Boris Zeide
Basic processes of stand dynamics
Technical problems of growth and yield studies
My professional activities are focused on understanding basic processes of stand dynamics, technical problems of growth and yield studies, and environmental issues. A brief summary of results is provided below.
Understanding stand density
Stand density characterizes one of the key factors of growth-scarcity of resources caused by competition among trees. Unlike site quality or precipitation, density can be controlled easily and profitably. What limits the utility of this variable is our inability come up with its definition, which would be both reasonable and widely accepted. A better definition can be developed when we realize that number of trees in fully stocked even-aged stands depends, in addition to tree size, on the area of canopy gaps inevitable even in the densest stands with a sizeable overlap of crowns. The lack of satisfactory definition may be a reason why our long search for a stand density that maximizes total volume growth has not yet produced a definite answer. The relationship between density and growth is known only in a graphical form (Langsaeter's curve). Recently, I found an analytical expression of the relationship, which allows one to calculate the optimal density. The past confusion about this density results from a paradox: maximum increments do not sum up to maximum volume. This is because volume depends on both density and average diameter. The same high density that assures maximal increments at younger ages reduces diameter and undermines total yield.
Publications
Zeide, B. 2001. Thinning and growth: a full turnaround. Journal of Forestry 99(1):20-25.
Zeide, B. 2002. Analysis of a concept: stand density. Journal of Sustainable Forestry 14(4):51-62.
Zeide, B. 2002. Density and the growth of even-aged stands. Forest Science, in press.
Zeide, B. In search of optimal density. Submitted to Canadian Journal of Forest Research.
Structure of growth equations: uncovering of two basic forms
Growth equations are the backbone of forest modeling and, therefore, of intelligent forest management. There are dozens of growth equations and the problem of selecting the most appropriate one has occupied foresters for over a century. My research deals with all of the equations used for growth modeling. By analyzing their structure, I showed that in the differential form all the equations can be presented as a product of two modules. As age and tree size increase, one, the expansion module, brings the increment up, while the other, the decline module, pushes it down. In all studied equations except Weibull's, the expansion module presents increment as a power function of tree size. The decline module has two forms: exponential and power. This may be explained by a greater number of factors that hinder growth: scarcity of resources, competition, reproduction, aging, diseases, herbivory, disturbances, etc. The Bertalanffy, Richards, logistic, and Gompertz equations belong to the group of exponential decline. The Korf, Hossfeld, Levakovic, and Yoshida equations comprise the group of power decline. This analysis indicates that although growth equations were developed mainly to mimic the dynamics of tree and stand dynamics, they express two basic processes of growth. Their parameters have biological interpretations and at least the parameters' sign can be predicted. While the processes of growth infuse meaning into empirical equations, the equations give shape to the processes, making them, if not tangible, then at least operational.
Publications
Zeide, B. 1989. Accuracy of equations describing diameter growth. Canadian Journal of Forest Research 19:1283-1286.
Zeide, B. 1990. Structure of growth equations. In the Forest Simulation Systems Conference, p. 349-354. Edited by L. C. Wensel and G. S. Biging. University of California, Division of Agriculture and Natural Resources, Bull. 1927. Berkeley. 420 p.
Zeide, B. 1992. Growth models with two pairs of opposing terms. In Research on growth and yield with emphasis on mixed stands, p. 107-111. Edited by T. Preuhsler. Bavarian Forestry Experiment and Research Station. Freising, Germany. 247 p.
Zeide, B. 1993. Analysis of growth equations. Forest Science 39:591-616.
Shvets, V., and B. Zeide. 1996. Investigating parameters of growth equations. Canadian Journal of Forest Research 26:1980-1990.
Combining bottom-up with top-down approach to process modeling
Models based on the currently popular bottom-up approach to growth modeling are inherently incomplete (because the actual number of physiological processes is too large to model and some of them are still unknown), require sophisticated and rarely available information, and, despite an unwieldy number of parameters, are inaccurate.
The opposite top-down approach to process modeling intends to decipher the causes of observed outcomes. It is attractive because it uses as input measurable variables (such as stem diameter, number of trees per unit area, or defoliation). The resulting models are complete at each step of development. These models avoid the trap of holding the whole as the sum of the parts. However, the top-down approach it is not practical: the knowledge of aging rate, accumulation of dead tissue, and other phenomena discovered while diving down into the inner mechanism of tree growth may be of interest to academics but not to foresters.
As foresters, we go down to learn about growth mechanisms only to resurface with future diameter, number of trees, volume, and other tangible variables. This means that our models must combine the top-down and bottom-up approaches. To single out specific processes, we need to see the whole. This combined approach:
1. Uses as input "top" variables, that is regular inventory data on the present stand;
2. Infers the underlying "bottom" mechanical, physiological, and ecological processes. Summon all relevant knowledge and present it in the form of meaningful relationships between expressive variables with the parameters crystallizing our learning, in order to
3. Produces as output predicted values of the input variables.
This U-approach promises to be meaningful, comprehensive, and, because it supplies growth information, practical.
Publications
Zeide, B. 1987. Methodology of biological modeling. In The VIII International Congress of Logic, Methodology and Philosophy of Science, volume 2, p. 324-327. Chairman I. T. Frolov. Moscow, U.S.S.R. 591 p.
Zeide, B. 1991. Quality as a characteristic of ecological models. Ecological modelling 55:161-174.
Zeide, B. 1998. Modeling based on ecological processes. In Process-Based Models for Forest Management. Abstracts, p. 28. Rovaniemi, Finland. 72 p.
Zeide, B. 1999. Long-term observations: from trials and errors to process modeling. Keynote paper. Pages 3-18 in C. Kleinn and M. Kohl, editors. Long Term Observations and Experiments in Forestry. Proceedings of IUFRO S4.11 International Symposium, CATIE, Costa Rica, February 23-26, 1999. 291 p.
Thompson, L. C., and B. Zeide. 1999. Impact of loblolly pine sawfly defoliation on growth of pine stands. Final Report submitted to the sponsoring companies (Georgia Pacific, International Paper, and Potlatch). 20 p
. Zeide, B. 2001. Natural thinning and environmental change: an ecological process model. Forest Ecology and Management 154 (1-2):165-177.
Zeide, B. 2001. Uniting the bottom-up and top-down approaches to growth modelling. Pages 437-449 in V. LeMay and P. Marshall, editors.. Proceedings of Forest Modelling for Ecosystem Management, Forest Certification, and Sustainable Management Conference. Vancouver, Canada, August 12-17, 2001. 506 p.
Coming to terms with competition
The Dictionary of Forestry published in 1998 by the Society of American Foresters accepted my definition of competition instead of the previous one by Eugene Odum. This dictionary entry is a result of an ongoing effort to understand, describe, and model a decisive process of forest stand dynamics. In 1985 I showed that it is important to distinguish between the inter- and intraspecific competitive abilities of trees or, using forestry terms, between tolerance and what can be called self-tolerance of trees. The fact that tolerant species survive better than intolerants in mixed stands does not mean that in pure stands tolerants have less mortality than intolerants. Actually, I found that for the southern pines tolerance is inversely related to self-tolerance. The least tolerant species (longleaf pine, Pinus palustris Mill.) turned out to be the most self-tolerant. This investigation was supported by a grant from the National Science Foundation.
Investigations of competition are hampered by insufficient understanding of this concept. Competition is commonly defined as the negative effects of interaction between two or more organisms. Such definitions are too narrow because, along with growth inhibition, competition involves a second process--phenotypic adaptation, most often in the form of redistribution of an organism's efforts to counter the resource depletion. Managing internal resources to obtain a larger share of, or to better utilize, external resources is as indispensable an attribute of competition as is suffering from resource deprivation. Adaptation is an ongoing component of competition as well as its lasting legacy. This view is reflected in the definition included in the dictionary and in the models I construct.
Publications
Zeide, B. 1985. Tolerance and self-tolerance of trees. Forest Ecology and Management 13:149-166.
Zeide, B. 1992. Intraspecific competitive ability of trees is independent from their interspecific competitive ability. Supplement to Bulletin of the Ecological Society of America 73(2):397.
Zeide, B. 1998. Competition. In The Dictionary of Forestry, page 34. Edited by J. A. Helms. The Society of American Foresters. 210 p.
Ecological processes
Not all my research is devoted to the manipulation of numbers. Several studies deal with mostly qualitative treatment of ecological processes that are important to growth modeling. Although search for biological meaning of models and parameters is present in any of my papers, some of them are specifically addressing ecological issues. In addition to the studies of competition, these include analysis of the 3/2 power law of self-thinning, ranking of forest growth factors, and others.
Publications
Zeide, B. 1980. Ranking of forest growth factors. Environmental and Experimental Botany 20:421-427.
Wolgast, L. J., and B. Zeide. 1983. Reproduction of trees in variable environment. Botanical Gazette 144:260-262.
Zeide, B. 1984. Space-biomass relations in plants and animals. Modelling, Simulation and Control, C 1(2):39-42.
Zeide, B. 1984. Self-thinning rule in application to southern pines. In Eighth North American Forest Biology Workshop, p. 177-178. Edited by R. M. Lanner. Utah State University, Logan, Utah. 196 p.
Zeide, B. 1984. Exponential diameter distribution: interpretation of coefficients. Forest Science 30:907-912.
Zeide, B. 1986. Crown width and stem diameter in open-grown trees. In Crown and Canopy Structure in Relation to Productivity, p. 146-158. Edited by T. Fujimori and D. Whitehead. Forestry and Forest Products Research Institute, Ibaraki, Japan. 448 p.
Zeide, B. 1986. The idea of invariance in biology. BioScience 36:494, 496-497.
Zeide, B. 1987. Analysis of the 3/2 power law of self-thinning. Forest Science 33:517-537.
Zeide, B. 1988. Search for a limiting density: reasons and approach. In the IUFRO Forest Growth Modelling and Prediction Conference, p. 652-659. Edited by A. R. Ek, S. R. Shifley, and T. E. Burk. USDA For. Serv. Gen. Tech. Rep. NC-120. 1149 p.
Zeide, B. 1991. Self-thinning and stand density. Forest Science 37:517-523.
Zeide, B. 1995. A relationship between size of trees and their number. Forest Ecology and Management72:265-272.
Investigation of fractal geometry of tree crowns
The diameter of a solid, such as a tree stem, makes sense, but the width of a porous crown is much less so. There is something intrinsically vague about the width of the maze of protruding branches and the voids in between. Similarly, we cannot talk about crown volume, which encompasses mostly empty space, in the same sense as we talk about solid stem volume. We, foresters, felt that our attempts to describe the crown are shaky but until recently could do nothing about it because the solution lies outside biology. Classical geometry with its rigid contrast between lines, surfaces, and volumes is not suitable for defining and measuring tree crowns and many other natural objects. The tree crown is neither a three-dimensional solid nor a two-dimensional photosynthetic surface. It can be viewed as a collection of holes that serves to conduct sunlight and gases, or as a multi-level hierarchy of clustered dots (pigment molecules and chloroplasts). The crown is a hybrid of surface and volume. Concepts and tools needed to describe such common in nature objects are provided by recently proposed fractal geometry. Fractal geometry allows one to condense information on crown structure into a few meaningful numbers such as fractal dimension, which is a generalization of the integer spatial dimension of classical geometry. Our School is the leader in the application of fractal geometry to the study of trees and their communities. Dr. Mandelbrot, the originator of this new geometry, invited me to visit him after I sent him my immature proposal to use fractal geometry in forestry. This meeting (1988) helped to clarify my ideas. As a result, I developed a novel method to calculate fractal dimensions of tree crowns for a group of trees because the standard method for determining fractal dimension, the box-counting method, is not practical. It would require slicing the crown into many layers without distortion of its structure. The first estimates of fractal dimensions of various tree species were obtained using the developed two-surface method. I am pleased to see that this method is applied by researchers in several countries.
My investigation of fractal geometry of tree crowns produced several unexpected results. One of them is the identification of the primary unit of the tree crown. Another is the detection of the two components of crown fractal dimensions. One of these is purely geometrical and characterizes the spatial depth of the crown. The other component, called functional, is determined by tree physiology and reflects shade tolerance of a species. Since the two-surface method cannot be applied to a single crown or its portions, I recently proposed another method for estimating fractal characteristics (fractal dimension and foliage density), called the method of natural units. It operates with volume and mass of shoots and branches, rather than with numbers of artificial cubes carved from the crown.
Publications
Zeide, B. 1990. Fractal geometry and forest measurements. In the State-of-the-Art Methodology of Forest Inventory, p. 260-266. Technical editors: V. J. LaBau and T. Cunia. USDA For. Serv. PNW-GTR-263. 592 p.
Zeide, B. 1990. Fractal analysis of crown structure. In the XIX IUFRO World Congress. Publication FWS-2-90, p. 232-241. Edited by H. E. Burkhart. Virginia Polytechnic Institute and State University. Blacksburg, Virginia. 241 p.
Zeide, B. 1991. Fractal geometry in forestry applications. Forest Ecology and Management 46:179-188.
Zeide, B., and P. Pfeifer. 1991. A method for estimation of fractal dimension of tree crowns Forest Science 37:1253-1265.
Zeide, B., and C. A. Gresham. 1991. Fractal dimensions of tree crowns in three loblolly pine plantations of coastal South Carolina. Canadian Journal of Forest Research 21:1208-1212.
Zeide, B. 1993. Measuring trees in the future. In Statistical Methods, Mathematics and Computers. Proceedings of IUFRO Centennial Meeting, p. 38-46. Edited by M. Kohl and G. Z. Gertner. Swiss Federal Institute for Forest, Snow and Landscape Research. Birmensdorf, Switzerland. 163 p.
Zeide, B. 1993. Primary unit of the tree crown. Ecology 74:1598-1602.
Zeide, B. 1995. Spatial patterns of canopy building blocks: arrangement and fullness of foliage clusters. In Designing the Forest Canopy Researcher's Workbench: Computer Tools for the 21st Century, pages 85-86. N. M. Nadkarni and J. B. Cushing, co-convenors. Published by the International Canopy Network. Olympia, Wa. 94 p.
Zeide, B. 1998. Fractal analysis of foliage distribution in loblolly pine crowns. Canadian Journal of Forest Research 28:106-114.
Zeide, B. 2000. Fractal geometry: addressing the intrinsic spatial uncertainty. Pages 755-758 in G.B.M. Heuvelink and M.J.P.M. Lemmens, editors. Proceedings of the 4 th International Symposium on Spatial Accuracy Assessment in Natural Resources and Environmental Sciences. Amsterdam, July 2000. 772 p.
Unification of site index curves and construction of growth types
Foresters spend much effort to determine growth of forest stands. Thus, hundreds of site index curves have been published for pine species in only one region, the southern United States. Given the diversity of forest growth and burgeoning needs for growth information, this number of curves is viewed as far from sufficient. After all, growth of forest stands is determined by combinations of many physical, climatic, ecological, genetic, and historical factors, as well as chance events. Since the number of these combinations is enormous, we may never have a sufficient number of growth curves. If several years ago somebody had told me that all this diversity could be expressed by one pattern, I would not have believed him.
Now such a pattern has been developed. It can be implemented instantly using a computer program available at my web site. What made this development possible is that along with its unique features, the dynamics of a given forest stand have much in common with known dynamics of previously studied stands. After all, many existing curves virtually coincide with each other. Years ago, I found that two points are necessary and sufficient to determine any growth curve. Based on this result, the diversity of height growth in forest stands studied throughout the world was condensed to 16 types. Further research showed that this number can be reduced to three. In a recent issue of Forest Ecology and Management, I report the next and final step that introduces the harmonizing function, which permits the ultimate compression of growth information to one guide type. The harmonizing function complements growth equations: it describes the cross-section of growth curves families, that is, their values at the same age. The constructed growth type for fast-growing species can be applied to any studied pine species and probably to other species as well.
Publications
Zeide, B. 1967. Unification of diameter growth series. In Voprosy drevesnogo prirosta v lesoustroistve, p. 303-313. Edited V. Antanaitis. Litovskaya Selskokhozyaistvennaya Akademia, Kaunas. 387 p.
Zeide, B. 1968. Standardization of forest stand growth series. Lesnoe Khozyaistvo, No. 10, 54-57.
Zeide, B. 1978. Standardization of growth curves. Journal of Forestry 76:289-292.
Zeide, B. 1993. A parsimonious number of growth curves. Northern Journal of Applied Forestry 10:132-136.
Zeide, B. 1994. To construct or not to construct more site index curves? Western Journal of Applied Forestry 9(2):37-40.
Zeide, B. 1997. Generalized site index curves for fast-growing species. Proceedings of IUFRO Conference Modelling Growth of Fast-Growing Species, p. 27-35. Edited by A. Ortega and S. Gezan. Valdivia, Chile. 309 p.
Zeide, B. 1999. Pattern of height growth for southern pine species. Forest Ecology and Management 118:183-196.
Dispelling the scare of pine decline
Not long ago, American foresters were scared by the so-called pine decline discovered in 1985 in southern pine plantations by the Forest Service. This discovery implied devastating consequences for the forest industry and the national economy. It would cost billions to phase out or relocate mills, shift investments, and revive the disrupted regional economy of the southeast. Substantial federal research funds were allocated to investigate the mechanisms of growth reduction. Given this potential impact, the Forest Service was requested to release the original data for reevaluation by independent analysts. Having being invited to reexamine the data, I showed that the only reason of the reported growth reduction was inadequate methods of forest inventory and analysis. After this analysis was published (1992, reprinted in 1995), no one talks about pine decline anymore.
Publications
Zeide, B. 1992. Has pine growth declined in the southeastern United States? Conservation Biology 6:185-195.
Reprinted in To Preserve Biodiversity. Readings from Conservation Biology, p. 61-71. Edited by D. Ehrenfeld. A joint publication of the Society for Conservation Biology and Blackwell Science, Inc. 249 p. and in Wildlife and Forests. Readings from Conservation Biology, p. 209-219. Edited by D. Ehrenfeld. A joint publication of the Society for Conservation Biology and Blackwell Science, Inc. 248 p.
Zeide, B. 1992. Reevaluation of forest inventory data from loblolly pine stands in the Georgia Piedmont and Mountain areas. In The Response of Southern Commercial Forests to Air Pollution, p. 17-35. Edited by R. B. Flagler. Transactions of the Air & Waste Management Association, Pittsburgh, PA. 333 p.
Zeide, B. 1994. Big projects, big problems. Environmental Monitoring and Assessment 33:115-133.
Zeide, B. 1995. Quality of data. Journal of Forestry 93(3):37.
Point sampling and national inventory
Another practical result of my investigation of the Forest Service inventory data was the recommendation to switch to plot-based methods instead of point sampling. Point sampling is a brilliant concept for quick estimation of basal area. Too often, however, its impeccable theoretical properties obscure the difficulties with the practical application of this method. Because of the limitations of human vision and the lack of precision inherent in point sampling, actual estimates of basal area are often inaccurate and biased. The problems with this technique worsen when it is used repeatedly on permanent sample plots. In my report, this technique was identified as the major source of inventory errors.
In 1995, the Forest Service discontinued the application of point sampling for national inventory.
Publications
Zeide, B., and J. Troxell. 1979. Selection of the proper metric BAF for Appalachian mixed hardwoods. In Forest Resource Inventories, p. 261-269. Edited by W. E. Frayer. Colorado State University, Fort Collins, Colorado. 1037 p.
Zeide, B., and J. Troxell. 1979. Plot versus point sampling. In Forest Resources Inventories, p. 923-929. Edited by W. E. Frayer. Colorado State University, Fort Collins, Colorado. 1037 p.
Zeide, B., J. Troxell, and D. Haag. 1979. Field instruction in point sampling. In Forest Resource Inventories, p. 917-922. Edited by W. E. Frayer. Colorado State University, Fort Collins, Colorado. 1037 p.
Wiant, H. V., and B. Zeide. 1979. A note on double sampling-point sampling. Resource Inventory Notes. BLM 24:14-15.
Zeide, B. 1985. Distance to point-sampled trees and their diameters. Forest Ecology and Management. 11:131-137.
Zeide, B. 1985. How much space does a seedling need? Forest Ecology and Management 11:225-229.
Zeide, B. 1985. Loblolly pine regeneration and overstory density. In the Third Biennial Southern Silvicultural Research Conference, p. 93-95. Edited by E. Shoulders. USDA For. Serv. Gen. Tech. Rep. SO-54. 589 p.
A practical guide for forest management: Good Forestry at a Glance
Specialists in forest growth and yield produce yield tables, site index curves, and growth models. Research in silviculture yields various methods for managing forest stands. Economists add their valuable contributions. The problem is that these ingredients typically exist separately, in dozens of sources, which are not always readily available to forest managers and landowners. At the same time people who practice forestry are concerned with the entire forest and they need a single and simple source of forestry knowledge. To satisfy this need, we developed a guide, called "Good Forestry at a Glance," that brings together the three key components of sound management: (1) Information on the growth of stands; (2) Schedule of recommended management activities; and (3) Costs and returns of every operation. At the same time the guide provides for a diversity of conditions and operations. When appropriate, the guide lists alternative techniques for a given operation, frequency of each alternative, as well as associated economic information. The recommended practices are sustainable and profitable: for naturally regenerated pine stands they provide annual returns of $47 per acre, which is about double what an average landowner in the South gets from loblolly pine stands. Due to smaller initial expenses, this figure is slightly higher than returns from plantation management ($45 per acre).
Publications
Zeide, B., and D. Sharer. 2000. Good forestry at a glance: a guide for managing even-aged loblolly pine stands. Arkansas Agricultural Experiment Station, Arkansas Forest Resources Center Series 003. 19 p.
Zeide, B., and D. Sharer. 2001. Loblolly pine plantation management in a nutshell. 2001 Manual Forest Landowner 60(2): 10-15.
Zeide, B., and D. Sharer. 2001. Naturally regenerated loblolly pine holds its ground. Forest Landowner 60(6): 30-33.
Zeide, B. and D. Sharer.
2002. Sustainable and profitable management of even-aged loblolly pine stands.
Journal of Sustainable Forestry 14(1):93-106.
Maximizing sustainable volume production
To get the highest harvestable volume, we need to have the lowest density at the beginning of tree life (to increase growth) and full stocking at the end. Keeping a certain number of trees per unit area (that which provides full stocking and maximum volume possible by harvest time) as constant as possible throughout the lifetime satisfies these requirements. Such a prescription can be called the minimum number-maximum yield (minimax) strategy. In addition to the chief advantage-maximum volume, this strategy reduces expenses on planting and thinning, root rot, insect infestation, and other hazards associated with high density, which would be maintained only during a relatively short period before harvest. For loblolly pine the number is close to 300 per hectare (this number was optimized simultaneously with the harvesting age).
In the beginning, 300 trees (or rather clusters) leave much of the land empty. To prevent undesirable vegetation from taking the ground, 10-meter wide alleys between rows of tree clusters are used to grow forage or any crop (wheat, oats, soybeans) that does not compete with trees for light. The coexistence of trees, forage, and livestock is natural and can be mutually beneficial for several biological and managerial reasons. Root systems of established pines are deeper than those of forage species, which minimizes competition for soil nutrients and moisture between pines and forage species. Livestock grazing reduces competition between trees and competing vegetation. Another reason for increased growth is natural (manure) and artificial fertilizers applied near the trees. In their turn, trees provide shade and wind shelter for cattle. These advantages could contribute to a substantial increase in income over growing trees or cattle separately. This design will also provide environmental benefits. When tree rows are planted along the contour, erosion is minimized. Cattle manure will increase soil fertility and activate many beneficial processes that are suppressed in dense forest monocultures.
Publications
Zeide, B. 1998. Design of an agroforestry system with structured tree clusters. In Proceedings of the VII International Congress of Ecology, p. 475. Edited by A. Farina, J. Kennedy, and V. Bossu. Florence, Italy. 480 p.
Zeide B. 1999. Long-term study of agroforestry systems based on structured tree clusters. Proceedings of IUFRO International Symposium "Long Term Observations and Research in Forestry." Dr. C. Kleinn, editor. CATIE, Costa Rica, February 23-27, 1999.
Zeide B. 1999. Evolution of agroforestry: from uniformity to diversity. The 6th North American Agroforestry Conference, Hot Springs, Arkansas, June 12-16, 1999.
Remeasurements of permanent plots
The accumulation of long-term observations is one of the greatest achievements of forest science. Much of what we know about tree growth and survival is obtained from permanent plots. Permanent plots extend in time and deepened our capabilities to explore nature. Since 1981, I have been responsible for remeasurement and maintenance of 45 permanent sample plots established in a typical loblolly pine stand, four miles south of our campus. The plots, currently 43 years old, were remeasured ten times. In addition to the customary measurements of height and diameter at breast height, we have measured many upper stem diameters and crown dimensions. The stems of the trees thinned at ages 24 and 35 years were analyzed. As a result, we have accumulated substantial information on tree growth as influenced by thinning, pruning, and vegetation control. Another factor that increased the plots' value is unplanned environmental events. The plots have withstood ice storms in 1974, 1979, and 1994. Damage caused by these storms was documented. All this history makes this Monticello Thinning and Pruning study one of the oldest, most diverse, and best maintained long-term projects in the South.
Publications
Leduc, D. J., and B. Zeide. 1987. The effect of thinning and pruning on the growth of planted loblolly pine stands. In the Fourth Biennial Southern Silvicultural Research Conference, p. 473-482. Compiled by D. R. Phillips. USDA For. Serv. Gen. Tech. Rep. SE-42. 598 p.
Leduc, D. J., and B. Zeide. 1987. Development of loblolly pine stands at various levels of density and pruning. Arkansas Farm Research 36(3):3.
Wiley, S., and B. Zeide. 1989. Thirty-year development of loblolly pine stands at various densities. In the Fifth Biennial Southern Silvicultural Research Conference, p. 199-204. Compiled by J. H. Miller. USDA For. Serv. Gen. Tech. Rep. SO-74. 618 p.
Wiley, S., and B. Zeide. 1990. Optimal density in loblolly pine: results of 30 years of growth. Arkansas Farm Research 39(1):5.
Wiley, S., and B. Zeide. 1991. Investigation of growth 14 years after glaze damage in a loblolly pine plantation. In the Sixth Biennial Southern Silvicultural Research Conference, volume 1, p. 272-281. Compiled and edited by S. S. Coleman and D. G. Neary. USDA For. Serv. Gen. Tech. Rep. SE-70. 504 p.
Wiley, S., and B. Zeide. 1992. Development of a loblolly pine plantation. Arkansas Agricultural Experiment Station Report Series 322. 44 p.
Zeide, B. 2002. Sharing data. Forestry Chronicle 78(1): 152-153.
Development of research methods
Another indispensable area of research is development of new methods to measure trees and their portions, select trees for various purposes, evaluate alternatives in forest management, and to perform other activities.
Publications
Zeide, B. 1980. Plot size optimization. Forest Science 26:251-257.
Zeide, B. 1981. Method of mound dating. Forest Science 27:39-41.
Zeide, B. 1981. Optimal allocation of time in resource inventories. In Arid Land Resource Inventories: Developing Cost-Efficient Methods, p. 103-105. H. G. Lund, M. Caballero, R. H. Hamre, R. S. Driscoll and W. Bonner, technical coordinators. USDA For. Serv. General Technical Report WO-28. 620 p.
Zeide, B., and V. Ozernoy. 1981. Evaluation of management strategies for southern pine forests. In Applied Modelling and Simulation, volume 4, p. 188-192. Edited by AMSE. Tassin-la-Demi-Lune, France. 254 p.
Dobelbower, K., and B. Zeide. 1981. Diagonal plots for arid land resource inventories. In Arid Land Resource Inventories: Developing Cost-Efficient Methods, p. 431-434. H. G. Lund, M. Caballero, R. H. Hamre, R. S. Driscoll, and W. Bonner, technical coordinators. USDA For. Serv. General Technical Report WO-28. 620 p.
Ozernoy, V., and B. Zeide. 1982. Evaluating alternatives in forest management: decision analysis. In In-Place Resource Inventories: Principles and Practices, p. 528-534. Edited by T. B. Brann. Society of American Foresters, University of Maine, Orono, Maine. 1101 p. University. 216 p.
Zeide, B., and W. T. Zakrzewski. 1993. Selection of site trees: the combined method and its application. Canadian Journal of Forest Research 23:1019-1025.
A balanced analysis of biodiversity and ecosystem management
Biodiversity is a key term and the goal of government-mandated ecosystem management on federal lands. Yet, ecologists are still unable to define this concept. Any definition pigeonholes and restricts the defined term. Biodiversity encompasses the total abundance of organisms, species, populations, communities, and their environments together with all of their complex interrelations. Extraterrestrial factors such as sunlight cannot be excluded either. In short, biodiversity embraces everything. As a result, it cannot be defined in principle. Although it may be impossible to define biodiversity, it is possible to assess this concept in the larger scientific and social framework, which was done in a series of dr. Zeide's publications. His analysis of the "what," "where," "how," and "why" of ecosystem management shows that we still cannot answer either of these questions. Without solving them, it is premature to talk about implementing ecosystem management.
Publications
Zeide, B. 1994. Ecological research and environmental problems: reflections on the National Biological Survey. Bulletin of the Ecological Society of America 75(1):53-54.
Zeide, B. 1996. Is "The Scientific Basis" of ecosystem management indeed scientific? Bulletin of the Ecological Society of America 77(2):123-124.
Zeide, B. and F. N. Semevski. 1996. Examination of deep ecology. In Problems of Ecological Monitoring and Ecosystem Modelling, Volume XVI, p. 58-62. Edited by Y. A. Izrael. Gidrometeoizdat, St. Petersburg. 293 p.
Zeide, B. 1997. Assessing biodiversity. Environmental Monitoring and Assessment 48(3):249-260.
Zeide, B. 1998. Another look at Leopold's land ethic. Journal of Forestry 96(1):13-19.
Reprinted in The Land Ethic: meeting human needs for the land and its resources, p. 91-105. Society of American Foresters, Washington, DC. 160 p.
Zeide, B. 1998. Forestry and ethics. Journal of Forestry 96(4):25-26.
Zeide, B. 1998. Affirmative action or parasitism? Bulletin of the Ecological Society of America 79(1): 130-131.
Zeide, B. 1998. Biodiversity: a mixed blessing. Bulletin of the Ecological Society of America 79(3): 215-216.
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