Diameter, Height, Crown, and Age Relationship in Eight Neotropical Tree Species

Diameter, height, crown shape, and crown area were measured on 23-42 trees ranging in size from saplings to large adults for each of eight common dicotyledonous tree species in a neotropical forest on Barro Colorado Island, Panama. Six species were canopy trees, one species was an emergent tree, and the remaining species was an understory tree. Crown areas and shapes were quantified by eight radii measured every 450 from the trunk to the vertically projected edge of the crown. Crown areas were calculated from the areas of circles with the average radius; crown shapes were measured by the coefficients of variation of the eight crown radii. Age-diameter relationships were estimated from diameter growth increments over an 8-yr period. Observed height-diameter relationships were compared to expectations based on the theories of elastic similarity, constant stress, and geometric similarity. Slopes of log-transformed height-diameter relationships differed from the theoretically expected value of 2/3 for elastic similarity in three of eight species; two canopy species had higher slopes, but not as high as the expected value of 1.0 for geometric similarity; one canopy species was shorter, but the slope was greater than the slope of 0.5 predicted by the constant stress theory. The theory of elastic similarity also predicts that canopy mass to trunk mass ratio should remain constant during tree growth. Observed ratios based on proxy variables for the masses were constant in six of eight species- the two deviant species had heavier crowns in large trees than expected from their diameters. Crown shapes were much more variable in some species than others. The understory species had much lower r2 values for height-diameter and crown-diameter relationships, suggesting that these relationships may be more variable in trees that live in the less windy understory than in trees that reach the canopy. The allometric relationships for the species in this study were not unique for each species, suggesting that it may be possible to model the allometric relationships of many species with fewer equations than species. If the primary adaptive forces acting on tree species in a diverse forest are their physical environment and the sum of competitive interactions with an ever-changing mix of neighbors, then different species may have similar resource allocation patterns. Thus, using the age-size relationships, we found three groups of species among the seven canopy species. Two groups had three species each and one species (Ocotea whitei) was in a group by itself. The understory species, Faramea occidentalis, was also in a group by itself.

[1]  Thomas J. Givnish,et al.  On the Adaptive Significance of Leaf Height in Forest Herbs , 1982, The American Naturalist.

[2]  D. Windsor.  Climate and moisture variability in a tropical forest : long-term records from Barro Colorado Island, Panamá , 1990 .

[3]  James N. Long,et al.  Validity of Constant-Stress and Elastic-Instability Principles of Stem Formation in Pinus contorta and Trifolium pratense , 1986 .

[4]  S. Hubbell,et al.  SHORT-TERM DYNAMICS OF A NEOTROPICAL FOREST : CHANGE WITHIN LIMITS , 1992 .

[5]  Karl J. Niklas,et al.  Plant Biomechanics: An Engineering Approach to Plant Form and Function , 1993 .

[6]  T. Kira,et al.  PRIMARY PRODUCTION AND TURNOVER OF ORGANIC MATTER IN DIFFERENT FOREST ECOSYSTEMS OF THE WESTERN PACIFIC , 1967 .

[7]  P. Snowdon,et al.  A ratio estimator for bias correction in logarithmic regressions , 1991 .

[8]  R. Lawton,et al.  ECOLOGICAL CONSTRAINTS ON WOOD DENSITY IN A TROPICAL MONTANE RAIN FOREST , 1984 .

[9]  T. Kira,et al.  A QUANTITATIVE ANALYSIS OF PLANT FORM-THE PIPE MODEL THEORY : I.BASIC ANALYSES , 1964 .

[10]  R. Norberg,et al.  Theory of Growth Geometry of Plants and Self-Thinning of Plant Populations: Geometric Similarity, Elastic Similarity, and Different Growth Modes of Plant Parts , 1988, The American Naturalist.

[11]  F. Putz.  How trees avoid and shed lianas , 1984 .

[12]  P. J. Edwards,et al.  The Ecology of a Tropical Forest. , 1985 .

[13]  O. Loucks,et al.  The theory of tree bole and branch form , 1978, Radiation and environmental biophysics.

[14]  S. Hubbell,et al.  Mortality Rates of 205 Neotropical Tree and Shrub Species and the Impact of a Severe Drought , 1995 .

[15]  R. Whittaker,et al.  Canopy-Understory Interaction and the Internal Dynamics of Mature Hardwood and Hemlock-Hardwood Forests , 1981 .

[16]  G. B. Williamson,et al.  Radial Variation in the Wood Specific Gravity of Joannesia princeps: The Roles of Age and Diameter , 1993 .

[17]  Francis E. Putz,et al.  INFLUENCE OF NEIGHBORS ON TREE FORM: EFFECTS OF LATERAL SHADE AND PREVENTION OF SWAY ON THE ALLOMETRY OF LIQUIDAMBAR STYRACIFLUA (SWEET GUM) , 1989 .

[18]  J. Ovington,et al.  Biomass and chemical content of El Verde lower montane rain forest plants , 1970 .

[19]  Ariel E. Lugo,et al.  Biomass Estimation Methods for Tropical Forests with Applications to Forest Inventory Data , 1989, Forest Science.

[20]  W. Silver,et al.  Biomass and Nutrient Content of the Bisley Experimental Watersheds, Luquillo Experimental Forest, Puerto Rico, Before and After Hurricane Hugo, 1989 , 1993 .

[21]  H. Shugart,et al.  Patterns and Dynamics of Forests: An Application of Simulation Models , 1981 .

[22]  T. McMahon,et al.  Tree structures: deducing the principle of mechanical design. , 1976, Journal of theoretical biology.

[23]  G. B. Williamson,et al.  WOOD SPECIFIC GRAVITY GRADIENTS IN TROPICAL DRY AND MONTANE RAIN FOREST TREES , 1989 .

[24]  S. Hubbell,et al.  Commonness and rarity in a neotropical forest: implications for tropical tree conservation , 1986 .

[25]  Stephen P. Hubbell,et al.  Diversity of canopy trees in a neotropical forest and implications for conservation , 1983 .

[26]  S. Hubbell,et al.  Crown Asymmetry, Treefalls, and Repeat Disturbance of Broad‐Leaved Forest Gaps , 1991 .

[27]  D. Tilman.  Plant Strategies and the Dynamics and Structure of Plant Communities. (MPB-26), Volume 26 , 1988 .

[28]  T. McMahon,et al.  Size and Shape in Biology , 1973, Science.

[29]  Annette Aiello,et al.  Uprooting and snapping of trees: structural determinants and ecological consequences , 1983 .

[30]  D. A. King,et al.  Tree form, height growth, and susceptibility to wind damage in Acer saccharum , 1986 .

[31]  F. Putz.  Liana biomass and leaf area of a «Tierra Firme» forest in the Rio Negro Basin, Venezuela , 1983 .

[32]  P. Richards,et al.  The Vegetation of Moraballi Creek, British Guiana: An Ecological Study of a Limited Area of Tropical Rain Forest. Part II , 1933 .

[33]  G. B. Williamson,et al.  Radial Gradients in the Specific Gravity of Wood in Some Tropical and Temperate Trees , 1989, Forest Science.