds (“east” and “west”) in eastern Washington, USA, from the patterns of two sets of reference conditions; one representing the broad variability of pre-management era (~1900) conditions, and another representing the broad...
Article
Full-text available
The understory layer encompasses the majority of plain species diversity ill forested ecosystems and may be sensitive to timber harvest disturbance. We hypothesize that (i) uneven-aged, low-intensity silvicultural systems can maintain understory plant diversity and support late-successional species following harvest disturbance; (ii) retaining and...
Chapter
Full-text available
Numerous decision support systems have been developed for forest management over the past 20 years or more. In this chapter, the authors briefly review some of the more important and recent developments, including examples from North America, Europe, and Asia. In addition to specific systems, we also review some of the more-significant methodologic...
Article
We use permanent-plot data from the USDA Forest Service's Forest Inventory and Analysis (FIA) program for an analysis of the effects of competition on tree growth along environmental gradients for the 14 most abundant tree species in forests of northern New England, USA. Our analysis estimates actual growth for each individual tree of a given speci...
Article
Full-text available
Recognizing the importance of private land in meeting society's needs for forest-related benefi ts, public agencies fund programs that provide aid to private landowners to enhance public benefi ts derived from these lands. This may include technical help, education, tax incentives, and cost-share programs for various management activities. It is im...
Article
Full-text available
NED-2 is a goal-driven system designed to help manage timber, wildlife, visual, and ecological goals for a forested ecosystem. The basic approach of the decision process modeled by NED-2 is to develop alternative management plans for the stands in a management unit, to simulate these plans over time, and then to analyze the results of the simulatio...
Article
NED-2 is a Windows-based system designed to improve project-level planning and decision making by providing useful and scientifically sound information to natural resource managers. Resources currently addressed include visual quality, ecology, forest health, timber, water, and wildlife. NED-2 expands on previous versions of NED applications by int...
Article
We present a flexible, extensible method for integrating multiple tools into a single large decision support system (DSS) using a forest ecosystem management DSS (NED-2) as an example. In our approach, a rich ontology for the target domain is developed and implemented in the internal data model for the DSS. Semi-autonomous agents control external c...
Article
Full-text available
For most of a century, beech bark disease has been spreading south and west from its point of introduction in Nova Scotia. The objective of this paper is to illustrate the impact of disease progression on beech trees across the northeastern United States. Beech trees were observed at each of 22 plots during summer months between 1979 and 1992. The...
Article
Decision making for forest ecosystem management can include the use of a wide variety of modeling tools. These tools include vegetation growth models, wildlife models, silvicultural models, GIS, and visualization tools. NED-2 is a robust, intelligent, goal-driven decision support system that integrates tools in each of these categories. NED-2 uses...
Article
Full-text available
Using innovative partnerships and a variety of decision support tools, we identified the needs and goals of Baltimore, Maryland, for their reservoir properties containing over 17000 forested acres; developed a management plan; determined the information necessary to evaluate conditions, processes, and context; chose tools to use; collected, organiz...
Technical Report
Full-text available
Five forest harvest methods (single-tree selection, group selection, two-age cut, shelterwood cut, and clearcut) are being demonstrated on 5-acre tracts near the Adirondack Park Agency's Visitor Interpretation Center (VIC) at Paul Smith's, New York. The tracts are part of the agency's Forest Ecology Research and Demonstration Area. A primary goal i...
Conference Paper
Full-text available
NED-2 is an intelligent information system for ecosystem management in devel- opment by the USDA Forest Service. Using PROLOG knowledge bases and inference engines, NED-2 evaluates forest inventories according to a set of predefined goals. NED-2 is a black- board system with agents implemented in PROLOG. The primary storage medium of NED-2 is a set...
Conference Paper
Full-text available
The following paper describes recent work on NED-2, an in- telligent information system for ecosystem management currently in de- velopment by the USDA Forest Service. Using knowledge bases created by forestry experts and inference engines, NED-2 evaluates forest inven- tories according to a set of predefined goals. By integrating third-party simul...
Conference Paper
Full-text available
For many years we have held to the notion that an Intelligent Information System (IIS) is composed of a unified knowledge base, database, and model base. The main idea behind this notion is the transparent processing of user queries. The system is responsible for “deciding” which information sources to access in order to fulfil a query regardless o...
Article
Full-text available
Decision making for forest ecosystem management can include the use of a wide variety of modeling tools. These tools include vegetation growth models, wildlife models, silvicultural models, GIS, and visualization tools. NED-2 is a robust, intelligent, goal-driven decision support system that integrates tools in each of these categories. NED-2 uses...
Article
The authors describe a process for simulating various forest management scenarios for the purposes of assessing profitability. This approach is based on a case study of a 400-hectare estate in South Carolina. It comprises several stages: defining the owner's goals with all the possible options, characterising the forest according to quantifiable cr...
Article
Silvicultural practices are important factors in determining water yield and quality from forested watersheds. Similarly, goals for water yield and quality significantly influence the acceptability of various silvicultural practices. Developed through a process of consulting experts in various subspecialties of natural resource management, the NED1...
Article
Full-text available
The United States Department of Agriculture — Forest Service (USDA-FS) has been involved in the development of computer models to simulate deposition from aerial pesticide spraying since the early 1970s. Originally, this work was driven by the need to improve the percentage of aerially sprayed material that actually deposited on a target area. The...
Article
1 The twolined chestnut borer, Agrilus bilineatus (Coleoptera: Buprestidae), is a major mortality agent of stressed oak trees. However, patterns of abundance and population change are not well understood. 2 We studied the spatial and temporal variation in abundance of twolined chestnut borer adults during a gypsy moth, Lymantria dispar (Lepidoptera...
Conference Paper
Full-text available
Abstract The AGDISP Aerial Spray Simulation Model is used to predict the deposition of spray material released from an aircraft. The prediction is based on a well-defined set of input parameter values (e.g., release height, and droplet size) as well as constant data (e.g., aircraft and nozzle type). But, for a given deposition, what are the optimal...
Article
We explore a goal-oriented as opposed to a problem-oriented approach to DSS development for ecosystem management. Ecosystem management ordinarily is guided by a set of goals that may conflict in various ways. Problems are perceived obstacles to realizing goals. Identifying and resolving conflicts between goals, testing current or projected situatio...
Article
NED is a collective term for a set of software intended to help resource managers develop goals, assess current and potential conditions, and produce sustainable management plans for forest properties. The software tools are being developed by the USDA Forest Service, Northeastern and Southern Research Stations, in cooperation with many other colla...
Article
Many authors have pointed out the need to firm up the ‘fuzzy’ ecosystem management paradigm and develop operationally practical processes to allow forest managers to accommodate more effectively the continuing rapid change in societal perspectives and goals. There are three spatial scales where clear, precise, practical ecosystem management process...
Article
The gypsy moth is one of North America's most devastating exotic forest pests because it can cause the loss of valuable oak species, degraded aesthetics, loss of wildlife habitat, and detrimental effects on watersheds. Due to the increasingly wide infestation of the gypsy moth, it is important to develop decision aids that help assess the risks of...
Article
We described a general pattern of cohort development following two types of even-aged reproduction methods in northern hardwoods. Three clearcut sites initially had divergent numbers of stems, because of variable amounts of advance regeneration. By 10 years, total stem densities became quite similar across sites. Three sites treated by shelterwood...
Article
Full-text available
The AGDISP Aerial Spray Simulation Model is used to predict the deposition of spray material released from an aircraft. The prediction is based on a well-defined set of input parameter values (e.g., release height and droplet size) as well as constant data (e.g., aircraft and nozzle type). But, for a given deposition, what are the optimal parameter...
Chapter
This chapter presents a management perspective on decision support for ecosystem management. The Introduction provides a brief historical overview of decision support technology as it has been used in natural resource management, discusses the role of decision support in ecosystem management as we see it, and summarizes the current state of the tec...
Article
Understanding the effects of silvicultural treatments on understory vegetation is important in predicting the consequences of such treatments, not only on regeneration but also on wildlife habitat, visual qualities, and recreation. We sought to develop an empirical model of understory response that could be generalized to other forest types. We ana...
Article
Spiders of 24 families were collected by pitfall traps in an oak-mixed hardwood forest in northcentral West Virginia during an 11-wk period in early summer of 1989-1992. All trapped individuals were identified at least to the family level. Quantitative vegetation data allowed assessment of spider habitat associations on a finer spatial scale than p...
Article
The Northeast Decision Model (NED) uses an original prescription design system to incorporate management goals for multiple objectives, analyze current forest conditions, produce recommendations for management alternatives, and predict future conditions under different alternatives. NED is designed to include a long-term, landscape-level view of th...
Article
Using the Scenic Beauty Estimation (SBE) approach, near-view color photographs were taken of 25 forested Central Appalachian Plateau sites exhibiting gypsy moth induced tree mortality from 6% (uninfested control site) to 98%. The slides were randomly arranged and presented to 400 subjects who rated the slides on a 10-point preference scale. Attitud...
Article
Full-text available
Of 603 central Pennsylvania plots that were established in 1978 to measure the short- term impact of repeated gypsy moth (Lymantria dispar) defoliation, 228 were selected for continued study in 1985. Individual observations of defoliation and tree vigor were continued through 1992. Although two gypsy moth outbreaks occurred across central Pennsylva...
Book
Full-text available
One workshop summary and 45 abstracts of oral and poster presentations on gypsy moth biology, molecular ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Gypsy Moth Research Forum.
Book
Full-text available
Eight workshop summaries and 27 abstracts of oral and poster presentations on gypsy moth biology, molecular biology, ecology, impacts, and management presented at the annual U.S. Department of Agriculture Interagency Gypsy Moth Research Forum.
Article
Full-text available
Defoliation of trees by the gypsy moth (Lymantria dispar L.) has many and varied effects. It causes economic losses through lost forest production and reduced aesthetic qualities of the forest. However, defoliation may improve habitat for many species of wildlife and contribute to increased diversity of eastern forests. Effects on water resources,...
Book
Full-text available
Eight invited papers and 68 abstracts of volunteer presentations on gypsy moth biology, ecology, impacts, and management presented at the U.S. Department of Agriculture Interagency Gypsy Moth Research Review.
Article
Rule-based methods are a useful alternative framework for scientific investigation. The incorporation of intelligent functions in a geographic information system provides a means to generate new information. Rules to classify ridges and channels in a triangular irregular network model to estimate slope position demonstrate the usefulness of this fr...
Conference Paper
Full-text available
Gypsy moth has affected pine-hardwood mixtures, especially oak-pine stands, since the late 1800's. Several old and new studies on impacts in mixed stands are reviewed. When pines are heavily defoliated, considerable growth loss and mortality can occur. Mortality is heaviest in understory white pine trees. Impact information is used to suggest silvi...
Article
Control of understory vegetation has frequently been suggested as a method of increasing overstory growth by reducing competition for soil moisture. However, past studies have given conflicting results: some show marked increases in growth rate resulting from understory removal, while others show no effect. Results of understory removal in an oak-d...
Article
The extent of beech bark disease (involving the scale insect Cryptococcus fagisuga and the fungus Nectria coccinea var. faginata) was examined on 41 permanent inventory plots in W Massachusetts and on 25 plots in Bartlett Experimental Forest, New Hampshire. The amounts of disease-caused mortality and defect were correlated to differences in species...
Article
Full-text available
An Intelligent Information System (IIS) is viewed as composed of a unified knowledge base, database, and model base. This allows an IIS to provide responses to user queries regardless of whether the query process involves a data retrieval, an inference, a computational method, a problem solving module, or some combination of these. NED-2 is a full-...
Article
Full-text available
Improving aerial spray application results is a major concern for the USDA Forest Service and Environmental Protection Agency. The AGDISP Aerial Spray Simulation Model is used to predict the deposition of spray material released from an aircraft. The prediction is based on a well-defined set of input parameter values (e.g., release height, and drop...
Article
Full-text available
Ushag the Scenic Beauty Estimator (SBE) approach, near-view color photographs ntroduction _ taken of 25 forested sites exhibiting gypsy moth induced tree mortality from 6% 97%. ms. 839p. were A quadratic function of tree mortality by preference rating best described the variability in ratings (R2 = .60). The effect of flowering mountain laurel flow...
Article
Full-text available
This paper describes research on the use of a multiobjective genetic algorithm (GA) to optimize prescriptive treatment plans for forest management. The algorithm is novel, in that (1) the plans generated by the algorithm are highly specific, stating precisely when and where treatments are to be applied; and (2) logical rules and inference engines d...
Article
Full-text available
Relatively few models have been developed to predict changes in forest structure as a result of BBD. A lack of understanding of the critical factors that control the severity of the disease in forests, and at what spatial scale these factors act, continues to limit our ability to predict changes in forest structure and composition following the est...
Article
Full-text available
NED-2 integrates decision support tools for forested ecosystems developed by the NED- 2 team with other third-party decision support tools. NED-2 is goal-driven and is designed to help manage for visual, wildlife, and ecological as well as traditional timber goals. Several tools are included to help manage for visual goals. (1) A knowledge based sy...
Article
Full-text available
The AGDISP Aerial Spray Simulation Model is used to predict the deposition of spray material released from an aircraft. The prediction is based on a well-defined set of input parameter values (e.g., release height, and droplet size) as well as constant data (e.g., aircraft and nozzle type). But, for a given deposition, what are the optimal paramete...
Article
Full-text available
We describe a research project that has as its goal development of a full-featured decision support system for managing forested land to satisfy multiple criteria represented as timber, wildlife, water, ecological, and wildlife objectives. The decision process proposed for what was originally conceived of as a Northeast Decision Model (NED) include...
Article
Full-text available
Trees distribute the production of xylem through the bole in an unequal manner. Defoliating insects such as the gypsy moth (Lymantria dispar) affect the balance of that distribution. Historical defoliation data were combined with detailed stem analysis of 49 mixed oaks (Quercur rubra, Q. alba, Q. prinus, Q. coccinea, Q. velutina) and associated spe...
Article
The AGDISP Aerial Spray Simulation Model is used to predict the deposition of spray material released from an aircraft. The prediction is based on a well-defined set of input parameter values (e.g., release height, and droplet size) as well as constant data (e.g., aircraft and nozzle type). But, for a given deposition, what are the optimal paramete...