Basal area growth for 15 tropical tree species in Puerto Rico

Research Highlights: We investigated the competitive interactions among three tree species (interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca [Moench] Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.)) in multi-aged stands in central British Columbia, Canada. Background and Objectives: Understanding competitive interactions among tree species in mixed-species stands is fundamental to supporting silvicultural decision-making in such stands. Using the periodic annual basal area increment for single trees as our dependent variable, we investigated whether neighboring trees competed with subject trees independently of species identity. We also examined the differences in single-tree basal area growth among the three conifer species over time under different levels of competition. Materials and Methods: We developed several spatially explicit, single-tree basal area growth models for interior Douglas-fir, interior spruce, and lodgepole pine using data from 16 plots in two blocks of a long-term study (five measurements over a 21-year period) on the response to pre-commercial thinning. We compared these equations to assess whether intraspecific or interspecific competition predominated. We also examined the differences in basal area growth among the three conifer species over time under different levels of competition. Results: We found asymmetrical relationships between the conifer trees and their neighbors for all species, indicating that the main driver limiting growth in these stands is aboveground competition for light. There was evidence of higher intraspecific competition for small (<10.0 cm DBH) interior Douglas-fir in one block. However, there was no general pattern among larger subject trees with respect to the identity of neighborhood competitive effects and the equivalence of neighbors. We observed a higher level of basal area growth over time for interior Douglas-fir than for lodgepole pine and interior spruce, irrespective of the competition intensity and, not surprisingly, the growth rate declined with increasing competition levels for the three species. Conclusions: Our results provide an understanding of how interior Douglas-fir stands will develop over time and information on species interactions that could help forest managers explore different silvicultural options and their effects on individual tree growth in these complex stands.

Download Full-text

Performance of Anthocephaluschinensis in Puerto Rico

Canadian Journal of Forest Research ◽

10.1139/x85-094 ◽

1985 ◽

Vol 15 (3) ◽

pp. 577-585 ◽

Cited By ~ 6

Author(s):

Ariel E. Lugo ◽

Julio Figueroa

Keyword(s):

Puerto Rico ◽

Growth Rates ◽

Calcareous Soils ◽

Basal Area ◽

Annual Rainfall ◽

Fast Growing ◽

Single Tree ◽

Basal Area Growth ◽

Area Growth ◽

The Tropics

The growth of kadam (Anthocephaluschinensis (Lam.) A. Rich. ex Walp.), a fast-growing Asiatic species, was studied under different soil and climatic conditions in Puerto Rico. Plantings included a 10-year-old line planting, a 12.5-year-old plantation, 12 localities with 20-year-old single tree plots, and 1 locality with four 52-year-old trees. Over 600 trees were measured in all. Growth rates were comparable to those of fast-growing species elsewhere in the tropics; e.g., the 12.5-year-old plantation had a volume growth of 27.8 m3•ha−1•year−1 (77% was merchantable wood), a basal area growth of 1.82 m2•ha−1•year−1, and a total aboveground biomass production of 11.5 t•ha−1•year−1. Trees grew well both in plantations and in lines under natural forest. The 20-year-old single tree plots averaged up to 1 m•year−1 in height growth and 53 cm2•year−1 in basal area growth. Highest rates were observed in localities with high annual rainfall (>2500 mm) and with phosphorus- and silt-rich soils of high bulk density and low pH. After 10 years, basal area growth of trees was fastest in volcanic deep clay locations, followed, in order, by trees on volcanic shallow loams, calcareous soils, and plutonic sandy loams. However, basal area growth during the first 5 years was fastest in the plutonic sandy loams and slowest in the calcareous soils. After 20 years, volcanic deep clay soils still supported the fastest basal area growth rate (about 100 cm2•year−1), while the other locations converged at about 30 cm2•year−1. Trees reached maximum height after 20 years (average, 19 m; maximum, 26.5 m). Kadam growth was limited by close spacings (below 2.5 × 2.5 m). Trees exhibited excellent form (ratio of diameter at 1.3 m to diameter at 4.9 m > 0.8). We found no evidence of pest or disease attacks on trees, but noted severe tapering and stem twist in localities having poor growth rates. Results underline the need for caution when making species adaptability assessments in the tropics with short-term (<10 years) data.

Download Full-text