Abstract
The selection and management of trees depend upon the availability of accurate information about the characteristics of the individual taxa involved. The development of a species profile utilizes a variety of sources of information, ranging from textbooks to personal experience. Both basic and practical knowledge are needed. Aspects of plant biology such as natural range and habitat, phenology and reproductive behavior may provide insights into management. In addition, practical guidelines for pruning, key pests and other management strategies may be invaluable.
A critical part of many arboricultural activities involves information about trees, from growth patterns to insect and disease problems to ornamental features. In many consulting and litigation situations, an in-depth knoweldge of a plant’s character is an absolute requirement. In short, arborists, urban foresters and scientists are continually reviewing, researching and updating their knowledge about individual plants.
Possessing a detailed set of facts about a “subject” does not set arboriculture apart from other professions. For any businessperson, in sales, or consulting, a detailed knowledge of both product and client is a necessary part of the road to success. An excellent overview of this concept can be found in: Swim With The Sharks—Without Being Eaten Alive, by Harvey Mackay (1988, Ivy Books, New York NY). One of Mackay’s central tenets is that information has value in obtaining and retaining clients and customers. How can you swim with sharks (your competition) if you aren’t informed?
Mackay was concerned with information about people. He developed a formal profile of each customer based upon a set of 66 questions. The profile was broad-ranging and comprehensive, covering such topics as general background, education, family, business background, special interests, lifestyle and his relationship with the customer.
We wholeheartedly agree that the “Mackay 66” is invaluable in learning about a client. And we also believe that an arboricultural version of the Mackay’s 66 - question profile would be very valuable to arborists. Urban foresters, consultants, landscape architects and arborists must frequently cross discipline lines to develop management ideas, protocols and practices. They must be well versed in plant biology, soils, nutrition, pathology, entomology and arboriculture. Such information is not compiled in any one reference work, but is distributed among many disciplines.
Moreover, in a given geographic region, arborists may concern themselves with a limited number of species, and thus, have a strong need for species-specific information. Such detailed information allows arborists to challenge traditional or general recommendations regarding the management needs of an individual taxon. For example, it is common to recommend crown thinning as a stabilizing measure for trees. Yet, deodar and Atlantic cedar may be more stable when crowns are not thinned. In such a case the general rule does not apply; a species-specific response is required.
As a way to work with this problem of compiling diffuse information from many disciplines, we have developed a species profile (Table 1). This set of questions/categories defines 96 pieces of information, divided into 5 general groups: 1) name and plant group, 2) general growth and development, 3) reproductive development, 4) culture and management, and 5) values.
We envision the species profile as a reference for individual species containing information about an individual plant in one source. In this article, we present a working example of our species profile; our version of Mackay’s 66 for valley oak (Quercus lobata) (Table 2).
Application of the Profile
The value of a species profile is measured by its ability to deal with a given species in a given management situation. Put another way, can the profile be used to make practical decisions? One perspective on this problem is to simply acknowledge that information is power, and the more we know about an individual plant, the better managers we will be. Additionally, collecting information about plants forces us to use a more precise terminology and vocabulary.
In developing a profile, we must search for information from related fields. Observations from forestry or ecology may have value when placed in the context of arboricultural practice. For example, information on the natural occurence of a species, its range, soils, plant associations, and response to seasonal precipitation patterns may be useful in a cultivated setting. In the Pacific northwest, where the precipitation pattern is winter rain/summer drought, Arbutus menziesii is most successful on dry, exposed sites with poor soils. Knowing madrone’s natural habitat allows arborists to recommend avoiding summer irrigation and wet/disturbed soils when working with this species.
Success in practices such as pest management, pruning and fertilization is dependent upon the general patterns of plant development. The timing of seasonal growth events such as cell division, shoot and root elongation, diameter expansion, and flowering and fruiting in relation to weather are collectively referred to as the phenological patterns. Fertilization and/or pruning practices may depend upon the timing of root, shoot and cambial activity. We might also consider how the timing of pruning differs for species whose shoot growth occurs all at once rather than in flushes. Or consider how the thickness of bark, presence of latent buds and seasonal development of foliage affect the potential for high temperature injury (sunburn) along the stem.
In some areas, the applicability of basic information to management practices is not clear. Xylem character is a useful example. Trees have three basic patterns of development within the secondary xylem: tracheid, diffuseporous, and ring-porous. In a tracheid system (conifers), vessels elements are lacking and 8-12 annual rings are active in transport. In a diffuse-porous system (sweetgum, sycamore), vessels are evenly distributed throughout an annual ring. Several rings function in transport. In a ring-porous system (some species of oak, elm), vessels develop early in the growing season. If elm is typical of this pattern, 90% of the water transport occurs in the outermost (i.e., the most recently formed) ring.
How three very different patterns of xylem development and water movement impact a tree’s response to disturbance, drought and/or pruning is unclear. Are valley oak trees more sensitive to disturbance in early spring, when the large vessels that transport the bulk of water are maturing? Are these patterns related to carbohydrate and nutrient storage? As far as we are aware, answers to these questions are not known.
Sources of Information
Answers to the “Tree 96” list cannot be obtained from anŷ single source. Nor should a consultant expect to find all of the material in standard arboriculture or plant materials texts. Basic terminology about tree development may be found in such classic references as Arboriculture—Care of Trees, Shrubs and Vines in the Landscape (R. Harris 1983 Prentice-Hall) and Physiology of Woody Plants (P. Kramer and T. Kozlowski 1979 Academic Press). Hortus III (Anonymous 1976 Macmillan) and the Sunset Western Garden Book (Anonymous 1988 Lane Publishing) may serve as excellent starting points for botanical or horticultural information. Yet, broader examinations of the literature are frequently needed. Arborists should be prepared and willing to explore information from different geographic regions and in fields related to arboriculture, such as forestry and natural resources.
University libraries
Access to a university library, especially one oriented towards agriculture or natural resources, will be invaluable. Services such as computerized literature searches, abstracts and reference texts are very beneficial.
Large libraries are generally more accessible than most of us would think. Public universities are supported by tax dollars. Most welcome outside agencies/businesses to their facilities. For example, at the University of Washington, businesses may obtain a corporate library card for $30 per year.
Libraries frequently subscribe to abstracting services, similar to the ISA’s Arboricultural Abstracts but on a larger scale. Forestry Abstracts and Horticultural Abstracts are two sources of value to arborists. Literature searches dealing with individual plants can be easily performed using these references.
For a first-time review of literature about a new plant, computer searches may be very productive. Instead of reviewing volumes of abstracts by hand, a computer makes the search effortlessly. These searches are tremendous time-savers, reviewing a large, diverse body of literature very rapidly and relatively inexpensively.
As an example, we recently conducted a search for literature dealing with a relatively uncommon California native, Platanus racemosa, the California sycamore. Two large databases were queried for any citation of this species dating back to 1969. Seventeen citations were found. The search took about 5 minutes with a total cost of $11.59. A similar search for Arbutus menziesii cost $26.68 and located 65 references. Computer searches will not be as inexpensive for common plants, where there may be hundreds of citations, but searches are an excellent entry point.
Another very valuable resource of many libraries is an inter-library loan service. If a given library does not have a publication in its collection, it will frequently sent a request to another library to copy or lend the volume.
Department of Agriculture-Forest Service literature
The Department of Agriculture’s Forest Service publications may be arboriculture’s most underutilized tool. Forest Service literature ranges from research reports to bibliographies to compiled books.
Access to Forest Service publications can occur through a number of channels. The Government Printing Office should be able to supply you with a list of available books in the forestry field (there are even federal bookstores in many large metropolitan areas). Regional Forest Range and Experiment Stations publish periodic summaries of new research and management publications (in our area, it is Forestry Research West). Examples of the type of books printed by the USDA include: 1) Silvics of Forest Trees of the U.S. Fowells, H., ed. 1965. USDA Agric. Handbk. 271. 762pp; (may be out-of-print). 2) Diseases of Forest and Shade Trees of the U.S. Hepting, G. 1971. USDA Forest Service Agric. Handbk. 386; (may be out-of-print). 3) Seeds of Woody Plants in the U.S. Anonymous 1974. USDA Agric. Handbk. 450. 883pp.
The Forest Service frequently publishes compilations of material, either as reviews or bibliographies. Examples we’ve employed include: 1) Rooting Habits of Selected Commercial Tree Species of the Eastern United States - A Bibliography. Smith, P. and L. Every (compilers). 1980. USDA Forest Service. Bibliog. Litera. Agric. No. 10. 59pp. 2) Comparative Autecological Characteristics of Northwestern Tree Species—A Literature Review. Minore, D. 1979. USDA Forest Service Pacific Northwest and Range Experiment Station, General Technical Report PNW-87. 72pp.
The Forest Service has an information service (no-cost), called FS-INFO. This information service has centers in each regional Forest Service office (for the Pacific northwest, it is in Portland OR; for the Pacific southwest, it is located in Berkeley CA). It offers monthly alerts (new publications), document delivery services and literature/reference services.
The Journal of Forestry is the only monthly publication (of which we are aware) that routinely announces new Forest Service books and bulletins.
State departments and agricultural experiment stations
State departments of agriculture, forestry, natural resources and agricultural experiment stations publish excellent summaries of tree-related information. As an example, we frequently use the following: 1) Sweetgum - A Bibliography. Hu, S., P. Fogg, N. Linnartz and P. Burns. 1987. Louisiana Agricultural Experiment Station Research Report No. 13. 78pp. 2) Natural Vegetation of Oregon and Washington. Franklin, J. and C. Dyrness. 1973. Oregon State University Press. Corvallis OR. 452pp.
State cooperative extension service newsletters, bulletins and reports are also valuable resources announcing new publications. Each state has a catalog of available publications.
Treenet
Treenet is the national urban forestry information network, originally developed by the American Forestry Association. It also encompasses the Sirius Gateway and ArborBase. For more information about Treenet, write: Treenet, P.O. Box 52015, Durham NC 27717-2105 or call: 919-493-1087 (voice), 919-489-7521 (data).
Experience
The value of personal experience with a species as a source of information cannot be overstated. Experience can provide specific information that is difficult to obtain from the literature. For some classes of information, there may be no published material, and an arborist must rely on field observation. For example, in the profile of valley oak (Table 2), over 50% of the information was developed from working knowledge, based upon direct field observations and accumulated experience.
Further, there may be characteristics of trees important to management which never appear in the literature. For example, consider crown reduction or crown containment pruning, a common arboricultural practice. Central to the success of this practice are appropriately placed thinning cuts. To do this requires the presence of foliated, lateral branches in the interior of the crown, with diameters two-thirds to three-quarters the size of the central leader. This is not strictly a matter of either apical dominance/control or excurrent/decurrent forms. It is more due to the distribution of foliage, the taper of branches and stems and their relative diameter. Determining which species are likely candidates for crown reduction is a matter determined in the field, using past experience, and not a question that can be answered from the literature.
Summary
Accurate, up-to-date information about clients and products is necessary for any business to remain competitive. Whether the activity is consulting or tree care, there is a tangible benefit to having resource material available. The same situation exists in arboriculture, where our working material consists of several hundred different taxa of plants. The species profile allows the compilation of a broad set of background information into a concise summary. We can use the profile to challenge ourselves to observe and learn more about the trees with which we work. We believe that answering these questions will enhance our perceptions and augment our ability to manage trees.
Acknowledgments
Thanks to Torrey Young, Van Bobbitt and Val Easton for their helpful suggestions and comments.
Footnotes
- © 1990, International Society of Arboriculture. All rights reserved.
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