The Southern Pine Beetle
Chapter 12: Recommendations for Future Work
Introduction
Making sure that the southern forestry community obtains maximum benefits from the 6-year Expanded Southern Pine Beetle Research and Applications Program is a job that will outlive the Program itself. In early 1979 the Southern Pine Beetle Task Force (Appendix, table 8) and eight SPB Technology Transfer Teams (Appendix, table 9) started working on this task. Their efforts (Belanger et al. 1979a) outline what must be done to derive the most from ESPBRAP research, now and into the future.
Through the Task Force effort, the Southeastern Area of State and Private Forestry took on the responsibility for coordinating all SPB technology transfer activities (Southeastern Area, State and Private Forestry 1979a). In order to accomplish this task, the position of implementation leader was created and filled. Writer/editor support was also provided as backup for this new position. State and Private Forestry continues to utilize selected Technology Transfer Teams to carry out certain activities. A regional planning group was brought together late in 1980 to set priorities and review accomplishments of integrated pest management (IPM) Program participants and Technology Transfer Teams.
In mid 1979, the team leaders for each Technology Transfer Team completed individual Activity Plans, which were combined into one Southwide plan (Belanger et al. 1979a). The accomplishment of the fiscal year 1980 tasks was impressive. Over 80 percent of all implementation activities identified in late 1979 were completed. That success provided the necessary momentum to encourage planning and implementing of followup activities in FY 1981. The Activity Plan also served as a basis for the applications and research community to develop an applications program for the 1981-1985 period. The Activity Plan served as a basis for this chapter.
We will direct our attention to activities that should be considered in the next 5 years. The first section will identify technology ready for validation, pilot testing, or transfer to users. The next section will focus on critical new or additional research needs. We will conclude with some remarks on needs for southern forestry community involvement in getting these jobs completed.
New Technology Ready for Validation, Pilot Testing, and Transfer to Users
Integrated Management Strategies
Integrated pest management (IPM) can be defined as "the maintenance of destructive agents, including insects, at tolerable levels by the planned use of a variety of preventive, suppressive, or regulatory techniques and strategies that are ecologically and economically efficient" (Waters 1974). Actions taken must be fully integrated into the total resource management process — in both planning and operation. This means that pest management must be geared to the lifespan of a tree crop as a minimum and to a longer span where the resource planning horizon so requires (Waters 1974). This definition contains four messages about the concept of IPM. First, the foundation of IPM rests on the principles of ecology. Second, the methodology involves a combination of tactics. Third, the functional goal is to reduce or maintain pest populations at tolerable levels (both economic and social values). Fourth, IPM is simply a component of total resource management.
During the last decade considerable thought has been given to defining the research components required to develop operational IPM systems. Although classified in various ways, information on the following four subjects is generally considered to be necessary: pest population dynamics, host population dynamics, impact assessment, and treatment tactics. Interactions between these components are extremely important (Waters and Stark 1980).
The ESPBRAP supported research on each of the components (see Chapter 11). A tremendous volume of information and new technology pertinent to development of integrated management strategies for the SPB has been accumulated. The organization of this information and technology has been a function of the Technology Transfer Teams.
The expectations and needs of the various user groups for information on SPB are obviously quite different (see Chapter 11). Basic technology and information for development of a decision-support system for SPB are available as result of the research provided by ESPBRAP. An outline for such a system is presented in Chapter 11.
Implementation —
- Identify opportunities for integrating pest management approaches into
- forest management planning
- forest inventory systems
- operational programs, including scheduling and harvesting activities.
- Prepare and release a handbook on how to apply direct suppression tactics to control SPB populations.
Aerial Survey and Navigation Systems
The first step in determining that there may be a problem that requires control is the detection of pest activity. For SPB, detection is usually accomplished from the air by locating groups of dead or dying trees (Chapter 10). To determine the size and potential of the problem, survey crews must accurately survey that portion of forested areas currently infested or most likely to suffer further losses. Aerial survey results can be used both to guide ground control operations and to quantify and predict future losses.
Accurate, low-cost methods for determining the status of SPB outbreaks have been developed. Using a digital computer-aided system, DeMars (1979) monitored spots on sequential photographs of a large ownership over time. Clerke and Ward (1979) reported on aerial sampling techniques to determine impacts of SPB at one point in time or over a year’s time. The Loran-C radio navigation system improved the accuracy and repeatability of the aerial survey flights in the latter study. Setting ground-check priorities following aerial surveys (Billings and Doggett 1980) and setting control priorities for spots having different characteristics (Billings and Pase 1979b) have helped the southern forestry community deal with SPB outbreaks.
Implementation —
- Provide field training, demonstrations, and workshops on the use of the Loran-C and digital computer systems for quantifying timber mortality over time.
- Develop a users’ guide for the digital computer-based system.
- Prepare and release a handbook on how to determine SPB impacts with aerial photography and digitized, computer-aided accounting system.
- Conduct symposium on new or improved aerial survey techniques.
Sampling Methods and Predictive Models
Lack of adequate sampling methods has hindered the development of successful control procedures for the southern pine beetle. The lack of sampling methods can be related to several problems. Evaluation of control tactics is dependent on reliable estimates of pre- and post-treatment measurements of beetle populations. Without good sampling methods we cannot fully understand the dynamics of beetle populations and their interactions with their immediate environment, i.e., their host trees. Without understanding insect population dynamics, we cannot develop reliable predictive capabilities that enable us to focus control on those spots most likely to grow at the fastest rate.
Sampling studies have provided us with a Southwide series of large data bases on southern pine beetle populations. These data have, in turn, provided some of the information needed to develop mathematical models that mimic beetle population dynamics. As with sampling methods, the spatial and temporal characteristics of models built during the ESPBRAP vary widely. By relating beetle numbers to numbers or characteristics of infested trees, predictions can be made not only of population trends over time but also of the amount of tree mortality that could be expected from growth. Thus damage can be predicted in terms of number of infested trees and expected volume loss as a function of beetle population trend over time (see Chapter 6).
Input and output for these models have purposely been made flexible to permit different levels of accuracy at different costs. Thus, the models can accept precise estimates of initial beetle numbers within a spot, and produce estimates of how these numbers will change as the infestation grows or declines. The population dynamics researcher may need such information. Using the same model but with less sophisticated input, the pest control specialist can obtain an estimate of expected damage in terms of infested trees and volume lost in a given area after some length of time. To calculate these outputs, he needs to input only numbers of infested trees and stand condition associated with a particular spot. Thus these models can be adapted to meet the needs of researchers or field practitioners.
Although much progress has been made in the area of population sampling and model construction, we are far from finished. (Stephen, Searcy, and Hertel 1980). Mathematical modeling abstracts pertinent information about complex systems. Therefore, a particular model can always be considered incomplete, since our abstract only approximates the information contained therein. However, the modeling approach forces the scientist to conceptualize and define objectively the system being modeled. As he gains additional experience and data, there may be good reason to reexamine the assumptions, logic, and techniques used in developing, validating, and implementing the models.
Users should be made aware of the potential applications for predictive techniques. Therefore, users should be included in the testing and improvement of the models. This is particularly important, as models must have input and output formats that the intended users can understand, accept, and use. For example, expressing loss in terms of cubic feet versus dollar value may be important to the potential user, and easily accommodated by simple programming changes within the model structure.
Validation —
- Validate spot growth models in Alabama, Georgia, Mississippi, and South Carolina.
- Refine and update the population models as time, data, and experience permit.
Implementation —
- Pilot test computer-based spot growth models, which determine population/damage trends and the need for action.
- Translate into FORTRAN and install insect population models on Forest Service computer or maintain on university computer.
- Develop user manuals for computer-based models.
- Integrate model components into forest pest management guidelines.
- Continue to refine and update computerized models as new information becomes available.
- Conduct workshops on the use of predictive models for forecasting population/damage trends.
- Use models for selecting and evaluating proposed control tactics and strategies that will provide optimum results in operational control programs.
Socioeconomic Guidelines
In recent years, there have been increasing demands from all segments of society for government-provided goods and services. Yet public agencies have come under intense pressure to reduce spending or, at the very least, limit the use of taxpayers’ dollars to those activities that demonstrate a favorable return on investment. In competing for funds, it is imperative that forest resource managers make a critical economic analysis of all proposed project costs and benefits.
To provide resource managers with the tools for making sound economic analyses, ESPBRAP has developed methods for measuring and/or analyzing the physical and economic impacts of SPB on various forest resources (e.g., timber, recreation, wildlife, grazing, water, and esthetics). Results from such analyses are needed to quantify the SPB’s impacts over time.
Several analytical procedures have been developed for use in making control decisions. These include the computer-based models FRONSIM, PTAEDA, TBAP, and DAMBUGS (see Chapter 7). Also available are the procedures for evaluating esthetic and recreation impacts.
Validation —
- Validate or refine socioeconomic models
Implementation —
- Implement the DAMBUGS model on the Forest Service computer to simulate damage levels over large areas in future years. Prepare and release user’s guide for the model.
- Incorporate models in integrated forest pest management guidelines.
Silvicultural Practices and Stand Rating Systems
Promotion of stand resistance through improved forest management is our best approach to preventing SPB infestation incidence and to minimizing losses should outbreaks occur. Research efforts of the ESPBRAP regional site-stand project were directed toward developing effective prevention strategies. Findings identified stand, site, host tree, and climatic conditions associated with SPB attack (see Chapter 4). Systems were developed to rank the susceptibility of stands to beetle infestations (Chapter 8). Overstocking and poor growth were common characteristics of high-risk stands. Silvicultural and management recommendations were developed to prevent or remedy these conditions (Chapter 9).
Several stand hazard-ranking systems have been implemented. Their uses vary with land management objectives and forest conditions. To identify current silvicultural treatment needs, one can rank stands that are already susceptible in order of priority. And knowing a stand’s likelihood of sustaining SPB damage facilitates surveillance and planning of control activities. As a result, the forest manager can anticipate where infestations are most likely to occur and undertake the most appropriate cultural measures on a timely basis.
The southern forestry community has demonstrated enthusiastic support for the development of hazard-ranking systems and management practices to reduce losses from the southern pine beetle. The assistance, suggestions, and constructive criticisms of interested persons and organizations have greatly benefited the research process. The involvement of user groups with technology transfer and implementation has also helped Program management identify additional work that remains to be done:
Validation —
- Validate stand hazard rating system
- on National Forests in the South
- in three States on State-owned and private lands
- on the lands of two forest industries.
Implementation —
- Conduct awareness workshops on stand hazard-ranking systems.
- Prepare and release "How-to" handbooks and fact sheets on stand rating systems for natural stands in the Gulf Coastal, Piedmont (Georgia), and southern Appalachian regions.
- Where appropriate, incorporate ranking systems into management guidelines for National Forests, industry, States, Soil Conservation Service, National Park Service, Corps of Engineers, and the Department of Defense.
- Establish demonstration areas to illustrate
- conditions favoring SPB infestations
- the field application of stand-ranking systems
- cultural treatments recommended to reduce losses from the SPB.
- Incorporate silvicultural practices and stand rating system(s) into integrated forest pest management guidelines.
- Implement, maintain, and monitor a Southwide evaluation of the effects of thinning in preventing or reducing SPB damage in plantations and natural stands.
Guidelines for Utilizing SPB-Killed Timber
Proper utilization of America’s timber resources is one of the most important endeavors of State and Federal resource agencies and the forest products industry. Over the years approximately one-half of all the SPB-killed wood has not been utilized. ESPBRAP-supported research has given us just about all the existing information on utilization of beetle-killed wood (Chapter 7). Possible uses include lumber, particle board, hardboard, pulp, blue-stained paneling, and plywood.
Contrary to popular opinion, wood from beetle-killed trees can be used even after the bark is loose and begins to slip off (Levi 1980). These trees are usable for pulpwood for at least 2 years in the northern part of the region. The effects of beetle damage on the properties of wood from these trees, presented in Levi’s handbook, can be determined by external appearance class of the tree on the stump.
Attempts are being made to get this information to loggers, wood dealers, and mill operators. Popular articles (Sinclair 1978, Sinclair and Ifju 1977), fact sheets (Southeastern Area, State and Private Forestry 1979b and c), and Agriculture Handbooks (Levi 1980, Sinclair 1979) have been used along with the awareness workshops and training sessions. Technology transfer in the wood utilization area should continue to have a high priority.
Validation —
- Validate cruising guidelines (uniform appearance classes) for determining state of deterioration of beetle-killed timber in several geographic subregions.
- Validate for the western Gulf States the mill operators’ guide (Sinclair 1979) that was developed in Virginia to determine the profitability of processing beetle-killed timber.
Implementation —
- Conduct workshops on utilization of SPB-killed wood.
- Present a symposium on utilization of beetle-killed timber at a forest products association meeting.
- Incorporate utilization results into integrated forest pest management guidelines.
Behavioral Chemicals
Historically, efforts to control the southern pine beetle have been primarily remedial in nature and principally involved the use of insecticides and salvage. These methods have only been partially successful in large areas, as evidenced by continuing epidemics of the pest. Salvage has become the principal approach in the last decade since cost and environmental concerns have all but eliminated the operational use of insecticides in the forest. As a result, the forest manager has few alternatives for dealing with the beetle.
Remedial control techniques are still urgently needed, and over the past 15 years, researchers have investigated behavioral chemicals for their potential use in filling that need. Several chemicals, including attractants and inhibitors, play a role in SPB landing and attack behavior (see Chapter 2). Attractants cause enough flying beetles to congregate on a common host tree over a relatively short period of time so that they are able to overcome the natural resistance of the tree and successfully colonize it.
Research on attractants and inhibitors is now at a point where they should be considered as potential control agents for suppressing southern pine beetle infestations. The attractants will likely be most practical for use in smaller infestations and will give foresters and/or pest management specialists the potential for reducing or halting spot growth where salvage is impractical. The inhibitors, on the other hand, could be applied to larger, unmanageable infestations. More work is needed in this area before use of behavioral chemicals can be recommended.
Validation —
- Pilot test area permeation with inhibitors applied from the ground and air in slow-release devices.
- Pilot test frontalure alone and in combination with other treatments for disrupting spot growth or suppressing beetle populations.
Implementation —
- Register a behavioral chemical for SPB spot disruption.
- Prepare and release a handbook on the use of behavioral chemicals for disrupting SPB spots and in combination with other suppression approaches.
- Organize and conduct workshops on the use and evaluation of behavioral chemical treatments.
- Hold a symposium on the use of behavioral chemicals in SPB surveys and suppression.
New Insecticides and Improved Spray Systems
Except for treating small spots (< 25 trees) during the winter, insecticides are little used for operational control projects in the forest. However, they can be used to protect high-value trees in areas such as seed orchards, campgrounds, or urban situations. The use of spray systems that limit insecticide drift is of special concern in such areas. Billings has summarized the various aspects of using insecticides to control bark beetles in Chapter 10.
Lindane has long been the standard insecticide for controlling SPB infestations. However, recent concerns about the longevity of chlorinated hydrocarbon pesticides in the environment and the Rebuttable Presumption Against Registration issued against lindane have caused concern about its continued availability. This concern resulted in an ESPBRAP-funded effort to identify potential replacements for lindane in chemical control of SPB. Several compounds were screened and tested under both field and laboratory conditions. Two—chlorpyrifos and fenitrothion—proved particularly efficacious and did not present any unreasonable adverse environmental impacts when used in forest ecosystems. Chlorpyrifos (Dursban 4E®) has been registered for use against SPB.
Implementation —
- Write fact sheets summarizing insecticide research results.
- Determine cost/benefits and include chemical treatments in integrated pest management guidelines.
Continuing and New Research Needs
Population Dynamics
The understanding of southern pine beetle population dynamics in individual trees has blossomed during the ESPBRAP. We have accumulated a storehouse of information on the bark beetle, host tree, and associated microorganisms. Much of our understanding at the infestation level comes through extrapolation from the individual tree level. What goes on in the relationship between beetle numbers and the forest is not completely understood.
There are, however, many knowledge gaps left to be filled:
- Interrelationships between bark beetle species
- Role and interrelationships between biological control agencies.
- Insect-host-climatic interactions
- Completion and validation of biological/physical models
- Nutritional and rearing requirements
- Genetic characteristics of populations
- Communication system of the SPB.
Stand Dynamics
Host-pest relationships are complex ecological phenomena that ultimately achieve a balance in undisturbed systems. The pest must be able to thrive and reproduce; but, equally important, it must permit the host to survive. Without a good understanding of host dynamics, the usefulness of the population dynamics information might never be realized. The following efforts should be undertaken.
- Characterize the host factors or processes regulating tree and stand susceptibility.
- Construct biological models of time, stand, site, and climatic interactions affecting tree and stand susceptibility to beetle attack.
- Validate predictive models for forecasting tree and stand susceptibility as influenced by variations in age and size class of trees, stand density, growth rate, site factors, climatic events, tree disease incidence, beetle population densities, and forest management objective.
- Simplify modeling inputs to encourage use by pest control specialists, analysts, and resource managers.
Treatments
The concern of most forest managers is "What can I do after the beetles are here?" The approach being taken today by integrated pest management specialists is to convince the land manager to "think insects" whenever he does anything. However, forest pest management can be accomplished only as part of the forest management process. Future research should consider the following items.
- Modification or development of new forest management techniques to reduce damage to residual forests and prevent or reduce beetle loss. Areas of consideration include
- Logging practices and equipment
- Single- v. mixed-species management
- Silvicultural systems
- Rotation lengths
- Thinning priorities, precommercial and commercial
- Development, testing, and validation of integrated management systems under varying management regimes.
- Development and testing of techniques for evaluating treatment effects before and after control.
Other Research Activities
The technology transfer teams have identified the following items for new and continued research.
Silvicultural Practices and Stand Rating Systems
- Develop a stand ranking system for pine plantations.
- Determine inherent differences in susceptibility to SPB attack between and within the major southern pine species.
- Determine effects of other cutting and harvesting practices in preventing or reducing damage caused by SPB, and develop management guidelines.
Guidelines for Utilizing SPB-Killed Timber
- Identify harvesting problems associated with beetle-killed timber.
- Determine potential for using beetle-killed timber as an energy source.
- Identify microorganisms responsible for destruction of beetle-killed wood.
- Determine potential for using beetle-killed wood for crossties, shingles, and shakes.
Socioeconomic Guidelines
- Develop, refine, or validate socioeconomic models.
New Insecticides and Improved Spray Systems
- Continue field and laboratory screening of insecticides showing potential for controlling SPB.
- Evaluate feasibility of using combinations of insecticides and pheromones for SPB control.
Sampling Methods and Predictive Models
- Determine relationship between spot growth and areawide damage trends.
- Continue to study low-level SPB populations in South Atlantic and Gulf Coastal States to determine factors regulating such populations.
- Develop input routine(s) for sampling and predicting population/damage that are more compatible with the needs and capabilities of pest management specialists and resource managers.
Aerial Survey and Navigation Systems
- Measure SPB impacts with small-scale photography.
- Test any new developments in previsual detection technology.
- Interface Loran-C system with digitizer and computer.
Behavioral Chemicals
- Develop deployment technology for attractants and inhibitors.
- Evaluate the use of inhibitors for protecting urban trees.
- Test spot distribution with frontalure applied from the air. Continue the isolation, identification, and synthesis of promising attractive and inhibitory compounds.
Integrated Management Strategies
- Develop decision support systems.
- Consolidate SPB findings into integrated pest management systems suited to local pest, forest, and environmental conditions.
- Refine, develop, and test integrated pest management systems for SPB in two geographic subregions.
To complete the research and applications jobs outlined in this chapter, the forestry community in the South has made a commitment. Activity flows developed from the original action plan have been considered by State and Private Forestry, Southeastern Forest Experiment Station, Southern Forest Experiment Station, Southern Agricultural Experiment Station Directors, State Foresters in the South, and the Cooperative Extension Service. At this time the details of who will actually do the work and how they will be supported are being worked out. It has been made clear through this cooperative venture that SPB remains a high-priority pest problem.
The bottom line to all the work is the implementation of new results. To achieve this implementation, the information must be offered, received, and acted upon. The research community must offer the information that was originally sought by users. The linker groups must receive it, use it, and pass it on to other users.
The movement of information from the research community to the user community requires a process that many organizations cannot deal with. We have seen over the years a stockpiling of research results. To develop a more uniform approach to this problem, the U.S. Forest Service put together a National Action Plan for Technology Transfer (1979). This Plan follows the USDA Interagency Agreement on Forestry (1978), which spells out the responsibilities of the U.S. Forest Service, Soil Conservation Service, State Foresters, conservation districts, and the Agricultural Stabilization Commodity Service as far as technology transfer is concerned.
As an attainment process, technology transfer involves (1) users’ perceiving a problem, need, or opportunity; (2) practitioners’ inquiring for knowledge source; (3) analyzing available information; (4) checking costs and benefits; and (5) adopting new technology or knowledge.
The forestry community clearly has a big job ahead. Technology development, translation, distribution, and implementation is no easy matter. This book has brought us up to date on the technology relating to the southern pine beetle as of April 1980. This chapter should give readers a feeling for the work left to be done. The work should be accomplished with the assistance of the southern forestry community.
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