Potential adaptive significance of vegetative regeneration in the monodominant tropical tree Dicymbe corymbosa (Caesalpiniaceae)

Graduation Date

2006

Document Type

Thesis

Program

Other

Program

Thesis (M.A.)--Humboldt State University, Biological Sciences, 2006

Committee Chair Name

Terry Henkel

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Guiana Shield, Vegetative regeneration, Dicymbe corymbosa, Organic soil, Humboldt State University -- Theses -- Biology, Phellinus robustus

Abstract

The tropical monodominant tree Dicymbe corymbosa, vegetatively regenerates via epicormic shoots and roots, resulting in multi-stemmed trees with stabilizing pseudotrunks and root mounds. In two 1-ha forest plots on the Guiana Shield, we quantified the regenerative structure and aboveground soil development of D. corymbosa individuals ≥ 10 cm dbh and investigated the potential adaptive significance of reiteration in terms of genet persistence and root exploitation of aboveground litter and soil accumulations. We also investigated the incidence of the heart rot fungus Phellinus robustus in D. corymbosa and examined its role in the reiteration process. Large trees contained more and larger shoots, greater trunk, root mound, and organic soil volumes, and a higher incidence of Phellinus. Roots and ectomycorrhizas were abundant in aboveground soils on the trees, occurred at higher densities than those from the surrounding forest floor, and may be important in recycling mineral nutrients. Shoot turnover and regeneration, while stimulated by Phellinus rot, appeared to be cumulative over time, resulting in stable, structurally complex trees of indeterminate lifespan which successfully recruit through mast fruiting. Dicymbe corymbosa provides a rare example of a tree species which exploits both persistence and recruitment niches.

https://scholarworks.calstate.edu/concern/theses/4f16c534q

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